Ebook Marinos the CIU book (4th edition): Part 1

(BQ) Part 1 book Marinos the CIU book presents the following contents: Vascular access, preventive practices in the ICU, hemodynamic monitoring, disorders of circulatory flow, cardiac emergencies, blood components, acute respiratory failure, mechanical ventilation.

The ICU

Book

FOURTH EDITION

Paul L Marino, MD, PhD, FCCM

Clinical Associate Professor

Weill Cornell Medical College

New York, New York

Illustrations by Patricia Gast

Marino’s The ICU Book FOURTH EDITION

Health

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10 9 8 7 6 5 4 3 2 1

To Daniel Joseph Marino,

my 26-year-old son, who has become the best friend

I hoped he would be.

I would especially commend the physician who,

in acute diseases,

by which the bulk of mankind are cut off,

conducts the treatment better than others.

H IPPOCRATES

Preface to Fourth Edition

The fourth edition of The ICU Book marks its 23rd year as a fundamental sourcebook forthe care of critically ill patients This edition continues the original intent to provide a

“generic textbook” that presents fundamental concepts and patient care practices thatcan be used in any adult intensive care unit, regardless of the specialty focus of the unit.Highly specialized topics, such as obstetrical emergencies, burn care, and traumaticinjuries, are left to more qualified specialty textbooks

This edition has been reorganized and completely rewritten, with updated references andclinical practice guidelines included at the end of each chapter The text is supplemented

by 246 original illustrations and 199 original tables, and five new chapters have beenadded: Vascular Catheters (Chapter 1), Occupational Exposures (Chapter 4), AlternateModes of Ventilation (Chapter 27), Pancreatitis and Liver Failure (Chapter 39), andNonpharmaceutical Toxidromes (Chapter 55) Each chapter ends with a brief sectionentitled “A Final Word,” which highlights an insight or emphasizes the salient informationpresented in the chapter

The ICU Book is unique in that it represents the voice of a single author, which provides auniformity in style and conceptual framework While some bias is inevitable in such anendeavor, the opinions expressed in this book are rooted in experimental observationsrather than anecdotal experiences, and the hope is that any remaining bias is tolerable

Acknowledgements are few but well deserved First to Patricia Gast, who is responsiblefor all the illustrations and page layouts in this book Her talent, patience, and counselhave been an invaluable aid to this author and this work Also to Brian Brown and NicoleDernoski, my longtime editors, for their trust and enduring support

SECTION I

Vascular Access

1 Vascular Catheters

2 Central Venous Access

3 The Indwelling Vascular Catheter

7 Arterial Pressure Monitoring

8 The Pulmonary Artery Catheter

9 Cardiovascular Performance

10 Systemic Oxygenation

SECTION IV

Disorders of Circulatory Flow

11 Hemorrhage and Hypovolemia

12 Colloid & Crystalloid Resuscitation

13 Acute Heart Failure in the ICU

14 Inflammatory Shock Syndromes

SECTION VI

Blood Components

18 Anemia and Red Blood Cell Transfusions

19 Platelets and Plasma

SECTION VII

Acute Respiratory Failure

20 Hypoxemia and Hypercapnia

21 Oximetry and Capnometry

22 Oxygen Therapy

23 Acute Respiratory Distress Syndrome

24 Asthma and COPD in the ICU

SECTION VIII

Mechanical Ventilation

25 Positive Pressure Ventilation

26 Conventional Modes of Ventilation

27 Alternate Modes of Ventilation

28 The Ventilator-Dependent Patient

Renal and Electrolyte Disorders

34 Acute Kidney Injury

SECTION XI

The Abdomen & Pelvis

39 Pancreatitis & Liver Failure

40 Abdominal Infections in the ICU

41 Urinary Tract Infections in the ICU

SECTION XII

Disorders of Body Temperature

42 Hyperthermia & Hypothermia

43 Fever in the ICU

Critical Care Drug Therapy

51 Analgesia and Sedation in the ICU

1 Units and Conversions

2 Selected Reference Ranges

3 Additional Formulas

Index

Section I

VASCULAR ACCESS

He who works with his hands is a laborer

He who works with his head and his hands is a craftsman

Louis Nizer Between You and Me

1948

of his superiors, and his actions were perceived as reckless and even suicidal Upondismissal, he was told that “such methods are good for a circus but not for a respectedhospital”(1) Forssman went on to become a country doctor, but his achievement invascular cannulation was finally recognized in 1956 when he was awarded the Nobel Prize

in Medicine for performing the first right-heart catheterization in a human subject

Werner Forssman’s self-catheterization was a departure from the standard use of needlesand rigid metal cannulas for vascular access, and it marked the beginning of the modernera of vascular cannulation, which is characterized by the use of flexible plastic catheterslike the ones described in this chapter

CATHETER BASICS

Catheter Material

Vascular catheters are made of synthetic polymers that are chemically inert,biocompatible, and resistant to chemical and thermal degradation The most widely usedpolymers are polyurethane and silicone

Polyurethane

Polyurethane is a versatile polymer that can act as a solid (e.g., the solid tires on lawnmowers are made of polyurethane) and can be modified to exhibit elasticity (e.g.,Spandex fibers used in stretchable clothing are made of modified polyurethane) Thepolyurethane in vascular catheters provides enough tensile strength to allow catheters topass through the skin and subcutaneous tissues without kinking Because this rigidity canalso promote vascular injury, polyurethane catheters are used for short-term vascularcannulation Most of the vascular catheters you will use in the ICU are made ofpolyurethane, including peripheral vascular catheters (arterial and venous), centralvenous catheters, and pulmonary artery catheters

Silicone

Silicone is a polymer that contains the chemical element silicon together with hydrogen,oxygen, and carbon Silicone is more pliable than poly-urethane (e.g., the nipple on babybottles is made of silicone), and this reduces the risk of catheter-induced vascular injury.Silicone catheters are used for long-term vascular access (weeks to months), such as thatrequired for prolonged administration of chemotherapy, antibiotics, and parenteralnutrition solutions in outpatients The only silicone-based catheters inserted in the ICUsetting are peripherally-inserted central venous catheters (PICCs) Because of theirpliability, silicone catheters cannot be inserted percutaneously without the aid of aguidewire or introducer sheath

for gauge sizes and corresponding outside diameters in peripheral catheters (2) Notethat each gauge size is associated with a range of outside diameters (actual OD), andfurther that there is no fixed relationship between the actual (measured) and nominaloutside diameters Thus, the only way to determine the actual outside diameter of acatheter is to consult the manufacturer Gauge sizes are typically used for peripheralcatheters, and for the infusion channels of multilumen catheters.

French Size

The French system of sizing vascular catheters (named after the country of origin) issuperior to the gauge system because of its simplicity and uniformity The French scalebegins at zero, and each increment of one French unit represents an increase of 1/3(0.33) millimeter in outer diameter (3): i.e., French size × 0.33 = outside diameter (mm).Thus, a catheter that is 5 French units in size will have an outer diameter of 5 × 0.33 =1.65 mm (A table of French sizes and corresponding outside diameters is included inAppendix 2 in the rear of the book.) French sizes can increase indefinitely, but mostvascular catheters are between 4 French and 10 French in size French sizes are typicallyused for multilumen catheters and for large-bore single lumen catheters (like introducersheaths, de-scribed later in the chapter)

Table 1.1 Gauge Sizes & Outside Diameters for Peripheral Catheters †

The properties of flow through rigid tubes was first described by a Ger-man physiologist(Gotthif Hagen) and a French physician (Jean Louis Marie Poiseuille) workingindependently in the mid-19th century They both observed that flow (Q) through rigidtubes is a function of the inner radius of the tube (r), the length of the tube (L) and theviscosity of the fluid (µ) Their observations are expressed in the equation shown below,which is known as the Hagen-Poiseuille equation (4).

This equation states that the steady flow rate (Q) in a rigid tube is directly related to thefourth power of the inner radius of the tube (r4), and is inversely related to the length ofthe tube (L) and the viscosity of the fluid (µ) The term enclosed in parentheses(≠r4/8µL) is equivalent to the reciprocal of resistance (1/R, as in equation 1.1), so theresistance to flow can be expressed as R = 8µL/≠r4

Since the Hagen-Poiseuille equation applies to flow through rigid tubes, it can be used todescribe flow through vascular catheters, and how the dimensions of a catheter caninfluence the flow rate (see next)

Inner Radius and Flow

According to the Hagen-Poiseuille equation, the inner radius of a catheter has a profoundinfluence on flow through the catheter (because flow is directly related to the fourthpower of the inner radius) This is illustrated in Figure 1.1, which shows the gravity-drivenflow of blood through catheters of similar length but varying outer diameters (5) (Instudies such as this, changes in inner and outer diameter are considered to beequivalent.) Note that the relative change in flow rate is three times greater than therelative change in catheter diameter (∅ flow/∅ diameter=3) Although the magnitude ofchange in flow in this case is less than predicted by the Hagen-Poiseuille equation (acommon observation, with possible explanations that are beyond the scope of this text),the slope of the graph in Figure 1.1 clearly shows that changes in catheter diameter have

a marked influence on flow rate

Catheter Length and Flow

The Hagen-Poiseuille equation indicates that flow through a catheter will decrease as thelength of the catheter increases, and this is shown in Figure 1.2 (6) Note that flow in thelongest (30 cm) catheter is less than half the flow rate in the shortest (5 cm) catheter; inthis case, a 600% increase in catheter length is associated with a 60% reduction incatheter flow (∅flow/∅length = 0.1) Thus, the influence of catheter length on flow rate is

proportionately less than the influence of catheter diameter on flow rate, as predicted bythe Hagen-Poiseuille equation.

Figure 1.1 Relationship between flow rate and outside diameter of a vascular catheter From Reference 5.

The comparative influence of catheter diameter and catheter length, as indicated by theHagen-Poiseuille equation and the data in Figures 1.1 and 1.2, indicates that when rapidvolume infusion is necessary, a large-bore catheter is the desired choice, and the shortestavailable large-bore catheter is the optimal choice (See Chapter 11 for more on thissubject.) The flow rates associated with a variety of vascular catheters are presented inthe re-maining sections of this chapter

FIGURE 1.2 The influence of catheter length on flow rate From Reference 6.

COMMON CATHETER DESIGNS

There are three basic types of vascular catheters: peripheral vascular catheters (arterialand venous), central venous catheters, and peripherally inserted central catheters

Peripheral Vascular Catheters

The catheters used to cannulate peripheral blood vessels in adults are typically 16–20gauge catheters that are 1–2 inches in length Peripher-al catheters are inserted using acatheter-over-needle device like the one shown in Figure 1.3 The catheter fits snuglyover the needle and has a tapered end to prevent fraying of the catheter tip duringinsertion The needle has a clear hub to visualize the “flashback” of blood that occurswhen the tip of the needle enters the lumen of a blood vessel Once flashback is evident,the catheter is advanced over the needle and into the lumen of the blood vessel

FIGURE 1.3 A catheter-over-needle device for the cannulation of peripheral blood vessels.

The characteristics of flow through peripheral catheters are demonstrated in Table 1.2

(7,8) Note the marked (almost 4-fold) increase in flow in the larger-bore 16 gaugecatheter when compared to the 20 gauge catheter and also note the significant (43%)decrease in flow rate that occurs when the length of the 18 gauge catheter is increased

by less than one inch These observations are consistent with the relationships in theHagen-Poiseuille equation, and they demonstrate the power of catheter diameter indetermining the flow capacity of vascular catheters

Table 1.2 Flow Characteristics in Peripheral Vascular Catheters

Central Venous Catheters

Cannulation of larger, more centrally placed veins (i.e., subclavian, internal jugular, andfemoral veins) is often necessary for reliable vascular access in critically ill patients Thecatheters used for this purpose, commonly known as central venous catheters, aretypically 15 to 30 cm (6 to 12 inches) in length, and have single or multiple (2–4) infusionchannels Multilumen catheters are favored in the ICU because the typical ICU patientrecquires a multitude of parenteral therapies (e.g., fluids, drugs, and nutrient mixtures),and multilumen catheters make it possible to deliver these therapies using a singlevenipuncture The use of multiple infusion channels does not increase the incidence ofcatheter-related infections (9), but the larger diameter of multilumen catheters creates

an increased risk of catheter-induced thrombosis (10)

Triple-lumen catheters like the one shown in Figure 1.4 are the consensus favorite forcentral venous access These catheters are available in diameterss of 4 French to 9French, and the 7 French size (outside diameter = 2.3 mm) is a popular choice in adults.Size 7 French triple lumen catheters typically have one 16 gauge channel and two smaller

18 gauge channels To prevent mixing of infusate solutions, the three outflow ports areseparated as depicted in Figure 1.4

The features of triple lumen catheters (7 French size) from one manufacturer are shown

i n Table 1.3 Note the much slower flow rates in the 16 gauge and 18 gauge channelswhen compared to the 16 and 18 gauge peripheral catheters in Table 1.2 This, of course,

is due to the much longer length of central venous catheters, as predicted by the Poiseuille equation There are 3 available lengths for the triple lumen catheter: theshortest (16 cm) catheters are intended for right-sided catheter insertions, while thelonger (20 cm and 30 cm) catheters are used in left-sided cannulations (because of thelonger path to the superior vena cava) The 20 cm catheter is long enough for most left-sided cannulations so (to limit catheter length tand thereby preserve flow), it seems wise

Hagen-to avoid central venous catheters that are longer than 20 cm, if possible

FIGURE 1.4 A triple-lumen central venous catheter showing the gauge size of each lumen and the outflow ports at the

distal end of the catheter.

Table 1.3 Selected Features of Triple-Lumen Central Venous Catheters

Insertion Technique

Central venous catheters are inserted by threading the catheter over a guidewire (atechnique introduced in the early 1950s and called the Seldinger technique after itsfounder) This technique is illustrated in Figure 1.5 A small bore needle (usually 20gauge) is used to probe for the target vessel When the tip of the needle enters thevessel, a long, thin wire with a flexible tip is passed through the needle and into thevessel lumen The needle is then removed, and a catheter is advanced over theguidewire and into the blood vessel When cannulating deep vessels, a larger and morerigid “dilator catheter” is first threaded over the guide-wire to create a tract thatfacilitates insertion of the vascular catheter

Antimicrobial Catheters

Central venous catheters are available with two types of antimicrobial coating: one uses

a combination of chlorhexidine and silver sulfadiazine (available from Arrow International,Reading PA), and the other uses a combination of minocycline and rifampin (availablefrom Cook Critical Care, Bloomington, IN) Each of these antimicrobial catheters hasproven effective in reducing the incidence of catheter-related septicemia (11,12)

A single multicenter study comparing both types of antimicrobial coating showed superiorresults with the minocycline-rifampin catheters (13) A design flaw in the chlorhexidine-silver sulfadiazine catheter (i.e., no antimicrobial activity on the luminal surface of thecatheter) has since been corrected, but a repeat comparison study has not beenperformed Therefore, the evidence at the present time favors the minocycline rifampincatheters as the most effective antimicrobial catheters in clinical use (12) This situationcould (and probably will) change in the future

FIGURE 1.5 The steps involved in guidewire-assisted cannulation of blood vessels (the Seldinger technique).

What are the indications for antimicrobial catheters? According to the most recentguidelines on preventing catheter-related infections (14), antimicrobial catheters should

be used if the expected duration of central venous catheterization is >5 days and if therate of catheter-related infections in your ICU is unacceptably high despite other infectioncontrol efforts

Table 1.4 Selected Features of Peripherally Inserted Central Catheters

Peripherally Inserted Central Catheters

Concern for the adverse consequences of central venous cannulation (e.g., pneumothoraxarterial puncture, poor patient acceptance) prompted the introduction of peripherallyinserted central catheters (PICCs), which are inserted in the basilic or cephalic vein in thearm (just above the antecubital fossa) and advanced into the superior vena cava (15).(Insertion of PICCs is described in the next chapter) In the ICU, PICCs are used primarilywhen traditional central venous access sites are considered risky (e.g., severethrombocytopenia) or are difficult to obtain (e.g., morbid obesity)

The characteristics of PICC devices from one manufacturer are shown in Table 1.4 Thesecatheters are smaller in diameter than central venous catheters because they areintroduced into smaller veins However, the major distinction between PICCs and centralvenous catheters is their length; i.e., the length of the catheters in Table 1.4 (50 cm and

70 cm) is at least double the length of the triple lumen catheters in Table 1.3 Thetradeoff for this added length is a reduction in flow capacity, which is evident whencomparing the flow rates in Table 1.4 and Table 1.3 Flow is particularly sluggish in thedouble lumen PICCs because of the smaller diameter of the infusion channels The flowlimitation of PICCs (especially the double lumen catheters) makes them ill-suited foraggressive volume therapy

SPECIALTY CATHETERS

The catheters described in this section are designed to perform specific tasks, and areotherwise not used for patient care These specialty devices include hemodialysiscatheters, introducer sheaths, and pulmonary art-ery catheters

Hemodialysis Catheters

One of the recognized benefits of intensive care units is the ability to provide emergenthemodialysis for patients with acute renal failure, and this is made possible by a speciallydesigned catheter like the one shown in Figure 1.6 The features of this catheter areshown in Table 1.5

Table 1.5 Selected Features of Hemodialysis Catheters

Hemodialysis catheters are the wide-body catheters of critical care, with diameters up to

16 French (5.3 mm), and they are equipped with dual 12 gauge infusion channels thatcan accommodate the high flow rates (200–300 mL/min) needed for effectivehemodialysis One channel carries blood from the patient to the dialysis membranes, andthe other channel returns the blood to the patient

Hemodialysis catheters are usually placed in the internal jugular vein and are left in placeuntil alternate access is available for dialysis Can-nulation of the subclavian vein isforbidden because of the propensity for subclavian vein stenosis (16), which hindersvenous outflow from the ipsilateral arm and thereby prevents the use of that arm forchronic hemodialysis access with an arteriovenous shunt

FIGURE 1.6 Large-bore double lumen catheter for short-term hemodialysis.

be removed and replaced with a central venous catheter, if needed, without a newvenipuncture.

Rapid Infusion

Introducer sheaths can also serve as stand-alone infusion devices by vir-tue of a sideinfusion port on the hub of the catheter The large diameter of introducer sheaths hasmade them popular as rapid infusion devices for the management of acute blood loss.When introducer sheaths are used with pressurized infusion systems, flow rates of 850mL/min have been reported (17) The use of introducer sheaths for rapid volume infusion

is revisited in Chapter 11

Pulmonary Artery Catheters

Pulmonary artery balloon-flotation catheters are highly specialized de-vices capable ofproviding as many as 16 measures of cardiovascular function and systemic oxygenation.These catheters have their own chapter (Chapter 8), so proceed there for moreinformation

A FINAL WORD

The performance of vascular catheters as infusion devices is rooted in the Hagen–Poiseuille equation, which describes the influence of catheter dimensions on flow rate.The following statements from this equation are part of the “essential knowledge base”for vascular catheters

1 Flow rate is directly related to the inner radius of a catheter (i.e., both vary in thesame direction), and is inversely related to the length of the catheter (i.e., vary inopposite directions)

2 The inner radius (lumen size) of a catheter has a much greater influence on flow ratethan the length of the catheter

3 For rapid infusion, a large bore catheter is essential, and a short, large bore catheter

is optimal

As for the performance of individual catheters, each ICU has its own stock of vascularcatheters, and you should become familiar with the sizes and flow capabilities of thecatheters that are available

1 Mueller RL, Sanborn TA The history of interventional cardiology: Cardiaccatheterization, angioplasty, and related interventions Am Heart J 1995; 129:146–172

5 de la Roche MRP, Gauthier L Rapid transfusion of packed red blood cells: effects ofdilution, pressure, and catheter size Ann Emerg Med 1993; 22:1551–1555.

6 Mateer JR, Thompson BM, Aprahamian C, et al Rapid fluid infusion with centralvenous catheters Ann Emerg Med 1983; 12:149–152

Common Catheter Designs

7 Emergency Medicine Updates (http://emupdates.com); accessed 8/1/2011

8 Dula DJ, Muller A, Donovan JW Flow rate variance of commonly used IV infusiontechniques J Trauma 1981; 21:480–481

9 McGee DC, Gould MK Preventing complications of central venous catheterization.New Engl J Med 2003; 348:1123–1133

10 Evans RS, Sharp JH, Linford LH, et al., Risk of symptomatic DVT associated withperipherally inserted central catheters Chest 2010; 138:803–810

11 Casey AL, Mermel LA, Nightingale P, Elliott TSJ Antimicrobial central venouscatheters in adults: a systematic review and meta-analysis Lancet Infect Dis 2008;8:763–776

12 Ramos ER, Reitzel R, Jiang Y, et al Clinical effectiveness and risk of emergingresistance associated with prolonged use of antibiotic-impregnated cath-eters CritCare Med 2011; 39:245–251

13 Darouche RO, Raad II, Heard SO, et al A comparison of antimicrobial-impregnatedcentral venous catheters New Engl J Med 1999; 340:1–8

14 O’Grady NP, Alexander M, Burns LA, et al, and the Healthcare Infection ControlPractices Advisory Committee (HICPAC) Guidelines for the prevention ofintravascular catheter-related infection Clin Infect Dis 2011; 52:e1–e32

(Available at www.cdc.gov/hipac/pdf/guidelines/bsi-guidelines-2011.pdf; accessed4/15/2011)

15 Ng P, Ault M, Ellrodt AG, Maldonado L Peripherally inserted central cath-eters ingeneral medicine Mayo Clin Proc 1997; 72:225–233

Specialty Catheters

16 Hernandez D, Diaz F, Rufino M, et al Subclavian vascular access stenosis in dialysispatients: Natural history and risk factors J Am Soc Nephrol 1998; 9:1507–1510

17 Barcelona SL, Vilich F, Cote CJ A comparison of flow rates and warming capabilities

of the Level 1 and Rapid Infusion System with various-size intravenous catheters.Anesth Analg 2003; 97:358–363

Chapter 2

CENTRAL VENOUS ACCESS

Good doctors leave good tracks.

J Willis Hurst, MD

Vascular access in critically ill patients often involves the insertion of long, flexiblecatheters (like those described in the last chapter) into large veins entering the thorax orabdomen; this type of central venous access is the focus of the current chapter Thepurpose of this chapter is not to teach you the technique of central venous cannulation(which must be mastered at the bedside), but to describe the process involved inestablishing central venous access and the adverse consequences that can arise

PRINCIPLES & PREPARATIONS

Small vs Large Veins

Catheters placed in small, peripheral veins have a limited life expectancy because theypromote localized inflammation and thrombosis The inflammation is prompted bymechanical injury to the blood vessel and by chemical injury to the vessel from causticdrug infusions The thrombosis is incited by the inflammation, and is propagated by thesluggish flow in small, cannulated veins (The viscosity of blood varies inversely with therate of blood flow, and thus the low flow in small, cannulated veins is associated with anincrease in blood viscosity, and this increases the propensity for thrombus formation.)

Large veins offer the advantages of a larger diameter and higher flow rates The largerdiameter allows the insertion of larger bore, multilumen catheters, which increases theefficiency of vascular access (i.e., more infusions per venipuncture) The higher flow ratesreduce the damaging effects of infused fluids and thereby reduce the propensity for localthrombosis The diameters and flow rates of some representative large and small veinsare shown in Table 2.1 Note that the increase in flow rate is far greater than theincrease in vessel diameter; e.g., the diameter of the subclavian vein is about three timesgreater than the diameter of the metacarpal veins, but the flow rates in the subclavianvein are as much as 100 times higher than flow rates in the metacarpal veins Thisrelationship between flow rate and vessel diameter is an expression of the Hagen-Poiseuille equation described in Chapter 1 (see Equation 1.2)

Table 2.1 Comparative Size and Flow Rates for Large and Small Veins

The major indications for central venous access are summarized as follows (1):

1 When peripheral venous access is difficult to obtain (e.g., in obese patients orintravenous drug abusers) or difficult to maintain (e.g., in agitated patients)

2 For the delivery of vasoconstrictor drugs (e.g., dopamine, norepinephrine), hypertonicsolutions (e.g., parenteral nutrition formulas), or multiple parenteral medications(taking advantage of the multilumen catheters described in Chapter 1)

3 For prolonged parenteral drug therapy (i.e., more than a few days)

4 For specialized tasks such as hemodialysis, transvenous cardiac pacing, orhemodynamic monitoring (e.g., with pulmonary artery catheters)

Contraindications

There are no absolute contraindications to central venous cannulation (1), including thepresence or severity of a coagulation disorder (2,3) However, there are risks associatedwith cannulation at a specific site, and these are described later in the chapter