Crit Care Resusc
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Critically ill patients are exposed to a combination of insults that affect both respiratory and peripheral skeletal muscle function. However, different muscle groups may not be affected to the same extent by a prolonged critical illness. ⋯ Currently available bedside methods of measuring respiratory and peripheral muscle function in critically ill patients are somewhat inadequate. Yet there is evidence suggesting that respiratory muscles may be relatively spared from the damage that can occur as a result of immobility, prolonged mechanical ventilation and systemic inflammation in critical illness.
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Pulmonary injury from smoke inhalation is common in burn victims, significantly contributing to the morbidity and mortality of fire-related injuries. The impacts of improvement in other aspects of burn care have not been mirrored in treatment of smoke inhalation. Smoke is heterogeneous and unique to each fire; it comprises particulates, respiratory irritants and systemic toxins as well as heat, all contributing to the pathological insult. ⋯ Many promising treatments are currently under investigation. The therapeutic strategy of decontaminating the lungs early after smoke exposure to prevent inhalation injury has received little attention and may be of significant value. This could potentially utilise amphoteric, hypertonic chelating agents developed for topical and ocular chemical exposures.
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There is now significant evidence that initial use of the correct antibiotic saves more lives than virtually all other intensive care therapy. This means covering all possible causative organisms with the initial empirical choice. For nosocomial sepsis, broad-spectrum antibiotics must be started as soon as the relevant samples have been taken for culture, with de-escalation of therapy targeted to the causative organisms when results and susceptibilities are available. ⋯ We have shown that some patients with normal serum creatinine levels have very high creatinine clearance rates; in ICU patients with sepsis, blood pressure and tissue perfusion are maintained with large fluid loads and inotropic agents, thereby raising creatinine clearance. High clearances produce low trough concentrations of antibiotic, with important implications for underdosing and the development of antibiotic resistance. The new paradigm for treating sepsis, particularly nosocomial sepsis, is: get it right the first time, hit hard up front, and use large doses of broad-spectrum antibiotics for a short period.
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The concept of relative adrenal insufficiency in patients with severe sepsis continues to be controversial. This arises in part from the lack of an accepted "gold standard" for the diagnosis of adrenal insufficiency in the critically ill. Historically, assessment of adrenal function in this population has relied on measurement of plasma total cortisol level, in a blood sample taken either at random or as part of a corticotropin stimulation test. ⋯ We review the mechanisms known to affect tissue glucocorticoid activity and examine how they may be modified by critical illness. These include both free and interstitial cortisol concentrations, intracellular cortisol generation, and glucocorticoid-receptor activity and density. Changes in these factors are not reflected in plasma total cortisol concentrations, and more sophisticated techniques, including genetic transcriptional surveys, may be required to reveal the role of glucocorticoid insufficiency in critical illness.
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Studies consistently show that nasogastric nutrition delivers only about 60% of nutritional goals in critically ill patients. The predominant reason is abnormal gastric motility, leading to delayed gastric emptying, which is evident clinically as large gastric residual volumes. Delayed gastric emptying occurs in about 50%-60% of critically ill patients who are fed enterally and can result in malnutrition. ⋯ Feed intolerance can be treated with prokinetic drugs and/or by the placement of postpyloric feeding catheters. The place of prokinetic agents in the treatment of feed intolerance is as yet unclear, but current evidence supports the administration of erythromycin combined with metoclopramide as first-line therapy. Other novel drugs, such as methylnaltrexone, mitemcinal, ghrelin agonists and dexloxiglumide, have potential advantages over these agents but require further investigation before widespread clinical use.