2014 bedside critical care guide

OMICS Group eBooks Bedside Critical Care Guide www.esciencecentral.org/ebooks Edited by Ramzy H Rimawi 001 Bedside Critical Care Guide Edited by: Ramzy H Rimawi Published by OMICS Group eBooks 731 Gull Ave, Foster City CA 94404, USA Copyright © 2014 OMICS Group This eBook is an Open Access distributed under the Creative Commons Attribution 3.0 license, which allows users to download, copy and build upon published articles even for commercial purposes, as long as the author and publisher are properly credited, which ensures maximum dissemination and a wider impact of our publications However, users who aim to disseminate and distribute copies of this book as a whole must not seek monetary compensation for such service (excluded OMICS Group representatives and agreed collaborations) After this work has been published by OMICS Group, authors have the right to republish it, in whole or part, in any publication of which they are the author, and to make other personal use of the work Any republication, referencing or personal use of the work must explicitly identify the original source Notice: Statements and opinions expressed in the book are these of the individual contributors and not necessarily those of the editors or publisher No responsibility is accepted for the accuracy of information contained in the published chapters The publisher assumes no responsibility for any damage or injury to persons or property arising out of the use of any materials, instructions, methods or ideas contained in the book Cover OMICS Group Design team First published January, 2014 A free online edition of this book is available at www.esciencecentral.org/ebooks Additional hard copies can be obtained from orders @ www.esciencecentral.org/ebooks Preface Critical care medicine is an intriguing, rapidly evolving medical field aimed to support and restore productive lives in seriously ill patients Critical care specialists often seek up-to-date, evidence-based literature applicable at the patient bedside for common and uncommon disorders encountered in the intensive care unit (ICU) In this review of adult critical care medicine, we provide a comprehensive guide of bedside ICU principles and best practice standards East Carolina University has a 24-bed medical ICU (MICU), a 24-bed cardiac ICU (CICU), and a 24-bed surgical ICU (SICU) The MICU commonly admits critically ill patients with infectious disease, central nervous system, respiratory, metabolic and endocrine, hematologic, oncologic, gastrointestinal, environmental, obstetric, pharmacologic disorders and renal disorders Our CICU typically admits patients suffering from myocardial infarctions, congestive heart failure, arrhythmias, cardiogenic shock and post-cardiovascular surgical complications The SICU cares for patients with surgical and trauma related conditions Currently, critical care is a multidisciplinary specialty that includes many subspecialties of medicine, surgery and anesthesiology I have personally asked the contributing authors of multidisciplinary departments at East Carolina University, including critical care medicine, pulmonology, infectious diseases, nephrology, cardiology, and trauma The contributing authors and I thank OMICS for their assistance is publishing this text Thank you, Ramzy H Rimawi About Editor Dr Ramzy Rimawi earned his BA in English and Biology at the State University at Stony Brook He then earned his medical doctorate degree from Ross University School of Medicine After completing his Internal Medicine residency training, he pursued a fellowship in Infectious Diseases followed by Critical Care Medicine at East Carolina University for the Brody School of Medicine His passion for critical care lies in its’ rapid physiologic and complex reasoning often in the face of uncertainty His clinical interests are nosocomial infections in the ICU, antibiotic stewardship, infection control and HIV Forewords Dr Ramzy Rimawi has established himself as not only a competent clinician, but also quickly becoming a leader in the field of infectious disease and critical care medicine At a young age he has been very successful in publishing several articles in his field of practice and continues to contribute to the progression of science and medicine He has presented and been recognized for his work at a national and local level He has board certifications in Internal Medicine, Infectious disease medicine and currently completing his training in critical care medicine Bowling Mark I had the pleasure to work with Dr Ramzy over the past years He is a great example of ambition, dedication, hard working and a great team player His shinning mind has brought our department to a whole new level I have