2010 core topics in critical care medicine

Core Topics in CriticalCare Medicine Edited by Fang Gao Smith Professor in Anaesthesia, Critical Care Medicine and Pain, Academic Department of Anaesthesia, Critical Care and Pain, Heart

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Core Topics in Critical Care Medicine

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Core Topics in Critical

Care Medicine

Edited by

Fang Gao Smith

Professor in Anaesthesia, Critical Care Medicine and Pain, Academic Department of Anaesthesia, Critical Care and Pain, Heart of England NHS Foundation Trust, Clinical Trials Unit, University of Warwick, UK

Associate editor

Joyce Yeung

Anaesthetic Specialist Registrar, Warwickshire Rotation, West Midlands Deanery and Research Fellow, Academic Department of Anaesthesia, Critical Care and Pain, Heart

of England NHS Foundation Trust, UK

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São Paulo, Delhi, Dubai, Tokyo

Cambridge University Press

The Edinburgh Building, Cambridge CB2 8RU, UK

First published in print format

ISBN-13 978-0-521-89774-7

Every effort has been made in preparing this publication to provide accurate and up-to-date information which is in accord with accepted standards and practice at the time of publication Although case histories are drawn from actual cases,

every effort has been made to disguise the identities of the individuals involved Nevertheless, the authors, editors and publishers can make no warranties that the information contained herein is totally free from error, not least because clinical standards are constantly changing through research and regulation The authors, editors and publishers therefore disclaim all liability for direct or consequential

damages resulting from the use of material contained in this publication Readers are strongly advised to pay careful attention to information provided by the

manufacturer of any drugs or equipment that they plan to use.

2010

Information on this title: www.cambridge.org/9780521897747

This publication is in copyright Subject to statutory exception and to the

provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press.

Cambridge University Press has no responsibility for the persistence or accuracy

of urls for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain,

accurate or appropriate.

Published in the United States of America by Cambridge University Press, New York

www.cambridge.org

eBook (NetLibrary) Hardback

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List of contributors pagevii

Foreword by Julian Bion ix

Preface xi

Acknowledgements xii

List of abbreviations xiii

Section I Speci ﬁc features of critical

Anil Kumar and Joyce Yeung

8 Critical care imaging modalities 49

Angeline Simons and Joyce Yeung

Section II Systemic disorders

15 Sepsis 99

Yasser Tolba and David Thickett

16 Multiple organ failure 108

24 Acute coronary syndromes 185

Harjot Singh and Tony Whitehouse

25 Cardiac arrhythmias 194

Khai Ping Ng and George Pulikal

26 Acute heart failure 202

Harjot Singh and Tony Whitehouse v

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Mamta Patel and Richard Skone

34 Severe acute pancreatitis 266

Andrew Burtenshaw and Neil

Crooks

35 Poisoning 275

Zahid Khan

36 Liver failure 284

Nick Murphy and Joyce Yeung

37 Acute renal failure 292

42 Traumatic brain injury 325

Randeep Mullhi and Sandeep Walia

43 Trauma and burns 334

Catherine Snelson

44 Eclampsia and pre-eclampsia 342

John Clift

45 Obstetric emergencies in the ICU 349

John Clift and Elinor Powell

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Frances Aitchison

Consultant Radiologist

Birmingham City Hospital

West Midlands Critical Care Research Network

Birmingham, UK

Prasad Bheemasenachar

Consultant Intensivist

Birmingham Heartlands Hospital

Birmingham, UK

John Bleasdale

Birmingham, UK

Andrew Burtenshaw

Worcestershire Royal Hospital

Worcester, UK

John Clift

Consultant Anaesthetist

Birmingham, UK

Neil Crooks

Anaesthetic Specialist Registrar

Birmingham, UK

Fang Gao Smith

Professor in Critical Care Medicine

Birmingham, UK

Nageena Hussain

Anaesthetic Specialist Registrar

University Hospital Coventry and Warwickshire

Birmingham, UK

Santhana KannanConsultant IntensivistBirmingham City HospitalWest Midlands Critical Care Research NetworkBirmingham, UK

Zahid KhanConsultant IntensivistBirmingham City HospitalWest Midlands Critical Care Research NetworkBirmingham, UK

Anil KumarAnaesthetic Specialist RegistrarUniversity Hospital Coventry and WarwickshireWest Midlands Critical Care Research NetworkBirmingham, UK

Edwin MitchellConsultant IntensivistBirmingham City HospitalWest Midlands Critical Care Research NetworkBirmingham, UK

Randeep MullhiAnaesthetic Specialist RegistrarUniversity Hospital BirminghamWest Midlands Critical Care Research NetworkBirmingham, UK

Nick MurphyConsultant IntensivistUniversity Hospital BirminghamWest Midlands Critical Care Research NetworkBirmingham, UK

Darshan PanditConsultant IntensivistRussell Hall HospitalWest Midlands Critical Care Research NetworkDudley, UK

Mamta PatelConsultant IntensivistBirmingham City HospitalWest Midlands Critical Care Research Network

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Gavin Perkins

Associate Clinical Professor in Critical Care Medicine

Birmingham, UK

Khai Ping Ng

Medical Specialist Registrar

Birmingham, UK

Elinor Powell

Anaesthetic Specialist Registrar/Research Fellow

Birmingham, UK

Angeline Simons

Medical Specialist Registrar

Birmingham, UK

Harjot Singh

Consultant Anaesthetist

University Hospital Birmingham

Birmingham, UK

Richard Skone

Paediatric Intensive Care Registrar

Birmingham Children’s HospitalBirmingham, UK

Catherine SnelsonMedical Specialist Registrar/Advanced Trainee inIntensive Care Medicine

Birmingham Heartlands HospitalWest Midlands Critical Care Research NetworkBirmingham, UK

Roger StedmanConsultant IntensivistBirmingham Heartlands HospitalWest Midlands Critical Care Research NetworkBirmingham, UK

David ThickettSenior Lecturer in Respiratory MedicineUniversity Hospital BirminghamWest Midlands Critical Care Research NetworkBirmingham, UK

Yasser TolbaConsultant IntensivistBirmingham Heartlands HospitalWest Midlands Critical Care Research NetworkBirmingham, UK

Bill TunnicliﬀeConsultant IntensivistUniversity Hospital BirminghamWest Midlands Critical Care Research NetworkBirmingham, UK

Sandeep WaliaConsultant AnaesthetistUniversity Hospital BirminghamWest Midlands Critical Care Research NetworkBirmingham, UK

Tony WhitehouseConsultant IntensivistUniversity Hospital BirminghamWest Midlands Critical Care Research NetworkBirmingham, UK

Joyce YeungAnaesthetic Specialist Registrar/Research FellowBirmingham Heartlands Hospital

West Midlands Critical CareResearch Network

Birmingham, UK

viii

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The range of chapter titles in this concise and focussed

textbook demonstrates how far intensive care

medi-cine has travelled along the road from theﬁrst steps of

providing co-located care for patients with a single

disease– respiratory paralysis from polio – to

becom-ing a speciality carbecom-ing for patients with life-threatenbecom-ing

disease of multiple organ systems The outcome from

the polio epidemics of the 1950s was transformed

by the anaesthetist Professor Bjorn Ibsen, who reduced

the mortality from 90% to 40% by combining

labo-ratory science with applied physiology to change the

way care was delivered– from iron lung respirator to

positive pressure ventilation via a cuﬀed tracheostomy

tube The‘power supply’ (medical students) was soon

replaced by the development of mechanical

ventila-tors, and the scientiﬁc innovation – arterial blood gas

measurement – rapidly become a standard

investiga-tion in any acutely ill patient Although polio has

virtually disappeared, intensive care was retained by

hospitals convinced of its apparent utility for

suppor-ting patients with an increasingly diverse mix of

diseases In the Western world at least, we now care

for patients with a substantial chronic disease burden

underlying their acute illness, and intensive care has

increasingly come to resemble general medical

prac-tice with its accompanying ethical issues for

individuals and for society Indeed, Professor HenryLassen’s data describing the polio epidemic (Lancet1953) demonstrated that although the new technique

of ventilatory management saved many lives, thosewho eventually died did so much later: intensive carehas the capacity to delay, but not always prevent,death

As a new multi-disciplinary speciality we havemany challenges and opportunities ahead, fromunderstanding the cellular mechanisms of organ dys-function and sepsis to improving the reliability andsafety of care delivered across multiple transitions intime, place and staﬀ The modern intensivist mustcombine many roles: compassionate clinician, scien-tist, educator and team leader amongst them Forthose wishing to participate, the experience will bedemanding and rewarding This textbook provides asound basis for that journey

Professor Julian Bion MBBS FRCP FRCA MDProfessor of Intensive Care Medicine

University Department of Anaesthesia and IntensiveCare Medicine

Royal College of AnaesthetistsChair, Professional Standards CommitteeChair, European Board of Intensive Care Medicine

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This book is primarily aimed at trainees from all

specialties who are undertaking subspecialty training

in critical care medicine The book aims to provide a

clear, highlighted guide, from the assessment to the

management of critically ill patients It also aims to

provide comprehensive, concise and easily accessible

information on all aspects of critical care medicine for

trainees preparing for their specialty examinations

We have endeavoured to provide up-to-date

evidence-based medicine and further reading which we encourage

our readers to turn to for more detailed information

The topics in the book have been selected to

comple-ment the curriculum of SHO and SpR training by the

Intercollegiate Board for training in intensive care

med-icine The more advanced trainee in critical care and

allied health professionals willﬁnd this book useful as a

quick reference and a stimulus for further research

Section Istarts with the di ﬀ erent practical aspec ts

in the day-to-day work in critical care There is an

overview of the practical skills such as advanced airway

management, transfer of the critically ill as well as the

theory behind severity scoring systems of patients and

the diﬀerent uses of modern technology in critical

care Principles of the use of common drugs such as

vasoactive drugs, sedation and analgesia are outlined.The often overlooked but crucial subjects of nutrition,ethics and organ donation are also discussed

