ACUTE MEDICAL EMERGENCIES - PART 1 pdf

PART II: STRUCTURED APPROACHChapter 3 A structured approach to medical emergencies 15PART III: PRESENTING COMPLAINTSChapter 8 The patient with breathing difficulties 83 Chapter 11 The pa

ACUTE MEDICAL EMERGENCIES

USEFUL WEBSITE ADDRESSES

Advanced Life Support Group http://www.alsg.org

Best Evidence in Emergency Medicine http://www.bestbets.org

Evidence based on-call http://cebm.jr2.ox.ac.uk/eboc/eboc.htmlRoyal College of Physicians http://www.rcplondon.ac.uk/

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ACUTE MEDICAL EMERGENCIES

The Practical Approach

Advanced Life Support Group

© BMJ Books 2001 BMJ Books is an imprint of the BMJ Publishing Group

All rights reserved No part of this publication may be reproduced, stored in a retrieval system, or mitted, in any form or by any means, electronic, mechanical, photocopying, recording and/or otherwise,

trans-without the prior written permission of the publishers.

First published in 2001

by BMJ Books, BMA House, Tavistock Square,

London WC1H 9JR

www.bmjbooks.com

British Library Cataloguing in Publication Data

A catalogue record for this book is available from the British Library

ISBN 0-7279-1464-2

Cover design by Goodall James, Bournemouth, Dorset Typeset by Phoenix Photosetting, Chatham, Kent Printed and bound by J W Arrowsmith Ltd, Bristol

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PART II: STRUCTURED APPROACHChapter 3 A structured approach to medical emergencies 15

PART III: PRESENTING COMPLAINTSChapter 8 The patient with breathing difficulties 83

Chapter 11 The patient with altered conscious level 147

Chapter 16 The patient with hot red legs or cold white legs 237Chapter 17 The patient with hot and/or swollen joints 245

v

PART IV: FAILURES

PART V: SPECIAL CIRCUMSTANCES

Chapter 21 Transportation of the seriously ill patient 309

PART VI: INTERPRETATION OF EMERGENCY INVESTIGATIONS

Chapter 22 Acid–base balance and blood gas analysis 323

PART VII: PRACTICAL PROCEDURES

Chapter 27 Practical procedures: airway and breathing 391

PART VIII: APPENDIX

Drugs commonly used in the management of medical emergencies 425

Answers to Time Out Questions 429

CONTENTS

vi

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WORKING GROUP

P Driscoll Emergency Medicine, Manchester

R Kishen Anaesthesia/ICU, London

K Mackway-Jones Emergency Medicine, Manchester

G McMahon Emergency Medicine, Manchester

F Morris Emergency Medicine, Sheffield

TD Wardle General Medicine, Chester

B Waters Anaesthesia/ICU, North Wales

J Whitaker Care of the Elderly, Harrogate

S Wieteska ALSG, Manchester

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M Bhushan Dermatology, Manchester

P Davies Emergency Medicine, Bristol

P Driscoll Emergency Medicine, Manchester

CEM Griffiths Dermatology, Manchester

C Gwinnutt Anaesthesia, Manchester

J Hanson Emergency Medicine, Preston

R Kishen Anaesthesia/ICU, London

K Mackway-Jones Emergency Medicine, Manchester

A McGowan Emergency Medicine, Leeds

G McMahon Emergency Medicine, Manchester

F Morris Emergency Medicine, Sheffield

C Moulton Emergency Medicine, Bolton

K Reynard Emergency Medicine, Manchester

P Sammy General Practice, Manchester

P Terry Emergency Medicine, Manchester

D Wallis Emergency Medicine, London

TD Wardle General Medicine, Chester

B Waters Anaesthesia/ICU, North Wales

J Whitaker Care of the Elderly, Harrogateviii

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This book has been written to enable health care workers to understand the principles ofmanaging an acute medical emergency safely and effectively To achieve this aim it pro-vides a structured approach to medical emergencies, describing relevant pathophysiologythat will also help to explain physical signs and the rationale behind treatment The firstedition of this manual (written by Terry Wardle) has undergone significant modificationdirected by the working group and also, in particular, candidates from the firstMedicALS courses The requirements of these contributing doctors has meant that thecontents and associated information may initially appear skewed – but this is evidencebased