no doubt that he will be an exceptional physician Bringing the critical care to bedside and presenting it in such simplified way to assist other medical providers is a true example of his thrives to provide a better care for patients Saadah Khalid This is my first year working with Dr Rimawi During my time with him, I have found him to be very smart and hardworking He is an ardent supporter of antibiotic stewardship, has worked a great deal in the use of procalcitonin assay, and his work in the field of Penicillin allergy skin testing to help choose appropriate antibiotics is remarkable Dr Rimawi has taken a lot of initiatives to help improve the healthcare at our hospital He is very active academically and has worked on multiple research projects and publications The initiative he took to get this eBook published is a testament to his academic inclinations The idea of a bedside ICU eBook was excellent, especially with the limited availability of content at the graduate medical education level for residents The book had to be something that was evidence based, concise and practical, and easy to understand I am sure this book meets the above requirements and will be of great benefit to all Nazia Sultana Ramzy Rimawi and I both did our training in Infectious Diseases together at East Carolina University for the Brody School of Medicine While there, Ramzy has been great mentor that helped oversee my fellowship training as a chief fellow and research career We presented several oral and poster presentations at national and international conferences together We have successfully published several articles in well-recognized, peer-reviewed journals on topics such as MRSA screening in an ICU setting, tularemia, and infectious disease/ critical care practitioner collaboration But other than being great academic partner, Ramzy and I have been great friends It was an honor to be able to work with him on this e-Book and I look forward to future joint collaborations with him and OMICS Kaushal B Shah I am pleased to write about Dr Ramzy Rimawi I have known Dr Rimawi since July 2013 as a colleague at ECU Brody School of Medicine (BSOM) He has extensive fund of knowledge and practices evidence based medicine He is very well respected as a finest clinician, avid clinical researcher and mentor for fellows/house staff at Vidant Medical Centre Dr Rimawi has done a great effort in compiling “Bedside Critical Care Guide” as excellent evidence based guide for house staff and busy clinicians Manjit Singh Dhillon Dr Rimawi is an outstanding clinician with excellent bedside manners He has demonstrated an ongoing commitment to research as well as teaching, and this book will go a long way in furthering the understanding of critical illness and its management Abid Butt It was a great experience for me to write the chapter on scoring systems in critically ill patients I thank Dr Ramzy Rimawi for the opportunity of writing the chapter He is a great physician and person Ogugua N Obi Acknowledgement I am pleased to say that the contributors have provided information that was accurate, up-to-date, evidence-based and unbiased I would like to express my sincere appreciation to them for their generous, voluntary contributions Ramzy H Rimawi Introduction The chapters in this eBook include topics from cardiology, nephrology, pulmonary, infectious disease (including sepsis), neuro-critical care, burns, and gastroenterology Highly specialized topics have been left to qualified authors of other specialty texts Each chapter is meant to provide pertinent clinical, diagnostic, and management strategies when caring for critically ill patients The chapters are relatively brief, clinically relevant and evidence-based according to currently accepted literature References are provided for readers wanting to explore subjects in greater detail I have edited and revised the content and style of each chapter so as to unify the voice of the entire text Contents Chapter 1: Principles of Mechanical Ventilation Chapter 2: Management of Common Respiratory Disorders in the ICU: Asthma, COPD, and ARDS Chapter 3: Bedside approach to Gastrointestinal Bleeding in the Intensive Care Unit Page # 01 06 13 Chapter 4: Renal Disorders in the ICU 18 Chapter 5: Nutritional Support in an ICU Setting 22 Chapter 6: An ICU Bedside Review of Burns 27 Chapter 7: Management of Common Neurocritical Care Disorders 30 Chapter 8: ICU Delirium - Attention to Inattention 35 Chapter 9: Approach to Fever In the Intensive Care Unit 39 Chapter 10: Bedside Fundamentals of Pneumonia in the ICU 44 Chapter 11: Antibiotic Therapy in Sepsis 49 Chapter 12: ICU Infection Control and Preventive Measures 54 Chapter 13: Bedside Management of Shock 59 Chapter 14: Acute