Shock remains a diagnosis of significant mortality and morbidity. The current definition defines shock as an acute clinical syndrome that results from inadequate tissue perfusion, which is significantly different from the previous definition of hypotension. Clinical manifestation varies broadly, and is based on the underlying etiology, degree of organ perfusion, and previous organ dysfunction. This review covers the classification, pathogenesis and organ response, evaluation, and management of shock. Figures show the balance between oxygen delivery and oxygen consumption, perfused capillary density, the Krogh Cylinder Model demonstrating the Anoxic-Hypercapnic Lethal Corner, the relation between systolic blood pressure, mean arterial pressure, and diastolic arterial pressure, glycolysis, and the approach to the patient with shock. Tables list clinical and metabolic markers of perfusion alteration to the organs, hemodynamic parameters in different types of shock, normal hemodynamic parameters, problems associated with the use of pulmonary artery catheter, clinical presentation of hypovolemic shock according to severity, causes of cardiogenic shock and cardiogenic pulmonary edema, and receptor activity of different vaspressors and clinical indication.

This review contains 6 figures, 15 tables, and 60 references

Keywords: Shock; Hypovolemic shock; Cardiogenic shock; Neurogenic shock; Vasogenic shock; Septic shock; Obstructive shock

Perhaps the most ubiquitous set of interlinked clinical issues to be addressed in inpatient medicine is fluids, electrolytes, and acid-base balance. Decision making for the first two directly and measurably impacts the latter. Unlike most other critical therapies whose management is tied to a specific skill set and competency, every practitioner is empowered to prescribe and direct fluid and electrolyte management and, secondarily, pH. Downstream consequences in terms of compensation, both pulmonary and renal, may be singularly important for those with preexisting conditions that impact organ function and drive the need for unanticipated monitoring and therapy, including organ support. Therefore, the basics of fluid and electrolyte management are essential to be mastered, as is specific knowledge of the consequences of that prescription to enhance recovery and avoid preventable errors with important sequelae. Accordingly, current different but complementary methods of assessing acid-base balance are presented so that the reader may have a systematic approach to determining pH before intervention as well as after the initiation of fluid and electrolyte therapy.

This review contains 12 figures, 7 tables, and 38 references

Keywords: acid, base, electrolyte disturbances, Henderson-Hasselbach, maintenance, proton, resuscitation, Stewart methodology

Shock represents hypoperfusion leading to cellular metabolic failure, with attendant clinical and biochemical markers indicating shock severity and response to therapy. While identifying and treating the underlying cause (source control for sepsis, hemostasis for exsanguination, etc) is paramount, the approach to shock is fundamentally straightforward. Assessment of volume responsiveness or volume tolerance, correction of vasoplegia, and modulation of pump function to improve forward flow aim to recover tissue perfusion at the macroscopic level and facilitate metabolic recovery. These strategies often must be applied simultaneously despite the traditionally used etiology-based classifications of shock. The intensivist should thus be familiar with a variety of invasive and noninvasive tools to determine the approach of greatest perceived yield and evaluate efficacy of interventions.

 This review contains 4 figures, 1 table, and 50 references.

Key Words: anaerobic metabolism, fluid responsiveness, hemorrhagic shock, lactic acidosis, measurement of intravascular volume, neurogenic shock, septic shock, shock, Swan-Ganz catheter, treatment of shock

The concept of and approach to multiple organ dysfunction syndrome (MODS), also known as progressive systems failure, multiple organ failure, and multiple system organ failure, have evolved over the last decade. Characterized by progressive but potentially reversible tissue damage and dysfunction of two or more organ systems that arise after a significant physiologic insult and its subsequent management, MODS evolves in the wake of a profound disruption of systemic homeostasis. Pre-existing illness, nutritional status, hospital course, and genetic variation all lead to the development of organ dysfunction in patients exposed to these risk factors. The ultimate outcome from MODS is influenced not only by a patient’s genetic and biological predisposition but also by specific management principles practiced by intensivists. This review details the clinical definitions, quantification, prevention, evaluation, support, and outcomes of organ dysfunction. A figure shows the increasing severity of organ dysfunction correlated with increasing intensive care unit mortality, and an algorithm details the approach to MODS. Tables list risk factors and prognosis for MODS, the multiple organ dysfunction (MOD) score, the sequential organ failure assessment (SOFA) score, intensive care unit interventions that reduce mortality or attenuate organ dysfunction along with unproven or disproven ICU interventions, and the temporal evolution of MODS.

