Critical care medicine
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Critical care medicine · Feb 1999
Porcine endotoxemic shock is associated with increased expired nitric oxide.
Nitric oxide (NO) is believed to decrease systemic vascular resistance in sepsis, but the data are mainly from studies on rats and mice. We tested this hypothesis in pigs and also whether there is induction of the inducible form of nitric oxide synthase (iNOS). ⋯ The time course and pattern of changes in expired NO during endotoxemia followed the change in systemic hemodynamics, which supports a causal role for NO in sepsis. However, this is not due to a large production of NO by iNOS induction. The hemodynamic pattern, nitrite in blood, and changes in expired NO also differed markedly from those findings in rodent models and caution should be used in extrapolating from rodents to higher order animals.
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Critical care medicine · Feb 1999
Comparative StudyEffects of adrenergic-receptor blockade and ligation of spleen vessels on the hemodynamics of dogs injected with scorpion venom.
In dogs, scorpion venom evokes a rapid increase in cardiac output (CO) that decreases below baseline level in 1 hr. The changes in CO have recently been shown to be related to the effect of the venom on venous return. In the present study, we tested the hypothesis that changes in determinants of venous return are secondary to sympathoadrenal stimulation evoked by the venom, which causes splenic contracture in the first stage of envenomation leading to increased mean circulatory pressure (MCP) and CO. Persistence of adrenergic response is the main factor leading to the second stage of envenomation, characterized by an increase in resistance to venous return (Rv) and a decrease in CO. ⋯ The changes in CO and MCP following scorpion venom injection in dogs are in part related to sympathetic stimulation. Adrenergic-receptor blockade attenuated the initial inotropic effect of the venom and completely prevented a late decrease in CO and MCP. The increase in Rv is the most important factor for late decrease in CO, and results from persistent adrenergic-receptor stimulation. In addition, an Rv increase apparently expresses vasoconstriction and redistribution of blood flow. The initial increase in CO and MCP is explained mainly by adrenergic-receptor effects on the spleen leading to augmented circulatory blood volume.
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Critical care medicine · Feb 1999
Editorial Comment ReviewPEEP: blood gas cosmetics or a therapy for ARDS?
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Critical care medicine · Feb 1999
Comparative StudyPerioperative predictors of extubation failure and the effect on clinical outcome after cardiac surgery.
To determine perioperative predictors of extubation failure (requirement for reintubation and mechanical ventilation after prior successful weaning from ventilator support and extubation) after cardiac surgery and the effect on clinical outcome. ⋯ Extubation failure after cardiac surgery is uncommon. Although extubation failure increased the utilization of ICU and hospital resources, it did not affect mortality after cardiac surgery. Protocols for early extubation and ICU discharge should be modified in the presence of certain preoperative and operative predictors of extubation failure to avoid unnecessary increase in the cost of care after cardiac surgery.
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Critical care medicine · Feb 1999
Comment Letter Comparative StudyIntensive care unit support formulations.