bluuebunny/crossref_metadata_2025 huggingface dataset:
Tissue perfusion monitoring in the ICU
Authors: Kipnis Eric , Vallet Benoit
Published: April 2016

Resuscitation endpoints have shifted away from restoring normal values of routinely assessed haemodynamic parameters (central venous pressure, mean arterial pressure, cardiac output) towards optimizing parameters that reflect adequate tissue perfusion. Tissue perfusion-based endpoints have changed outcomes, particularly in sepsis. Tissue perfusion can be explored by monitoring the end result of perfusion, namely tissue oxygenation, metabolic markers, and tissue blood flow. Tissue oxygenation can be directly monitored locally through invasive electrodes or non-invasively using light absorbance (pulse oximetry (SpO2) or tissue (StO2)). Global oxygenation may be monitored in blood, either intermittently through blood gas analysis, or continuously with specialized catheters. Central venous saturation (ScvO2) indirectly assesses tissue oxygenation as the net balance between global O2 delivery and uptake, decreasing when delivery does not meet demand. Lactate, a by-product of anaerobic glycolysis, increases when oxygenation is inadequate, and can be measured either globally in blood, or locally in tissues by microdialysis. Likewise, CO2 (a by-product of cellular respiration) and PCO2 can be measured globally in blood or locally in accessible mucosal tissues (sublingual, gastric) by capnography or tonometry. Increasing PCO2 gradients, either tissue-to-arterial or venous-to-arterial, are due to inadequate perfusion. Metabolically, the oxidoreductive status of mitochondria can be assessed locally through NADH fluorescence, which increases in situations of inadequate oxygenation/perfusion. Finally, local tissue blood flow may be measured by laser-Doppler or visualized through intravital microscopic imaging. These perfusion/oxygenation resuscitation endpoints are increasingly used and studied in critical care.
Monitoring the microcirculation in the ICU
Authors: Ince Can , Lima Alexandre
Published: April 2016

The microcirculation is the key physiological compartment of the cardiovascular system where oxygen is delivered by convection and diffusion to respiring parenchymal cells to support cellular, and thereby organ, function. The microcirculation consists of microvessels less than 100 µmin diameter consisting of arterioles, capillaries, and venules. The smallest vessels (<6 µm) are the capillaries where most oxygen leaves the circulation by passive diffusion to cells. The critical role of the microcirculation has long been recognized, although it has recently been possible to image its function at the bedside, thus making it a clinically important compartment to monitor. Prior to this type of monitoring, peripheral perfusion was used as a surrogate before more advanced optical techniques were developed to image microcirculatory function both non-invasively and at the bedside. This chapter provides a brief overview of microcirculatory assessment.
Imaging the cardiovascular system in the ICU
Authors: Paul Richard , Price Susanna
Published: April 2016

Cardiac imaging in the critically ill can be challenging. Interpretation requires a broad knowledge of cardiovascular pathophysiology, the range of available investigations, and their sensitivity and specificity in diagnosing individual conditions. Applying first principles and interpreting findings in the clinical context are mandatory. Useful non-invasive investigations include simple chest X-ray, thoracic ultrasound, and computed tomography (CT) to detect pulmonary and extrapulmonary pathology, whilst CT coronary angiography can evaluate stent and graft patency, and identify extramural plaques, undiagnosed with conventional angiography. Invasive left heart cardiac catheterization may be indicated in patients with cardiovascular instability and particularly in patients where cardiac surgery has involved manipulation of the coronary arteries, whilst right heart catheterization remains the gold standard for haemodynamic assessment of pulmonary hypertension. Echocardiography has many applications in the ICU, ranging from haemodynamic monitoring to aiding diagnosis of complex pathology and rapid diagnosis in cardiac arrest. Other investigation modalities less frequently used in the critical care population are also discussed within this chapter.
Pathophysiology, diagnosis, and management of aortic dissection
Authors: Youssef Samuel J. , Elefteriades John A.
Published: April 2016

Aortic dissection represents a splitting apart of the layers of the aortic wall, with blood under pressure entering the dissection plane and propagating for long distances along the aorta. The pain is said to be the most severe that a human being can experience. Pain is felt substernally with ascending dissection and between the shoulder blades for descending dissection. A high degree of clinical suspicion is essential in order for the diagnosis not to be missed. Because the dissection process can impair any branch of the aorta, the patient may present with symptoms related to any organ in the body. D-dimer is 100% sensitive at detecting aortic dissection (but non-specific). The ‘Triple Rule-Out CT Scan’ can confirm the clinical suspicion of aortic dissection, while at the same time ruling-out the other two cardiac conditions that can take a patient’s life acutely. Ascending dissection (Type A) is a surgical emergency because of the likelihood of intra-pericardial rupture. Descending dissection (Type B) is usually treated medically (with ‘anti-impulse’ therapy with β‎-blockers and afterload reducers). This condition is highly litigated and lethal if missed on initial presentation. Using D-dimer and liberal imaging will prevent mis-diagnosis and save lives.
Therapeutic strategy in cardiac failure
Authors: Mebazaa Alexandre , Singer Mervyn
Published: April 2016