Myocardial Infarction in an ICU 62 Chapter 15: Heart failure in an ICU 66 Chapter 16: Critical Care Scoring Systems and Checklists 69 Principles of Mechanical Ventilation Robert A Shaw* Critical Care & Sleep Medicine, Section of Pulmonary, Department of Internal Medicine, Brody School of Medicine, East Carolina University, USA *Corresponding author: Robert A Shaw, Critical Care & Sleep Medicine, Section of Pulmonary, Department of Internal Medicine, Brody School of Medicine, East Carolina University, Brody 3E-149, Greenville, NC 27834, USA, Tel: 252-744-4650 Introduction In this chapter, you will learn basic pulmonary physiology necessary to understand the modes of mechanical ventilation You will then learn how these ventilator modes can be applied in the different types of respiratory failure Using ventilator monitoring to trouble shoot patient/ventilator asynchrony problems will be discussed Finally clinical cases to illustrate teaching points will be presented Basic Respiratory System Mechanics and Pathophysiology In the spontaneously breathing patient, downward movement of the diaphragm during inspiration generates negative pressure in the chest relative to atmospheric pressure, and air moves from the atmosphere into the lungs In spontaneously breathing patients on mechanical ventilators, positive pressure from the ventilator assists this effort by the patient and reduces the work the patient must to inhale a given tidal volume In patients who have respiratory failure, the ventilator reduces the work of breathing and aids in inflating the lungs The work of breathing is related to a pressure-time product, which is the pressure needed to inflate the lungs multiplied by the time of inspiration For our purpose, we will assume that expiration does not involve significant work by the patient The pressure which is needed to drive air into the lungs is related to the resistance and compliance of the system Resistance is increased by narrowing of the airways or narrowing of the endotracheal tube, which can occur if a patient bites on the tube or secretions collect on the inside Calculation of resistance, which modern ventilators can estimate, is related to Δ pressure/Δ flow (R= ΔP/ΔFlow) Compliance is simplistically understood as the work needed to inflate a balloon Stiff balloons like stiff alveoli require more pressure to inflate Compliance = Δvolume/Δpressure [1] Compliance is the opposite of elastance, thus alveoli with high elastance have low compliance There are components of compliance: compliance related to the alveoli and compliance related to the chest wall Diseases which cause low compliance of the lungs include fibrosis, interstitial edema, and pneumonia Conditions in which there is low chest wall compliance include abdominal distention, pleural effusion, or obesity The following image demonstrates how at low lung volumes compliance is low, but as the lungs are inflated compliance increases It is also important to know that diseased lungs are heterogeneous, and there are areas with low compliance (severely injured areas) and high compliance (emphysema), and also areas with high resistance (bronchospasm) and less resistance If the physician orders a high tidal volume to be delivered by the ventilator, that volume may go mostly to the more compliant (normal) part of the lung and cause over distention and injury to that part of the lung This is called volutrauma and is why lower tidal volumes (6-8 mL/ kg/IBW) are recommended in patients with ARDS Lower tidal volumes (i.e mL/kg/IBW) have also been described) Positive end expiratory pressure (PEEP) is used to inflate the lungs and usually improves the compliance by putting the lung in a more favorable place on the pressure volume curve seen in Figure [2] A sudden drop in compliance would be manifested by the ventilator graphics showing a higher pressure at the end of both inspiration and expiration and sudden drop in tidal volumes This could be seen with a pneumothorax OMICS Group eBooks Figure 1: Compliance in Relation to Pressure and Volume 001 Intravenous loop diuretics (i.e furosemide, bumetanide) can be given to reduce edema stemming from pulmonary congestion Reducing the plasma volume with diuretics can decrease the hydrostatic pressure within the pulmonary vessels and thus, decrease the propensity for fluid to travel out of the vessels and into the interstitial space For patients already on a loop diuretic regimen, non-loop diuretics are sometimes used to supplement this natriuresis and diuresis, reduce systemic edema, and reduce pulmonary edema due to SHF Additionally, excess volume can be removed mechanically via a simplified peripheral ultrafiltration system Ultrafiltration systems have been shown to be effective