New horizons (Baltimore, Md.)
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Reported survival rates for severe adult respiratory distress syndrome (ARDS) patients vary from 9% to 84%. Animal study results have suggested that application of the high pressures needed to deliver commonly used tidal volumes (10 to 15 mL/kg) may induce an overexpansion of the remaining small fraction of compliant ARDS lung still capable of gas exchange. Conventional ventilatory therapy might thus superimpose an iatrogenic lung injury on the ARDS lung. ⋯ By standardizing therapy, protocols may significantly reduce the random and nonrandom noise (bias) introduced into the clinical environment by clinical care team members. This is especially important fo the many pertinent clinical questions addressed by clinical trials that cannot be double blinded. Conclusions from protocol-controlled clinical trials should be more credible and more likely to lead to action than those of the past.
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Critically ill patients experience many unpleasant and frightening events while in an ICU. Appropriate concern for pain, discomfort, and anxiety is required from caregivers. The use of reassuring mannerisms, honest communication, and analgesics and sedatives, especially during therapeutic paralysis, improves patient comfort and reduces the morbidity rate. This article reviews the therapeutic options for sedation and experience with these agents in the critically ill.
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Paralysis via neuromuscular blockade in ICU patients requires mechanical ventilation. This review historically addresses the technological advances and scientific information upon which ventilatory management concepts are based, with special emphasis on the influence such concepts have had on the use of neuromuscular blocking agents. Specific reference is made to the scientific information and technological advances leading to the newer concepts of ventilatory management. ⋯ However, adequate analgesia, amnesia, and sedation are required. For patients with severe lung disease, alveolar overdistention and hyperoxia should be avoided and may be best accomplished by total ventilatory support techniques, such as pressure control. Total ventilatory support requires neuromuscular blockade and may not provide eucapnic ventilation.
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Aggressive methods of decreasing oxygen consumption, such as therapeutic musculoskeletal paralysis, are used in patients with marginal oxygen delivery associated with cardiac and respiratory insufficiency. This is especially true of new mechanical ventilation methods designed to decrease tidal volume and peak airway pressures. ⋯ Escalated doses of sedatives, followed by oppressive hemodynamic and ventilatory side-effects, sometimes indicate the need for therapeutic musculoskeletal paralysis to quickly control life-threatening agitation syndromes. Cerebral-function monitoring with portable, noninvasive, computer-processed monitors allows quick recognition of brain functions under titrated, suspended animation in real time, facilitating modulation of therapy when the visual clues of neuronal function disappear.
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Review
Persistent paralysis in critically ill patients after the use of neuromuscular blocking agents.
Neuromuscular blocking agents (NMBAs), an important part of the pharmacologic armamentarium of the intensivist, have a long and admirable history of safety when used in the operating room for periods of time (almost always < 12 hrs). Since 1985, dozens of medical journals have reported a multitude of studies on persistent paralysis when these same agents are exported from the operating room to the ICU. Most of these reports are case presentations of patients who failed to move for days to weeks after discontinuation of NMBAs. ⋯ This article sorts through the issues surrounding persistent paralysis, and defines it as a short-term and a long-term problem. The short-term problem seems to have a pharmacologic explanation that is not difficult to correct. The long-term problem is much more complex and may have a toxic explanation that may also be more difficult to manage.