Critical Care Clinics

Published by WB Saunders
Print ISSN: 0749-0704
Publications
Knowledge of the airway is expanding. New conditions, modern management strategies, and a more complete understanding of the interaction between the airway and fluid flux in the lung are presented.
 
The creation of a partnership, the hallmark of true collaborative practice, is an ongoing, dynamic process. It demands commitment, energy, and creativity. It is learned and therefore must be role modeled. One must remember that it takes time to develop collaborative relationships. One must begin slowly, walk not run, and have realistic expectations. It is a joy to work in an environment that has developed and is in the process of continually developing true collaborative practice. Hope for the future of health care lies in our ability to deliver coordinated and collaborative care. Nursing, medicine, and administration together can and must provide the solutions to our health care delivery problems before those solutions are legislated. We must set policies and priorities to appropriately allocate scarce resources. We must address personnel needs, credentialing, and compensation to ensure adequate numbers of qualified staff to meet the growing needs of our patients. We must evaluate technology and our physical environments to determine the types of services that we will offer. We must continue to broaden our collaborative efforts to extend from the patient care arena into the realms of education, research, and administration. It is up to each of us and each of our colleagues to work every day toward a more collaborative practice environment. By empowering each other, we can put into place a collaboration which "works jointly with others in intellectual endeavors" rather than one which merely "cooperates with an enemy force."
 
The evidence supports quality controlled chest compression as the initial intervention after "sudden death" before attempted defibrillation, if the duration of cardiac arrest is more than 5 minutes. The new guidelines mandate lesser interruptions for ventilation, before and following electrical shocks, and single rather than multiple electrical shocks before resuming chest compression. The new guidelines refocus on uninterrupted chest compression after cardiac arrest of nonasphyxial cause and modifications in practices that reduce the need for interruptions.
 
This article discusses current efforts to develop hemoglobin-based oxygen carriers as blood substitutes in light of the worldwide shortage of safe and viable allogeneic donor blood. There are now viable approaches to modify the intrinsic biologic properties of hemoglobin to produce improved hemoglobin-based oxygen carriers. Polymerized hemoglobin preparations have proved most successful in clinical trials due to their improved side effect profile. The goal is to evaluate blood substitutes with enhanced intravascular retention, reduced osmotic activity, and attenuated hemodynamic derangements such as vasoconstriction. Although not without substantial morbidity and mortality, the current safety of allogeneic blood transfusion demands that comparative studies show minimal adverse effects as well as efficacy and potential for novel applications.
 
Traumatic brain injury (TBI) remains the leading cause of death of children in the developing world. In 2012, several international efforts were completed to aid clinicians and researchers in advancing the field of pediatric TBI. The second edition of the Guidelines for the Medical Management of Traumatic Brain Injury in Infants, Children and Adolescents updated those published in 2003. This article highlights the processes involved in developing the Guidelines, contrasts the new guidelines with the previous edition, and delineates new research efforts needed to advance knowledge. The impact of common data elements within these potential new research fields is reviewed.
 
This article reviews important literature on the FAST and E-FAST examinations in adults. It also reviews key pitfalls, limitations, and controversies. A practical "how-to" guide is presented. Lastly, new frontiers are explored.
 
This article reviews the hypothesis that staffing with full-time intensive care physicians leads to improvements in the management of ICUs and in the outcome for ICU patients. Variations in the professional organization of critical care units in the United States are discussed. The advantages and disadvantages of open, closed, and transitional (comanagement) ICU organizational structures are presented.
 
The following six points offer a summary of principles to the manager who must develop a QA program: Institutional commitment to the QA process is essential for success. This must be embodied in the table of organization for QA and the commitment of resources to the task. The QA plan should address mechanisms for data collection, data review, and outcome reporting. Lines of responsibility should be stated clearly. The manner in which the outcomes of the QA process are implemented and communicated back to the front-line workers must be clearly stated and continually fed back to them. Clinical evaluations work best in the presence of politically neutral practice guidelines. Vociferous complainers frequently can be made part of the process, harnessing their energy to good effect. Self survey should precede an accreditation site visit by at least 6 months. The best sources of JCAHO thinking on QA methods are the many JCAHO publications, several of which focus on the critical care arena.
 
