Anesthesia and analgesia
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Anesthesia and analgesia · Jan 1991
Effect of obesity on safe duration of apnea in anesthetized humans.
Obese patients have a decreased functional residual capacity and, hence, a reduced oxygen supply during periods of apnea. To determine whether obese patients are at greater risk of developing hypoxemia during induction of anesthesia than patients of normal weight, 24 patients undergoing elective surgical procedures were studied. Group 1 (normal) were within 20% of their ideal body weight. ⋯ The time taken for oxygen saturation to decrease to 90% was 364 +/- 24 s in group 1, 247 +/- 21 s in group 2, and 163 +/- 15 s in group 3; these times are significantly different at P less than 0.05 between groups. Regression analysis of the data demonstrated a significant negative linear correlation (r = -0.83) between time to desaturation and increasing obesity. These results show that obese patients are at an increased risk of developing hypoxemia when apneic.
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Anesthesia and analgesia · Jan 1991
Nitrous oxide potentiates succinylcholine neuromuscular blockade in humans.
Sixty ASA physical status I and II adults received 0.3 mg/kg succinylcholine to determine the effect of prolonged administration of thiopental and that of nitrous oxide on succinylcholine neuromuscular blockade. Succinylcholine was administered either 1 min (group 1) or 6 min (groups 2 and 3) after induction of anesthesia with thiopental. In group 2, anesthesia was maintained with thiopental and the patients' lungs were ventilated with oxygen. ⋯ The degree of twitch augmentation, i.e., greater than maximal response, and times to twitch augmentation and to maximum blockade did not vary significantly among the groups. It is concluded that nitrous oxide increases succinylcholine neuromuscular blockade and that this is manifest within 6 min. This effect is not due to the duration of the anesthetic because thiopental, administered over a similar time period, did not potentiate succinylcholine.