The fundamental therapeutic principles of heart failure management are for acute heart failure with mainly signs of pulmonary congestion, normal or high blood pressure, and no signs of low cardiac output to reduce pulmonary congestion without affecting blood pressure. Management principles of cardiogenic shock management comprise improvement of forward flow with restoration/maintenance of adequate organ perfusion. Appropriate management requires sound appreciation of the underlying pathophysiology, awareness of the actions and potential side-effects of each therapeutic intervention, and a level of monitoring and investigation sophisticated enough to assess disease severity, and the effectiveness (or otherwise) of any treatment being given. Where possible, consideration of previous comorbidity factors and chronic symptomatology should guide how aggressive intervention should be. However, these must be based on documented fact, rather than hearsay or supposition. The patient should always be given the benefit of the doubt.
Intra-aortic balloon counterpulsation in the ICU
Authors: Combes Alain , Bréchot Nicolas
Published: April 2016

The intra-aortic balloon pump (IABP) is a mechanical device consisting of a cylindrical polyethylene balloon that sits in the aorta, approximately 2 cm from the left subclavian artery. A computer-controlled console linked to either an electrocardiogramor a pressure transducer inflates the balloon with helium during diastole (counterpulsation) and actively deflates in systole. This results in an increase in coronary artery blood flow and cardiac output, and reduced left ventricular afterload. These actions combine to decrease myocardial oxygen demand and increase supply. Major complications include bleeding at the insertion site and retroperitoneal haemorrhage, critical ischaemia of the catheterized leg, catheter infection, and stroke. IABP duration usually varies from 48 to 72 hours. Weaning from IABP is not well defined; the most common approach is to reduce cycling of inflation to 1:2 or 1:4 for 15 minutes to several hours before device removal.
Ventricular assist devices in the ICU
Authors: Combes Alain
Published: April 2016

Despite major advances in pharmacological therapies for heart failure with left ventricular pump dysfunction, the number of hospitalizations for decompensated heart failure is increasing, with most patients ultimately dying of disease complications. Heart transplantation remains the only treatment providing substantial individual benefit for patients with advanced disease. However, fewer than 3000 organ donors are available worldwide per year, limiting its overall impact. Therefore, alternative approaches, such as mechanical circulatory support have been the subject of intense research over recent decades. The development of mechanical circulatory devices parallels that of cardiac surgery and cardiac transplantation. Current practice and the development of economically affordable short-term devices have resulted in updated indications for mechanical circulatory assistance for both short- and long-term support.
Causes and diagnosis of tachyarrhythmias
Authors: Walkey Allan J. , McManus David D.
Published: April 2016

Tachyarrhythmias occur during approximately 12% of medical and surgical intensive care unit hospitalizations. The haemodynamic, metabolic, autonomic, inflammatory, and pharmacological factors associated with critical illness may act as arrhythmia triggers. The occurrence of new tachyarrhythmia in a critically-ill patient may be associated with an acute decrease in cardiac output, resulting in haemodynamic instability, an event that often results in increased morbidity and mortality. Accurate electrocardiographic arrhythmia diagnosis is necessary for instituting effective therapy. This chapter reviews the various strategies for identifying the causes, and obtain accurate diagnosis for supraventricular and ventricular tachyarrhythmias that commonly occur during critical illness.
Causes, diagnosis, and therapeutic strategy in bradyarrhythmias
Authors: Gill Harminder S. , Gill Jaswinder S.
Published: April 2016

Bradyarrhythmias (defined as a heart rate <60 beat/min) occur frequently in the critical care setting. Most are related to underlying disease processes and the multidrug therapies administered. Because of the intense monitoring of these patients, recognition is generally easy. Examination of the ECG will allow diagnosis of the type of bradycardia based on the sinus node, atrioventricular node and the infra-Hissian conducting system. The extent of conduction system disease can be estimated and this has an influence on the prognosis. Bradycardias causing haemodynamic collapse require treatment of underlying causes, resuscitation, and administration of atropine and epinephrine. If there is no response to these then either transcutaneous pacing, or temporary transvenous pacing is necessary. This can be followed by implantation of a permanent pacing system. The outcome of correctly diagnosing and treating a bradyarrhythmia is excellent as long as the causative pathology can be stabilized.
Therapeutic strategy in valvular problems
Authors: Deen Jason F. , Stout Karen K.
Published: April 2016

Valvular heart disease constitutes considerable disease burden in the elderly and surgery remains the definitive treatment. Most valve dysfunction is chronic in nature and may not meet sufficient criteria for surgical consideration; however, additional stressors such as hypovolaemia, arrhythmia, or infection may lead to cardiovascular symptoms and haemodynamic compromise, necessitating intensive care unit management. Acute valve dysfunction is typically a surgical emergency, and medical therapy is selectively used to bridge to more definitive therapy. Some situations, such as mitral stenosis, may be effectively medically managed to delay a surgical procedure, but the majority of acute valve dysfunction that requires intensive care will eventually come to surgery.
Pathophysiology and causes of endocarditis
Authors: Thuny Franck , Raoult Didier
Published: April 2016

