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(BQ) Part 1 book Handbook of critical and intensive care medicine has contents: Approach to the intensive care unit, the basics of critical care, cardiovascular disorders, endocrinologic disorders, environmental disorders,... and other contents.
Joseph Varon Handbook of Critical and Intensive Care Medicine Third Edition 123 Handbook of Critical and Intensive Care Medicine Handbook of Critical and Intensive Care Medicine Third Edition Joseph Varon, MD, FACP, FCCP, FCCM, FRSM Professor of Acute and Continuing Care, The University of Texas Health Science Center at Houston Clinical Professor of Medicine, The University of Texas Medical Branch at Galveston Professor of Medicine and Surgery UAT, UABC, USON, UPAEP, BUAP - Mexico President Dorrington Medical Associates, PA Houston, TX, USA With 25 Illustrations Joseph Varon MD, FACP, FCCP, FCCM, FRSM Professor of Acute and Continuing Care The University of Texas Health Science Center at Houston Clinical Professor of Medicine The University of Texas Medical Branch at Galveston Professor of Medicine and Surgery UAT, UABC, USON, UPAEP, BUAP - Mexico President Dorrington Medical Associates, PA Houston, TX, USA ISBN 978-3-319-31603-1 ISBN 978-3-319-31605-5 DOI 10.1007/978-3-319-31605-5 (eBook) Library of Congress Control Number: 2016941876 © Springer International Publishing Switzerland 2016 This work is subject to copyright All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed The use of general descriptive names, registered names, trademarks, service marks, etc in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made Printed on acid-free paper This Springer imprint is published by Springer Nature The registered company is Springer International Publishing AG Switzerland This book is again dedicated to my children Adylle, Jacques, Daryelle, and Michelle for their understanding as youngsters and adults, about those countless days, nights, and weekends, in which I was away from home caring for those patients who needed me the most at the time Joseph Varon, MD, FACP, FCCP, FCCM, FRSM Preface Why write another book on the management of critically ill patients? When I wrote the first edition of this book, over 20 years ago, I had realized the importance of a small pocket book that would be useful for those caring for critically ill patients Over the past six decades we have seen an enormous growth in the number of intensive care units (ICU) across the world Indeed, it is estimated that a large proportion of health-care expenses are devoted to patients in these specialized units Medical students, residents, fellows, attending physicians, critical care nurses, pharmacists, respiratory therapists, and other health-care providers (irrespective of their ultimate field of practice) will spend several months or years of their professional lives, taking care of critically ill or severely injured patients These clinicians must have special training, experience, and competence in managing complex problems in their patients Moreover, these clinicians must interpret data obtained by many kinds of monitoring devices, and they must integrate this information with their knowledge of the pathophysiology of disease Even more important is the fact that anyone working in an ICU or with a critically ill patient must approach patients with a multidisciplinary team The phrase there is no I in TEAM comes to mind This 3rd edition of this book was written for every practitioner engaged in Critical Care Medicine across the world I have attempted to present basic and generally accepted clinical information, my own personal experience in the field, facts and some important formulas, as well as laboratory values and tables which we feel will be useful to the practitioner of Critical Care Medicine The chapters of this book follow an outline format and are divided by organ-system (i.e., neurologic disorders, cardiovascular disorders), as well as special topics (i.e., environmental disorders, trauma, toxicology) Every chapter has