Section II covers systemic disorde rs and theirmanagement This includes familiar conditions inthe majority of critical care patients such as sepsis,multi-organ failure, the immunosuppressed and post-operative and post-resuscitation care Basic theorybehind acid–base disturbances, ﬂuids and electrolytedisorders and antibiotic use is also examined here

Section IIIfocuses o n speci ﬁ c organ dysfunctionsand their speciﬁc management This section expands

on disorders of each organ system, including anexamination of the diﬃcult and often confusing con-cepts of ventilation and weaning and renal replace-ment therapy There are separate chapters coveringobstetric and paediatric emergencies to cover therange of scenarios encountered by the critical caretrainee

Final ly, Section IVoutlin es higher examinat ions inintensive care medicine in UK and Europe Advancedtrainees in intensive care willﬁnd this a particularlyuseful resource and sample questions are included asreference

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We are indebted to all of the contributors of the book

for all their huge eﬀorts and also to our families and

loved ones for their unyielding support

We are grateful to Dr Seema, Dr Nick Crooks,

Dr Krishsrik and Dr Ellie Powell for critically

review-ing and commentreview-ing on a number of chapters

We thank Nicola Morrow of Warwick MedicalSchool, University of Warwick and Dawn Hill ofWest Midlands Critical Care Research Network,Birmingham Heartlands Hospital for their help withthe abbreviation list

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A&E Accident and Emergency

ABC Airways, Breathing, Circulation

ABCDE airways, breathing, circulation,

disability, exposureABGs arterial blood gases

ABS analgesic-based sedation

ACE angiotensin-converting enzyme

ACE-Is angiotensin-converting enzyme

inhibitorsACPE acute cardiogenic pulmonary

oedemaACS acute coronary syndrome

ACT activated clotting time

ACTH adrenocorticotropic hormone

ADH antidiuretic hormone

AED anti-epileptic drug

AEP auditory evoked potentials

AF atrialﬁbrillation

AFE amnioticﬂuid embolism

AHA American Heart Association

AHF acute heart failure

AIDF acute inﬂammatory demyelinating

polyneuropathyAIDS acquired immunodeﬁciency

syndromeAIS abbreviated injury scoring

AKI acute kidney injury

ALERT™ Acute Life Threatening Events–

Recognition and TreatmentALF acute liver failure

ALI acute lung injury

ANP atrial (A type) natriuretic peptide

AoCLD acute on chronic liver disease

APACHE acute physiology and chronic health

evaluationAPC activated protein C

APH antepartum haemorrhage

APRV airway pressure release ventilation

APTT acitvated partial thromboplastin time

ARB angiotensin II receptor antagonist

ARDS acute respiratory distress syndrome

ARF acute renal failureARR absolute risk reductionASV adaptive support ventilation

ATC automated tube compensationATLS Advanced Trauma Life Support

CourseATN acute tubular necrosisATP adenosine triphosphateATS American Thoracic Society

AV atrioventricularAVNRT atrioventricular nodal re-entrant

tachycardiaAVPU patient is alert, responding to voice,

responding to pain, unresponsiveAVRT atrioventricular re-entrant

tachycardiaBBB bundle branch blockBIS bispectral indexBMI body mass indexBMR basal metabolic rateBNP brain (B type) natriuretic peptideBOOP bronchiolitis obliterans organizing

pneumoniabpm beats per minuteCABG coronary artery bypass graftingCAD coronary artery diseaseCAMP cyclic adenosine monophosphateCBF cerebral bloodﬂow

CBV cerebral blood volumeCCK cholecystokininCCO critical care outreachCCRISP™ Care of the Critically Ill Surgical

PatientCEMACH conﬁdential enquiries into maternal

and child health

CI cardiac index

CI conﬁdence intervalCIRCI critical illness related corticosteroid

insuﬃciency

CK creatine kinaseCMV continuous mandatory ventilation xiii

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CNS central nervous system

CoBaTrICE Competency Based Training in

Intensive Care Medicine in EuropeCOPD chronic obstructive pulmonary

diseaseCOX cyclo-oxygenase

CPAP continuous positive airway pressure

CPFA coupled plasmaﬁltration absorption

CPP cerebral perfusion pressure

CPR cardiopulmonary resuscitation

CrCU Critical Care Unit

CRF chronic renal failure

CSF cerebrospinalﬂuid

C-spine cervical spine

CSS Canadian Society Classiﬁcation

of Angina

CT computed tomography

CVA cerebrovascular accident

CVP central venous pressure

CVVH continuous veno-venous

haemoﬁltrationCVVHD continuous veno-venous

haemodialysisCVVHDF continuous veno-venous

haemodiaﬁltrationCXR chest X-ray

DAI diﬀuse axonal injury

DI diabetes insipidus

DIC disseminated intravascular

coagulationDVT deep vein thrombosis

EBV Epstein–Barr virus

ECCO2R extracorporeal carbon dioxide

removalECG electrocardiograph

ECLA extracorporeal lung assist

ECLS extracorporeal lung support

ECMO extracorporeal membrane

oxygenationEDH extradural haematoma

cholangiopancreatographyERV expiratory reserve volume

ESC European Society of Cardiology

ETCO2 end-tidal carbon dioxide

EVLW extravascular lung waterF/VT frequency/tidal volume ratio

FAST focused assessment sonography

in traumaFLAIR ﬂuid-attenuated inversion recoveryFRC functional residual capacityGABA γ-aminobutyric acid (inhibitory

neurotransmitter)GCS Glasgow Coma ScoreGCSE generalized convulsive status

epilepticusGEDV global end diastolic volumeGFR glomerularﬁltration rateGIT gastrointestinal tractGTN glyceryl trinitrateGvsHD graft versus host diseaseHAART highly active antiretrovival therapyHBD heart-beating donation

HBDs heart-beating donorsHBS hypnotic-based sedationHCAP healthcare-associated pneumoniaHCV hepatitis C virus

HDU High Dependency Unit

HE hepatic encephalopathyHELLP haemolysis, elevated liver enzymes

and low platelets syndromeHepB hepatitis B

HES hydroxyl-ethyl starchHFOV high-frequency oscillatory

ventilationHib Haemophilus influenzae type BHIT heparin-induced thrombocytopeniaHIV human immunodeficiency virusHME heat and moisture exchange unitHPV hypoxic pulmonary vasoconstrictionHSCT haematopoietic stem cell transplantHUS haemolytic uraemic syndromeHVHF high-volume haemofiltrationIABP intra-aortic balloon pump

IC inspiratory capacityICD implantable cardiovertor–

deﬁbrillatorICF intracellularﬂuidICH intracranial hypertensionICNARC Intensive Care National Audit

and Research CentreICP intracranial pressureICS Intensive Care SocietyIHD intermittent haemodalysis

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IJV internal jugular vein

INR international normalized ratio

IRV inspiratory reserve volume

IRV inverse ratio ventilation

ISP increase pressure support

ITBV intrathoracic blood volume

IVF in vitro fertilization

JVP jugular venous pressure

LBBB left bundle branch block

LDL low-density lipoprotein

LED light emitting diode

LMA left mentoanterior

LMWH low-molecular-weight heparin

LOC loss of consciousness

LV liquid ventilation

LVEDP left ventricular end diastolic pressure

LVH left ventricular hypertrophy

MAP mean airway pressure

MAP mean arterial pressure

MARS molecular absorbent recirculation

systemMCQ multiple choice questions

MDMA methylenedioxymethamphetamine;

ecstasyMENDS maximizing eﬃcacy of targeted

sedation and reducing neurologicaldysfunction

MET medical emergency team

MI myocardial infarction

MIC minimum inhibitory concentration

MIP maximum inspiratory pressure

MMDS microcirculatory and mitochondrial

distress syndromeMODS multiple organ dysfunction syndrome

MOF multiple organ failure

MOST multi-organ support therapy

MPAP mean pulmonary artery pressure

MPM mortality probability model

MRI magnetic resonance imaging

MRSA methicillin resistantStaphylococcus

aureusMSBT safety of blood and tissues for

transplantationMSOF multiple systems organ failure

assistanceNCSE non-convulsive status epilepticusNETI nasotracheal endotracheal intubationNHBD non-heart beating donor

NHS National Health ServiceNICE National Institute for Clinical

ExcellenceNICO non-invasive cardiac outputNIV non-invasive ventilationNKH non-ketotic hyperglycemiaNMDA N-methyl-d-aspartate

NO nitric oxideNPPV non-invasive positive pressure

ventilationNRTI nucleoside reverse transcriptase

inhibitorsNSAID non-steroidal anti-inﬂammatory

drugNTG nitroglycerineODTF organ donation taskforceOHSS ovarian hyperstimulation syndrome

PA pulmonary arteryPACS picture archiving and

communication systemPACT patient-centred acute care trainingPAE post antibiotic eﬀect

PAFC pulmonary arteryﬂotation catheterPAV proportional assist ventilationPAWP pulmonary artery wedge pressure