Endocarditis is defined as an inflammation of the endocardial surface of the heart. This may include heart valves, mural endocardium or the endocardium that covers implanted material, such as prosthetic valves, pacemaker/defibrillator leads and catheters. Infective and non-infective-related causes must be distinguished. In most cases, the inflammation is related to a bacterial or fungal infection with oral streptococci, group D streptococci, staphylococci and enterococci accounting for 85% of episodes. Infective endocarditis (IE) is a serious disease with an incidence ranging from 30 to 100 episodes/million patient-years. From various portals of entry (e.g. oral, digestive, cutaneous) and a subsequent bacteraemia, pathogens can adhere and colonize intracardiac foreign material or onto previously damaged endocardium due to numerous complex processes based on a unique host–pathogen interaction. Rarely, endocarditis can be related to non-infective causes, such as immunological or neoplastic. Mortality is high, with more than one-third dying within a year of diagnosis from complications such as acute heart failure or emboli. This disease still remains a diagnostic challenge with many cases being identified and subsequently treated too late. Diagnosis of IE usually relies on the association between an infectious syndrome and recent endocardial involvement. Blood cultures and echocardiography are the main diagnostic procedures, but are negative in almost 30% of cases, requiring the use of more sophisticated techniques. Computed tomography, magnetic resonance imaging and positron emission tomography are promising imaging modalities. Improved understanding of its pathophysiology and the development of relevant diagnostic strategies enables accelerated identification and treatment, and thus an improved prognosis.
Prevention and treatment of endocarditis
Authors: Grisoli Dominique , Raoult Didier
Published: April 2016

Initially always lethal, the prognosis of infective endocarditis (IE) has been revolutionized by antibacterial therapy and valve surgery. Nevertheless, it remains one of the deadliest infectious diseases, with ≥30% of patients dying within a year of diagnosis. Its incidence has also remained stable at 25–50 cases per million per year, and results predominantly from a combination of bacteraemia and a predisposing cardiac condition, including endocardial lesions and/or intracardiac foreign material. While antibiotic prophylaxis is recommended by various learned societies to cover healthcare procedures with the potential of causing bacteraemia in at-risk patients, there is no evidence to support this strategy. Even though the benefits are hypothetical, national guidelines should still be followed to avoid medico-legal issues. General preventive measures, such as education of clinicians and at-risk patients appear to be more crucial. Invasive procedures, especially intravenous catheterization, should be kept to the minimum possible. The severity of IE mandates a multidisciplinary and standardized approach to treatment, with involvement of dedicated surgeons within specialist centres. Standardized antibiotic protocols have produced dramatic reductions in hospital and 1-year mortality in reference centres. Most deaths now result from complications that constitute definite surgical indications, so optimization of surgical management and avoidance of delay will clearly improve prognosis. This disease has now entered an ‘early surgery’ era, with a more aggressive surgical approach showing promising results. Conditions such as septic shock, sudden death, and vancomycin-resistant staphylococcal endocarditis still constitute therapeutic and research challenges, and justify an important role for specialist centres.
Diagnosis and management of pulmonary embolism
Authors: Singer Mervyn
Published: April 2016

Computerized tomographic pulmonary angiography is the current gold standard tool for the diagnosis of pulmonary embolism. Mortality risk stratification based on clinical, imaging, and biochemical indices dictates the treatment strategy employed in an individual patient from outpatient anticoagulation to surgical or percutaneous embolectomy for severe, life-threatening cases.Presentation of acute pulmonary embolism ranges from a chance diagnostic finding in an otherwise asymptomatic patient through to shock and cardiac arrest. The degree of obstruction and the ability (or otherwise) of the patient to compensate for any cardiorespiratory derangement will dictate the symptomatology, clinical findings, and eventual outcome. The scale of medical intervention—ranging from anticoagulation through to thrombolysis and, on occasion, embolectomy—can be based on a variety of clinical, biochemical and imaging risk indices.
Normal physiology of the gastrointestinal system
Authors: Blaser Annika Reintam , Deane Adam M.
Published: April 2016

The gastrointestinal (GI) system is responsible for digestion and absorption, but also has important endocrine, immune and barrier functions. Additionally, the GI system plays a major role in fluid, electrolyte and acid-base balance. The GI system is regulated by complex myogenic, neural and humoral mechanisms, and, in health, these are affected by the presence of luminal nutrient, thereby modulating function of the GI system. Accordingly, GI function varies depending on whether a person is fasted or in the postprandial state. Adequate fasting and postprandial perfusion, motility and exocrine secretion are required for ‘normal’ functioning. The protective mechanisms of the GI system consist of physical (intact gut mucosa), non-immune (gastric acid, intestinal mucin, bile and peristalsis) and immune (gut-associated lymphoid tissue, GALT) elements. Disruption of GI protection is a putative mechanism underlying the development of multiple-organ dysfunction syndrome. Maintenance of GI function is increasingly recognised as an important factor underlying survival in critical illness.
Normal physiology of the hepatic system
Authors: Bernal William , Quaglia Alberto
Published: April 2016