Most text books are out of date by the time they are published – this manual is ent in that it is both pragmatic and dynamic Medicine is a rapidly evolving disciplineand in order to ensure that this manual remains dynamic and up to date, reference websites are available to ensure that the reader has constant access to relevant information.This will facilitate continual professional development that is the responsibility of theindividual

differ-The book provides a structured approach that is applicable to all aspects of acutemedicine, ensures the early recognition of signs of critical illness and will empower theindividual to take immediate and appropriate action

The text alone cannot provide all the necessary knowledge and skills to manage anacute medical emergency, therefore readers are encouraged to attend the MedicALScourse to further their theoretical and practical knowledge

This book will continue to change to include new evidence based practices and cols to ensure a solid and safe foundation of knowledge and skills in this era of clinicalgovernance

proto-Continued professional development is mandatory for all medical practitioners Thismanual and the associated course will ensure both new knowledge acquisition andrevision – and stimulate further learning

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We would like to thank members of faculty and candidates who have completed theMedicALS course for their constructive comments that have shaped both the text andthe course

We would also like to thank Helen Carruthers, MMAA for her work on many of thefigures within the text

Finally, our thanks to the members of staff both at the BMJ and within ALSG for theiron-going support and invaluable assistance in the production of this text

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INTRODUCTION

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Introduction

INTRODUCTION

After reading this chapter you will understand:

● the current problems in the assessment of acute medical emergencies

● the need for a structured approach to the medical patient

THE PROBLEM

A medical emergency can arise in any patient, under a variety of circumstances, forexample:

● a previously fit individual

● acute on chronic illness

● post surgical

● precipitating or modifying the response to trauma

The acute problem can be directly or indirectly related to the presenting condition,

an associated complication, any treatment instituted, and the result of inappropriateaction

Furthermore, with the increase in the elderly population there is a correspondingincrease in the number and complexity of medical problems The management of suchpatients is compromised by the drive to cut costs, but maintain cost effective care; ensureefficient bed usage; reduce junior doctors’ hours; and increase medical specialisation.There is an annual increase of emergency admissions in excess of 5% and they accountfor over 40% of all acute National Health Service beds In the UK the mean hospital bedcomplement is 641, but only 186 are allocated for medical patients with an average 95%

of these housing medical emergencies

The common acute conditions can be broadly classified according to the body systemaffected (Table 1.1)

Key point

Inappropriate action costs lives

3Reading: 15 minutes

Table 1.1. Classification of medical emergencies

This information may be broken down further to reveal the common reasons foradmission:

● myocardial infarction

● stroke

● cardiac failure

● acute exacerbation of asthma

● acute exacerbation of chronic obstructive pulmonary disease

● deliberate self harm

Despite the fact that these are common conditions, frequent management errors andinappropriate action result in preventable morbidity and mortality

A recent risk management study examined the care of medical emergencies One ormore avoidable serious adverse clinical incidents were reported Common mistakes arelisted in the box

This was only a small study but of the 29 patients who died, 20 would have had a goodchance of long term survival with appropriate management In addition, of the 11patients who survived, three were left with serious neurological defects, three underwentavoidable intestinal resection and four patients suffered unnecessary prolonged hospitaladmission

Diagnostic errors were made in 80% of patients because of inadequate interpretation

of the clinical picture and initial investigations These errors are given in the box

Errors in patient assessment

● Available clinical evidence incorrectly interpreted

● Failure to identify and focus on very sick patients

● Investigations misread or ignored

● Radiological evidence missed

● Standard procedures not followed

● Inadequate assessment or treatment

● Discharge from hospital without proper assessment

Common mistakes

● Failure to recognise and treat serious infection

● Error in investigating – acute headache

acute breathlessness epilepsy

The overall problems were identified as follows:

● medical emergencies were not assessed by sufficiently experienced staff

● a second opinion was not obtained

● assessment was inadequately performed before discharge

● X-rays were not discussed with radiologists

● protocols were not used for standard conditions

Furthermore, the assessment of medical patients for intensive care was either plete, inappropriate or too late to prevent increased morbidity and mortality

incom-Therefore, there are problems in the fundamental areas of medical patient care, i.e.