been updated and many chapters are completely new It is important for the reader of this handbook to understand that Critical Care Medicine is not a static field and changes occur every day Therefore, this handbook is not meant to define the standard of care, but rather to be a general guide to current clinical practice used in Critical Care Medicine I wrote this book hoping that it will benefit thousands of critically ill patients, but more importantly that it will aid practicing clinicians to assume a multidisciplinary approach Joseph Varon, MD, FACP, FCCP, FCCM, FRSM Contents Approach to the Intensive Care Unit (ICU) Welcome to the ICU What Is an ICU? Historical Development of the ICU Economical Impact of the ICU Organization of the ICU Teamwork The Flow Sheet The Critically Ill Patient System-Oriented Rounds Identification Major Events Over the Last 24 h System Review Do Not Resuscitate (DNR) and Ethical Issues 1 1 2 3 6 The Basics of Critical Care Cardiac Arrest and Resuscitation The Alveolar Air Equation Oxygen Transport Mechanical Ventilation Hemodynamics The Cardiopulmonary Interaction Integrated Cardiopulmonary Management Principles 11 11 18 24 29 40 46 48 Cardiovascular Disorders Ischemic Heart Disease Unstable Angina Pectoris Myocardial Infarction Cardiac Pacemakers Congestive Heart Failure Cardiomyopathies Myocarditis Pericarditis 51 51 51 54 62 62 64 66 66 228 10. Nutrition Table 10.3. Energy expenditure correction factors Activity factor Confined to bed 1.2 Out of bed 1.3 Injury factors Surgery Minor 1.0–1.1 Major 1.1–1.2 Infection Mild 1.0–1.2 Moderate 1.2–1.4 Severe 1.4–1.8 Trauma Skeletal 1.2–1.35 Head injury with steroid therapy 1.6 Blunt 1.15–1.35 Burns (body surface area) Up to 20 % 1.0–1.5 20–40 % Over 40 % 1.5–1.85 1.85–1.95 Table 10.4. Macronutrient nutritional requirements % of total calories Quantity of nutrients Example for 70-kg patient 15–25 25 kcal/kg/day 1.2–2.0 g/kg/day 1750 kcal/day Protein/amino acids Carbohydrates 30–65 (50 % avg pt) 2–4 g/kg/day (3.13 g/kg/day avg) 219 g/day (875 kcal/day) Fats 15–30 (30 % avg pt) 0.7–1.5 g/kg/day (0.83 g/kg/day avg) Nutrient Total calories 95 g/day (380 kcal/day) (based on 1.35 g/kg/day) 58 g/day (525 kcal/day) C Water Must be individualized, as needs vary greatly between patients (differences in insensible losses, GI losses, and urine losses) Initially estimate: 1-mL water per kilocalorie of energy in adults VI. Role of Specific Nutrients (Quality) 229 D Vitamins Fat-soluble vitamins: A, D, E, and K Water-soluble vitamins: Ascorbic acid (C), thiamine (B1), riboflavin (B2), niacin, folate, pyridoxine (B6), B12, pantothenic acid, and biotin Published recommended daily allowances (RDAs) are based on oral intake in healthy individuals Vitamin needs for critically ill patients have not been determined See Table 10.5 for estimates of nutritional requirements of the vitamins Commercial enteral formulas generally supply the RDA of the vitamins (if patients receive their caloric needs) An adult parenteral vitamin formulation was approved by the FDA in 1979 and is available for addition to TPN solutions; this should be added just before administration, since degradation can occur E Minerals (Na, K, Ca, PO4, Mg) See Table 10.5 for estimates of daily nutritional requirements of the minerals Minerals are present in sufficient quantities in enteral products (special formulas limit electrolytes for renal failure) Must be supplemented in TPN F Trace elements (iron, copper, iodine, zinc, selenium, chromium, cobalt, manganese) Needs in critically ill patients have not been determined (See Table 10.5 for estimates of requirements.) Sufficient quantities are thought to be present in enteral products Must be supplemented in TPN (all except iron can be added to the solution) (a) Deficiency states have been reported in long-term TPN patients (b) Specifics are best managed by specially trained nutritional support teams VI. Role of Specific Nutrients (Quality) A Nitrogen Sources Choices (a) Amino acids (b) Hydrolyzed protein (peptides) (c) Intact