Journal of anesthesia
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Journal of anesthesia · Mar 1994
Electrophysiologic effects of volatile anesthetics, sevoflurane and halothane, in a canine myocardial infarction model.
The effects of sevoflurane and halothane on the effective refractory period (ERP) and ventricular activation were examined in a canine myocardial infarction model. Sevoflurane (1 MAC) reduced the heart rate and prolonged ERP in both normal and infarcted zones. A prolongation of ERP with sevoflurane was observed also during atrial pacing at a fixed rate, but the effect was less than during sinus rhythm. ⋯ Halothane (1 MAC) prolonged ERP during sinus rhythm and atrial pacing, but to a lesser extent during the latter. Halothane also depressed ventricular activation in the infarcted zone during atrial pacing. In conclusion, sevoflurane as well as halothane selectively depresed the delayed activation and the prolongation of ERP in myocardial infarction, which may inhibit ventricular arrhythmias in myocardial infarction.
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Journal of anesthesia · Mar 1994
Effects of a forced-air system (Bair Hugger, OR-type) on intraoperative temperature in patients with open abdominal surgery.
Intraoperative hypothermia is difficult to avoid and may present a significant clinical risk during the early postoperative phase. We evaluated a forced-air system [Bair Hugger, OR-type (BH)] for warming intraoperative patients with open abdominal surgery. Twenty patients received BH warming [BH(+) group] and another 20 patients, who served as controls, did not [BH(-) group]. ⋯ Rectal and fingertip temperatures in the BH(+) group were significantly higher than those in the BH(-) group, and central-peripheral temperature gradients in the BH(+) group were significantly smaller than those in the BH(-) group during the study, except at 180 min. No shivering occurred in either group. Therefore, BH is an effective warming device during open abdominal surgery.
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The stability of enflurane in soda lime was examined. A product of enflurane decomposition was detected after the reaction of enflurane with soda lime, but not in the absence of soda lime. ⋯ The same decomposition product was produced by the reaction of enflurane with potassium, sodium, or calcium hydroxides, and it was also detected in the gas phase at a maximum concentration of 1.29 ppm at 420 min after 5% enflurane circulated with 200 ml/min carbon dioxide gas in a closed anesthesia circle system with a soda lime canister and a model lung. We concluded that enflurane was decomposed to 1-chloro-1,2-difluorovinyl difluoromethyl ether by soda lime.