Critical care medicine
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Critical care medicine · Jan 1996
Clinical TrialInitial experience with partial liquid ventilation in pediatric patients with the acute respiratory distress syndrome.
Liquid ventilation with perfluorocarbon previously has not been reported in pediatric patients with respiratory failure beyond the neonatal period. We evaluated the technique of partial liquid ventilation in six pediatric patients with the acute respiratory distress syndrome of sufficient severity to require extracorporeal life support (ECLS). ⋯ Perfluorocarbon may be safely administered into the lungs of pediatric patients with severe respiratory failure on ECLS and may be associated with improvement in gas exchange and pulmonary compliance.
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Critical care medicine · Jan 1996
Comparative StudySpirometric versus Fick-derived oxygen consumption: which method is better?
Oxygen consumption (VO2) is often measured in critically ill patients using the Fick equation: VO2 = cardiac output x arterial-venous oxygen content difference. To determine if this method is accurate, it was compared with a spirometric technique. ⋯ The bias between the Fick and spirometrically determined VO2 values was 58 mL/min. The precision (SD of the bias) between the Fick and spirometrically determined Vo2 was 35 mL/min. Fick-derived Vo2 was greater than Vo2 measured spirometrically. The correlation coefficient was 0.90. CONCLUSIONS; Despite all attempts to reduce measurement error, there was an unexplained difference in Fick-derived and spirometrically measured Vo2. Therefore, I feel that the two methods are not interchangeable, and that calculations of Vo2 using the Fick method should be used cautiously when therapeutic maneuvers are based on these data.
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Critical care medicine · Jan 1996
Adrenergic vasopressor agents and mechanical ventilation for the treatment of experimental septic shock.
Vasopressor agents and mechanical ventilation are routine interventions for the treatment of sepsis complicated by hypotension. It was our hypothesis that such treatment singly or in combination increases the duration of survival. ⋯ No benefit or detriment was demonstrated when vasopressor agents were administered to sustain arterial pressure in the course of experimental peritonitis in this murine model of septic shock. This finding contrasted with highly significant prolongation of survival when animals were mechanically ventilated. There was no evidence that routine vasopressor therapy, under these controlled experimental conditions in rats, improved duration of survival.
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Critical care medicine · Jan 1996
Comparative StudyOxygen consumption calculated from the Fick equation has limited utility.
To determine if oxygen consumption (VO2) calculated using the Fick relationship (calculated VO2) determines total body VO2 accurately and precisely enough to employ this method during clinical assessment of oxygen transport. ⋯ Even in a tightly controlled, clinical simulation in the laboratory, calculated VO2 from the Fick relationship systematically underestimated VO2 measured with a water-sealed spirometer. If true VO2 changes, the magnitude and direction of change will be reflected by calculated VO2 but with approximately 20% error in the absolute value. Heart failure, acute lung injury, and their combination did not affect the accuracy of calculated VO2. Therefore, calculating VO2 using the Fick relationship is too inaccurate to be used for research purposes. Because assessment of the directional change of VO2 may be clinically useful, calculated VO2 can be employed with discretion during clinical oxygen transport evaluation, bearing in mind the calculation's inherent imprecision.
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Critical care medicine · Jan 1996
Hypertonic saline does not improve cerebral oxygen delivery after head injury and mild hemorrhage in cats.
To investigate the effects of hypertonic saline for resuscitation after mild hemorrhagic hypotension combined with fluid-percussion traumatic brain injury. Specifically, the effects of hypertonic saline on intracranial pressure, cerebral blood flow (radioactive microsphere method), cerebral oxygen delivery (cerebral oxygen delivery = cerebral blood flow x arterial oxygen content), and electroencephalographic activity were studied. ⋯ After a combination of hemorrhage and traumatic brain injury, neither 10% hydroxyethyl starch nor 3.0% hypertonic saline restored cerebral oxygen delivery. Although neither trauma alone nor hemorrhage alone altered electroencephalographic activity, the combination produced significant decreases in electroencephalographic activity at 60 and 120 mins after resuscitation in groups 3 and 4, suggesting that cerebral oxygen delivery is inadequately restored by either resuscitation fluid. Therefore, traumatic brain injury abolished compensatory cerebral blood flow increases to hemodilution, and neither hydroxyethyl starch nor 3.0% hypertonic saline restored cerebral blood flow, cerebral oxygen delivery, or electroencephalographic activity after hemorrhagic hypotension after traumatic brain injury.