proteins Evidence suggests that proteins generated from the diet possess specific physiologic activities (i.e., organic catalyst for structural formation of cells, acting as antibodies or controlling cell metabolism) Nitrogen is best delivered as intact protein (if digestion and absorption intact) or hydrolyzed protein (impaired digestion) Protein is absorbed primarily as peptides (60 %) and amino acids (33 %) Essential amino acid formulas should not be used Some amino acids become essential during critical illness (a) These are called conditionally essential amino acids (b) Examples include glutamine, cysteine, arginine, and taurine Some amino acids appear to have specific roles (a) Glutamine is a fuel source for rapidly dividing cells, such as the GI tract and immune system (patients with bone marrow transplant, supplementation with glutamine was associated with lower rates of infection) 230 10. Nutrition Table 10.5. Micronutrient nutritional requirements Enteral nutrition Parenteral nutrition Example for TPN for a 70-kg patient Sodium 60–140 mmol/day 60–120 mmol/day 80 mmol/day Potassium 50–140 mmol/day 50–120 mmol/day 50 mmol/day Magnesium 8–15 mmol/day 8–12 mmol/day 10 mmol/day Phosphorous 25 mmol/day 14–16 mmol/day 15 mmol/day Calcium 20 mmol/day 7–10 mmol/day 10 mmol/day Iron 10 mg/day 1–2 mg/day none Zinc 15 mg/day 2–5 mg/day 5 mg/day Copper 2–3 mg/day 0.5–1.5 mg/day 1 mg/day Chromium 50–200 μg/day 10–20 μg/day 10 μg/day Selenium 50–200 μg/day 80–150 μg/day 100 μg/day Iodine 150 μg/day 120 μg/day 120 μg/day Manganese 2.5–5.0 mg/day 0.2–0.8 mg/day 0.5 mg/day Vitamin A RDA = 4000–5000 IU/ day ND 3300 IU/day Vitamin D RDA = 200–400 IU/day ND 200 IU/day Vitamin E RDA = 12–15 IU/day ND 10 IU/day Vitamin K RDA = 60–80 μg/day ND 10 mg/weekb Thiamine RDA = 1.1–1.4 mg/day ND 3 mg/day Riboflavin RDA = 1.2–1.7 mg/day ND 5 mg/day Niacin RDA = 13–19 mg/day ND 40 mg/day Pantothenic acid 4–7 mg/dayc ND 15 mg/day Micronutrient Minerals Trace elements Vitaminsa c (continued) VI. Role of Specific Nutrients (Quality) 231 Table 10.5. (continued) Example for TPN for a 70-kg patient Micronutrient Enteral nutrition Parenteral nutrition Pyridoxine RDA = 1.6–2.0 mg/day ND 4 mg/day Folic acid RDA = 0.4 mg/day ND 0.4 mg/day Vitamin B12 RDA = 3 μg/day ND 5 μg/day Vitamin C RDA = 40 mg/day ND 100 mg/day Biotin RDA = 30–100 μg/day ND 60 μg/day ND not defined, RDA recommended daily allowance a Enteral requirements should always exceed parenteral requirements; most recommend supplying one to three times the RDA of each vitamin to patients with critical illness b None if anticoagulation used c RDA not established (b) Arginine is required for optimum wound healing and is important in immune function (Target patients are critically ill adults and preterm infants.) (c) Cysteine is needed for synthesis of glutathione (d) Branched-chain amino acids (BCAA) may improve mental status in patients with hepatic encephalopathy; it is primarily metabolized by peripheral muscle instead of the liver (e) Note that glutamine and cysteine are not stable (or present) in TPN solution Dietary nucleic acids may be important for immune function Lipids B Linoleic Acid (a) Essential fatty acid (need 7–12 % of total calories supplied as linoleic acid) (b) ω-6 Polyunsaturated, long-chain fatty acid (immunosuppressive) (c) Precursor to membrane arachidonic acid ω-3 Polyunsaturated Fatty Acids (PUFA) (a) Fish oils and linolenic acid (b) Profound effects upon cell membrane fluidity and stability Decrease production of dienoic prostaglandins (i.e., PGE2), tumor necrosis factor, interleukin-1, and other proinflammatory cytokines (c) Supplementation of omega-3 fatty acids in patients with acute lung injury improves oxygenation and shortens length of mechanical ventilation Medium-Chain Triglycerides (a) Good energy source (b) Water-soluble (c) Enter circulation via GI tract Short-Chain Fatty Acids (SCFA) (a) Examples: butyric and propionic acid (b) Major fuel for the gut (especially the colon) (c) Derived from metabolizable fiber 232 10. Nutrition