Critical care medicine
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To evaluate the effects of "ego bias" on physicians' prognostic judgments. Ego bias is defined as systematic overestimation of the prognosis of one's own patients compared with the expected outcome of a population of similar patients. ⋯ The critical care attending physicians exhibited reverse ego bias that was mainly a function of their optimism about the overall survival rate for critically ill patients. The house officers exhibited ego bias that was mainly a function of their pessimism about the overall survival rate for critically ill patients.
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Critical care medicine · Dec 1991
Anatomical variations of internal jugular vein location: impact on central venous access.
To evaluate whether underlying anatomical variations in the position of the internal jugular vein may account for difficulty in obtaining central venous access in individual patients. ⋯ These findings suggest that anatomical variation may partly account for the inability to cannulate the internal jugular vein in certain patients. In these cases, ultrasound examination quickly establishes the position of the internal jugular vein and may allow for easy and rapid access.
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Critical care medicine · Dec 1991
Effects of acute hypothermia and beta-adrenergic receptor blockade on serum potassium concentration in rats.
We hypothesized that beta-adrenergic receptor blockade would result in an increase in serum potassium concentration in hypothermic rats given a potassium load compared to non-beta-blocked, hypothermic, potassium-loaded rats. To test this hypothesis, we investigated the interaction between body temperature and beta-adrenergic receptor blockade on serum potassium concentrations in ureter-ligated rats with and without potassium loading. To achieve this goal, we performed three experiments. In the first experiment, serum potassium concentrations were determined in 16 rats as they were continuously cooled from 37 degrees C to 22 degrees C. In the second experiment, 12 ureter-ligated rats were cooled to 31 degrees C, after which they were rewarmed to 37 degrees C. Serum potassium concentrations were determined before and after cooling and on rewarming. Twelve other ureter-ligated rats were cooled to 31 degrees C, then given a potassium load until their serum potassium concentrations returned to their baseline values, after which they were rewarmed to 37 degrees C. Serum potassium concentrations were determined before and after cooling, during the potassium infusion, and on rewarming. In the third experiment, 14 rats were pretreated with propranolol and 14 rats served as controls. Half of the rats in each of these two groups were kept at 37 degrees C and half were cooled to 25 degrees C. All rats were then given a 690-mumol potassium chloride infusion. Serum potassium concentrations were determined before and after the potassium infusion. ⋯ These results suggest that acute hypothermia causes a decrease in serum potassium, probably secondary to redistribution, which is reversible on rewarming. Supplementation of potassium during hypothermia can cause a significant increase in serum potassium concentration on rewarming. Blocking beta-adrenergic receptors with propranolol did not effect hypothermia-induced hypokalemia, suggesting that the beta-adrenergic mechanism may not be functional in hypothermia.
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Critical care medicine · Dec 1991
Systemic and regional oxygen uptake and delivery and lactate flux in endotoxic dogs infused with dopexamine.
To test whether dopexamine, a dopaminergic and beta 2-adrenergic receptor agonist, would: a) direct a greater share of cardiac output to gut than to muscle when used to increase systemic oxygen delivery (DO2) in endotoxic dogs; and b) enhance the ability of peripheral tissues to extract oxygen. ⋯ Dopexamine temporarily increased systemic DO2 and VO2 in volume-expanded endotoxic dogs during normoxia and may have caused gut mucosa to be preferentially perfused and thus to be kept better oxygenated.
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Critical care medicine · Dec 1991
Resuscitation fluids for the treatment of hemorrhagic shock in dogs: effects on myocardial blood flow and oxygen transport.
The efficacy of using colloids vs. crystalloids in the treatment of hemorrhagic shock remains controversial. An important aspect in the treatment of hemorrhagic shock is the reestablishment of normal myocardial blood flow after fluid resuscitation. This study, therefore, was designed to investigate the effect of resuscitation with different plasma substitutes on myocardial blood flow and oxygen transport after acute hemorrhage in dogs. Forty-three dogs were anesthetized and bled into a heparinized Wiggers' reservoir to a mean arterial pressure of 35 mm Hg. The animals were maintained at this level of hypotension for 90 mins, whereupon the animals were infused with one of five randomly selected fluids: a) succinylated gelatin (Gelofusine); b) urea-linked gelatin (Haemaccel); c) 6% hetastarch (Hespan); d) lactated Ringer's solution; or e) shed blood. Myocardial blood flow was measured using the radiolabeled microsphere technique. ⋯ These results suggest that in lieu of blood, the artificial colloids are more effective than crystalloids in restoring myocardial blood flow and oxygen transport after acute experimental hemorrhage in dogs.