This review contains 1 figure, 7 tables, and 159 references.

Pulmonary insufficiency is the most common complication after surgical procedures. From minor atelectasis to acute respiratory distress syndrome (ARDS), postoperative pulmonary insufficiency occurs in up to 50% of surgeries. Here we discuss the anatomy, mechanics, and pathophysiology of pulmonary insufficiency; preoperative and postoperative assessment of lung function; and treatment for pulmonary insufficiency with regard to atelectasis, pulmonary edema, and ARDS. Pulmonary insufficiency secondary to cardiac disease, thromboembolism, and central nervous system depression are discussed elsewhere. Preoperative identification of risk factors for pulmonary insufficiency and understanding the physiologic changes in the perioperative period can potentially mitigate postoperative respiratory failure.

Acute renal failure definitions have changed dramatically over the last 5 to 10 years as a result of criteria established through the following consensus statements/organizations: RIFLE (Risk, Injury, Failure, Loss of function, End stage renal disease), AKIN (Acute Kidney Injury Network), and KDIGO (Kidney Disease: Improving Global Outcomes). In 2002, the Acute Dialysis Quality Initiative was tasked with the goal of establishing a consensus statement for acute kidney injury (AKI). The first order of business was to provide a standard definition of AKI. Up to this point, literature comparison was challenging as studies lacked uniformity in renal injury definitions. Implementing results into evidence-based clinical practice was difficult. The panel coined the term “acute kidney injury,” encompassing previous terms, such as renal failure and acute tubular necrosis. This new terminology represented a broad range of renal insults, from dehydration to those requiring renal replacement therapy (RRT). This review provides an algorithmic approach to the epidemiology, pathophysiology, diagnosis, prevention, and management of AKI. Also discussed are special circumstances, including rhabdomyolysis, contrast-induced nephropathy, and hepatorenal syndrome. Tables outline the AKIN criteria, most current KDIGO consensus guidelines for definition of AKI, differential diagnosis of AKI, agents capable of causing AKI, treatment for specific complications associated with AKI, and options for continuous RRT. Figures show the RIFLE classification scheme and KDIGO staging with prevention strategies.

This review contains 1 management algorithm, 2 figures, 6 tables, and 85 references.

Keywords: Kidney, renal, KDIGO, azotemia, critical, urine, oliguria, creatinine, dialysis

There are multiple congenital and acquired disorders of coagulation that may result in unplanned bleeding or clotting. These disorders can result in an increase in morbidity and mortality to surgical patients. Unexpected bleeding during and after surgery can be prevented by having an adequate understandings of these entities and by being aware of the available treatment options. In addition to awareness of bleeding disorders, it is important to recognize the risks associated with disorders predisposing patients to clotting, or thrombophilias. This review discusses the major inherited disorders of the coagulation cascade resulting in bleeding or clotting tendencies in relation to surgical patients. von Willebrand Disease (vWD), hemophilia A, hemophilia B, hemophilia C, acute coagulopathy of trauma, disseminated intravascular coagulation (DIC), uremic bleeding, bleeding in cirrhosis, clotting disorders, and acquired thrombophilias are covered. 

This review 4 figures, 25 tables, and 47 references.

Keywords: Thrombosis, bleeding, coagulation, disseminated intravascular coagulation, factor deficiency, factor V Leiden, von Willebrand disease, thrombophilia, clotting, hemophilia

The stress system receives and integrates a diversity of cognitive, emotional, neurosensory, and peripheral somatic signals that arrive through distinct pathways. Activation of the stress system leads to behavioral and physical changes that are remarkably consistent in their qualitative presentation. The stress response is mediated largely by the hypothalamic-pituitary-adrenal (HPA) axis and the sympathoadrenal system, which includes the sympathetic nervous system and the adrenal medulla. The stress response is normally adaptive and time limited and improves the chances of the individual for survival. The time-limited nature of this process renders its accompanying antigrowth, antireproductive, catabolic, and immunosuppressive effects temporarily beneficial and/or of no adverse consequence to the individual. However, chronic activation of the stress system as occurs in critically ill patients may lead to a number of disorders, including stress hyperglycemia, dysfunction of the HPA and hypothalamic-pituitary-thyroid (HPT) axes, and hypothalamic-pituitary growth hormone (GH) dysfunction. These disorders are reviewed in this chapter. Diagnosis of adrenal insufficiency/critical illness–related corticosteroid insufficiency and who to treat with steroids are also covered in depth. The author emphasizes the controversial management of these deregulated hormonal axes with only limited data supporting an improvement in outcome with hormonal replacement therapy.