PC pressure controlPCA patient-controlled analgesiaPCI percutaneous coronary interventionPCP Pneumocystis jiroveci/carinii

pneumoniaPCR polymerase chain reactionPCV pressure control ventilationPCWP pulmonary capillary wedge pressurePDEIs phosphodiesterase enzyme inhibitors

PE phenytoin, equivalents

PE pulmonary embolusPECLA pumpless extracorporeal lung assistPEEP positive end expiratory pressurePEG percutaneous endoscopic

gastrostomy

PF parenteral feedingPF4 platelet factor 4

Abbreviations

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PiCCO pulse-induced contour cardiac

outputPLEDs periodic lateralizing epileptiform

activitiesPLV partial liquid ventilation

POP pancreatitis outcome prediction

PPH postpartum haemorrhage

PSS physiological scoring systems

PSV pressure support ventilation

PTA post-traumatic amnesia

RAP right atrial pressure

RAS reticular activating system

RBCs red blood cells

RBF renal bloodﬂow

RCT randomized controlled trial

RDS respiratory distress syndrome

REM rapid eye movement

RM recruitment manoeuvre

ROSC return of spontaneous circulation

RPGN rapidly progressive

glomerulonephritisRRT renal replacement therapy

RSBI rapid shallow breathing index

RTA renal tubular acidosis

RV residual volume

rVII recombinant activated factor VII

SAFE saline versus albuminﬂuid

evaluationSAP severe acute pancreatitis

SAPS simpliﬁed acute physiology score

SBP systolic blood pressure

SBT spontaneous breathing trial

SCCM Society of Critical Care Medicine

SCUF slow continuous ultraﬁltration

SDD selective digestive decontamination

SDH subdural haematoma

SE status epilepticus

SIADH syndrome of inappropriate diuretic

hormoneSID strong ion diﬀerence

SIMV synchronized intermittent

mandatory ventilationSIRS systemic inﬂammatory response

syndromeSLE systemic lupus erythematosus

SMT standard medical therapy

SN sick sinus syndromeSOFA sequential organ failure assessmentSpO2 spot oxygen saturation

SSI signs and symptoms of infectionSSRIs selective serotonin reuptake

inhibitors

ST sharp transients

SV stroke volumeSvO2 mixed venous saturationSVR systemic vascular resistanceSVT supraventricular tachycardiaTBI traumatic brain injuryTCAs tricyclic antidepressantsTDS total dissolved solidsTEDs thromboembolic disease preventing

stockingsTEG thromboelastography

TF tissue factorTFPI tissue factor pathway inhibitorTGI transtracheal gas insuﬄationTIPS transjugular intrahepatic

portosystemic shuntTLC total lung capacityTLV total liquid ventilation

VA volume assistVAD ventricular assist deviceVAP ventilator-associated pneumonia

VC vital capacity

VC volume controlVCV volume control ventilation

VF ventricularﬁbrillationVILI ventilator-induced lung injuryV/Q ventilation–perfusion

VRE vancomycin resistant enterococci

VT tidal volume

VT ventricular tachycardiaVTE venous thromboembolismVZV Varicella zoster virusWBC white blood cellWHF World Heart FoundationWPW Wolﬀ–Parkinson–White syndrome

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* Critical illness, simply deﬁned, is a state where

death is likely or imminent All of us will

experience a critical illness by deﬁnition, but the

aim of intensive care is to identify patients whose

critical illness pathway can be altered and steered

away from a fatal outcome

* Over the past decade, it has become clearer that

intervening earlier in a patient’s critical illness may

lead to improved survival Even when

life-prolonging treatment is no longer in the patient’s

best interests, acknowledging a patient is critically

ill and in the terminal phase of their illness allows

appropriate palliative care to be given

* Critical illnesses are characterized by the failure of

organ systems, and it is the signs of these organ

failures that the initial assessment hopes to identify

Commonly, organ systems fail in sequence over time

leading to multi-organ failure, and resuscitation

aims to limit this Mortality is proportional to the

number of failed organs, duration of dysfunction

and severity of organ failure

* In contrast to the treatment of many routine

medical conditions, where deﬁnitive treatment is

based on a thorough assessment of the patient, the

assessment of the critically ill patient typically

occurs simultaneously with treatment due to

clinical urgency

Assessment

* The initial assessment of the critically ill patient

should begin with a brief, targeted history and an

appraisal of the patient’s vital signs to identify

life-threatening abnormalities that merit immediate

attention Signs suggesting severe illness are listed

inTable 1.1

* Most physicians are familiar with the‘ABCDE’(Airway, Breathing, Circulation, Disability,Exposure) approach to patient assessment taught onAdvanced Life Support™, Advanced Trauma LifeSupport™and other nationally recognized courses.This approach is speedy, thorough and adaptable,compared to the traditional medical‘clerking’

* The principle behind the ABCDE approach is thatproblems are prioritized according to the severity ofthreat posed Serious physiological derangementsshould be dealt with at each stage before moving on

to assess the next step For example, an obstructedairway should be identiﬁed and cleared beforeassessing breathing and measuring blood pressure

* In reality, information is gathered in a non-linearfashion, but it is helpful to have a clear guidelinewithin which to work With adequate staﬀ trainingand numbers, it should be possible to dealsimultaneously with multiple problems

* Common signs of organ failure should be sought,and bedside monitoring equipment (such as pulseoximetry, automated blood pressure measurementdevices and thermometers) may augment theclinical examination Near-patient testing, usingequipment such as the Haemacue™, and arterialblood gas sampling can provide useful and rapidinformation regarding the oxygenation of thepatient and common derangements in acid–basestatus and haemoglobin

Resuscitation

* The purpose of resuscitation is to restore orestablish eﬀective oxygen delivery to the tissues, inparticular those of the vital organs– brain, heart,

Core Topics in Critical Care Medicine, eds Fang Gao Smith and Joyce Yeung Published by Cambridge University Press.

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kidneys, liver and gut Oxygen delivery depends on

adequate oxygen uptake from the lungs, an

adequate cardiac output to deliver the oxygen to

the tissues and an adequate haemoglobin

concentration to carry the oxygen

* These goals of resuscitation are usually achieved by

the use of supplemental oxygen,ﬂuid or red blood

cell transfusion, inotropic support or antibiotics as

needed In certain circumstances, such as

penetrating trauma, a surgical approach to limiting

life-threatening bleeding is considered to be a part

of the resuscitation process

* Resuscitation should begin as soon as the need for

it has been identiﬁed There is now evidence

showing that early intervention (within a few

hours of admission) limits the degree of organ

dysfunction and improves survival Waiting until

the patient reaches the intensive care unit may be

too long a delay if further deterioration in the

patient’s condition is to be prevented

* In some situations, such as head injury, even single

episodes of hypotension or hypoxia are associated

with worsened outcomes

* Early and complete resuscitation is associated with

improved outcomes

Monitoring the progress of resuscitation

At present, there are only limited ways in which the

function of individual tissue beds can be assessed

Assessing the adequacy of resuscitation is usually

based on either global markers of oxygen supply and

utilization (such as the normalizaton of mixed venous

oxygen saturations and lactate concentration), or the

clinical responses of the aﬀected organs – urine output

from the kidneys for example Whilst resuscitation is

ongoing, invasive monitors such as an arterial

can-nula, a central venous cannula and a urinary catheter

may be placed, but these additional monitors should

not detract from the clinical monitoring of the patient

* Resuscitation must be tailored to the individualpatient There are now data to suggest appropriategoals or parameters for resuscitation in certainclinical states, notably sepsis (Table 1.2), acutehead injury and penetrating trauma

* Over-enthusiastic attempts at resuscitation canlead to problems withﬂuid overload, worseninghaemorrhage through dilution of clotting factors,

or rapid electrolyte shifts leading to cerebraloedema

* The importance of early assessment by adequatelytrained staﬀ, with regular review of clinicalprogress, cannot be over-emphasized

Once resuscitation is under way and the patient isstabilized, it is appropriate to begin an in-depth assess-ment of the patient This means taking a more com-plete history, making a thorough examination andordering clinical investigations as indicated Thisphase of the process aims to establish an underlyingdiagnosis and guide deﬁnitive treatment If deteriora-tion occurs over this time, the cycle of assessment andresuscitation should begin again

Physiology monitoring systems

Physiology monitoring systems are systems that allowthe integration of easily obtained and measured phys-iological variables into a single score or code thattriggers a particular action or care pathway (see also

Chapter 5: Scoring systems and outcome)

* The commonly measured physiological variablesare heart rate, blood pressure, respiratory rate,temperature, urine output and consciousness level,and these can be assessed at the bedside

* Action may be triggered by a single abnormality or

by an aggregate score Aggregate scoring systemsare generally preferred as they may also allow agraded response depending on the score

* Physiological Scoring Systems (PSS) developedfrom the recognition that critically ill patients, and

Table 1.1 Signs suggestive of critical illness

* Obstructed/threatened airway

* Respiratory rate >25 breaths/min or <8 breaths/min

* Oxygen saturations <90% on air

* Heart rate >120 bpm or <40 bpm

* Systolic blood pressure <90 mmHg

* Capillary re ﬁll >3 seconds

* Urine output <0.5 ml/kg per hour more than last 4 hours

* Glasgow coma score <15 or status epilepticus or patient not

fully alert

Table 1.2 Suggested goals to be achieved within 6 hours of presentation for the resuscitation of septic shock refractory to ﬂuid therapy (after Rivers et al.)