High-Fat Formulas (a) If the patient is not overfed, these have little effect on CO2 production (despite being marketed for decreasing the respiratory quotient [RQ]) (b) Poor GI tolerance Carbohydrates C CHO are the principle source of energy with their form ranging from a starch to simple sugar Fiber (a) Metabolizable fiber (i.e., pectin, guar) is converted to SCFA in the colon by bacteria (b) Bulk increases stool mass, softens stool, adds body to stool, and provides some stimulation of gut mass VII. Monitoring Responses to Nutritional Support A Visceral Proteins (1) Prealbumin (a) Half-life is 2 days (b) Normal range is 10–40 mg/dL Transferrin (a) Half-life is 8–9 days (b) Normal range is 160–355 mg/dL Albumin (a) Half-life is 20 days (b) Normal range is 3.2–5.0 mg/dL B Visceral protein levels are affected by nutritional intake as well as the disease state (especially presence of inflammation) C Increasing levels of visceral proteins suggest that nutritional support is adequate D Nitrogen Balance NB is the most direct measurement of actual protein status, by comparing nitrogen output and input Determined from 12- to 24-h urine collections and measurements of total urinary nitrogen (more accurate than total urea nitrogen), compared to total nitrogen intake May be inaccurate: (a) In patients with renal failure (b) If urine is not correctly collected by staff (c) If the patient has increased nitrogen losses in stool or from wounds (i.e., burns) N-balance = protein intake (g/day)/6.25 – {total urinary nitrogen (g/day) + 2} Negative nitrogen balance is not necessarily detrimental over the short term (i.e., 1–2 weeks) Improvement in nitrogen balance suggests that nutritional support is adequate Be aware that nitrogen balance may improve as catabolism decreases despite inadequate nutritional support IX. Nasoduodenal Feeding Tube Placement 233 E Caloric goals: Caloric needs can be determined using 25 kcal/kg of ideal body weight as an estimate Another option is indirect calorimetry: Measures oxygen consumption and CO2 production for 15–30 min, estimates energy expenditure, and then extrapolates to 24 h Keep RQ 1 suggest lipogenesis from excessive caloric intake; values ≈ 0.7 are found in starvation and reflect fat oxidation F Other Nutritional Parameters Not Generally Useful in the Critically Ill Weight Skinfold thickness Delayed cutaneous hypersensitivity (DCH) Lymphocyte counts VIII. Nutrition for Specific Disease Processes A Acute Renal Failure Use intact protein or peptide formula with moderate fat Do not restrict protein (it is required for healing and for other organ functions) May limit fluid intake with double-strength formula (2 cal/mL) Watch K, Mg, Ca, and PO4 levels B Hepatic Failure Use intact protein or peptide formula Usually 1.0–1.2 g/kg/day of protein are needed to support repair and immune function BCAA may be of value if encephalopathy persists following use of intact protein or peptide diets C Inflammatory Bowel Disease/Pancreatitis Enteral nutrition is possible if a jejunal tube is placed (endoscopically or radiologically) distal to Treitz ligament Enteral nutrition should be attempted before initiating TPN D Multiple Organ Failure Nutritional support is usually of marginal value Nutritional support needs to be started before organ failure develops IX. Nasoduodenal Feeding Tube Placement Used in patients who not tolerate oral or gastric feeding A B Patients with abdominal surgery should have the tube placed during surgery under direct visualization The anesthesiologist inserts the tube into the stomach The surgeon locates the tube and directs it into the duodenum or jejunum Eliminates need for confirmatory X-rays 234 10. Nutrition Allows immediate feeding upon admission into intensive care unit (ICU) Feeding tubes may also be placed into the small bowel using a gastrostomy or jejunostomy C Tubes placed into the stomach will rarely (5–15 %) migrate spontaneously into the small bowel in critically ill patients (due to gastroparesis) D Bedside method: Place patient in left