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Methods: We studied nine healthy volunteers in two sessions during steady state sedation with 0.5, 1.0, and 1.5 [mu]g/l (targeted plasma concentration) propofol or 0.2 and 0.4 vol% (end-tidal) sevoflurane. Following a 15-min equilibration period, motor responses to transcranial magnetic stimulation and peripheral (H-reflex, F-wave) stimulation were recorded, while electroencephalography and auditory evoked responses were recorded in parallel.
Results: At concentrations corresponding to two thirds of C50 awake, motor responses to transcranial magnetic stimulation were reduced by approximately 50%, H-reflex amplitude was reduced by 22%, F-wave amplitude was reduced by 40%, and F-wave persistence was reduced by 25%. No significant differences between sevoflurane and propofol were found. At this concentration, the Bispectral Index was reduced by 7%, and the middle-latency auditory evoked responses were attenuated only mildly (Nb latency increased by 11%, amplitude PaNb did not change). In contrast, the postauricular reflex was suppressed by 77%. 相似文献
Methods: Thirty-one healthy volunteers, aged 28 +/- 4 yr (mean +/- SD), were tested with verbal memory and standard, computerized neuropsychologic tests before and twice after acute isovolemic reduction of their hemoglobin concentration to 5.7 +/- 0.3 g/dl. Two sets of tests were performed in randomized order at the lower hemoglobin concentration: with the volunteer breathing room air or oxygen. The subject and those administering the tests and recording the results were unaware which gas was administered. As an additional control for duration of the experiment, 10 of these volunteers also completed the same tests on a separate day, without alteration of hemoglobin concentration, at times of the day similar to those on the experimental day. Heart rate, mean arterial blood pressure, and self-assessed sense of energy were recorded at the time of each test.
Results: Reaction time for digit-symbol substitution test increased, delayed memory was degraded, mean arterial pressure and energy level decreased, and heart rate increased at a hemoglobin concentration of 5.7 g/dl (all P < 0.05). Increasing Pao2 to 406 +/- 47 mmHg reversed the digit-symbol substitution test result and the delayed memory changes to values not different from those at the baseline hemoglobin concentration of 12.7 +/- 1.0 g/dl, and decreased heart rate (P < 0.05). However, mean arterial pressure and energy level changes were not altered with increased Pao2 during acute anemia. 相似文献
Methods: The authors studied a random selection of 489 adult patients undergoing ambulatory surgery. Smoking status was determined by self-report and confirmed with end-expired carbon monoxide analysis. The risk of respiratory complications (i.e., desaturation, cough, laryngospasm, bronchospasm, breath-holding, or apnea) and wound infection (i.e., wound redness or discharge +/- positive microbial culture, requiring antibiotic therapy) in smokers versus nonsmokers was ascertained. Odds ratios were estimated from multivariable logistic regression and adjusted for age, gender, body mass index, partner's smoking status, domiciliary smoking exposure, and extent and duration of surgery.
Results: Most smokers continued to smoke up until the day of surgery. Smokers had a higher rate of respiratory complications (32.8%vs. 25.9%; adjusted odds ratio, 1.71; 95% confidence interval, 1.03-2.84;P = 0.038) and wound infection (3.6%vs. 0.6%; odds ratio, 16.3; 95% confidence interval, 1.58-175;P = 0.019). Odds ratios comparing current plus ex-smokers with nonsmokers were of similar magnitude for most of these complications. 相似文献