in decreasing orthopnea, JVD, rales, S3 gallop, and peripheral edema Because supraventricular and ventricular arrhythmias can be associated with pulmonary edema, this presents another motive to remove the fluid to alleviate or prevent worsening of cardiac arrhythmias While morphine can reduce heart rate and cause arterial and venous dilatation, its efficacy in treating pulmonary edema remains unknown Anticoagulants have only been proven beneficial in critically ill patients with AHF withmyocardial ischemia or atrial flutter, and atrial fibrillation Beta-blocking agents and calcium antagonists are contraindicated in patients with significant left ventricular systolic dysfunction ACE-inhibitors and angiotensin-receptor blockers may not be applicable in patients with low cardiac output and impaired renal function and are also not recommended in the initial management of AHF Low doses of intravenous dopamine in ICU patients does not significantly protect against renal dysfunction [14] Patients with end organ hypoperfusion and edema can develop cariogenic shock While there is mixed data about the use of positive inotropic agents in managing decompensated heart failure, positive inotropes used (i.e milrinone, dobutamine, and dopamine)can reduce heart rate and strengthen contractility of the heart muscle if a patient is in cardiogenic shock A distinction may exist between the effectiveness of drugs and therapies in patients with stable congestive heart failure versus critically ill patients with decompensated heart failure in the ICU While patients with stable congestive HF and reduced left ventricular ejection fraction benefit from ACE-inhibitors, beta-blockers, aldosterone antagonists, implantable cardioverter defibrillators, and cardiac resynchronization therapy, the same reduction in morbidity and mortality is not proven in patients with decompensated heart failure [2] B Mechanical Ventilation: Positive pressure ventilation canprovide therapeutic benefits in AHF patients with pulmonary edema, acidosis related to hypercapnia, andhypoperfusion This allows for improved oxygen diffusion across the alveolar membrane and reduces vasoconstriction of pulmonary vessels.Several trials have illustrated the benefical effect of continuous positive airway pressure (CPAP) ventilation in patients with AHF [15] Other than reducing the need for endotracheal intubation, CPAP may also reduce hospital mortality when implanted in AHF patients C Intraaortic Balloon Pump (IABP): Based on a counterpulsation principle, an IABP has clinical efficacy in AHF patients with a correctable underlying condition and severe myocardial ischemia refractory to medical therapy, severe mitral insufficiency, and intraventricular septum rupture In patients with aortic regurgitation or aortic dissection, IABP should not be used D Ventricular Assist Devices (VAD): VADs are indicated in patients with severe myocardial ischemia/infarction refractory to medical management and IABP There are several types of ventricular assist devices, none of which are appropriate for all patients with AHF Various types include pulative versus non-pulsative flow, right versus left, and internal versus external VADs Conclusion In summary, acute heart failure is a frequentailment encountered in an ICU setting Rapid interventions can have a profound impact on morbidity, mortality, length of stay and healthcare costs Early detection and optimal therapy by those with expertise in the management of AHFcan improve the outcome for this exceedingly common condition References Alan S Go, Dariush M., Véronique L Roger (2013) Heart Disease and Stroke Statistics—2013 Update: A Report From the American Heart Association Circulation 127: 6-245, published online before print December 12 2012, doi:10.1161/CIR.0b013e31828124ad Centers for disease control and prevention heart failure fact sheet Accessed October1, 2013 from: Jessup M, Brozena S (2003) Heart failure N Engl J Med 348: 2007-2018 Fonarow GC, Abraham WT, Albert NM, Stough WG, Gheorghiade M, et al (2008) Factors identified as precipitating hospital admissions for heart failure and clinical outcomes: findings from OPTIMIZE-HF Arch Intern Med 168: 847-854 Allen LA, O’Connor CM (2007) Management of acute decompensated heart failure CMAJ 176: 797-805 Arnold M (2008) Merck Manual: Heart Failure Retrieved October 12, 2013, from Merck Manual Home Health Handbook: Chatterjee Kanu MB, Otto Catherine (2012) Examination of the jugular venous pulse UpToDate He J, Ogden LG, Bazzano LA, Vupputuri S, Loria C, et al (2001) Risk factors for congestive heart failure in US men and women: NHANES I epidemiologic follow-up study Arch Intern Med 161: 996-1002 Maisel A (2002) B-type natriuretic peptide levels: diagnostic