Hepatic blood inflow is from two sources—high-pressure, well-oxygenated blood from the hepatic artery and low-pressure, partly deoxygenated blood from the portal vein. Hepatic inflow is maintained by variation in flows in these two systems. Although less than a third of total blood flow is delivered via the hepatic artery, it is responsible for the majority of hepatic oxygen supply. The liver can be subdivided into eight functionally independent segments, each with its own vascular inflow, outflow, and biliary drainage. The tri-dimensional hepatic microstructure is complex with geographic heterogeneity of hepatocellular function, and resistance to toxic, ischaemic, and metabolic damage. The liver is central to a wide variety of synthetic, metabolic, and detoxification functions. The overall balance of activity may be altered rapidly in response to systemic inflammatory stimuli.
Diagnosis and management of upper gastrointestinal haemorrhage in the critically ill
Authors: Pirani Tasneem , Rahman Tony
Published: April 2016

Upper gastrointestinal haemorrhage is a medical emergency that may present with haematemesis and/or melena. An exhaustive history and careful examination aids in identifying the cause of bleeding and directing appropriate management. Validated scoring systems exist to guide the urgency of endoscopic therapy, although these should not be used in isolation, but in conjunction with complete patient assessment. The initial priority should be to resuscitate and stabilize the patient using the airway, breathing, circulation, and disability framework. Resuscitation should be guided by clinical and physiological parameters. Patients should be managed in an environment where vital signs such as heart rate, blood pressure, respiratory rate, conscious level, and urine output are monitored at least hourly. Attempts should be made to correct coagulopathy. Specialist advice should be sought from haematologists for guidance on the most appropriate use of packed red cells and blood products. Over-transfusion should be avoided. Initiation of pre-endoscopy proton pump inhibitor therapy, in particular to avoid definitive endoscopic therapy, is not recommended. Diagnostic endoscopy and therapy should be conducted within 24 hours of presentation. Numerous endoscopic therapies exist—when epinephrine is used for local tamponade and vasoconstriction, application of dual modality treatment is recommended. In cases where endoscopic therapy fails or is not possible, radiological diagnosis, and embolization may become necessary. Occasionally, surgery is required for definitive treatment—close liaison with surgeons is therefore necessary, especially where initial endoscopy is considered suboptimal or re-bleeding occurs.
Pathophysiology and causes of lower gastrointestinal haemorrhage
Authors: Kobayashi Leslie M. , Coimbra Raul
Published: April 2016

Lower gastrointestinal bleeding (LGIB), presenting as melena or haematochezia, is a common cause of emergency department visits and hospital admission, and is responsible for significant health care expenditure in the United States. LGIB is increasing in frequency and is particularly prevalent among the elderly, where polypharmacy and anticoagulants can both cause and exacerbate LGIB. The most common causes of LGIB are diverticulosis, haemorrhoids, and both benign and malignant masses. However, when occurring in the intensive care unit, more unusual causes, such as ischaemic colitis and solitary rectal ulcer, should be strongly considered.
Ileus and obstruction in the critically ill
Authors: Stevens Philip , Dark Paul
Published: April 2016

Obstruction is the commonest cause of acute intestinal failure in critical care. Management is dependent upon whether it is adynamic or mechanical in origin. Paralytic ileus is managed conservatively by correction of electrolyte disturbances, nutritional support, and minimization of enterostatic drug use. Pharmacological agents aimed at reducing sympathetic stimuli may be useful, although widespread application is limited due to anti-muscarinic side effects. Peripherally acting μ‎-opioid receptor antagonists, may have a role, although data in critical illness are lacking. Prokinetic agents have not been shown to reduce ileus in clinical trials. Colonoscopic decompression may be required when conservative management fails. Rarely, surgical decompression becomes necessary if ileus arises in the context of abdominal compartment syndrome. Mechanical obstruction is more likely to require surgery, although adhesional obstruction, responsible for 80% of small bowel obstruction, may settle within 7 days of conservative management. Large bowel obstruction is more commonly due to tumours, diverticular stricture, or volvulus, and more likely to require endoscopic or surgical intervention. The hallmark of obstruction is colic, characterized by an inability to settle, in contrast to the peritonitic patient who lies completely still. Peritonitis in the presence of obstruction indicates possible perforation or necrosis for which urgent operative intervention is required. Clinical features may be absent in sedated patients hence the index of suspicion should remain high in any critically-ill patient intolerant of enteral feeding.
Pathophysiology and management of raised intra-abdominal pressure in the critically ill
Authors: De laet Inneke E. , Malbrain Manu L. N. G.
Published: April 2016

The deleterious effects of raised intra-abdominal pressure (IAP) on organ function and mortality have been known for decades, even centuries. Interest in this phenomenon has revived since the 1980s and, recently, the World Society for the Abdominal Compartment Syndrome has published new consensus definitions and guidelines. This chapter will focus on the new definitions for intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS), identify risk factors for the development of IAH/ACS, provide guidelines for IAP monitoring (including when to start, how to measure, and when to stop), and discuss both surgical and medical treatment options for both IAH and ACS. The effect of increased IAP on different organ systems is explained and suggestions on how to adjust ICU management of the patient with IAH are offered.
Perforated viscus in the critically ill
Authors: Rotstein Ori D.
Published: April 2016

Visceral perforation presents with either localized or diffuse abdominal pain and tenderness depending on the ability of the peritoneal host defence mechanisms to contain the spread of gastrointestinal content from the site of perforation. The most common causes of perforation are appendicitis, diverticulitis, and peptic ulcer disease. The diagnosis is based on clinical symptoms and signs, supported by appropriate imaging. CT scanning is an accurate method of diagnosing perforation and can provide information about the underlying pathological process. The principles of treatment include adequate physiological support, appropriate antimicrobial therapy and intervention to control the source of infection and prevent its recurrence.
Intra-abdominal sepsis in the critically ill
Authors: Doyle Jeffrey D. , Marshall John C.
Published: April 2016

Intra-abdominal infection encompasses a broad group of infections arising both within the peritoneal cavity and the retroperitoneum. The probable bacteriology reflects patterns of normal and pathological colonization of the gastrointestinal tract. Anaerobic bacteria are found in the distal small bowel and colon. The abdomen is the second most common site of infection leading to sepsis in critically-ill patients. Intra-abdominal infections can be complex to manage and require excellent collaboration between intensivists, diagnostic and interventional radiologists, surgeons, and sometimes gastroenterologists and infectious disease specialists. Prompt diagnosis, appropriate antimicrobial coverage and timely source control are the cornerstones of successful management. The spectrum of pathologic conditions responsible for intra-abdominal infection is broad, although some common biological features facilitate an understanding of their diagnosis and management.
Management of the open abdomen and abdominal fistulae in the critically ill
Authors: Stevens Philip , Carlson Gordon
Published: April 2016

Management of the open abdomen and intestinal fistulae remains a significant challenge. Leaving the abdomen open when it is possible to close it confers no benefit and may increase morbidity. The abdomen may be left open as part of a ‘damage control’ strategy in an unstable patient with abdominal trauma, or in other conditions in which it may be impossible to close because swollen intestinal loops, retroperitoneal haematoma, or oedema may lead to abdominal compartment syndrome. It may also be inappropriate to close the abdomen when there has been infection that cannot be readily controlled. Intestinal fistulae are associated with considerable morbidity and mortality. Management is described by the four ‘R’s of resuscitation, restitution, reconstruction and rehabilitation. Eradication of sepsis, improved wound and skin care, safe nutritional support and appropriate timing of surgical intervention have reduced mortality related to enterocutaneous fistulae from 65 to <10% over the last 30 years. However, mortality from enteroatmospheric fistulae remains high. Fifty to eighty per cent of enterocutaneous fistulae close spontaneously, compared with only 10% of colonic fistulae. Refistulation rates are high despite operative repair.
Pathophysiology, diagnosis, and assessment of acute pancreatitis
Authors: Skipworth James R. A. , Pereira Stephen P.
Published: April 2016

The incidence of acute pancreatitis continues to increase, but the attendant mortality has not decreased for >30 years. The pathogenesis remains poorly understood, but the initial mechanism appears to be intracellular activation of pancreatic enzymes, with micro- and macrovascular dysfunction, in conjunction with a systemic inflammatory response acting as a key propagating factor and determinant of severity. A multitude of causes or initiators exist, but there is a common pathophysiological pathway. The use of conventional scoring systems, combined with repeated clinical and laboratory assessment, remain the optimal method of predicting early severity and organ dysfunction. Death occurs in a biphasic pattern with early mortality (<2 weeks) secondary to SIRS and MODS; and late deaths (>2 weeks) due to superinfection of pancreatic necrosis. Assessment of severity should reflect this, with early severity being diagnosed in the presence of organ failure for >48 hours, and late severity defined by the presence of pancreatic and peri-pancreatic complications on CT or other appropriate imaging modalities.
Management of acute pancreatitis in the critically ill
Authors: Rajendram Rajkumar
Published: April 2016

The major causes of morbidity and mortality in acute pancreatitis are organ dysfunction and infection of necrotic tissue. Management should aim to prevent, or to diagnose and treat, the complications of pancreatic inflammation, and any predisposing factors to avoid recurrence. Medical management is essentially supportive with oxygen, intravenous fluids, analgesia, enteral or parenteral nutrition, and correction of metabolic abnormalities. Patients with severe acute pancreatitis are unlikely to resume prompt oral intake so nutritional support is also required. Post-pyloric feeding is not required if nasogastric feeding is tolerated. However, enteral nutrition, whether oral, gastric, or post-pyloric, can cause pain, recurrence of pancreatitis or an increase in fluid collections, so parenteral nutrition may be necessary. The necrotic pancreas becomes infected in a third of patients with severe acute pancreatitis. Treatment of infection includes systemic antimicrobials, enteral nutrition, percutaneous aspiration, and necrosectomy. However, compared with open necrosectomy, a minimally invasive step-up approach consisting of percutaneous drainage followed, if necessary, by open necrosectomy, reduces morbidity and mortality. The aetiology of the pancreatitis must also be treated to prevent recurrence and the complications of pancreatic failure. Gallstones are the most common cause of pancreatitis that requires specific treatment. Endoscopic or surgical removal of stones may reduce the severity of pancreatitis. Patients should also have cholecystectomy after recovery from gallstone pancreatitis. Effective management of acute pancreatitis requires multidisciplinary engagement. The mainstay of management involves supportive prevention and treatment of complications, infection, and organ failure to avoid or delay surgery.
Diagnosis and assessment of acute hepatic failure in the critically ill
Authors: Patel Sameer , Wendon Julia
Published: April 2016

Establishing the aetiology of acute hepatic failure is essential for correct and timely management. An exhaustive history and examination is crucial in targeting investigations and initiating management. Clinical assessment allows risk stratification, identifying those patients who can be managed locally from those best served in a specialist centre with liver transplantation capability. History should focus on the presenting problem, time of onset and speed of deterioration, and establish features consistent with hyperacute, acute or subacute ALF to guide prognostication. Examination should initially focus on rapid assessment and resuscitation before searching for signs leading to more specific differential diagnoses. Investigations should encompass the variety of potential causes, ranging from basic to more specialist studies. Prognostication is critical for stratification of those patients who may benefit from a potentially life-saving transplantation. Several risk stratification and predictive tools exist to differentiate those patients likely to recover, those unlikely to survive despite maximal intervention, and those who would potentially benefit from transplantation.
Management of acute hepatic failure in the critically ill
Authors: Joshi Deepak , Auzinger Georg
Published: April 2016

Acute liver failure occurs in patients with acute hepatic necrosis resulting in hepatic encephalopathy, jaundice and coagulopathy. Acute liver failure is a multisystem disorder. The management is initially supportive. Intravenous N-acetylcysteine is recommended for all patients. Brain dysfunction is common. Elective intubation is recommended for all patients who develop Grade III hepatic encephalopathy. Liver transplantation is an appropriate and viable treatment for acute liver failure. Early and safe transfer to a transplant centre for transplant assessment is advised.
Extracorporeal liver support devices in the ICU
Authors: Jalan Rajiv , Agarwal Banwari
Published: April 2016

Liver failure is common and carries high morbidity and mortality. Liver transplantation (LT) is the only definitive treatment available performed as an emergency in acute liver failure and electively for chronic liver disease. In the last 50 years, a number of extracorporeal liver support devices and modifications have emerged , some of them purely mechanical in nature aimed at detoxification, while others are cell based systems possessing bio-transformational capability. Mechanical devices are mainly based on albumin dialysis, albumin being a key transporter protein that is severely deficient and irreversibly destroyed in liver diseases. Despite a sound scientific rationale and good safety profile, none of the currently available devices have shown enough promise to be incorporated in routine clinical practice, their use being limited to specific clinical situations. This chapter describes currently available devices, their operational characteristics, current evidence of their utility and limitation, and the future developments in the field of extracorporeal liver support.
Indirect calorimetry in the ICU
Authors: Nates Joseph L. , Tajchman Sharla K.
Published: April 2016

Critically-ill patients have unpredictable and dynamic metabolic demands that are difficult to predict and quantify. Combined with the high incidence of pre-existing or development of malnutrition in the ICU, these metabolic demands have deleterious effects on outcomes when patients are provided with inadequate or inappropriate nutrition support. Providing adequate nutritional support that meets these varying metabolic demands is a long-standing challenge in the intensive care unit (ICU). Indirect calorimetry (ICal) is a tool that allows ICU practitioners to accurately assess energy expenditure (EE) in critically-ill patients with unpredictable metabolic demands to optimize nutrition support. ICal provides clinicians with a patient’s measured EE (MEE), a quantification of cellular metabolism, and respiratory quotient (RQ), a reflection of which substrates are primarily being utilized for fuel. Study results help clinicians target optimal nutritional goals and prevent adverse effects associated with both under- and overfeeding patients. Recent studies have suggested avoiding caloric deficits and providing tight caloric control may improve morbidity and mortality outcomes in critically-ill patients, though more studies are needed to verify this potential benefit. Currently, there are no specific guideline recommendations to help clinicians utilize ICal in the ICU. Although ICal is considered to be the gold standard for determining EE in critically-ill patients, its use remains limited by availability, cost, and the need for trained personnel for correct use.
Monitoring renal function in the critically ill
Authors: Palevsky Paul M.
Published: April 2016

Renal function needs to be monitored in critically-ill patients to detect changes in glomerular filtration rate (GFR) and promptly diagnosis acute kidney injury (AKI). In the absence of reliable bedside techniques for the assessment of GFR, continuous monitoring of urine output and frequent assessment of serum creatinine levels remain the cornerstone of renal functional monitoring. Calculated estimations of GFR should not be relied upon in critically-ill patients, particularly if kidney function is not stable. The role of serum cystatin C as a marker of GFR and biomarkers of tubular injury in routine monitoring of kidney function is uncertain.
Pathophysiology of oliguria and acute kidney injury
Authors: Bellomo Rinaldo , Prowle John R.
Published: April 2016

Oliguria and acute kidney injury (AKI) are common in critically-ill patients with studies reporting AKI affecting more than 50% of critically-ill patients. AKI is independently associated with increased mortality and is a potentially modifiable aspect of critical illness. The pathogenesis of AKI is complex and varies according to aetiology. The most common trigger in ICU patients is sepsis—the pathophysiology of septic AKI is poorly understood and probably involves intrarenal haemodynamic and inflammatory processes. In the setting of septic AKI, the classic acute tubular necrosis described in experimental models does not occur and histological changes are only minor. Activation of neurohormonal mechanisms is also important, particularly in the hepatorenal syndrome, where activation of the remain-angiotensin system appears to play a major role. The treatment of oliguria and AKI in ICU patients has traditionally relied on the administration of intravenous fluids. While such therapy is warranted in patients with a clear history, and physical examination suggestive of intravascular and extravascular volume depletion, its usefulness in other patients (e.g. septic patients) remains controversial. Removal of nephrotoxins, rapid treatment of the triggering factors, and attention to cardiac output and mean arterial pressure remain the cornerstones of the prevention and treatment of AKI in ICU.
Management of oliguria and acute kidney injury in the critically ill
Authors: Ahmed Mohammed , Bagshaw Sean M.
Published: April 2016

Acute kidney injury (AKI) remains a challenging clinical problem for clinicians caring for critically-ill patients due largely to the paucity of specific therapeutic interventions aimed at mitigating poor outcome. Those patients most at risk for the development of AKI can often be identified by an assessment of demographic, clinical, diagnostic, and procedure-related factors couple with early and intensive bedside monitoring. Importantly, critically-ill patients are often exposed to multiple discrete risks that can accumulate during their course that can negatively impact not only the duration and severity of AKI, but also probability of recovery, and long-term functional decline and risk of development of chronic kidney disease. All critically-ill patients at risk of or with milder forms of AKI should have support individualized. A clear understanding of the scope, complexity, and general principals of prevention and management of AKI are indispensable in the care of these patients and will discussed in this chapter.
Continuous haemofiltration techniques in the critically ill
Authors: Ricci Zaccaria , Ronco Claudio
Published: April 2016

Continuous renal replacement therapy (CRRT) is currently considered the mainstay of treatment for severe acute kidney injury. CRRT helps in restoration of fluid balance, control of hyperazotaemia, acid-base imbalances, and electrolyte abnormalities. Most importantly, due to its gradual, low efficiency, continuous solute and water removal, it ensures haemodynamic stability in critically-ill patients being treated with a high level of inotropic support and those with cardiovascular failure. This chapter will discuss the different solute removal techniques (diffusion and convection) and CRRT modalities (ultrafiltration, haemofiltration and haemodialysis). Insights on CRRT prescription and anticoagulation regimens will also be described on the light of the most recent clinical evidence.
Haemodialysis in the critically ill
Authors: Claure-Del Granado Rolando , Mehta Ravindra L.
Published: April 2016

Haemodialysis was the first method available to treat patients with kidney failure and remains an important treatment for critically-ill patients with acute kidney injury. Recent studies have shown that intermittent haemodialysis, sustained low-efficiency dialysis, and continuous renal replacement therapies provide similar outcomes for intensive care unit patients. Haemodialysis techniques offer several advantages—informed decisions regarding choice of mode require consideration of the operational characteristics of each method with its advantages and limitations. The choice of modality should be driven by patient characteristics and clinical scenario, ensuring that an adequate delivered dose of dialysis is achieved and there is good haemodynamic tolerance to minimize further insults to the kidney and other organs. This chapter reviews the current concepts and controversies in haemodialysis methods for renal support in the ICU.
Normal anatomy and physiology of the spinal cord and peripheral nerves
Authors: Casha Steve , Mercier Philippe
Published: April 2016

The spinal cord and peripheral nerves carry motor and autonomic efferents, as well as sensory afferents connecting the cerebrum with the body. Efferent and afferent fibres form predictable tracts within the spinal cord, forming spinal nerves as they exit the spinal canal. Peripheral nerves are often formed from complicated plexuses of spinal nerves in the cervical, lumbar, and sacral spine. Dermatomes are formed from spinal nerves that innervate specific areas of skin, while myotomes innervate a specific set of muscles. The detailed anatomy of these structures are discussed. Knowledge of the anatomy of these structures is relevant to many clinical situations encountered in the intensive care unit especially with caring for neurological, neurosurgical, orthopaedic, and trauma patients.
Assessment and therapeutic strategy for agitation, confusion, and delirium in the ICU
Authors: Balas Michele C. , Ely E. Wesley
Published: April 2016

Agitation and delirium are conditions that are highly prevalent in the intensive care unit (ICU). Both are believed to be caused by a number of modifiable and non-modifiable risk factors, and present with a variety of signs and symptoms. Consequently, these conditions are notoriously difficult to detect and treat. Variations in sedative practices, misperceptions regarding delirium and its association with outcomes, and lack of knowledge regarding screening tools, may all impede effective assessment, and management of agitation and delirium. A further complication is that many of the medications used to treat critically-ill patients are now known to increase the risk of delirium. While studies conducted over the last decade have significantly contributed to our understanding of how best to diagnose, prevent, and manage these common conditions, this knowledge is not always successfully adopted into everyday clinical practice. This chapter provides readers with an evidence-based review of agitation and delirium assessment and therapeutic strategies applicable for use in the ICU setting.
Management of unconsciousness in the ICU
Authors: Kornbluth Joshua , Stevens Robert D.
Published: April 2016

The key to the treatment of unconsciousness is an understanding of the underlying pathophysiology. Management of the unconscious patient should be targeted towards the diagnosis and treatment of the cause combined with supportive care of the patient, while the ultimate cause is elucidated. The basic tenants of emergency and critical care medicine—the ABC’s—apply to the unconscious patient with particular care if occult cervical spine injury is a possibility. The prognosis of disorders of consciousness depends heavily on the aetiology and accurate prognostication can be difficult even when the underlying cause has been determined.
Causes and management of intracranial hypertension
Authors: Stocchetti Nino , Maas Andrew I. R.
Published: April 2016

Intracranial hypertension may damage the brain in two ways—it causes tissue distortion and herniation, and reduces cerebral perfusion. The many different pathologies that can result in intracranial hypertension include subarachnoid haemorrhage, spontaneous intra-parenchymal haemorrhage, malignant cerebral hemispheric infarction, and acute hydrocephalus. The pathophysiology and specific treatment of intracranial hypertension may be different and depend on aetiology. In patients with subarachnoid haemorrhage a specific focus is on treating secondary hydrocephalus and maintaining adequate cerebral perfusion pressure (CPP). Indications for surgery in patients with intracranial hypertension due to intracerebral haemorrhage (ICH) are not only related to the mass effect, but also to remove the toxic effect of extravasated blood on brain tissue. Decompressive surgery should be considered for patients with a malignant hemispheric infarction, but in order to benefit the patient this surgery should be performed within 48 hours of the onset of the stroke. Hydrocephalus may result from obstruction of cerebrospinal fluid (CSF) flow, from impaired CSF re-absorption and occasionally from overproduction of CSF. Emergency management of acute hydrocephalus can be accomplished by external ventricular drainage of CSF. More definitive treatment may be either by third ventriculostomy or implantation of a CSF shunt diverting CSF to the abdominal cavity (a ventriculoperitoneal shunt) or to the right atrium of the heart (ventriculo-atrial shunt).
Epidemiology, diagnosis, and assessment on non-traumatic subarachnoid haemorrhage
Authors: Rao Chethan P. Venkatasubba , Suarez Jose Ignacio
Published: April 2016

Non-traumatic subarachnoid haemorrhage (ntSAH) is a neurological emergency. Clinical presentation is usually with severe headache, with or without abnormal neurological signs on clinical examination. NtSAH affects both males and females from 30 to 70 years, and the incidence increases with age. The incidence varies widely around the world. The gender distribution also varies in different countries, although overall the incidence is higher in women than in men. The commonest cause is rupture of an intracranial aneurysm, accounting for around 80% of cases. Diagnosis is usually by finding blood in the classical subarachnoid distribution on a cranial computed tomography scan. A number of grading systems are used to classify ntSAH.
Epidemiology, diagnosis, and assessment of meningitis and encephalitis
Authors: Nadel Simon , Canlas Johnny
Published: April 2016

Despite advances in antimicrobial therapy, central nervous system infections have a high morbidity and mortality. Most pathogens reach the brain by haematogenous spread following invasion through the mucosal surface of the nasopharynx. The cerebrospinal fluid inflammatory response is responsible for most of the deleterious effects of the infection. Understanding this response has allowed a more rational approach to therapy. Patients may present with non-specific features, especially neonates, infants, post-neurosurgical patients, and the elderly. This chapter will review the epidemiology, pathophysiology, clinical presentation, and diagnosis of acute bacterial meningitis and encephalitis.
Management of meningitis and encephalitis in the critically ill
Authors: Nadel Simon , Canlas Johnny
Published: April 2016

Management of CNS infections requires specific antimicrobial agents, as well as specific supportive treatment targeted at reducing raised intracranial pressure and other life-threatening complications. It is important that the need for management in an intensive care setting is considered early in the illness. Antibiotic resistance amongst the most common organisms causing bacterial meningitis is becoming more common and antibiotic therapy should be adjusted accordingly. Anti-inflammatory treatment such as steroids should be started as soon as possible in patients with proven acute bacterial meningitis. Optimally, this should be before or with the first dose of antibiotics. Vaccine research is progressing so that effective vaccines should be available in the future against all the common causes of bacterial meningitis and encephalitis, including Neisseria meningitidis serogroup b.