Critical care medicine
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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.
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Critical care medicine · May 1996
Comparative StudyNitric oxide synthase inhibition versus norepinephrine for the treatment of hyperdynamic sepsis in sheep.
To investigate the effects of Nomega-mono-methyl-L-arginine (L-NMMA), an inhibitor of nitric oxide synthesis, on hemodynamics, oxygen transport, and regional blood flow in an ovine model of hyperdynamic sepsis and to compare these effects with the responses to norepinephrine. ⋯ Blocking nitric oxide synthase had a marked vasoconstrictive effect. Both norepinephrine and L-NMMA increased arterial pressure without reducing renal blood flow, leading to an improved renal function.
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Critical care medicine · May 1996
Effect of human hemoglobin on systemic and regional hemodynamics in a porcine model of endotoxemic shock.
Excessive release of nitric oxide has been implicated as being an important factor contributing to systemic arterial hypotension in septic shock. Hemoglobin is an effective nitric oxide scavenger. The purpose of this study was to test the hypothesis that treatment with cross-linked human hemoglobin can ameliorate systemic arterial hypotension and improve organ perfusion in a porcine model of normodynamic endotoxemic shock. ⋯ Treatment with hemoglobin improved mean arterial pressure in endotoxemic swine without significantly impairing blood flow to the renal or mesenteric vascular beds. Infusion of hemoglobin, however, significantly exacerbated endotoxin-induced pulmonary hypertension and arterial hypoxemia. Additional pharmacologic strategies may be necessary to ameliorate the potential adverse pulmonary effects of administering hemoglobin solutions to patients with sepsis.
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Critical care medicine · May 1996
Relationship between arterial carbon dioxide and end-tidal carbon dioxide in mechanically ventilated adults with severe head trauma.
To examine the agreement and association of a noninvasive method of measuring CO2 (using end-tidal PCO2) with PaCO2 in mechanically ventilated adults with severe head trauma. ⋯ This study indicated that end-tidal PCO2 monitoring correlated well with PaCO2 in patients without respiratory complications or without spontaneous breathing, resulting in rebreathing of gases. However, its clinical validity is questionable in patients who have the greatest need for end-tidal PCO2 monitoring (i.e., patients who have respiratory distress or who are breathing spontaneously and overriding the ventilator.