and prognostic in congestive heart failure: what’s next? Circulation 105: 2328-2331 Mant J, Doust J, Roalfe A, Barton P, Cowie MR, et al (2009) Systematic review and individual patient data meta-analysis of diagnosis of heart failure, with modelling of implications of different diagnostic strategies in primary care Health Technol Assess 13: 1-207, iii 10 Januzzi JL, van Kimmenade R, Lainchbury J, Bayes-Genis A, Ordonez-Llanos J, et al (2006) NT-proBNP testing for diagnosis and short-term prognosis in acute destabilized heart failure: an international pooled analysis of 1256 patients: the International Collaborative of NT-proBNP Study Eur Heart J 27: 330-337 12 Heart Failure Society of America, Lindenfeld J, Albert NM, Boehmer JP, Collins SP, et al (2010) HFSA 2010 Comprehensive Heart Failure Practice Guideline J Card Fail 16: e1-194 13 Cotter G, Metzkor E, Kaluski E, Faigenberg Z, Miller R, et al (1998) Randomised trial of high-dose isosorbide dinitrate plus low-dose furosemide versus high-dose furosemide plus low-dose isosorbide dinitrate in severe pulmonary oedema Lancet 351: 389-393 14 Bellomo R, Chapman M, Finfer S, Hickling K, Myburgh J (2000) Low-dose dopamine in patients with early renal dysfunction: a placebo-controlled randomised trial Australian and New Zealand Intensive Care Society (ANZICS) Clinical Trials Group Lancet 356: 2139-2143 15 Pang D, Keenan SP, Cook DJ, Sibbald WJ (1998) The effect of positive pressure airway support on mortality and the need for intubation in cardiogenic pulmonary edema: a systematic review Chest 114: 1185-1192 16 OMICS Group eBooks 11 Ramírez A, Abelmann WH (1974) Cardiac decompensation N Engl J Med 290: 499-501 068 Critical Care Scoring Systems and Checklists Ogugua N Obi* MD, MPH, Department of Pulmonary and Critical Care Medicine, Brody School of Medicine, East Carolina University, Greenville, NC *Corresponding author: Ogugua N Obi, Department of Pulmonary and Critical Care Medicine, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, Tel: 1.800.722.3281; E-mail: obio@ecu.edu Abstract Scoring systems are widely used in the ICU to predict outcome, characterize disease severity and degree of organ dysfunction, assess resource use, evaluate new therapies, compare ICU care across various settings, and demonstrate equivalence of study and control patients in clinical research In this article, we will review the most commonly used scoring systems in the ICU, briefly examine the history of their development and address when and how to use these systems We also note the fact, that the different scoring systems should be seen as complementary and not as mutually exclusive and emphasize the fact, that scoring systems should not replace individualized care and/or decision making in the ICU Introduction Scoring systems are necessary in the ICU for several reasons – to predict outcome and prognosis, guide the clinical decision making process, monitor and assess new therapies, compare care between different centers, standardize medical research and perform cost-benefit analysis with regard to resource utilization While not specifically designed for individual patient care, scoring systems may guide (but will NOT replace) clinical decision making regarding withdrawal of treatment and/or futility of continued aggressive care This latter reason will become progressively more important as families become more involved in medical decision making in the ICU A good scoring system should meet some basic requirements (Table 1) First, it should assess an important, relevant and easily determined outcome Most ICU scoring systems assess mortality while others predict long-term morbidity and functional status Next, it should be simple, reliable, easy to use, and in-put data should be readily obtainable A good scoring system should also have wide patient applicability, high sensitivity and specificity, and be able to perform well across a wide range of predicted mortalities Discrimination and calibration are two characteristics used to judge a scoring system Discrimination refers to the accuracy of a given prediction –e.g., if a scoring system predicts a mortality of 90%, discrimination is perfect if the observed mortality is 90% Calibration describes how an instrument performs over a wide range of predicted mortalities An instrument would be highly calibrated if it were accurate at mortalities of 90%, 50% and 20% Unfortunately however, there is no ideal score Several scores used in conjunction would be complementary although potentially more time consuming and labor intensive It should be noted, that scoring systems are meant as a guide to clinical care and should not replace good clinical judgment, limit treatment of individual patients or result in