Critical care medicine
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Critical care medicine · Jul 1987
Comparative StudyHemodynamic effects of continuous norepinephrine infusion in dogs with and without hyperkinetic endotoxic shock.
We compared, at constant preload maintained by polygeline (gelatin) infusion, the hemodynamic effects of continuous infusion of norepinephrine (0.5, 1, and 1.5 micrograms/kg X min) in anesthetized dogs with and without hyperdynamic endotoxic shock. In both groups, norepinephrine infusion increased systolic, diastolic and mean aortic BP, cardiac index, stroke index, index of myocardial contractility, and mean pulmonary artery pressure. No significant change in right atrial pressure, left ventricular end-diastolic pressure, heart rate, systemic vascular resistance, or pulmonary vascular resistance was observed. ⋯ Stroke index increased as contractility improved. The slight alpha-adrenergic effect of continuous, low-dose norepinephrine infusion did not impede the beneficial effects of the marked beta-adrenergic stimulation on cardiac function. The combination of these two effects improved hemodynamic disturbances of hyperdynamic endotoxic canine shock.
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Critical care medicine · Jul 1987
Continuous arteriovenous hemofiltration in critically ill children with acute renal failure.
Last year, five critically ill children with acute renal failure were treated by continuous arteriovenous hemofiltration. Mean treatment duration was 326 +/- 89 (SD)h, for a total of 1632 h. ⋯ In the four surviving patients, urinary output started between 12 and 42 days after the onset of acute renal failure. Continuous arteriovenous hemofiltration is a very effective extracorporeal therapeutic system to control azotemia, fluid, and electrolyte balance in critically ill children with acute renal failure and hemodynamic instability.
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Pulmonary gas exchange after tracheal extubation was evaluated in 25 patients to determine the effect of 50% oxygen administered during mechanical ventilation following aortocoronary bypass grafting. Twenty-five patients received postoperative mechanical ventilation for 16 to 24 h, 13 with an inspired oxygen fraction (FIO2) of no more than 0.30 and 12 with an FIO2 of 0.50. After tracheal extubation, all patients spontaneously breathed room air (FIO2 0.21). ⋯ Consequently, the PaO2 of patients who had received 50% oxygen (60 +/- 5 torr) was significantly (p less than .03) lower than the PaO2 of patients who had received no more than 30% oxygen (66 +/- 7 torr). Thus, administration of 50% oxygen, supposedly nontoxic, to mechanically ventilated patients may cause impairment of pulmonary gas exchange after tracheal extubation. Although high concentrations of supplemental oxygen are sometimes required, unnecessary elevation of FIO2 is not likely to significantly increase oxygen delivery and may contribute to postextubation pulmonary dysfunction.
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Critical care medicine · Jun 1987
Randomized Controlled Trial Comparative Study Clinical TrialRestoration of volume by crystalloid versus colloid after coronary artery bypass: hemodynamics, lung water, oxygenation, and outcome.
We compared Ringer's acetate-gluconate solution with 6% dextran-70 infused during rewarming after coronary bypass surgery. In a randomized study, 18 patients received 56 +/- 15 ml/kg of crystalloid (group 1), and 14 patients received 16 +/- 6 ml/kg of dextran (group 2). Data were taken at the following intervals: 4 to 5 h after terminating the cardiopulmonary bypass, after rewarming, the next morning on controlled ventilation and continuous positive airway pressure (CPAP) breathing, and after extubation. ⋯ After transition to the CPAP mode, hydrostatic pressures increased, more in group 2, doubling the pulmonary shunt flow. Pulmonary extravascular thermal volume did not change in either group. We conclude that hemodynamic stability occurred faster with dextran, and ventilatory weaning was somewhat easier with crystalloid.
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Critical care medicine · May 1987
Comparative StudyComparison of arterial blood gas with continuous intra-arterial and transcutaneous PO2 sensors in adult critically ill patients.
We compared the partial pressure of oxygen directly via a continuous intra-arterial probe (PiaO2) and indirectly using a transcutaneous device (PtcO2) with simultaneously obtained arterial blood PaO2. The PiaO2 values were measured using a bipolar oxygen sensor placed through an 18-ga arterial catheter. The PtcO2 values were measured using a transcutaneous O2-CO2 sensor placed on the abdomen. ⋯ To assess these instruments as trend monitors, we compared the changes in simultaneous PaO2, PiaO2, and PtcO2 values; by linear regression: delta PiaO2 = 0.90 delta PaO2 + 3.88 (r = .96, SEE = 27.7); delta PtcO2 = 0.43 delta PaO2 + 5.6 (r = .94, SEE = 15.2). We conclude that, although these instruments correlate highly with the PaO2, the SEE was substantial and therefore may limit their clinical reliability in adults. Any acute or clinically significant change in PiaO2 or PtcO2 should be confirmed with a blood gas PaO2.