Critical care medicine
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Critical care medicine · May 1996
Comparative Study Clinical Trial Controlled Clinical TrialVolume-controlled versus biphasic positive airway pressure ventilation in leukopenic patients with severe respiratory failure.
To study comparatively the effects of volume-controlled vs. biphasic positive airway pressure mechanical ventilation on respiratory mechanics and oxygenation in leukopenic patients with severe respiratory failure. ⋯ Biphasic positive airway pressure ventilation offers the advantage of significantly reduced peak inspiratory and positive end-expiratory pressures at a lower FIO2 and with at least similar oxygenation and CO2 removal as achieved by volume-controlled mechanical ventilation. Our results are in line with previous reports on nonleukopenic patients and suggest that the positive effects of pressure-limited mechanical ventilation are independent of circulating white blood cells. Further studies are mandatory to demonstrate clinical benefit in this critically ill patient population.
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Critical care medicine · May 1996
Randomized Controlled Trial Clinical TrialClosed-loop control of airway occlusion pressure at 0.1 second (P0.1) applied to pressure-support ventilation: algorithm and application in intubated patients.
Airway occlusion pressure at 0.1 sec (P0.1) is an index of respiratory center output. During pressure-support ventilation, P0.1 correlates with the mechanical output of the inspiratory muscles and has an inverse relationship with the amount of pressure-support ventilation. Based on these observations, we designed a closed-loop control which, by automatically adjusting pressure-support ventilation, stabilizes P0.1, and hence patient inspiratory activity, at a desired target. The purpose of the study was to demonstrate the feasibility of the method, rather than its efficacy or even its influence on patient outcome. ⋯ The study shows that P0.1 can be automatically controlled by pressure-support ventilation adjustments with a computer. Inspiratory activity can thus be stabilized at a level prescribed by the physician.
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Critical care medicine · May 1996
Multicenter StudyPRISM III: an updated Pediatric Risk of Mortality score.
The relationship between physiologic status and mortality risk should be reevaluated as new treatment protocols, therapeutic interventions, and monitoring strategies are introduced and as patient populations change. We developed and validated a third-generation pediatric physiology-based score for mortality risk, Pediatric Risk of Mortality III (PRISM III). ⋯ PRISM III resulted in several improvements over the original PRISM. Reassessment of physiologic variables and their ranges, better age adjustment for selected variables, and additional risk factors resulted in a mortality risk model that is more accurate and discriminates better. The large number of diverse ICUs in the database indicates PRISM III is more likely to be representative of United States units.
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Critical care medicine · May 1996
Randomized Controlled Trial Clinical TrialPhysiology and pharmacokinetics of a novel hemoglobin-based oxygen carrier in humans.
To evaluate the physiology and pharmacokinetics of a novel hemoglobin-based oxygen carrier of bovine origin. ⋯ The plasma concentrations of bovine hemoglobin were directly proportional to the doses administered. An increase in diffusion capacity paralleled the plasma bovine hemoglobin concentrations. Dosing of the hemoglobin-based oxygen carrier of bovine origin to a target plasma hemoglobin concentration can be achieved using pharmacokinetic principles with measurable effects on oxygen physiology.
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Critical care medicine · May 1996
ReviewCan healthcare providers obtain judicial intervention against surrogates who demand "medically inappropriate" life support for incompetent patients?
This article analyzes, from a legal perspective, a recent phenomenon involving a clash between the values of attending medical personnel and the instructions of surrogate decision-makers acting on behalf of incompetent patients. Some hospitals have gone to court to challenge decisions by surrogates to continue life support for permanently unconscious or other gravely debilitated patients. Their claim has been that continuation of life support would be medically inappropriate and that the surrogates' decisions ought to be overridden. These petitions have thus far been rejected. The objective here is to explain those decisions and to predict the outcome of future, similar litigation. ⋯ Judicial rejection of healthcare providers' claims in the decided cases is explainable under traditional guardianship principles. The explanation lies in surrogates' authority to make decisions in the best interests of incompetent patients, and in judicial reluctance to brand life preservation of nonsuffering patients as abusive or contrary to patient interests. At the same time, the author anticipates a change in judicial posture, as courts acknowledge the widespread antipathy of people toward being indefinitely preserved in a noncognitive status. Because the judicial approach to the handling of dying persons often seeks to replicate what the patient would have wanted, there is room to consider consensus preferences where the particular patients has never indicated any deviation from those preferences. Courts will eventually override surrogate decisions that do not conform to widely shared preferences for avoiding the indignity of permanent unconsciousness or other gravely debilitated states.