* Mean arterial pressure >65 mmHg

* Central venous pressure 8 –12 mmHg

* Urine output >0.5 ml/kg per hour

* Central venous oxygen saturation >70%

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in particular patients who suﬀered cardiac

arrests, often had long periods (hours) of

deterioration before the‘crisis’ or medical

emergency occurred

* PSS scores are often termed‘track and trigger’

scores; they aim to identify and monitor patients

whose clinical state is worsening over time, and

then trigger an appropriate clinical response

* The Department of Health has recognized the need

for the early identiﬁcation of critically ill patients

and recommends the use of track and trigger

systems in all acute hospitals in the UK The

current recommendation is to use PSS to

assess every patient at least every 12 hours

or more frequently if they are at risk of

deterioration

* PSS may have variable sensitivity and speciﬁcity

for predicting hospital mortality, cardiac arrest

and admission to critical care Triggering scores

may need to be set locally to maximize the beneﬁts

from these scoring systems Typically, these

scoring systems are not very sensitive but have

high negative predictive power for the outcomes

mentioned above Advantages and disadvantages

of PSS are summarized inTable 1.3

Medical emergency team

and outreach

It has been recognized that intensive care units will

never have the capacity for all the patients that may

beneﬁt from some degree of critical care provision

The concept of ‘critical care without walls’ is that

patients’ critical care needs may be met irrespective

of their geographical location within the hospital

Medical emergency teams (METs) and critical careoutreach (CCO) aim to redress the mismatch betweenthe patient’s needs when they are critically ill and theresources available on a normal ward, in terms ofmanpower, skills, and equipment

* At present there is no clear consensus in theliterature about the exact composition and role ofthese teams, nor their nomenclature

* Currently there is emphasis in teaching criticalcare skills to all hospital doctors via courses such asALERT™(Acute Life threatening Events–Recognition and Treatment) and CCRISP™ (Care

of the Critically Ill Surgical Patient)

* METs are usually understood to be physician-led.The team might typically consist of the dutymedical registrar and intensive care registrar, asenior nurse and a variable number of other juniordoctors

* METs are often formed from people who do notusually work together, coming together as a teamonly when the clinical need dictates The MET has

an obligation to arrive quickly, to contain thenecessary skill mix in its members, to documentthe extent of its involvement accurately, and toliaise with the team responsible for the patient’susual treatment

* METs are summoned to critically ill patients whohave been identiﬁed either by a scoring system asoutlined above, because they have attracted aparticular diagnosis (e.g status epilepticus), orbecause of general concerns that the nursing staﬀhave about a patient

* METs have been shown to reduce the numbers ofunexpected cardiac arrests in hospital in someobservational studies, but the exact level of beneﬁt

is controversial In some hospitals METs havereplaced the traditional cardiac arrest team

Critical care outreach (CCO) teams are typicallynurse-led, and have a variety of roles compared tothe MET, depending on local policy (Fig 1.1) Thenurses in CCO are typically senior nurses who havebeen recruited from an intensive care, coronary care oracute medical background CCO nurses are oftenemployed full-time in this role and may perform addi-tional duties, such as following up patients on dis-charge from the intensive care unit, acute painservices, tracheostomy care and providing non-invasive ventilation advice

Table 1.3 Advantages and disadvantages of Physiological Scoring

* Not validated in target populations

* May not be appropriate for all patients (chronic health conditions, terminally ill, children, etc.)

* Scores may not be calculated correctly

Chapter 1: Recognition of critical illness

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* When summoned to a critically ill patient, CCO

will typically make an assessment and refer directly

to intensive care services, or make suggestions to

the parent medical team according to the

requirements of the patients

* At present, not all CCO are staﬀed to provide a

round-the-clock service and thus patients still

often rely on junior medical staﬀ to provide their

care out of hours

In the UK, CCO is the most frequently used model,

following on from Department of Health

recommen-dations made in the late 1990s Their explicit purpose

is to avert ITU admissions, support discharge from

ITU and to share critical care skills with the rest of the

hospital Other countries, most notably Australia, have

pioneered the MET model since 1990 In some

hospi-tals both systems run side by side Currently the

sys-tems are in a state ofﬂux The rapid introduction of

MET/CCO systems in most hospitals has made the

assessment of its impact on patient survival diﬃcult

It is also diﬃcult to assess how many patients at any

one time need the input of a MET/CCO, and the

implications that this may have for resource

alloca-tion At the time of writing, most of the available data

suggest that the MET is under-utilized

Referral to critical care team

Critical care can oﬀer:

* organ support technologies

* high nurse : patient ratio

* intensive/invasive monitoring

* specialist expertise in managing the critically ill

Patients who need these services should be referred to

the critical care team

Intensive care units exist to support patientswhose clinical needs outstrip the resources/manpowerwhich can be safely provided on the general wards Thepatient must also generally be in a position to beneﬁtfrom the treatment, rather than simply to prolongthe process of dying from an underlying condition.Chronological age alone is a poor indicator of survivalfrom a critical illness; chronic health problems andfunctional limitations due to these are better predic-tors There should be a discussion with the patient (ifpossible), or their family, to explain the proposedtreatment and to seek their consent for escalatingmanagement

Most critical care facilities operate a ‘closed’policy, in which the referring team temporarilydevolves care to the intensive care team The latter

is led by a clinician trained in intensive care There

is evidence that this approach leads to reducedlengths of stay and increased survival rates inpatients As part of this strategy, all referrals tointensive care should be passed through the dutyintensive care consultant The referring team stillhas an important role to play as deﬁnitive manage-ment of a condition (e.g surgery) is still oftenprovided by them

Referral to the critical care team may occur via avariety of routes The admission may be planned well

in advance in the case of elective surgery, or pated and discussed with the ITU consultant in thecase of emergency surgery Acute medical admissionsshould be referred to the ITU consultant directly fromthe medical consultant, but in emergencies referralmay be made via the MET/CCO The patient is usuallyreviewed on the ward prior to admission in order tofacilitate resuscitation and safe, timely transfer to crit-ical care

* Physiological scoring systems are widely used, butnot always well validated

* METs and CCOs aim to provide critical care skillsrapidly to critically ill patients

* Referrals to the critical care services may happenfrom any level, but theﬁnal decision to admit a

Fig 1.1 Critical care outreach (CCO) teams often carry portable

equipment to help stabilize patients in places outside of critical care

areas.

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patient to a critical care bed should be made by an

experienced critical care physician

Further reading

* Bickell W, Wall M, Pepe Pet al (1994) Immediate versus

delayedﬂuid resuscitation for hypotensive patients with

penetrating torso injuries.N Engl J Med.331: 1105–9

* Intensive Care Society (2003)Evolution of Intensive

Care www.ics.ac.uk/icmprof/downloads/icshistory.pdf

* Intensive Care Society (2008) Levels of Critical Carefor Adult Patients: Standards and Guidelines www.ics.ac.uk/downloads/Levels_of_Care_13012009.pdf

* National Institute for Clinical Excellence (2007)Clinical Guideline CG59: Acutely Ill Patients inHospital www nice.org.uk/guidance/index.jsp?

action=byID&o=11810#summary

* Rivers E, Nguyen B, Havstad Set al (2001) Early directed therapy in the treatment of severe sepsis andseptic shock.N Engl J Med.345: 1368–77

goal-Chapter 1: Recognition of critical illness

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2 Advanced airway management

Isma Quasim

Critically ill patients may need respiratory support as

part of their treatment on the intensive care unit The

provision of respiratory support is a core function of

the intensive care unit; internationally around a third

of patients admitted to intensive care units receive

some form of mechanical ventilation for more than

12 hours Advanced airway skills form an essential part

of the intensive care clinician’s armoury and are

invaluable in times of emergency

This chapter will focus mainly on the aspects of

advanced airway management used most commonly

in critical care: intubation and extubation,

tracheos-tomy, cricothyroidotomy and‘mini-tracheostomy’

Intubation

Indications for intubation (Table 2.1)

Bag–valve-mask and non-invasive ventilation are two

methods of providing short-term positive pressure

ven-tilation or intermittent airway management However,

intubation is often necessary to provide more long-term

and continuous positive pressure ventilation and/or to

secure and protect the airway of patients with reduced

level of consciousness

Airway assessment

Studies have suggested that diﬃcult intubation in

patients for elective operative procedures occurs

approximately in 1–3% of cases, and this incidence

increases up to 10% in critical care patients In

anaes-thesia, there are a number of methods and parameters

of airway assessment used to predict potential diﬃcult

intubation These include the modiﬁed Mallampati

score, thyromental distance, inter-incisor distance

and neck mobility In addition, diﬃcult intubation

should be anticipated in patients with certain

anatom-ical features (protruding teeth, morbid obesity, large

breasts and short necks) or pathologies such as upperairway infection (e.g epiglottitis, laryngitis), trauma,inhalational injury, tumour, cervical spine injury, pre-vious upper airway operations or radiotherapy

In critical care practice, given the relative urgencyfor intubation in sick or non-cooperative patients,full assessments are not always possible or practical.Some vital information can still be found on ananaesthetic chart such as preoperative assessment ofthe airway, the grade of laryngoscopic view and tech-niques of airway managements Patients should beintubated by a clinician experienced in advanced air-way management with diﬃcult airway adjunctsavailable

When dealing with sick patients on the ward, ditions in the ward setting are often unfavourable due

con-to limited equipment and lack of assistance, makingintubation more diﬃcult Ideally patients should betransferred to a safer environment such as the criticalcare unit, the anaesthetic room or the operating thea-tre where trained assistance is available