This review contains 3 Figures, 1 Table, 39 References, 5 Board-Styled MCQs, and a Teaching Slide Set for teaching and reference purposes.

Nutritional optimization of the surgical patient remains a cornerstone of perioperative care. Significant effort and scrutiny are routinely directed to the field as it has the potential to improve outcomes, limit infectious complications, and decrease hospital length of stay and mortality. As such, previously identified cornerstones of care have been called into question. The timing, route, and intensity of nutritional supplementation remain the subject of controversy in an ever-evolving field. Previous methods of nutritional assessment, such as albumin and transthyretin, have proved unreliable, and their use is no longer recommended. In their place, new scoring systems are available to risk assess patients for malnutrition. We review the most pressing changes and assess the landscape of the field today.

Key words: critical illness, enteral, glutamine, malnutrition, nutrition, outcomes, parenteral, protein

Palliative care is a multidisciplinary approach to care that includes relief of suffering and attention to the social, spiritual, physical, and psychological needs of patients and families. The intent of palliative care is to help patients live as well as possible for as long as possible, and relevant domains of palliative care include symptom relief, prognostication, communication with patients, families and clinicians, transitions of care, and end-of-life care. Palliative care is distinct from hospice in many respects including that it can be provided simultaneously with recovery-directed treatments rather than reserved for individuals at end of life. Patients with surgical disease are particularly in need of palliative care due to the common occurrence of severe symptoms such as pain and nausea, complex decision-making, and the often sudden onset of the disease or injury which precludes preparation for the new health state.

This review contains 3 figures, 14 tables, and 63 references

Keywords: communication, end-of- life, goals of care, high-risk surgery, palliative, palliative care, palliative surgery, patient comfort, surgical decision-making, surgical prognostication

Nosocomial infections are a threat to all hospitalized patients. They can increase morbidity, mortality, length of stay, and costs and occur in almost every body site. This review features an algorithmic approach to the risk, detection, and treatment of nosocomial infections. Respiratory infections include pneumonia, tracheitis or tracheobronchitis, paranasal sinusitis, and otitis media. Operative site or injury-related infections include those occurring in wounds, the intra-abdominal space, methicillin-resistant Staphylococcus aureus (MRSA), empyema, posttraumatic meningitis, osteomyelitis, and sternal and mediastinal infection. A review of intravascular device--associated infection focuses on catheter-related bacteremia and its management. Catheter-associated urinary tract infections (UTIs) and enteric infections are also considered. Enteric infections and transfusion-associated infections are covered in depth, reviewing the most important recent advances and studies. A discussion of postoperative fever addresses the magnitude and incidence of hospital infections, UTIs, and catheter duration and pathogens typically involved and considers the associated costs and the risks of acquiring a nosocomial infection.

This review contains 5 figures, 13 tables and 292 references

Keywords: Nosocomial infection, hospital-acquired infection, MRSA, empyema, meningitis, osteomyelitis, urinary tract infection, peritonitis, postoperative fever, surgical site infection

Cell function and thus life depend on the preservation of several electrochemical gradients. Evolutionary pressures have developed several regulatory mechanisms, the penultimate goal of which is to maintain total body and distribution of each electrolyte within the intracellular and extracellular compartments at concentrations compatible with life. Ultimately, patient survival depends on this balance despite the continual changes imposed by both internal physiologic processes and external stressors. During periods of critical illness, however, these mechanisms can be overwhelmed, necessitating additional support. Indeed, disorders of electrolyte homeostasis are highly prevalent among intensive care unit patients, and severe disturbances are associated with elevated mortality. As has been previously learned, merely normalizing laboratory abnormalities without addressing the underlying pathophysiology does little to improve outcome. Thus, for those providing this care, an in-depth understanding of the biochemistry and physiology of electrolyte disorders and a systematic approach to diagnosis and therapy are complementary components essential for patient survival. This chapter discusses the major electrolytes—sodium, potassium, calcium and phosphate, and magnesium—and covers the hyper- and hypodeficiencies and disturbances for each electrolyte.