nihilistic, depersonalized care Based on easily/routinely recordable variables Well calibrated A high level of discrimination Applicable to all patient populations Can be used in different countries The ability to predict functional status or quality of life after ICU discharge No scoring system currently incorporates all these features Table 1: The ideal scoring system [40] Classification of Scoring Systems • Anatomical scoring – these depend on the anatomical area involved and are mainly used for trauma patients [e.g Abbreviated Injury Score (AIS) and Injury Severity Score (ISS) • Disease specific – based on the ongoing disease process ,[e.g Ranson’s criteria for acute pancreatitis, subarachnoid hemorrhage assessment using the World Federation of Neurosurgeons score, and liver failure assessment using Child-Pugh or Model for EndStage Liver Disease (MELD) scoring] • Physiological assessment - based on the degree of derangement of routinely measured physiological variables [e.g Acute Physiology and Chronic Health Evaluation (APACHE) and Simplified Acute Physiology Score (SAPS)] OMICS Group eBooks There is no agreed method of classification of scoring systems used in critically ill patients Several methods of classification have been suggested as shown below [1]: 069 • Organ-specific scoring - The underlying premise here is that the sicker a patient is, the more organ systems will be involved (ranging from organ dysfunction to failure) and the poorer the expected outcome will be [e.g Sepsis-Related Organ Failure Assessment (SOFA)]• Therapeutic weighted scores - These are based on the assumption that very ill patients require a greater number of interventions and procedures that are more complex than patients who are less ill Examples include the Therapeutic Intervention Scoring System (TISS) • Simple scales - based on clinical judgment (e.g., survive or succumb) For the purpose of simplicity and ease of understanding, we will simplify the scoring systems into broad functional categories: ¾¾ Disease-specific scores - specific for an organ or disease (for example, the Glasgow Coma Scale (GCS), the Ransons’s Criteria for acute pancreatitis, the Intra Cranial Hemorrhage (ICH) score or the Maddrey’s discriminant function for alcoholic hepatitis etc.) ¾¾ Generic ICU score – these are generic and applicable to a very wide range of ICU patients independent of their disease specifics This category will include the physiologic assessment scores, the organ dysfunction scores and the therapeutic weighted scores ¾¾ Scores and check lists used to assess everyday care in the ICU including adequacy of pain control, depth of sedation/degree of agitation and presence or absence of delirium and adherence to infection prevention In this chapter, we focus on the latter broad groups The objective of this review chapter is to give the ICU provider without any particular knowledge or expertise in this area an overview of the current status of these instruments and their possible applications Generic ICU scores Generic ICU scores maybe further sub-categorized into: • Outcome prediction scores - based on disease severity on admission (e.g Acute Physiology and Chronic Health Evaluation (APACHE), Simplified Acute Physiology Score (SAPS), Mortality Probability Model (MPM)) • Organ dysfunction scores - assess the presence and severity of organ dysfunction (e.g Multiple Organ Dysfunction Score (MODS), Sequential Organ Failure Assessment (SOFA)) • Scores that assess nursing workload use (e.g Therapeutic Intervention Scoring System (TISS), Nine Equivalents of Nursing Manpower Use Score (NEMS)) Outcome prediction scores The original outcome prediction scores were developed over 25 years ago to provide an indication of the risk of death in groups of ICU patients They were not designed for individual prognostication They have all undergone recent updates to account for the changing patient demographics, disease severity and intensive care practices to ensure continued accuracy in today’s ICU We will limit our discussion to the three most common outcome prediction scores: • Acute Physiology and Chronic health Evaluation Score (APACHE, APACHE II, APACHE III, APACHE IV) • Simplified Acute Physiology Score (SAPS, SAPS II, SAPS III) • Mortality Prediction Model (MPM, MPM II, MPM III) Acute Physiology and Chronic Health Evaluation (APACHE) score In 1985, the original model was revised and simplified to create APACHE II by using 12 physiological variables instead of 34 and incorporating age and chronic health status directly into the model to give a single point score with a maximum score of 71 [3] The worst value recorded during the first 24 hours of a patient’s admission to the ICU is used for each physiological