Rapid sequence induction

Patients who present in emergency situations areassumed to have a full stomach and in the UK, it isrecommended that a rapid sequence induction (RSI)

is used in intubation This is a technique that mizes the risks of regurgitation and subsequent aspi-ration of gastric contents The principles involvedare:

mini-(1) Patient should be on a bed that can be tilted ifnecessary Mandatory monitoring should becommenced including ECG, pulse oximetry, bloodpressure, end-tidal CO2monitoring

(2) Preparation of all essential emergency drugs beforethe start of procedure

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(3) Equipment needed should be checked prior to the

procedure including two working Macintosh

laryngoscopes, endotracheal tubes, laryngeal mask

airways, working suction Airway adjuncts such as

oropharyngeal airways, longer laryngoscope

blades, McCoy laryngoscope or bougie that might

be required in an unexpectedly diﬃcult intubation

should also be available

(4) Trained assistance familiar with the technique

should be available

(5) Preoxygenation with highﬂow 100% oxygen for

3–5 minutes to maximize oxygen reserves and

prevent hypoxaemia until tracheal intubation is

established

(6) A rapidly acting intravenous induction agent such

as thiopentone and suxamethonium should be

used to achieve rapid muscle relaxation and

tracheal intubation

(7) Sellick’s manoeuvre or cricoid pressure should be

applied just before patient loses consciousness

This involves digital pressure against the cricoidcartilage of the larynx, pushing it backwards(Fig 2.1) This causes compression of theoesophagus between the cricoid cartilage and theC5/C6 vertebrae posteriorly, thus minimizingpassive regurgitation of gastric contents (Fig 2.2).Force applied should be 30 N to 40 N and should bemaintained until the correct placement of

endotracheal tube has been confirmed byauscultation and cuff inflated It must be releasedduring active vomiting, to reduce the risk ofoesophageal rupture

The majority of anaesthetic induction agents arevasodilators and have cardiodepressant eﬀects Theuse of these induction agents can lead to a precipitousfall in blood pressure and cardiac output in dehydrated,septic or haemodynamically unstable patients It is goodpractice to monitor patients’ cardio-respiratory param-eters closely including invasive blood pressure mon-itoring prior to induction and have ﬂuid bolusesand vasopressor drugs prepared and immediatelyavailable

It is beyond the realm of this chapter to go into thepharmacology in depth but a few of the commonly

Cricoid Cartilage

Fig 2.1 Cricoid cartilage (With permission of Update in Anaesthesia, Issue

2 (1992), Article 4: Cricoid pressure in Caesarean section.)

Table 2.1 Critical care indications for intubation

Protect the airway Glasgow Coma Scores <8

Secure the airway Airway obstruction, inadvertent or

failed extubation

Chapter 2: Advanced airway management

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used intravenous induction agents and muscle

relax-ants are outlined below:

Propofol – The induction dose is 1.5–2.5 mg/kg

but this should be reduced in haemodynamically

unstable patients as it can cause profound

hypoten-sion It has the advantage of being able to be continued

as an infusion for sedation and is a drug familiar to the

majority of anaesthetists and intensivists

Etomidate – The dose of 0.3 mg/kg causes less

haemodynamic instability than propofol, and has

been used as drug of choice for critically ill patients

Its use has declined as major concerns have been raised

over adrenocortical suppression even when given as a

single dose at induction

Thiopentone – The classical induction agent used in

RSI along with suxamethonium It provides smooth

rapid induction in a dose of 3–6 mg/kg but also produces

dose-related cardiac depression Its metabolism is slow

and sedation can persist for many hours afterwards

Muscle relaxants

In a RSI situation, only suxamethonium should be

used and it is given immediately after the IV induction

agent without bag-mask ventilation In a situation in

which it is safe and appropriate to use a longer-acting

muscle relaxant as the primary agent, then hand

ven-tilation must be checked prior to its administration to

avoid the‘can’t intubate, can’t ventilate’ scenario

Suxamethonium – Suxamethonium is a

depolariz-ing neuromuscular blocker and is the only available

neuromuscular blocker with a rapid onset of eﬀect and

an ultra short duration of action of around 5 min Given

in a dose of 1–1.5 mg/kg it provides excellent intubatingconditions within 60 sec but is contraindicated in con-ditions such as burns (>24 hours old), hyperkalaemia,malignant hyperpyrexia, myotonia and other neurolog-ical diseases Suxamethonium is metabolized rapidly byplasma pseudocholinesterase and the duration of action

is increased in patients who carry an atypical gene for thisenzyme In patients who are heterozygous for the atyp-ical gene duration of action is increased by 50–100%; inpatients who are homozygous for the atypical gene dura-tion of action is increased to 4 hours

Rocuronium – A dose of around 0.6 mg/kg providesgood intubating conditions within 2 min; however whengiven in a dose of 1–1.2 mg/kg it can facilitate intubationwithin 60 sec and can be used in a ‘modiﬁed rapidsequence induction’ when suxamethonium is contrain-dicated It has duration of action of around 30 min.Atracurium – The initial dose is 0.5 mg/kg andprovides intubating conditions within 2 min It is useful

in patients with renal or hepatic impairment as it isbroken down by spontaneous Hoﬀmann degradation Ithas a short duration of action of around 20–25 min and ifprolonged muscle relaxation is necessary it can be given

by IV infusion at 0.5 mg/kg per hour

SeeTable 2.2 for a summary of induction agentsand muscle relaxants

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obstruction, burns or status asthmaticus, and sevoﬂurane

is one of the most commonly used agents within the UK

for this technique Inhalational induction is usually

car-ried out by an anaesthetist and requires an anaesthetic

machine and circuit

Endotracheal intubation

Endotracheal intubation is usually via the oral route but

historically nasal intubation was common practice The

oral endotracheal tube avoids the risk of sinusitis and

allows a tube with a larger internal diameter to be used,

reducing the work of breathing Nasal endotracheal tubes,

on the other hand, are better tolerated in awake patients

and are used in some paediatric critical care units

During intubation, the patient should be fully

moni-tored Equal breath sounds should be auscultated to rule

out oesophageal intubation but this is not always

reli-able Capnography should be used to conﬁrm tracheal

intubation as recommended by the Royal College of

Anaesthetists Lightweight portable capnography

devi-ces are available when intubation is required to be

performed outside of the critical care, operating theatre

or anaesthetic room environment Chest X-rays should

be performed to conﬁrm the position of the tip of the

endotracheal tube to avoid inadvertent endobronchialintubation

Di ﬃcult and failed intubation

In an unanticipated diﬃcult intubation situation, genation should be maintained with hand ventilationuntil appropriate help arrives Clinicians experienced

oxy-in advanced airway management should familiarizethemselves with the failed intubation drill (Fig 2.3).The Diﬃcult Airway Society UK website (see Furtherreading) has the following management plans:

(1) Unanticipated diﬃcult tracheal intubation duringrapid sequence induction of anaesthesia

(2) Rescue techniques for the‘can’t intubate, can’tventilate’ situation

Extubation/ weaning protocols

In 2000, a study investigated characteristics of tional mechanical ventilation in 412 medical and sur-gical ICUs involving 1638 patients across NorthAmerica, South America, Spain and Portugal Thestudy conﬁrmed that there was similarity betweencountries for the primary indications for mechanical

conven-Table 2.2 Commonly used induction agents and muscle relaxants

Propofol Rapid onset; una ﬀected by renal or

hepatic disease

1.5 –2.5 mg/kg Intravenous

induction agent Given by infusion for sedation Anticonvulsant

Vasodilatory and depressant

cardio-Etomidate Rapid onset; less cardiodepressant 0.3 mg/kg Induction agent Not for use in porphyria

Adrenocortical suppression even after single dose Thiopentone Smooth rapid onset 3 –6 mg/kg Induction agent;

anticonvulsant

Avoid in porphyria Slow hepatic metabolism Suxamethonium E ﬀective within 60 sec; lasts

3 –5 min 1–1.5 mg/kg Depolarizingmuscle relaxant

Not for use in malignant hyperthermia and myotonia Caution in burns, renal failure, spinal cord injuries Atracurium Adequate muscle relaxation within

3 min; lasts 20 –25 min Safe for use in renal and hepatic failure

0.3 –0.6 mg/kg Non-depolarizing

muscle relaxant

Histamine release may cause bronchospasm and hypotension Rocuronium Rapid onset if dose of 1 –1.5 mg/kg

used Longer duration of action

of 30 –40 min

0.6 mg/kg gives adequate relaxation in

2 min

Non-depolarizing muscle relaxant

Intermediate risk of anaphylaxis

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Failed intubation, increasing hypoxaemia and difficult ventilation in the paralysed

anaesthetized patient: Rescue techniques for the ‘can’t intubate, can’t ventilate’ situation

failed intubation and difficult ventilation (other than laryngospasm)

Face maskOxygenate and ventilate patientMaximum head extensionMaximum jaw thrustAssistance with mask sealOral ± 6 mm nasal airwayReduce cricoid force – if necessary

call for help

LMATM Oxygenate and ventilate patientMaximum 2 attempts at insertionReduce any cricoid force during insertion

Oxygenation satisfactoryand stable: Maintainoxygenation andawaken patient

Equipment: Kink-resistant cannula, e.g.

Patil (Cook) or Ravussin (VBM)

High-pressure ventilation system, e.g Manujet III (VBM)

Technique:

1 Insert cannula through cricothyroid membrane

2 Maintain position of cannula – assistant’s hand

3 Confirm tracheal position by air aspiration –

20 ml syringe

4 Attach ventilation system to cannula

5 Commence cautious ventilation

6 Confirm ventilation of lungs, and exhalation

through upper airway

7 If ventilation fails, or surgical emphysema or any

other complication develops – convert immediately

1 Identify cricothyroid membrane

2 Stab incision through skin and membrane Enlarge incision with blunt dissection (e.g scalpel handle, forceps or dilator)

3 Caudal traction on cricoid cartilage with tracheal hook

4 Insert tube and inflate cuff Ventilate with low-pressure source Verify tube position and pulmonary ventilation

Notes:

1 These techniques can have serious complications – use only in life-threatening situations

2 Convert to definitive airway as soon as possible

3 Postoperative management – see other difficult airway guidelines and flow-charts

4 4 mm cannula with low-pressure ventilation may be successful in patient breathing spontaneously

Fig 2.3 Failed intubation algorithm (With permission of Di ﬃcult Airway Society, UK.)

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ventilation and ventilator settings, but considerable

variability on the modes of ventilation or the methods

of weaning

Weaning assessment

One of the most diﬃcult issues in critical care

medi-cine is trying to determine which patients will be

successfully extubated There are instances where this

may be easily achieved especially in patients with

nor-mal respiratory function who have been intubated for

an acute event, e.g following a drug overdose or post

surgical procedure In a signiﬁcant proportion of

patients however, the reduction and subsequent

with-drawal from ventilatory support is more gradual and

this is deﬁned as weaning

Weaning techniques

There are a number of ways in which weaning can be

achieved The mechanical ventilations may be changed

from an assist-control mode to:

* Pressure support ventilation (PSV) High levels of

support are gradually reduced over time as the

patient increases the ability of his/her own

breathing Initially the pressure support is set to

achieve a comparable tidal volume as with the

assist mode and then decreased whilst the patient is

monitored for weaning failure Once the PS is at a

low level (5–8 cm H2O), they may be considered

for extubation

* Synchronized intermittent mandatory ventilation

(SIMV) The initial high respiratory rate is

decreased over time Once a low level has been

reached and the patient shows no signs of fatigue,

then a trial of PSV/CPAP can be provided

* Continuing full ventilation with periods of low

levels of PSV (5cm H2O)/CPAP (5 cm H2O) This

is comparable to a T-piece trial

In 1995, the Spanish Lung Failure Collaborative

Group conducted a prospective, randomized,

multi-centre study on comparison of four methods of

wean-ing patients from mechanical ventilation:

(1) SIMV with an initial rate of 10 and then decreased

at least twice a day Patients were extubated once

they tolerated a ventilator rate of 5 breaths/min for

2 hours with no distress

(2) PSV initially set with pressure support around

18 cm HO and then reduced at least twice a day

Once the patients tolerated a pressure support of

5 cmH2O for 2 hours with no distress they could

(4) Once a day spontaneous breathing trial (SBT)

After 2 hours on a T-piece or CPAP 5 cmH2O with

no signs of distress the patients were extubated Ifunsuccessful, full assist ventilation was continuedfor another 24 hours before another trial wasattempted

They found that the rate of successful weaning wassignificantly higher in the spontaneous breathinggroups (groups 3 and 4) and that there was no signifi-cant difference in the success rate between once a day(group 4) and multiple trials of spontaneous breathing(group 3) Further work in 2002 demonstrated thatspontaneous breathing trials carried out for 30 or

120 min were equivalent in recognizing those patientswho would be successfully extubated

Criteria for failed spontaneous breathing trials

Spontaneous breathing trials are the most eﬀective way

of determining whether mechanical ventilation can bediscontinued A failed SBT is said to have occurred if thepatient shows signs of distress, agitation, tachypnoea(>35 breaths/min), hypoxia (SpO2<90%) and extremes

of systolic blood pressure The patient is then put back onfull ventilatory support for the weaning process to con-tinue at a later time

Extubation

Critical care clinicians often use the following criteria

to consider patients ready for extubation:

* Resolution of the pathology that necessitated IPPV

* Adequate arterial oxygenation on a FiO2≤ 0.5 andPEEP≤ 5 cmH2O

* Haemodynamic stability

* Normal acid–base status

* Normalﬂuid and electrolyte status

* Adequate protective airway reﬂexes and ability tocough

* Awake and co-operative

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There are a number of bedside tests that may be used

to assess the likelihood of extubating a patient;

how-ever, they may be poor predictors of success in an

individual patient

Parameters that can be used include:

(1) PaO2/FiO2ratio >200 mmHg (26 kPa)

Indications for tracheostomy

Tracheostomies are commonly used in critical care

units to:

* Facilitate weaning after prolonged ventilation

* Secure and clear the airway in upper respiratory

tract obstruction

* Facilitate removal of bronchial secretions,

e.g inadequate cough

* Protect the airway in the absence of laryngeal

reﬂexes, e.g bulbar palsy

* Provide an airway in patients with injuries or

surgery to the head and neck

Contraindications for tracheostomy

The only absolute contraindication to a surgical or

percutaneous tracheostomy is local severe sepsis or

uncontrollable coagulopathy Relative contraindications

to a percutaneous tracheostomy are abnormal anatomy,

moderate coagulopathy, children under 12 years (due to

diﬃculty identifying anatomical landmarks) and high

FiO2and PEEP requirements

Timing of tracheostomy

The timing of when to perform a tracheostomy is still a

clinical decision rather than one based on medical

evidence Some studies suggest that a tracheostomy

performedearlier rather than later leads to improved

weaning, a shorter ICU length of stay and a reduction

in the incidence of nosocomial pneumonia A

system-atic review performed in 2005 comparing early

trache-ostomy (up to 7 days after admission to ICU) with late

tracheostomy (any time thereafter) suggested early

tracheostomy led to a reduction in the duration ofmechanical ventilation and length of ICU stay butthe numbers involved in the studies were relativelysmall A study investigating the eﬀect that the timing

of tracheostomy has on 30-day mortality in UK sive care units (TrachMan trial) has been completed

inten-to compare early tracheosinten-tomy (days 1 inten-to 4) with latetracheostomy (day 10 or after) in patients expected torequire mechanical ventilation for 7 days or more.Early tracheostomy (n = 450) was not associatedwith any beneﬁcial eﬀect on the development ofventilator-associated pneumonia, ICU length of stay,use of sedation or 30-day mortality compared to latetracheostomy (n = 450) Interestingly, only 45% ofthe patients in the late group actually received atracheostomy

Techniques of percutaneous tracheostomy

The two methods of performing a tracheostomy aresurgical or percutaneous Surgical tracheostomies arebest carried out by experienced surgeons and willnot be discussed in any detail here Percutaneoustracheostomy carried out using a Seldinger techni-que is rapidly becoming more established withinthe critical care setting

At present there are at leastﬁve diﬀerent ques for carrying out a percutaneous tracheostomy,but there is no evidence that one technique is superior

Complications

Complications of tracheostomy are numerous and therates vary considerably; generally complication ratesare higher for emergency tracheostomy and for airwayobstruction

Complications can be divided into:

Immediate – e.g haemorrhage,

pneumo-thorax, misplacement of tube.Delayed – e.g tube blockage by secretions,

infection of stoma site, infection of

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bronchial tree, mucosal ulcerationdue to cuﬀ inﬂation.

Late – e.g persistent sinus at

tracheos-tomy site, tracheal stenosis at cuﬀsite, scar formation requiringrevision

Tracheostomy tubes

A variety of tracheostomy tubes are available which

have diﬀerent properties A patient may require many

diﬀerent types of tracheostomy tubes during their

critical care admission

Cuﬀed tracheostomy tubes – generally used for

patients on positive pressure ventilation (Fig 2.5) The

cuﬀ must be inﬂated to prevent air/oxygen leaking

is identi fied, and the skin is anaesthetized with 1% lidocaine with 1: 100 000 adrenaline below the cricoid cartilage The endotracheal tube is withdrawn so cu ff is visible at the vocal cords to avoid accidental puncture Some clinicians like to perform procedure under direct vision with fibreoptic bronchoscope (a) A 1.5- to 2-cm transverse skin incision is made on the level of the first and second tracheal rings A 22-gauge needle is inserted between the first and second or the second and third tracheal rings (b) When air is aspirated into the syringe, the guidewire is introduced (c) After the guidewire is protected, the dilators are introduced (d) All dilators are inserted in a sequential manner from small to large diameter The tracheostomy tube is then introduced along the dilator and guidewire The guidewire and dilator are removed, the cu ff of the tracheostomy tube is in flated, and the breathing circuit is connected The ET tube can then be removed (With permission from Update in Anaesthesia Issue 15 (2002), Article 16:

Percutaneous tracheostomy.)

Fig 2.5 Cu ﬀed tracheostomy tube.