lateral decubitus position (if possible) Lubricate the nostril with generic lubricant or 2 % viscous lidocaine Insert an eight to ten French small-bore feeding tube (containing wire stylet) into the nostril, and gently advance it through the nasopharynx into the esophagus and then the stomach If resistance is met or the patient coughs, becomes agitated, or decreases oxygen saturation, then: (a) Pull the tube back into the nasopharynx (b) Repeat step and reinsert the tube into the stomach (c) Change the position of the patient’s neck (slightly flex or extend) before reattempting insertion Confirm position of the tube in the stomach (a) Auscultate over the abdomen (b) Aspirate gastric contents (pH ≈ 2–5, unless on H2 blocker) Remove wire stylet, and place a 45-degree bend approximately 1 in from the distal end of the wire Gently reinsert the wire stylet (should not meet resistance) Slowly advance the tube while rotating it in a clockwise direction Check the position every 10–15 cm (a) Auscultation will reveal higher pitched sounds when the tube is in the pylorus and proximal small bowel (b) Bile may be aspirated from the tube in the small bowel (c) Bile/small bowel secretions have pH ≈ 6–7 (d) Abdominal X-ray: Can confirm small bowel location May not be cost-effective Will avoid feeding into lung in rare case of misplaced feeding tube E With this bedside method, we (faculty, residents, and medical students) successfully place >90 % of attempted small bowel tubes into the duodenum or jejunum F Aggressive surgical and bedside placement allows us to feed >97 % of our critically ill patients enterally within 24–48 h of admission into the ICU G If bedside placement is not possible, place the feeding tube into the small intestine using: Endoscopy Fluoroscopy X. Recommendations for TPN Use Use only when enteral nutrition is not possible (e.g., short gut syndrome, chylothorax) (a) Failure of the stomach to empty is not an indication for TPN but rather for a small bowel feeding tube XI. Approach to Enteral Feeding 235 (b) Most patients with diarrhea can be managed with enteral nutrition Initial TPN orders may be based on recommendations in Tables 10.4 and 10.5 Overall TPN management is best performed by specially trained nutritional support teams For more specifics, the reader is referred to entire texts written about TPN XI. Approach to Enteral Feeding Enteral nutritional support should be initiated within 12–48 h of admission to the ICU A B The oral route is preferred (but frequently not possible) C The gastric route is second choice and should be tried before placing a small bowel tube in most patients D Patients at high risk for aspiration or known gastric paresis should be fed with a small bowel tube E Feeding formulas should not be diluted F Gastric paresis is best assessed and monitored by measuring gastric residuals Residuals must be checked every 4–6 h and should remain 100 suggests osmotic diarrhea Impaction May be secondary to narcotics Other causes Inflammatory bowel disease, pancreatic insufficiency, short gut syndrome Rectal exam SOG stool osmolality – (stool Na+ + K+) where alb = serum albumin (g/dL), TSF = triceps skin fold (mm), tfn = serum transferrin (mg/dL), and DSH = delayed skin hypersensitivity (1 = anergy, = reactive) The probability of survival (POS) based on the nutritional status of a critically ill patient can be calculated as follows: POS = 0.91( alb ) − 1.0 ( DSH ) − 1.44 (SEP ) + 0.98 ( DIA ) − 1.09 where alb = serum albumin (g/dL), DSH = delayed skin hypersensitivity (1 = anergy, = reactive), SEP = sepsis (1 = no sepsis, = sepsis), and DIA = diagnosis of cancer (1 = no cancer, = cancer) Another way to calculate the nutritional deficit is by utilizing the index of undernutrition (IOU), as shown in Table 10.9 10. Nutrition 240 Table 10.9. Index of undernutrition Points 10 15 20 >3.5 >70 3.1–3.5 56–70 2.6–3.0 46–55 2.0–2.5 30–45 80 76–80 61–75 40–60 2.0 1.76–2.0 1.41–1.75 1.0–1.4 20 The calculation of daily protein requirements (PR) can be done utilizing the following formula: