Anesthesiology
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Cardiac morbidity and mortality after coronary artery bypass graft (CABG) surgery continue to be significant problems. To determine the prevalence, characteristics, and prognostic importance of postoperative myocardial ischemia after CABG surgery, the authors monitored 50 patients continuously for 10 perioperative days with the use of two-lead electrocardiography (ECG). ECG changes consistent with ischemia were defined as a reversible ST depression of 1 mm or greater or an elevation of 2 mm or greater from baseline, lasting at least 1 min. ⋯ Five adverse cardiac outcomes occurred on the day of surgery; all five were preceded by postoperative ischemia, three by intraoperative ischemia before bypass, and none by preoperative ischemia. Patients with late postoperative ischemia did not have an adverse cardiac outcome. The authors conclude the following: 1) ischemia is more prevalent postoperatively than preoperatively or intraoperatively before bypass; 2) the incidence of postoperative ischemia peaks shortly after revascularization, during which time it is symptomatically silent, difficult to detect, and related to adverse cardiac outcome; 3) late postoperative ischemia also is silent, but it is less prevalent and not associated with in-hospital adverse cardiac outcome; and 4) a relationship between ischemia and persistently elevated postoperative heart rate may exist and warrants additional investigation.
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Randomized Controlled Trial Clinical Trial
The electroencephalographic effects of desflurane in humans.
The electroencephalographic (EEG) effects of a new inhaled anesthetic are of interest because of the potential of such agents to produce excitatory (convulsant) activity and because of the potential usefulness of the EEG as an indicator of anesthetic depth and cerebral activity. Accordingly, we examined the EEG in 12 healthy, young male volunteers during desflurane anesthesia. Each subject had a baseline recording and then steady-state exposure to 6, 9, and 12% (0.83, 1.24, and 1.66 MAC) desflurane in O2 alone, and to 3, 6, and 9% desflurane in O2 with 60% N2O. ⋯ Desflurane significantly suppressed EEG activity; prominent burst suppression was seen at 1.24 MAC and higher. Substitution of N2O for 0.42 MAC desflurane reduced the degree of EEG suppression relative to the equipotent administration of desflurane and O2. Quantitative EEG measures for the early doses and for the later, repeated exposures did not differ.
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Randomized Controlled Trial Comparative Study Clinical Trial
Desflurane and isoflurane in surgical patients: comparison of emergence time.
In order to examine the clinical potential of desflurane (difluoromethyl-1-fluoro-2,2,2-trifluoroethyl ether) in humans, a randomized, controlled study was designed to compare time of emergence from anesthesia in patients undergoing elective surgery under desflurane anesthesia to that of patients under isoflurane anesthesia. Twenty-eight patients were randomly divided into four groups. Group 1 received isoflurane 0.65 MAC; group 2, desflurane 0.65 MAC; group 3, isoflurane 1.25 MAC; and group 4, desflurane 1.25 MAC. ⋯ Patients receiving isoflurane 0.65 MAC responded to commands 15.6 +/- 4.3 min after discontinuation of the anesthetic; patients in the desflurane 0.65 MAC group responded in 8.8 +/- 2.7 min (P less than 0.01). Emergence time for isoflurane 1.25 MAC was 30.0 +/- 11.0 min; for desflurane 1.25 MAC it was 16.1 +/- 6.0 min (P less than 0.05). Our results confirm that emergence from desflurane anesthesia is more rapid than from isoflurane.
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Comparative Study
Clinical characteristics of desflurane in surgical patients: minimum alveolar concentration.
Desflurane (formerly I-653) is a new inhalaticnal anesthetic with a promising pharmacokinetic profile that includes low solubility in blood and tissue, including fat. Since its lipid solubility is less than that of other volatile agents, it may have lower potency. Low solubility would be expected to increase the rate at which alveolar concentration approaches inspired concentration during induction as well as to increase the rate of elimination of desflurane from blood at emergence. ⋯ The MAC of desflurane in O2 was 7.25 +/- 0.0 (mean +/- SD) in the 18-30-yr age group, and 6.0 +/- 0.29 in the 31-65-yr group; the addition of 60% N2O reduced the MAC to 4.0 +/- 0.29 and 2.83 +/- 0.58, respectively. The median time from discontinuation of desflurane to an appropriate response to commands was 5.25 min. Desflurane appears to be a mild airway irritant but was well tolerated by all patients.