variable The principal diagnosis leading to ICU admission was added as a category weight so that the predicted mortality is computed based on the patient’s APACHE II score and their principal diagnosis at admission [1,3].Although the original APACHE system was not primarily developed to be used for individual patient treatment decisions, APACHE II can provide the clinician with a systematic evaluation and an improved understanding of how an individual patient’s severity of disease influences his outcome [3] The APACHE II scoring system is now the world’s most widely used severity of illness score (1,3) APACHE II score calculators are widely available online The APACHE III prognostic system was developed in 1991 and was validated and further updated in 1998 [1,4,5] It consists of two options: (i) an APACHE III score, which can provide initial risk stratification for severely ill hospitalized patients within homogenous independently defined patient groups; and (ii) an APACHE III predictive equation, which uses APACHE III score and reference data on major disease categories and treatment location immediately prior to ICU admission to provide risk estimates for hospital mortality for individual ICU patients [4] APACHE III uses 17 physiological variables with a different weighting system assigned to the original 12 from the APACHE II scoring system It provides a composite score with a range of to 299 and accounts for any selection bias OMICS Group eBooks The original APACHE score was developed in 1981 to classify groups of patients according to severity of illness so as to compare outcomes, evaluate new therapies and study the utilization of ICU’s [2] It was not designed to assist in making individual treatment decisions It was divided into two sections: a physiology score to assess the degree of acute illness; and a preadmission evaluation to determine the chronic health status of the patient before acute illness A composite numerical physiological score was obtained by using the worst value from 34 possible physiological measurements obtained in the first 32-hours of ICU admission, reflecting the degree of derangement of one or more of the body’s major physiological systems [2] The pre-admission health status was assigned a letter score of A (excellent health) through D (severe chronic organ system dysfunction) for details concerning functional status, productivity and medical attention approximately months before admission The patients complete APACHE classification was indicated by the numerical sum of the weights for physiological measurements and a letter reflecting chronic health evaluation Thus designations such as 13-A or 33-D reflect patients with different levels of acute illness and preadmission health status, while designations 13-A and 13-D would reflect patients with same level of acute illness but differing levels of preadmission health status 070 that may result from the location of a patient prior to ICUcare.ICU readmissions, transfers from other ICUs and admissions from the hospital wards have marginally increased risk of death relative to patients admitted directly to the ICU from the emergency room Like its predecessors, the APACHE III uses the worst physiological variable in the first 24-hours of ICU admissions to obtain a 1st day score It can be updated daily to provide a daily risk estimate, which may be used to calculate individual risk estimates over time Commercially available APACHE III calculators are available for purchase APACHE IV was developed in 2006 using a database of over 110,000 patients admitted to 104 ICUs in 45 hospitals in the USA in 2002/2003, and remodeling APACHE III with the same physiological variables and weights but different predictor variables and refined statistical methods [6] A recent study out of medical-surgical Brazilian Intensive Care Units showed that the APACHE IV and the SAPS III had good discrimination but poor calibration Simplified Acute Physiology Score (SAPS) The Simplified Acute Physiology Score was developed and validated in 679 consecutive patients admitted to multi-disciplinary referral ICUs in France in 1984 using 13 weighted physiological variable and age to predict the risk of death in ICU patients [7] (Table 2) Like the APCHE scores, SAPS used the worst values obtained during the first 24 hours of ICU admission The Simplified Acute Physiology Score performed comparably to the APACHE score and is lauded as being simpler and less time-consuming to compute Like the APACHE score, it is used to predict mortality for patient subgroups and should not be used for individual prognosis or treatment decisions Variable SAPS Scale Age (yr) 46-55 55-65 66-75 >75 40-54 5.0 3.5-4.99 0.7-3.49 29-35.9 7.5-28.9 3.5-7.4 0.50-0.69