clinical examination, requesting appropriate investigations and their correct tion, and communication However, probably most important of all, knowing when andwho to ask for help One answer to this important problem is to provide a structuredapproach to patient assessment that will facilitate problem identification and prioritisemanagement

interpreta-All that is required to manage medical emergencies is focused knowledge and basicskills These will ensure prompt accurate assessment and improve patient outcome.Avoidable deaths are due to inappropriate management, indecision or delays in treat-ment Another important issue is the time patients wait for appropriate medical care.Theaverage time for initial review after admission is 30 minutes with a further 130 minutespassing before definitive management occurs

In the United Kingdom, numerous studies have shown that specialist care is betterthan that provided by a generalist; for example, prompt review by a respiratory physicianhas been shown to reduce both morbidity and mortality from asthma The mortalityfrom gastrointestinal haemorrhage falls from 40% to approximately 5% if the manage-ment is provided by a specialist in gastroenterology Further supportive evidence hasbeen provided by studies in the United States where mortality from myocardial infarc-tion or unstable angina was greater in patients managed by generalists

However, there are insufficient numbers of “specialists” to manage all of these tions and some will require review by a general physician

condi-Thus, physicians need to know how to manage medical emergencies This course willteach a structured approach for assessment that will enable you to deliver safe, effective,and appropriate care

Traditional medical teaching dictates that a history should always be taken from thepatient before the clinical examination This will subsequently allow a diagnosis ordifferential diagnosis to be postulated and dictate the investigations required.Unfortunately this approach is not always possible; for example, trying to obtain ahistory from a patient who presents with breathlessness may not only exacerbate the con-dition but also delay crucial therapy

This course has been developed by observing how experienced physicians managemedical emergencies The results have shown quite an interesting cultural shift Most of

us, as we approach the patient, quickly scan for any obvious physical signs, for examplebreathlessness, and then focus our attention on the symptoms until the diagnosis is iden-tified Only when the patient’s symptoms have been improved can a history be taken andthe remainder of the examination performed This process has been refined and for-malised to produce a structured approach to patient assessment.This will ensure that themost immediately life threatening problems are identified early and treated promptly Allother problems will be identified subsequently as part of the overall classical approach tothe medical patient, i.e taking a history and examining the patient

However, if the patient deteriorates at any stage a reassessment should start at thebeginning Thus, this structured approach considers the conditions that are most likely

to kill the patient If these are excluded the physician will then have time to approach thepatient in a traditional fashion

INTRODUCTION

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The key principles of MedicALS are shown in the box.

SUMMARY

The number and complexity of acute medical emergencies are increasing However, themajority of mistakes result from a failure to assess acutely ill patients, interpret relevantinvestigations, and provide appropriate management This manual and the associatedcourse will equip you with both knowledge and skills to overcome these difficulties andprovide safe, effective, and appropriate care

Key principles of MedicALS

● Do no further harm

● Focused knowledge and basic skills are essential

● A structured approach will identify problems and prioritise management

● Prompt accurate assessment improves patient outcome

ACUTE MEDICAL EMERGENCIES:THE PRACTICAL APPROACH

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2

Recognition of the medical emergency

OBJECTIVES

After reading this chapter you will be able to:

● understand the clinical features of potential respiratory, cardiac, and neurologicalfailure

● describe these clinical features and use them to form the basis of the primary assessment.Irrespective of underlying pathology, the acute medical patient will die from failure ofeither the respiratory, circulatory or central neurological systems, or a combination of

these It is therefore of paramount importance that the physician can recognise

poten-tial failure of these three systems as early recognition and management will reduce

morbidity and mortality The ultimate failure, a cardiorespiratory arrest, is too large atopic to be added to this course

This chapter will provide an overview of the clinical assessment of patients with tial respiratory, circulatory, and neurological failure.The chapters in Part II will then usethis format to develop an in-depth assessment that will eventually produce a structuredapproach to the patient with a medical emergency

poten-RECOGNITION OF POTENTIAL RESPIRATORY FAILURE

This can be quickly assessed by examining the rate, effort, symmetry, and effectiveness

of breathing

Respiratory rate

The normal adult respiratory rate is 14–20 breaths per minute.Tachypnoea (greater than

30 breaths per minute at rest) indicates that increased ventilation is needed because ofhypoxia associated with either disease affecting the airway, lung or circulation, or meta-bolic acidosis Similarly, a respiratory rate ≤10 breaths per minute is an indication forventilatory support

Effort of respiration

If the patient can count to 10 in one breath there is usually no significant underlyingrespiratory problem Other features which suggest increased respiratory effort are

7Reading: 15 minutes

intercostal and subcostal recession, accessory muscle use, and a hoarse inspiratory noisewhile breathing (stridor; this is a sign of laryngeal/tracheal obstruction) In severeobstruction, stridor may also occur on expiration but the inspiratory component is usu-ally more pronounced In contrast, lower airway narrowing results in either wheezingand/or a prolonged expiratory phase.

find-Pulse oximetry can be used to measure the arterial oxygen saturation (SaO2) These

instruments are inaccurate when the SaO2is below 70%, there is poor peripheral sion, and in the presence of carboxyhaemoglobin

perfu-Effects of respiratory inadequacy on other organs

Heart rate

Hypoxaemia produces a tachycardia; however, anxiety and fever will also contribute tothis physical sign, making it non-specific Severe or prolonged hypoxia eventually willlead to a bradycardia – a preterminal sign

Key point

A silent chest is an extremely worrying sign

ACUTE MEDICAL EMERGENCIES:THE PRACTICAL APPROACH

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Effectiveness of circulation

Pulse

Although blood pressure is maintained until shock is very severe (loss of at least onethird of the circulating volume) a rapid assessment of perfusion can be gained byexamining peripheral and central pulses The radial pulse will disappear if the systolicblood pressure is below 80 mm Hg Thus the combination of absent peripheral pulsesand weak central pulses is a sinister sign indicating advanced shock and profoundhypotension

Perfusion

Capillary refill following pressure on a digit for five seconds should normally occurwithin two seconds A longer time indicates poor skin perfusion However, this sign is notvalid if the patient is hypothermic

oppo-Conscious level

A rapid assessment of the patient’s conscious level can be made by assigning the patient

to one of the categories shown in the box

RECOGNITION OF THE MEDICAL EMERGENCY

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A painful stimulus should be applied by pressure over the superior orbital ridge Anadult who either only responds to pain or is unconscious has a significant degree of comaequivalent to 8 or less on the Glasgow Coma Scale.

Posture

Abnormal posturing such as decorticate (flexed arms, extended legs) or decerebrate(extended arms, extended legs) is a sinister sign of brain dysfunction A painful stimulusmay be necessary to elicit these signs

Pupils

Many drugs and cerebral lesions have effects on pupil size and reactions The mostimportant pupillary signs to seek are dilation, unreactivity, and inequality.These indicatepossible serious brain disorders

Respiratory effects of central neurological failure on other systems

There are several recognisable breathing patterns associated with raised intracranialpressure However, they are often changeable and may vary from hyperventilation toperiodic breathing and apnoea The presence of any abnormal respiratory pattern in apatient with coma suggests brain stem dysfunction

Circulatory effects of central neurological failure

Systemic hypertension with sinus bradycardia indicates compression of the medullaoblongata caused by herniation of the cerebellar tonsils through the foramen magnum.This is a late and preterminal sign

TIME OUT 2.1

List the clinical features that can be used to diagnose potential failure of:

a respiration

b circulation

c central neurological function

Note how many features assess more than one system Rearrange your list of clinicalfeatures into a logical order to produce a system for rapid assessment

AVPU grading of consciousness

In the acutely ill medical patient a rapid examination will detect potential respiratory,circulatory, and neurological failure The clinical features are:

● respiratory – rate, effort, and effectiveness of respiration

● circulatory – heart rate and effectiveness

● neurological – conscious level, posture, and pupils

These features will form the framework of the primary assessment The componentswill be discussed in detail in Part II

RECOGNITION OF THE MEDICAL EMERGENCY

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