Over the last 20 years, hands-only cardiopulmonary resuscitation (CPR) has been investigated as an alternative to conventional CPR with rescue breathing for sudden cardiac arrest. Studies suggest that hands-only CPR is at least as effective as conventional CPR for bystander out-of-hospital cardiac arrest. Despite the value of hands-only CPR, it is less effective and should be avoided with a prolonged bystander CPR period or cardiac arrest of noncardiac origin, typically asphyxial. Because pediatric cardiac arrests and adult in-hospital cardiac arrests are most commonly caused by asphyxia, conventional CPR with assisted ventilation should be provided in these settings.
 
The plain film of the abdomen usually is the first radiographic examination ordered to evaluate the abdomen in the ICU patient. It is inexpensive, universally available and may be done at the bedside in the ICU. This article details and describes what to look for when interpreting a plain radiograph of the abdomen.
 
Among patients with life-threatening sepsis that has no clear site of origin, the abdomen continues to be a probable and tractable possibility. The cavity has the microbiologic and anatomic potential for sudden or indolent sepsis and the cause may be either obvious or obscure. The abdomen or the various structures may be primary sources that are secondary and independent of disease that brought the patient to peril. They also could be secondary and dependent upon an abdominal operation complicated by sepsis. The partnership of intensivist and surgical consultant, addressing possibilities and challenges, must identify the most probable cause and the most timely response for positive intervention in the critically ill patient threatened by sepsis.
 
In one's attempt to arrive at the most accurate diagnosis in the critically ill, the selection of the most efficacious and rapid imaging modality can be problematic to clinicians, especially if the clinical presentation is confusing. The selection most often, is between US and CT. In general, US is advantageous in that it can be performed at bedside and is a faster and less costly examination. Its main disadvantages are interference from intestinal gaseous distention, restricted field of view from surgical dressings or wounds, and operator-dependence for accuracy. With the newer and faster CT scanners, CT is gaining an increasingly important role in the evaluation of the critically ill, despite the need for patient transport to the radiology department. It is more effective in displaying and localizing abnormalities and more helpful for drainage guidance than US. The potential benefit of CT should outweight the risk of transport of the unstable patient, and because of CT's high cost, appropriate timing of the study and expected diagnostic benefit should be taken into consideration. Norwood reported that CT was not positive for abscess prior to the eighth postoperative day, only 55% of examinations aided in or altered the pre-examination diagnosis, and more than 70% were of no benefit to the patient. An organized approach is essential in solving complex diagnostic problems if one is to enhance patient care and efficacious use of personnel and resources. This can be accomplished best by direct communication between clinicians and radiologists before and after the examination. Radiologists who understand the clinical problems and are familiar with all diagnostic modalities should be consulted for the selection of the modality best suited to answering the question at hand. Similarly, critically ill patients should benefit most if clinicians and radiologists review the examination results together in light of the clinical presentation for more accurate and meaningful diagnosis.
 
In summary, ultrasonography and its recent advances appear ideally suited to a number of conditions common in the critically ill patient and the ICU setting. Depending on the clinical situation, and, providing appropriate technical expertise is available, ultrasonography can both gather diagnostic information and, where indicated, guide therapeutic intervention.
 
Patients in the setting of the intensive care unit can develop intra-abdominal complications that may worsen outcome. Clinical suspicion of such complications coupled with early diagnosis and treatment may reduce morbidity and mortality associated with these processes. This article addresses the diagnosis and management of some of the common causes of intra-abdominal catastrophes.
 
Trauma is the leading cause of death between the ages of 1 and 44 years. In all age groups, it is surpassed only by cancer and atherosclerosis in mortality [1]. The evaluation and treatment of abdominal injuries are critical components in the management of severely injured trauma patients. Because missed intra-abdominal injuries are a frequent cause of preventable trauma deaths, a high index of suspicion is warranted. Multiple factors, including the mechanism of injury, the body region injured, the patient's hemodynamic and neurologic status, associated injuries, and institutional resources influence the diagnostic approach and the outcome of abdominal injures.
 