This review contains 7 Figures, 6 Tables, 5 Etiologic Algorithms, and 106 References.

A wide variety of factors and processes are involved in the metabolic response to critical illness; this chapter reviews some of these factors and metabolic responses in the critically ill surgical patient to help the clinician minimize patient debility. The features of critical illness that can cause debility include wounds, pain, inflammation, infection, and iatrogenic factors. The three major features of the metabolic response are discussed: the hyperdynamic or hypermetabolic state, muscle wasting, and glucose intolerance. Other topics considered include altered temperature regulation, the role of the central nervous system, the role of the gut, manipulating the response to critical illness, altered protein metabolism, altered carbohydrate metabolism, and systemic mediators (e.g., hormones and cytokines). 

This review contains 3 highly rendered figures, 17 tables, and 59 references

Keywords: Critical illness, metabolic response, thermoregulation, muscle wasting, glucose intolerance, burn victim, sepsis

Inflammation is a highly complex process involving vascular, neurogenic, humoral, and cellular responses. Although the descriptive features of acute inflammation have long been known (i.e., heat, redness, pain, swelling), a single satisfactory definition of this phenomenon is still lacking. Successful therapy for inflammation rests not only on investigating the type of injury, but also on the timing of the intervention. This review focuses on humoral and cellular responses to injury, defining essential and interrelated inflammatory pathways. Systemic inflammatory response system (SIRS), in relation to sepsis syndrome, is defined by the global proinflammatory physiologic response to a stimulus. In contrast, compensatory antiinflammatory response (CARS) results from a predominant antiinflammatory response to an insult, also causing immunosuppression and increased susceptibility to infection. Also discussed are the roles of cytokines, adhesion molecules, inflammatory cells such as neutrophils, mast cells, and lymphocytes, extracellular vesicles, sphingolipids, reactive oxygen metabolites, nitric oxide, the complement cascade, and eicosanoids. Therapeutic implications and trials are examined in relation to cytokines in SIRS and CARS, activated protein C, and inflammatory bowel disease.

This review contains 11 figures, 4 tables, and 79 references.

Postoperative pneumonia is currently the third most common complication seen in surgical patients and is associated with an increase in both patient morbidity and hospital costs. The incidence of postoperative pneumonia varies among the different surgical subspecialties. A number of evidence-based strategies exist regarding the prevention and management of pneumonia. However, the majority of studies on ventilator-associated pneumonia (VAP) do not specifically focus on surgical patients but rather are based on mixed medical-surgical ICU patients. The aim of this review is to define the incidence, pathogenesis, and risk factors of both postoperative and VAP; determine what pathogens are commonly encountered; discuss treatment methods; and introduce measures that can be implemented in both the surgical wards and the ICU aimed at preventing this complication.

This review contains 5 figures, 7 tables, and 64 references. 

Key Words: antimicrobial therapy, disease prevention, postoperative pneumonia, surgical critical care; ventilator associated pneumonia, culture, prevention, management, bundles, diagnosis

Sepsis accounts for approximately one in three hospital deaths, and is associated with very high health care costs due to prolonged lengths of stay in the intensive care unit and hospital. Sepsis is essentially an immunologic response to infection that is propagated systemically, leading to diffuse cellular and microcirculatory dysfunction, vasodilation, vital organ hypoperfusion, and eventual failure. This review covers the pathophysiology, stabilization/assessment, diagnosis, treatment, and disposition and outcomes of sepsis. Figures show the inflammatory and thrombotic response to infection, the action of nitric oxide on vascular smooth muscle cells, accelerated glycolysis and increased lactate production as a result of the catecholamine surge seen in septic shock, sepsis mortality associated with number of organ failures identified in the emergency department (ED), and protocolized therapy for septic shock. Tables list definitions of sepsis syndromes; frequently cited scoring systems for mortality prediction in emergency department patients with sepsis; Sequential Organ Failure Assessment (SOFA) score; current recommendations regarding treatment bundles at 3 and 6 hours of resuscitation; antibiotic recommendations based on suspected source; and vasopressors used in septic shock with recommended dosing, mechanism of action, and indications.

