Anesthesia and analgesia
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Anesthesia and analgesia · Jul 1978
Increasing halothane concentrations reduce nitroprusside dose requirement.
There has been no description of the hemodynamic dose-response relationship between halothane and sodium nitroprusside (SNP), although these drugs are used together frequently for induction of deliberate hypotension. Utilizing aortic root cannulation and thermister-tipped pulmonary artery catheterization, this relationship was studied in 6 beagles receiving a standard 100 microgram/kg infusion of SNP solution administered at 3 different infusion rates (5, 10, and 20 microgram/kg/min) while anesthetized with 3 different concentrations of halothane (0.5, 1, and 2%). Sodium nitroprusside infusion resulted in dose-related reductions in mean arterial pressure, systemic vascular resistance, and left ventricular stroke work. ⋯ Sodium nitroprusside predictably induced hypotension during halothane anesthesia at the cost of a dose-related metabolic acidosis. Increasing the depth of halothane anesthesia afforded a greater percentage reduction in arterial pressure at each SNP infusion rate studied. Metabolic acidosis, however, developed no more rapidly at 2% halothane than it did at 0.5 or 1%.
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Anesthesia and analgesia · Mar 1978
Comparative StudyVenous air embolism: comparative merits of external cardiac massage, intracardiac aspiration, and left lateral decubitus position.
The treatment of venous air embolism was compared in adult mongrel dogs utilizing left lateral decubitus position, external cardiac massage, and intracardiac aspiration of air. Following the rapid injection of a lethal dose (15 ml/kg) of air, it was found that the left lateral decubitus position and external cardiac massage each produced 57.1 percent survival, both being as effective as intracardiac aspiration of air (61.9 percent survival). ⋯ Our data did not show intracardiac aspiration to be superior to either external cardiac massage of left lateral decubitus position despite the shorter resuscitation time. External cardiac massage has the advantage of simplicity and speed of initiation.
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One-hundred and eight-five pairs of gas samples were collected from inspired gas (10 cm behind the head at nose level) and end-tidal gas of persons administering anesthesia in 3 operating rooms during daily routine anesthesia. Mean operating-room N2O concentrations from 22 to 144 ppm (volume/volume [V/V]) were measured by gas chromatography, and large moment-to-moment variations (temporal gradients) were seen in individual operating rooms. ⋯ This poor relationship is presumably due to spatial and temporal gradients of N2O in the operating rooms. We conclude that the temporal and spatial gradients in N2O concentrations within active operating rooms are sufficiently large to invalidate estimation of exposure of anesthetic personnel to N2O from "spot" or "grab" samples collected in the breathing area.