During the past 15 years, many different studies have documented improved blood pressure and blood flow above the diaphragm when some type of abdominal compression was added to conventional CPR, either in animals or in humans. Rhythmically interposed abdominal compressions seem to provide even greater hemodynamic benefit than continuous abdominal binding. Both total flow and the distribution of flow to vital organs above the diaphragm are improved, while the chances of liver entrapment and damage during chest compression are reduced. The technique of interposed abdominal compression can be performed with the bare hands of a second or third rescuer. It requires no special equipment, and could be easily incorporated into existing training programs for basic rescuers. In this sense the technique may constitute a logical evolution in basic life support, if subsequent clinical research confirms that it improves outcome.
 
Markedly elevated intra-abdominal pressures will result in predictable hemodynamic consequences related to compromised venous return. When the hemodynamic abnormalities are associated with organ dysfunction of failure, patients suffer from the abdominal compartment syndrome. At-risk patients should be routinely monitored for intra-abdominal hypertension, and a multidisciplinary care paradigm should be established. Vigorous resuscitation of both surgical and medical patients highly correlates with IAH and ACS risk. Vigilance, prompt diagnosis, and intervention for abdominal compartment syndrome will reduce the morbidity and mortality in critically ill. Future challenges include altering resuscitation strategies to reduce ascites formation, earlier diagnosis of organ dysfunction, and intra-organ monitoring techniques.
 
Abdominal pathology in the critically ill or injured patient frequently leads to the use of open abdominal techniques or the actual performance of abdominal surgery in the ICU. All individuals responsible for the care of patients in the ICU should be familiar with the concepts and techniques of open abdomen wound management. ICU bedside abdominal surgery may be indicated if the patient is too unstable for transport to the operating room and the surgeon believes a limited procedure, such as a decompression of IAH, will be life-saving. Smaller procedures are also feasible, such as intra-abdominal packing changes for which the operating room is unnecessary. Development of a successful Surgery Outside the Operating Room program depends on mature cooperation between the surgeons and other professional ICU staff. Logistic details of such a program should be discussed and a scheduling protocol should be prepared before an emergent need for bedside surgery.
 
Cancer patients are at risk for profound derangements in the hemostatic mechanism due to multiple factors. Depending upon the dominant abnormality, bleeding, thrombosis or both, in conjunction with disseminated intravascular coagulation, may occur. Critical care physicians should have a high index of suspicion for underlying hemostatitic defects when a cancer patient presents with hemorrhage. Blood replacement therapy tailored to specific abnormalities coupled with effective treatment of the underlying malignancy will render the best result. Thrombosis in malignancy is a frequent occurrence and increasing in incidence due in part to the widespread use of indwelling venous catheters. Fibrinolytic therapy is effective and probably under-utilized in treating thrombosis but must be approached with care in these patients. A thorough understanding of diagnostic techniques, indications, and potential complications of anticoagulant therapy in cancer patients is essential.
 
Systemic acidosis has a negative inotropic effect on myocardial function, which in the intact animal, is counteracted by the activation of the sympathoadrenal system. Although there are extensive animal data in this field, human studies quantifying the influence of systemic acidosis on myocardial function in various disease states is lacking. In patients with hypocalcemia, a single infusion of calcium does not sustain increased calcium levels, and the hemodynamic improvement is only transient. Hemodynamic changes in septic shock are complex, and there are convincing data documenting myocardial dysfunction in sepsis. There is a need for elucidating the biochemical characteristics of the myocardial depressant factor (or factors).
 
CINMAs occur commonly in acutely critically ill inflamed patients, and can prolong respiratory failure, lead to ventilator dependency, and contribute to the development of chronic critical illness. The etiology of NMDs are diverse and overlap, and distinguishing different disease entities by clinical exam and electrophysiologic studies can be difficult. CIP, which has been the most widely studied CINMA, represents the peripheral nervous system manifestation of the MODS. Patients with CIP, particularly those with severely reduced nerve function, have a prolonged rehabilitation and a high mortality rate. Although there are no definitive treatments, diagnosing a CINMA may provide helpful prognostic information. Future preventative measures may include immunoglobulin, nerve growth factors, or strict glycemic control, although in the CCI phase general supportive care is given, including prevention of iatrogenic complications, nutritional support, psychosocial support, and physical therapy. The early recognition of CINMAs and prevention of associated complications are important to enabling CCI patients with CINMAs to recover and return home with an acceptable functional level and quality of life.
 
Patients with cancer are at risk for developing a variety of fluid and electrolyte disturbances caused by the disease process or by complications from therapy. An understanding of the pathophysiology of these potential abnormalities allows the clinician to manage patients expectantly and to avoid severe metabolic disarray by correcting imbalances promptly.
 
This article reviews the life-threatening fluid and electrolyte abnormalities that develop in association with, or as a result of neoplasms or their therapy. Ectopic hormone secretion by tumors and their resultant electrolyte aberrancies are also discussed. The emphasis of this article is on clinical phenomena encountered in the ICU that are specific to cancers and their therapy rather than being a review of electrolyte abnormalities in general. Each topic includes a discussion of the management of the abnormality.
 
Despite our heightened awareness of placental abruption, this condition remains largely unpreventable. The incidence of placental abruption may actually be on the rise due to increasing use of cocaine and "crack" and a greater contribution from abdominal trauma. Whether recurrence of abruption associated with hypertension can be prevented with low-dose aspirin is yet to be determined. Unfortunately, although our recognition of this condition may have improved, placental abruption remains a high cause of perinatal morbidity and mortality.
 
Substance use is common among individuals admitted to the critical care setting and may complicate treatment of underlying disorders. It is imperative for the critical care team to have a high index of suspicion for substance intoxication and withdrawal. This article reviews the epidemiology of substance use in this population and the treatment of common withdrawal syndromes. General principles regarding the management of substance withdrawal syndromes include general resuscitative measures, use of a symptom-triggered approach, and substitution of a long-acting replacement for the abused drug in gradual tapering dose. The authors stress the importance of long-term planning as part of the overall treatment protocol beyond the acute presentation.
 
The world has to cope with the results of an increasing number of disasters. If the planning and preparation for these disasters are to be effective, then national and international organizations are necessary to integrate the sources of advice and relief. Studies of disaster management have consistently highlighted coordination of resources as an essential element of effective response. These organizations, both governmental and voluntary, aim to do just that, and awareness of them and their work will add support.
 
Individuals at extremes of age and those who have certain underlying medical conditions are at greatest risk for hypothermia. Hypothermia may occur during any season of the year and in any climate. Prompt recognition of hypothermia and early institution of the rewarming techniques are imperative for a successful outcome with minimal complications. Several rewarming techniques are available and the decision to use any of them depends on the degree of hypothermia, the condition of the patient, and the rewarming rate possible with the technique chosen.
 
Central line-associated bloodstream infection (CLABSI) is one of the most common health care-associated infections in the United States. The costs associated with CLABSIs include an estimated 28,000 deaths in the intensive care unit and up to $2.3 billion annually. Best practice guidelines, checklists, and establishing a culture of safety in hospitals are all initiatives designed to reduce the rate of CLABSI to zero.
 
The processes involved in the lactate shuttle hypothesis (Brooks, 1986 218 ). The pathway proposes that (1) glucose enters the cell, where it is sequentially broken down to pyruvate; (2) pyruvate enters the mitochondrion, allowing respiration to continue in the tricarboxylic acid (TCA) cycle; (3) lactate is subsequently formed via the lactate dehydrogenase (LDH) reaction (4) and is then exported from the cytosolic compartment via monocarboxylate transporter (MCT) transport (5), where it is redistributed to a variety of functional sites. Note the suggested presence of mitochondrial lactate dehydrogenase (mLDH) (6), which forms the construct of the intracellular shuttle system (7). (Reproduced from Philp A, Macdonald AL, Watt PW. Lactate—a signal coordinating cell and systemic function. J Exp Biol 2005;208(Pt 24):4561–75; with permission. Available at jeb.biologists.org doi:10.1242/jeb.01961.)  
Kaplan-Meier survival curves. Kaplan-Meier survival curves (truncated at 28 days) for the three a priori defined groups of initial lactate values: low, 0.0–2.0 mmol/L (n 5 827); intermediate, 2.1–3.9 mmol/L (n 5 238); and high, 4.0 mmol/L or above (n 5 112). Time 0 represents the day of lactate measurement. LA, lactic acid. (From Springer Science1Busi- ness Media. Trzeciak S, Dellinger RP, Chansky ME, et al. Serum lactate as a predictor of mortality in patients with infection. Intensive Care Med 2007;33(6):970–7; with permission.)  
28-Day in-hospital mortality risk stratified by blood pressure and serum lactate level. (From Springer Science1Business Media. Howell MD, Donnino M, Clardy P, et al. Occult hypoperfusion and mortality in patients with suspected infection. Intensive Care Med 2007;33(11):1892–9; with permission.)  
Proposed etiologies of type B lactic acidosis. Selected pathways in glycolysis, citric acid cycle, and oxidative phosphorylation and the proposed effect of various conditions and medications on those pathways leading to lactic acidosis. ADP, adenosine diphosphate; CoQ, coenzyme Q; FADH 2 , reduced flavin adenine dinucleotide; H 1 , hydrogen ion; NAHD, reduced nicotinamide adenine dinucleotide; TCA, tricarboxylic acid; I, complex I; II, complex II; III, complex III; IV, complex IV; V, complex V.  
Lactic acidosis is a common condition encountered by critical care providers. Elevated lactate and decreased lactate clearance are important for prognostication. Not all lactate in the intensive care unit is due to tissue hypoxia or ischemia and other sources should be evaluated. Lactate, in and of itself, is unlikely to be harmful and is a preferred fuel for many cells. Treatment of lactic acidosis continues to be aimed the underlying source.
 
A metabolic acidosis is a process whose net effect would be the lowering of the pH of the body if it were unopposed. Normal blood pH is between 7.38 and 7.42, corresponding to a hydrogen ion concentration of 42 to 38 nanomoles/liter. Conceptually, a metabolic acidosis is the result of the accumulation of nonvolatile acid or the loss of serum bicarbonate, usually through the gastrointestinal or genitourinary systems. Because of the very nature of the illnesses found in critically ill patients it is understandable that metabolic acidosis is a common derangement in the intensive care unit. Metabolic acidosis results in a compensatory increase in minute ventilation; near-complete respiratory compensation can be expected within hours. A decrease in pH sensitizes peripheral chemoreceptors, which triggers an increase in minute ventilation. This compensatory hyperventilation is relatively slow and is not complete for 12-24 hours [5]. The expected PCO2 for any given degree of metabolic acidosis can be predicted using the formula: PCO2 = (1.5 x [HCO3]) + 8 +/- 2 [3]. In mechanically ventilated patients, inadequate minute ventilation will prevent this compensation.
 
This article discusses the role of amino acids in nutritional support during critical illness. The basis for assessing the requirements for protein and amino acids is presented, and the case for enhanced requirement of particular amino acids is discussed. Specific requirements for branched-chain amino acids, glutamine, and arginine are evaluated.
 
Acinetobacter is a formidable challenge to managing critically ill patients. This pathogen's ability to rapidly develop antimicrobial resistance to all currently available antimicrobial agents is concerning because increasing data support attributable mortality to these bacteria when associated with hospitalized patients with comorbidities and severe illness. The role of dual therapy is currently unclear and might be associated with increased toxicities without proven synergy or ability to prevent the development of resistance. Infection control and antibiotic control measures might have the greatest impact on these bacteria. Continued efforts are needed to develop new antimicrobial agents against this pathogen and assess the ideal currently available agents.
 
The ability to diagnose and treat infectious diseases and handle infectious disease outbreaks continues to improve. For the most part, the major plagues of antiquity remain historical footnotes, yet, despite many advances, there is clear evidence that major pandemic illness is always just one outbreak away. In addition to the HIV pandemic, the smaller epidemic outbreaks of Legionnaire's disease, hantavirus pulmonary syndrome, and severe acute respiratory syndrome, among many others, points out the potential risk associated with a lack of preplanning and preparedness. Although pandemic influenza is at the top of the list when discussing possible future major infectious disease outbreaks, the truth is that the identity of the next major pandemic pathogen cannot be predicted with any accuracy. We can only hope that general preparedness and the lessons learned from previous outbreaks suffice.
 
Increasing numbers of infants and children with AIDS are being admitted to the PICU, especially in certain geographic areas. Clear diagnostic criteria are available to aid in the diagnosis. As many as 50 per cent of these patients may be first diagnosed with AIDS during their PICU stay. Most patients are admitted because of ARF, but septic shock and CNS disorders are also common. Acute PICU mortality is in excess of 80 per cent, and presently the long-term mortality for this syndrome stands at 100 per cent. The economic impact of this epidemic is enormous and may become catastrophic if a national strategy to deal with these costs is not developed promptly. The PICU has an important role both in terms of resource use and cost containment. Awareness of unique stresses on medical and nursing staff caring for these children, as well as the unique psychoemotional needs of the patients themselves, is vital. Specific infection control, nutritional, and medical-legal strategies will facilitate safe, effective delivery of care to these infants and children in the PICU. The appropriate long-term role of the PICU in the care of children with an ultimately terminal disease has yet to be determined.
 
Purpose of review: This review examines the epidemiology, diagnosis, prognosis, treatment and prevention of community-acquired pneumonia (CAP) in adults. Recent findings: CAP is a significant cause of morbidity and mortality. Streptococcus pneumoniae is the most common CAP pathogen; however, microbial cause varies by geographic location and host factors. Identification of a microbial cause in CAP remains challenging - 30-65% of cases do not have a pathogen isolated. The use of molecular techniques in addition to culture, serology and urinary antigen testing has improved diagnostic yield. Scoring systems are useful for CAP prognostication and site of care decisions. Studies evaluating novel biomarkers including pro-B-type natriuretic peptide and procalcitonin suggest potential adjunctive roles in CAP prognosis. Guideline-based treatment for CAP has changed little in recent years. Effective and timely antimicrobial therapy is crucial in optimizing outcomes and should be based on local antimicrobial susceptibility patterns. Macrolides may have additional anti-inflammatory properties and a mortality benefit in severe CAP. Preventive strategies include immunization and modification of specific patient risk factors. Summary: CAP is common and causes considerable morbidity and mortality. A comprehensive approach including advanced diagnostic testing, effective and timely antimicrobial therapy and prevention is required to optimize CAP outcomes.
 
Excessive bleeding frequently complicates the care of critically ill patients. Except in the case of trauma or inpatients with known coagulopathies, the bleeding is generally not directly related to the illness that results in admission to the intensive care unit. In general, the causes of the bleeding can be divided into three categories: consumptive coagulopathies, bleeding related to "hepatic issues," and iatrogenic causes. In most circumstances, the pathogenesis and management of these acquired coagulopathies do not differ between the adult and child patient. However, some differences do exist in regards to the clinical manifestations and management of some consumptive coagulopathies. This article reviews the more common causes of bleeding in the critically ill patient and outlines diagnostic and treatment approaches for these patients. Particular emphasis will be placed on the differences in presentation and management where differences exist.
 
CAP is traditionally considered a medical disease, and is managed with intravenous fluids and antibiotics on medical floors. Recent cost-containment efforts have shifted the provision of care to the outpatient settings, and only those with most severe disease and multiple comorbid illnesses are admitted to hospitals. Therefore, the proportion of hospitalized patients with severe CAP that need intensive care and life support is increasing. Furthermore, the incidence of severe CAP is also rising due to disproportionate growth of the elderly population that is most vulnerable to this deadly disease. Many of these elderly patients have advanced underlying diseases, and CAP might often be a terminal event superimposed on an underlying chronic debilitating illness. As ICU physicians, we need to be familiar with this disease, its complications, and its prognosis to provide intensive care in a timely and rational fashion in some patients, and refrain from life support in others. Just as prior efforts have sought to improve and standardize criteria for hospital admission, future efforts should aim to improve and standardize decisions regarding intensive care and life support in these very sick elderly patients. Future efforts in the management of CAP need to consider the postdischarge period where most deaths occur. Prevention is an important issue especially for those at high risk for CAP.
 
Intravascular catheters are essential devices in the intensive care unit, yet catheter-related bloodstream infections (CR-BSI) are associated with increased morbidity and mortality, prolonged hospitalization, and increased medical costs. Management of a CR-BSI requires antibiotics, with or without catheter removal, depending on patient and etiologic factors. Because of the high frequency of staphylococcal infections, it is wise to use a glycopeptide empirically. Extra coverage for Gram-negative bacilli should be administered in severely ill or immunocompromised patients. Once culture and sensitivity results are known, antibiotic therapy can be more selective.
 
Technological advances in critical care will undoubtedly find their way into the ICU of the 21st century. The challenge for critical care practitioners is to meticulously assess these innovations and adopt the most appropriate and efficient technologies that will improve unit function and staff efficiencies, support educational programs, and most importantly, enhance patient outcome at a reasonable cost. Hospital-based intensivists have excellent opportunities to establish leadership roles in the technology evaluation process by cultivating relationships with administrators, and through active participation in the hospital-based Technology Committee and the ICU-based multidisciplinary committee. The authors' experience has left them with the lasting impression that the evaluation and introduction of new technology is time consuming and requires perseverance and patience. Ultimately, it is hoped that technological breakthroughs coupled with a standardized approach to delivery of ICU services in the coming decades will ensure better and more efficient care to critically ill patients.
 
The competition for scarce finances for equipment/technology purchases can be won with careful preparation and documentation. Planning and implementing effective negotiation strategies can lower the cost of new technology acquisitions.
 
Intracellular magnesium is an important modulator of calcium and potassium channels in cardiac myocytes. Hypomagnesemia is common in hospitalized patients and may contribute significantly to cardiac morbidity and mortality, particularly in states associated with myocardial ischemia. Therefore, it is important to maintain the plasma magnesium concentration within the normal range in asymptomatic patients and in patients with cardiac disease as prophylaxis against the occurrence of significant arrhythmias.
 
Recombinant activated factor VII (rFVIIa) is currently licensed in the United States for treatment of bleeding episodes in patients with deficiencies of factor VIII (FVIII) or IX (FIX) who are refractory to factor replacement because of circulating inhibitors. A 1999 report of its successful use to stop what was deemed to be lethal hemorrhage after an abdominal gunshot wound in a young soldier without pre-existing coagulopathy has prompted exploration of other uses for rFVIIa. The virtual explosion of proposed uses of rFVIIa raises issues not only regarding our understanding of the coagulation system, but also regarding its efficacy, cost-effectiveness, and safety.
 
PAF is a phospholipid formed from the action of phospholipase A2 upon cellular membranes in response to immunologic or hypoxic stimuli. PAF does not exist in its active form as a storage product within cells, but is synthesized rapidly after phospholipase A2 activation. A potent lipid released by multiple cell types in mammalian systems, the emerging perspective is that PAF is a major endogenous mediator influencing the pathogenesis and outcome of ischemia and conditions of circulatory shock. These effects appear to be especially relevant to the syndrome of MSOF during critical illness. All of the major criteria for validation of a shock factor have been fulfilled for PAF. First, PAF has been measured in biological fluid of animals during shock states, although this is not an easy task since PAF is formed in minute amounts and is rapidly metabolized. Nevertheless, combinations of high pressure liquid chromatography (HPLC) and bioassay methods employing washed rabbit platelets have been successfully utilized in this regard. Second, synthetic PAF has been injected into cell suspensions, isolated tissues, and live animals, where it produces most of the effects attributed to endogenous PAF released by immunologic or hypoxic stimuli. These studies have shown that PAF exerts a variety of pathophysiologic actions, including (1) cardiodepression (that is, a negative inotropic effect), (2) reductions in systemic blood pressure, (3) leakage of fluid from the microvasculature, (4) bronchoconstriction, and (5) platelet aggregation. All of these actions of PAF can initiate or exacerbate shock and ischemic injury in multiple organ systems. Third, specific PAF receptor antagonists have been found to markedly attenuate the severity of endotoxic, anaphylactic, hemorrhagic, and traumatic shock, as well as acute myocardial ischemia. In all these conditions, a variety of PAF receptor antagonists (including PAF analogues and structurally dissimilar substances) have improved survival and have retarded pathophysiologic processes believed to be important in causing tissue injury. These processes include lysosomal membrane damage and proteolysis. Moreover PAF receptor antagonists attenuate the release of secondary toxic factors in shock, such as myocardial depressant factor. Thus, administration of specific PAF receptor antagonists early in the course of circulatory shock and organ ischemia may prove to be useful therapeutic agents in a variety of life-threatening disorders. In addition to having direct actions, PAF appears to function as a pivotal agent in a chain of mediators producing tissue injury. Recent evidence suggests that tumor necrosis factors (i.e., cachectin) stim
 
Patients with acute brain injury are a distinct group within the ICU who may develop non-neurologic organ dysfunction in the absence of systemic injury or infection. This dysfunction may arise directly as a result of the brain injury or indirectly with complications of brain-specific therapies. This article reviews the current literature with respect to the incidence of organ dysfunction or failure and its association with outcome in patients with acute brain injury. Organ system-specific etiologic considerations and management are discussed.
 
The extent and level of the spinal cord injury as well as the presence of associated injuries affects the choice of anesthetic agents, techniques, and monitoring modalities. The role of the anesthesiologist is not limited only to the administration of anesthesia, but frequently his active participation in the team approach care of the spinal cord injury patient is needed during preoperative treatment and postoperatively in the ICU setting. Understanding of the pathophysiologic changes related to the spinal cord injury helps in the delivery of better anesthetic care for severely handicapped patients.
 
This article describes the technique of left heart bypass in the treatment of both experimental and clinical acute myocardial infarction. A new technique of closed-chest percutaneous left heart bypass that can be used in patients with acute evolving myocardial infarction and cardiogenic shock is also described.
 
Traditional mechanical ventilation practices used generous tidal volumes in patients with acute lung injury and acute respiratory distress syndrome (ALI/ARDS). This approach may have caused overdistention of aerated lung units, thus exacerbating lung injury in some patients. Several recent clinical trials of traditional versus lower tidal volume strategies in ALI/ARDS yielded disparate results. In the largest study, the lower tidal volume approach was associated with lower mortality and more ventilator-free days. This article reviews the rationale for tidal volume reduction in ALI/ARDS and the differences between the studies. Several different interpretations of the recent clinical trial results are addressed.
 
Acute lung injury (ALI) involves the activation of multiple pathways leading to lung injury, resolution, and repair. Exploration of the roles of individual pathways in humans and animal models has led to a greater understanding of the complexity of ALI and the links between ALI and systemic multiorgan failure. However, there is still no integrated understanding of the initiation, the progression, and the repair of ALI. A better understanding is needed of how pathways interact in the human ALI syndrome and how complementary treatments can be used to modify the onset, severity, and outcome of ALI in humans.
 
Acute respiratory distress syndrome (ARDS) is a clinical syndrome of acute respiratory failure presenting with hypoxemia and bilateral pulmonary infiltrates, most often in the setting of pneumonia, sepsis, or major trauma. The pathogenesis of ARDS involves lung endothelial injury, alveolar epithelial injury, and the accumulation of protein-rich fluid and cellular debris in the alveolar space. No pharmacologic therapy has so far proved effective. A potential strategy involves cell-based therapies, including mesenchymal stem cells (MSCs). Herein we review basic properties of MSCs, their use in preclinical models of lung injury and ARDS, and potential therapeutic mechanisms.
 
Although there are no specific therapies for septic shock or acute lung injury that have proven efficacy in humans, a growing understanding of mechanisms of tissue injury has suggested interventions that may prevent or treat this injury. These therapies range from immunization against the glycopolysaccharide core of endotoxin to cyclooxygenase inhibitors to specific oxygen radical scavengers. Each of these treatments is effective in ameliorating at least one of the pathophysiologic manifestations of acute lung injury, although the effect of these agents in the prevention of the sequelae of fibrosis is unknown. Interaction between several factors and mediators is likely necessary for the development of acute lung injury. It is hoped that with additional knowledge regarding mechanisms of injury gained through basic science and clinical research, we can apply definitive therapy that may salvage patients who now die with sepsis and acute lung injury.
 
Top-cited authors
Bruce R Bistrian
  • Harvard University
Karen Mccowen
  • University of California, San Diego
Atul Malhotra
  • University of California, San Diego
Robert A Balk
  • Rush University Medical Center
Mitchell P Fink
  • University of California, Los Angeles