This review contains 5 figures, 7 tables, and 57 references

Keywords: Sepsis; Surviving Sepsis Campaign guidelines, definitions, SEP-1 sepsis quality measure, time-to-antibiotics, volume resuscitation, lactated ringers

The goal of this review is to discuss basic principles for the appropriate use of antibiotics in the surgical patient, largely focusing on the treatment of intra-abdominal infections. Limited pharmacologic data on common antibiotics are provided. Current reference sources and institutional guidelines should be used for specifics on dosing and administration. This review covers general principles, including treatment of surgical infections, laboratory tests, pharmacokinetics and pharmacodynamics, adverse reactions, antimicrobial resistance, and antibiotic prophylaxis in surgical patients. In addition,  specific considerations of appropriate antimicrobial therapy, such as acute cholecystitis/cholangitis, pancreatitis, appendicitis, diverticulitis, Clostridium difficile, and skin and soft tissue infections are presented. Tables list high-risk factors in intra-abdominal infections, empirical antibiotic based on risk stratification for the treatment of community-acquired intra-abdominal infections, dose adjustments for obese patients, most common isolated pathogens from intra-abdominal infections, 2005–2010, with resistance trends, adaptation of Tokyo guidelines on severity scoring and recommended antimicrobial therapy,  and recommended antibiotics for necrotizing soft tissue infections.

This review contains 9 tables and 59 references

Brain failure consists of a wide spectrum of central nervous system pathologies with many different neurologic manifestations. The causes of brain failure include several disease processes that result in decreased supply of blood and oxygen to the brain or metabolic derangements that affect the central nervous system. Brain failure usually results in some altered level of consciousness. Brain failure and brain death result in several pathophysiologic changes. The definition of brain death is controversial and evolving. However, clear guidelines to determine brain death have been established. These guidelines state that three cardinal findings be present to establish brain death: (1) coma or unresponsiveness, (2) absence of brainstem reflexes, and (3) apnea. Several clinical parameters must be met when these findings are made. Adjunctive studies such as four-vessel cerebral angiography, electroencephalography, and nuclear brain scintigraphy can help make a diagnosis of brain death. When brain death is established, suitability for organ transplantation should be evaluated. After obtaining consent, potential organ donation should be optimized for possible donation.

This review contains 2 figures, 6 tables, and 71 references

Keywords: brain failure, brain death, consciousness, coma, death, delirium, organ donation

This three-part review is intended to enable the reader to manage the fundamentals of mechanical ventilation in both the urgent and the nonurgent setting. This first chapter provides a functional understanding of basic pulmonary physiology as a prerequisite knowledge base prior to reviewing the concepts central to basic, traditional, and cyclical ventilation that is regularly employed in the air or ground ambulance, emergency department, operating room, and intensive care unit. Subsequent chapters will review advanced ventilation modes, adjuncts, and special problems encountered in patients with respiratory failure requiring mechanical ventilation. Each segment is intended to build on the preceding one and therefore establishes a functional unit with regard to mechanical ventilation, whether it is provided in an invasive or a noninvasive fashion.  

This review contains 5 figures, 3 tables and 13 references

Key Words: acute respiratory failure, acute respiratory distress syndrome, hypercapnia/therapy, hypoxia/therapy, mechanical ventilation, pulmonary gas exchange

In this chapter, we continue the discussion of mechanical ventilation by reviewing advanced ventilation modes such as airway pressure release ventilation and high-frequency oscillation as well as adjuncts that can be used in patients with respiratory failure. Each segment is intended to build on the preceding one and therefore establishes a functional unit with regard to mechanical ventilation, whether it is provided in an invasive or a noninvasive fashion.

This review contains 6 figures, 4 tables and 72 references.

Key Words: acute respiratory failure, airway pressure–release ventilation, acute respiratory distress syndrome, high-flow nasal cannula, mechanical ventilation, non-invasive ventilation, prone positioning

In this chapter, we complete the discussion of mechanical ventilation by examining approaches to mechanical ventilation for different patient populations and how to assess whether a patient is ready for liberation from mechanical ventilation. Each of the three chapters is intended to build on the preceding one and therefore establishes a functional unit with regard to mechanical ventilation, whether it is provided in an invasive or a noninvasive fashion. 