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backwards and reduce the chance of aspirate entering

the lungs Obstruction of a cuﬀed tracheostomy tube

by secretions is potentially life-threatening To

mini-mize this risk, tracheostomy tubes should be changed

frequently Changing a tracheostomy tube carries the

risk of misplacement and causes patient discomfort

Tracheostomy tubes with an inner cannula – allows

an inner cannula to be changed frequently to reduce the

risk of obstruction The main disadvantage of these tubes

is the reduced inner diameter, which causes an increased

work of breathing

Fenestrated tracheostomy tubes – allow airﬂow to

pass through the oropharynx as well as the tracheal

stoma and reduce the work of breathing provided the

cuﬀ is deﬂated (Fig 2.6) These should not be used if the

patient is at risk of aspiration or is on positive pressure

ventilation unless the fenestrations are blocked by an

inner cannula

Tracheostomy tubes with adjustable ﬂange –

useful in patients with abnormal anatomy such as

obesity, neck swelling and spinal deformities (Fig 2.7)

Theﬂanges allow the tracheostomy tube to be adjusted

to a certain length

Decannulation of tracheostomy tubes

Tracheostomy tubes should be removed as soon as

possible once:

* Resolution of the primary cause of the

tracheostomy has occurred

* Patient is able to expectorate past the tube and not

require regular suctioning

* Eﬀective swallow, gag and cough reﬂexes are

present

* Patient is comfortable with the cuﬀ deﬂated

* Nutritional status is adequate

* No airway obstruction is present above thetracheostomy

Weaning often involves increasing length of time withthe cuﬀ deﬂated or ‘downsizing’ the tube to one with asmaller diameter allowing the patient to breathe pastthe tracheostomy

Speaking valves or occlusion/decannulation capsshould only be used on non-cuffed tubes, cuffedtubes with the cuff deflated or fenestrated tubes withthe cuff deflated If the patient tolerates at least 4 hourswith the occlusion cap and is able to effectively cough,then decannulation can take place

Cricothyroidotomy and mini tracheostomy

Acricothyroidotomy is usually performed as an gency procedure when a secure airway is needed andattempts at orotracheal or nasotracheal intubationhave failed The patients are likely to be profoundlyhypoxic and it is important that the airway is securedquickly This can be done either as a needle or as asurgical cricothyroidotomy

emer-There are several ways in which a omy can be carried out All the techniques involve anincision of the cricothyroid membrane, which isbetween the thyroid cartilage superiorly and cricoidcartilage inferiorly

cricothyroidot-* A small cannula (usually inserted over a needle),which needs a high-pressure gas source such as theManuJet system (VBM, GmbH, Sulz, Germany) toFig 2.6 Fenestrated tracheostomy tube Fig 2.7 Tracheostomy tube with adjustable ﬂange.

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provide adequate lung inﬂation The patient’s

airway is generally patent enough to allow

exhalation, as the positive pressure within the

trachea tends to open up the upper airway

* Larger cannula (usually as a preassembled kit using

a Seldinger technique, e.g Portex, Melker), but as

these are uncuﬀed they lead to an unprotected

airway with suboptimal ventilation

* Surgical cricothyroidotomy allows a large cuﬀed

endotracheal tube to be placed but requires

familiarity with the technique and should not be

carried out by inexperienced practitioners

Exhaled gases must be able to escape otherwise

sig-niﬁcant barotrauma can result, and in the case of an

upper airway obstruction a second air outlet may be

needed

Mini tracheostomies are now available as kits

which are not only used in the emergency scenario,

but also in situations where sputum retention is

prob-lematic, e.g inadequate cough, respiratory tract

infec-tion or in the post-operative period The anatomical

landmark and insertion of a mini tracheostomy are

similar to performing cricothyroidotomy Generally

they are not recommended for ventilation as the

air-way resistance is high but recent small studies have

been carried out where the combination of a mini

tracheostomy plus non-invasive ventilation (NIV) has

been used in patients with respiratory failure due to

neuromuscular disorders This technique avoids

endo-tracheal intubation and IPPV and seemed to be well

tolerated although patient selection may have played a

role

Key points

* Intubation of critical care patients can be diﬃcult

and the clinician should have a management plan

for the unanticipated diﬃcult airway

* A daily assessment of ventilated patients to seewhether theyﬁt the criteria for weaning andsubsequent extubation is important

* Tracheostomies can be a useful weaning tool incertain patient groups but it is important toensure the patients are looked after in a safeenvironment if they are discharged from the ICUwith one in situ

* Cricothyroidotomy is a valuable tool in securingthe airway in an emergency situation Make sureyou know what equipment is available in yourhospital and how to use it

Further reading

* Esteban A, Anzueto A, Alia Iet al (2000) How ismechanical ventilation employed in the Intensive CareUnit?Am J Respir Crit Care Med.161: 1450–8

* Esteban A, Frutos F, Tobin MJet al (1995) Acomparison of four methods of weaning patients frommechanical ventilation: Spanish Lung Failure

Collaborative Group.N Engl J Med.332(6): 345–50

* Griﬃths J, Barber VS, Morgan L, Young JD (2005)Systematic review and meta-analysis of studies of thetiming of tracheostomy in adult patients undergoingartiﬁcial ventilation Br Med J 330: 1243

* Henderson JJ, Popat MT Latto IP, Pearce AC (2004)Diﬃcult Airway Society guidelines for the management ofthe unanticipated diﬃcult intubation Anaesthesia 57(7):675–94 www.das.uk.com/guidelines/downloads.html

* Perren A, Domenighetti G, Mauri S, Genini F, Vizzardi

N (2002) Protocol-directed weaning from mechanicalventilation: clinical outcome in patients randomised for

a 30-min or 120-min trial with pressure supportventilation.Intens Care Med.28: 1058–63

* Scrase I, Woollard M (2006) Needle vs surgicalcricothyroidotomy: a short cut to eﬀective ventilation

Anaesthesia61(10): 962–74

* Young D (2009) TracMan investigators: early and latetracheostomy on 30-day mortality www.tracman.org.ukChapter 2: Advanced airway management

15

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3 Patient admission and discharge

Santhana Kannan

The critical care unit (CrCU) is one of the most

resource-intensive areas of a hospital The 233 General CrCU in

England and Wales treated nearly 81 000 patients in 2003

at a cost of around £540 million, equating to

approxi-mately £1328 per day per patient Interestingly, more

recentestimates of costs have quoted either similar or

slightly lower ﬁgures! A typical general ward patient

costs £195 per day Consider this along with the fact

that the average mortality in critical care is around 30%

with another 10–20% surviving less than 1 year post

discharge, it is not diﬃcult to see why the available

resources have to be used in the best possible way

In comparison to non-intensive care treatment, the

incremental cost per quality adjusted life year gained

of treatment in CrCU is £7010 A recent study

esti-mated that adult intensive care represents good value

for money in terms of lower cost per quality adjusted

life year when compared to statin therapy

CrCU is considered to be a ‘safe haven’ by most

physicians, surgeons and anaesthetists leading to a

per-sistent demand for beds Resource crunch leads to

opera-tional levels of high bed occupancy rates in the region of

90% Hence it is essential that robust admission and

discharge procedures exist to maximize resource

utiliza-tion The increasing life expectancy, higher complexity

of therapeutic interventions, higher expectations from

the public and unpredictability of arrival of critically ill

patients add to the challenge This chapter will provide

an outline of indications of admission to CrCU, decision

to admit, a suggested admission procedure, options

when the unit is full, indications for patient discharge

and a suggested discharge procedure Related issues are

covered inChapters 1, 4, 5, 6, 7, 13, 21 and 22

Who should be admitted?

Ideally, patients who will beneﬁt from critical care

should be admitted and those who wouldn’t shouldn’t!

The diﬃculty lies in the accuracy of predicting the

outcome The degree of dependency of patients incritical care is classiﬁed as follows (Table 3.1)

If a patient needs invasive ventilation (e.g for acutesevere asthma), they will be classified as level 3 eventhough it is only single organ support In general, highdependency units care for level 2 patients Patients onnon-invasive ventilation alone are typically classified aslevel 2 This classification is used to aid nurse staffing.Some factors influencing decision to admit patient ornot are outlined in Fig 3.1

Indications for admission

Ideal scoring systems

It would be helpful if there was a simple scoring systemwhich was 100% sensitive and 100% speciﬁc in identify-ing patients who will beneﬁt from admission to criticalcare To date, no such system exists Reasons for limi-tations include the high number of variables that deter-mine patient outcome and variable predictive value fordata collected at the beginning of critical illness

Potential drawbacks of scoring systems

There areearly warning scoring systems and some labinvestigations (e.g Procalcitonin) proposed in aneﬀort to aid early identiﬁcation of critical illness.These work on the assumption that early interventionwill minimize complications and improve outcome Ithas been shown that early goal-directed therapy incritically ill patients can improve outcome However,

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it is likely that there is a window of opportunity

beyond which this may lose its full beneﬁt

There is one other problem with the scoring

sys-tems A 90%probability of survival still means that 10%

of patients will die Conversely, a 90% probability of

mortality still means that 10% will survive It is

impos-sible to know which particular group the patient in

question will fall under However, the above statistics

may aid decisions on issues such as treatment

limita-tion and withdrawal For example, the outcome in

neutropenic sepsis requiring invasive ventilation and

inotropes has a survival of around 10–15% The

majority of such patients could be in the younger age

group with minimal co-morbidities Hence, such

patients are still treated in the hope that the survivorwill have successful outcome with chemotherapy

Although the correlation betweenadvancing age andmortality in hospital patients is well known, age aloneshould not be a criterion for admission to critical care

An 80-year-old active patient with no known morbidities is likely to have a better prognosis than a55-year-old patient with history of myocardial infarc-tion, diabetes, renal failure and limited exercise tolerancewhen treated for respiratory failure due to pneumonia It

co-is also important that probability of survival to warddischarge is not used as a sole criterion for admission

to critical care Return to an acceptable quality of lifeshould be aimed for Deﬁning this criterion has highpotential for disagreement between patients, relativesand physicians This can present diﬃcult ethical andlegal issues It is important that all decisions and discus-sions with relatives are clearly documented The decisionmaking process should be based on evidence or acceptedguidelines The patient and relatives should be given anopportunity to clarify any doubts and also consult bodiessuch as Patient Advocate Liaison Service

Some interventions including certain drugsinvolvehigh direct costs In order to ensure that costdoes not become a sole criterion for provision ofpotentially beneﬁcial treatment, it is essential thatinstitutional guidelines and policies are in place.These could be in the form of a checklist where adrug is authorized if certain criteria are met