This review contains 1 figure, 4 tables and 34 references.

Key Words: acute respiratory failure, ARDS, mechanical ventilation liberation, spontaneous breathing trial, tracheostomy 

Chest imaging techniques are evolving with recent advances in computed tomography, magnetic resonance imaging, and ultrasonography. While conventional radiography remains an important screening tool because of its low relative cost, ease of acquisition, general availability, and familiarity, physicians must understand all techniques so as to provide patients with the most appropriate diagnostic imaging. Consultation with radiologists, use of online clinical decision support, and adherence to national guidelines such as the American College of Radiology Appropriateness Criteria®, can help clinicians make imaging decisions, especially in light of medical imaging risks that are of concern in the medical community and the general population. Choosing appropriate imaging, including whether or not to image, requires careful consideration.

This review contains 6 figures, 7 tables, and 20 references.

Key Words: Chest Radiographs, Dual-Energy Chest Radiographs, Computed Tomography, High-Resolution Chest Computed Tomography, Multidetector Row Computed Tomography, Computed Tomographic Angiography for Pulmonary Embolism, Magnetic Resonance Imaging, Single-Photon Emission Tomography (SPECT), Ultrasonography 

The human body is programmed to maintain constant homeostasis of all body systems through a complex neuroendocrine and autonomic network. Through a variety of exaggerated autonomic and cytokine responses, illness and injury alter this homeostasis. Mechanisms that are impaired include glucose cellular transport and peripheral and hepatic insulin uptake. Over the past several decades, numerous reports have described the deleterious effects of glucose variability and hyperglycemia. In a randomized prospective study of critically ill patients, Van den Berghe first reported that intensive glucose control (≤ 110 mg/dL) significantly decreased morbidity and mortality. This study was a catalyst for a multitude of subsequent reports evaluating the effects of glycemic control in other patient populations. 

This review contains 1 figures, 5 tables, and 90 references.

Keywords: Hyperglycemia, critical illness, intensive care unit, tight glycemic control, stroke, myocardial infarction, postoperative period, sepsis

A wide variety of factors and processes are involved in the metabolic response to critical illness; this chapter reviews some of these factors and metabolic responses in the critically ill surgical patient to help the clinician minimize patient debility. The features of critical illness that can cause debility include wounds, pain, inflammation, infection, and iatrogenic factors. The three major features of the metabolic response are discussed: the hyperdynamic or hypermetabolic state, muscle wasting, and glucose intolerance. Other topics considered include altered temperature regulation, the role of the central nervous system, the role of the gut, manipulating the response to critical illness, altered protein metabolism, altered carbohydrate metabolism, and systemic mediators (e.g., hormones and cytokines). 

This review contains 1 highly rendered figure, 10 tables, and 101 references

Keywords: Critical illness, metabolic response, thermoregulation, muscle wasting, glucose intolerance, burn victim, sepsis

Nosocomial infections are a threat to all hospitalized patients. They can increase morbidity, mortality, length of stay, and costs and occur in almost every body site. This review features an algorithmic approach to the risk, detection, and treatment of nosocomial infections. Respiratory infections include pneumonia, tracheitis or tracheobronchitis, paranasal sinusitis, and otitis media. Operative site or injury-related infections include those occurring in wounds, the intra-abdominal space, methicillin-resistant Staphylococcus aureus (MRSA), empyema, posttraumatic meningitis, osteomyelitis, and sternal and mediastinal infection. A review of intravascular device--associated infection focuses on catheter-related bacteremia and its management. Catheter-associated urinary tract infections (UTIs) and enteric infections are also considered. Enteric infections and transfusion-associated infections are covered in depth, reviewing the most important recent advances and studies. A discussion of postoperative fever addresses the magnitude and incidence of hospital infections, UTIs, and catheter duration and pathogens typically involved and considers the associated costs and the risks of acquiring a nosocomial infection.

This review contains 5 figures, 13 tables and 292 references

Keywords: Nosocomial infection, hospital-acquired infection, MRSA, empyema, meningitis, osteomyelitis, urinary tract infection, peritonitis, postoperative fever, surgical site infection