Decision to admit (Fig 3.1)

The critical care consultant in charge should havethe responsibility and be informed for all admissions,discharges and transfers The consultant may choose

to decide based on input from other members ofthe critical care team including Critical CareOutreach Outreach typically consists of experiencedcritical care nurses The Department of HealthComp rehen sive Critical Car e docu ment (2000 ) iden-

tiﬁed three main aims for outreach services: to avertadmissions (or to ensure that admissions are timely)

by identifying patients who are deteriorating; to enabledischarges; and to share critical care skills

Management of critically ill patients when unit is full

The admission criteria to the critical care unit should

be based on need of the patient rather than bed ability This means that if a patient is deemed not a

avail-Table 3.1 Classi ﬁcation of levels of patient care

Level Description

Nurse topatientratio

Level 0 Patients whose needs can be met

through normal ward care

1 : 6

Level 1 Patients whose needs are greater

than what can provided by

normal ward care, but may be

met on acute wards with

support from critical care team

1 : 4

Level 2 Patients needing support for a

single failing organ system

1 : 2

Level 3 Patients needing advanced

respiratory support alone, or

basic respiratory support

together with support of at

least two organ systems

1 : 1

Table 3.2 Indications for admission to critical care

Invasive or non-invasive ventilation for acute respiratory failure

Optimization of ﬂuid balance requiring invasive procedures

Post-operative monitoring (cardiac surgery, neurosurgery, major

vascular surgery, long surgical or interventional procedures,

massive blood loss, multiple co-morbidities with low systemic

reserve)

Haemodynamic instability requiring inotropic support

Potential for deterioration (e.g airway swelling, metabolic disorders,

coagulopathies, hypoxaemia, hypercarbia, hypovolaemia,

intracranial events, acute arrhythmias)

Interventions that cannot be performed in a general ward –

continuous veno-venous haemo ﬁltration, extra-corporeal gas

exchange

Chapter 3: Patient admission and discharge

17

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candidate for critical care, this should be applied even

if a bed is available Conversely, if a patient is

consid-ered a candidate for critical care, all measures should

be taken to accommodate the patient in the critical

care environment as early as possible

Methods of looking after critically ill

patients without CrCU beds

A number of steps could be taken if a critically ill

patient presents in the absence of an available bed in

the unit The choice is often determined by the severity

of illness, haemodynamic stability, ease of

oxygena-tion, necessity of advanced interventions, time of the

day and availability of medical staﬀ

(1)Transfer out to another unit – usually done in

daytime hours, if the patient is haemodynamically

stable and/or not too diﬃcult to oxygenate If

deﬁnitive therapy is only available in another hospital

(e.g neurosurgery), then early transfer is essential

(2)Stabilization in the theatre recovery area – aftercritical care nurses, the theatre recovery staﬀ arebest placed to manage a critically ill patient.Limitations include management of ventilatorsand limited ability to provide interventions such ascontinuous haemoﬁltration in the recovery area.This option is usually chosen out of hours or if abed is imminently going to be available in the unit.(3)Earlier than planned discharge of eligiblepatients – it is a common practice to dischargepatients from critical care after the morning round.However, some patients may be suitable fordischarge at other times Discharge to the ward after

2200 h should be an exception rather than the rule.(4)Manipulation of nursing staﬀ workload –exceptionally, the number of nurse shift leaderscould be reduced so that one of them couldaccommodate an additional critically ill patient.The risk and beneﬁt of this intervention should bediscussed between the nurse in charge and

Good systemic reserve

of life (e.g severe brain damage)

Low survival probability, poor systemic reserve and premorbid status

Advance Directives, Documented treatment limitations

Stable patients with a high risk of acute deterioration

Interventions needing CrCU environment (e.g CVVH, pre- optimization, ventilation)

High probability

of hospital discharge

Factors influencing decision to accept [or refuse] admission

Fig 3.1 Factors in ﬂuencing decision to accept (or refuse) admission to critical care.

18

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consultant so that an optimum nursing skill mix is

still available Any such measures should ensure

that adequate numbers of staﬀ are available for all

future shifts

(5)Accommodate in critical care with the aid of

outreach and/or medical staﬀ – this option is

chosen if the staﬀ availability is likely to improve

within a few hours or if the patient presents late at

night when risk of transfer is deemed to be higher

(6)Utilize services of other monitored beds in the

hospital (e.g medical assessment unit, surgical

assessment unit, coronary care unit) – these areas

have their own limitations in terms of level of

monitoring and nursing skills However, in certain

circumstances, and depending upon the type of

patient, their services could be used as an interim

measure

(7)Utilize the resuscitation room in Emergency

Department – some ED nurses are trained in the

management of critically ill patients This option is

least desirable since it has the potential to block ED

beds

Decision not to admit

Patients who would potentially beneﬁt from critical

care but have issued advance directives which prohibit

the use of such interventions should have their views

respected These may still mean that they are admitted

but have treatment limitations in place to take into

account their wishes Similarly, patients with a‘Do not

resuscitate’ order in place may still be admitted to

critical care with treatment limitations

Patients who are deemed to have irreversible or

severe organ system damage which is likely to prevent

reasonable recovery should have treatment limits in

place Some patients discharged from critical care may

not be suitable for readmission to critical care in the

event of deterioration (e.g advanced lung disease with

prolonged weaning) Adequate communication with

the patient, relatives and other team members is

essen-tial in such situations

Admission procedure

Adequatecommunication is vital The priority of

indi-vidual patient will vary depending upon their systemic

status For example a patient with potassium of

6.5 mmol/l unresponsive to standard measures will

need urgent renal replacement therapy However, a

patient who is stable after major surgery for

post-operative monitoring could wait in the recovery areafor a short period before a bed is ready

All patients who are admitted to the unit should behanded over to one of the critical care doctors Thisshould include a summary of the history, treatmentreceived and any planned investigations, etc Thepatient should then have a relevant detailed clinicalexamination Appropriate documentation regardingthe treatment plans should be made Inadequate doc-umentation and secondary errors are an importantreason for weak defence in the event of litigation It

is helpful to have a‘critical care admission template’ sothat any relevant details are not missed As soon aspossible, the patient and/or the relatives should begiven an explanation of current condition and plan

of treatment This will also be the ideal opportunity

to address any concerns

Discharge

A timely discharge from the CrCU is just as important

as timely admission

Risks of delayed discharge

Risks solely attributable to prolonged stay in criticalcare include potential cross-infection and psycholog-ical disturbances Since a critical care bed is severaltimes costlier than a ward bed, it is not a good use ofresource if patients are kept longer than necessary.Also, with the high demand on beds, it is possiblethat the admission of a more deserving patient might

be delayed as a result of bed blockages Delayed charge to wards also leads to cancellation of majorelective surgery It is essential that appropriate systemsare in place to minimize delayed discharges

dis-Outcomes of ‘premature’ discharge

On the other hand, data also show that about 5% ofpatients are probably‘prematurely’ discharged It hasbeen estimated that about a third of these patientshave a higher mortality and might not have died ifthey had stayed in the critical care for 48 hours If eachpatient has their bed‘held’ in the ward, there will be nodelay when a decision for their discharge is made.However, most hospitals in the UK and elsewhere donot have this facility due to resource issues If theincidence of ‘delayed discharges’ from CrCU is lowand the number of cancelled elective surgery patientsdue to non-availability of CrCU beds is high, it willprobably be more economical to‘hold’ a ward bed for

Chapter 3: Patient admission and discharge

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selective CrCU patients at least for the ﬁrst 24–48

hours (e.g elective post-operative patients)

Discharge criteria

Eﬀorts have been made to predict likelihood of a

successful discharge, i.e the patient does not

deterio-rate after discharge Like any scoring system, they are

not 100% sensitive or speciﬁc and hence cannot be

used in a given patient They could be applied to

estimate the probability of deterioration which in

turn could decide on the degree of follow up

Discharge criteria commonly used are provided in

Table 3.3

Discharge procedure

If astep down unit (e.g level 1 unit) is available, the

patient could be sent there prior to transfer to a

normal ward Like admissions, the decision to

dis-charge should be the responsibility of the

consul-tant The availability of outreach has certainly

inﬂuenced decisions regarding discharge The ability

to follow up patients is an important part of the

critical care process Several units have long-term

follow-up clinics which aid in the management of

potentially diﬃcult and challenging post-critical care

phase of survivors

It is desirable to have acritical care discharge

tem-plate which has the details such as summary of critical

care stay, signiﬁcant events, procedures and

investiga-tions, infection risk, current medicainvestiga-tions, follow-up

medications, follow-up investigations and suggestions

for further management including any restrictions on

readmission to critical care It is important that a warddoctor receives ahandover of the patient when trans-ferred This should ensure that the parent team is keptinformed about the developments The patient’sGeneral Practitioner should be informed of patient’sadmission and information of what to expect should

be provided during the convalescence An explanation

tothe patient and relatives also helps to alleviate ety about ward care

anxi-Key points

* Critical care is a complex combination of highdemand, proportionately higher mortality andhigher cost Appropriate systems should be inplace so that this resource is optimally used

* Lack of critical care beds should not delaynecessary treatment

* Advance decisions with regard to suitability forcritical care and‘Do not resuscitate’ orders help inminimizing communication gaps and sub-optimalcare

* Scoring systems cannot accurately predictoutcome in an individual patient They could beused to aid decisions with regard to treatmentlimitations and withdrawal

* Timely discharge is as important as timelyadmission to critical care

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