Anesthesia and analgesia
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Anesthesia and analgesia · Aug 1991
Clinical Trial Controlled Clinical TrialEffect of prior anesthetic solution on epidural morphine analgesia.
The quality and duration of analgesia and incidence of side effects following epidurally administered morphine after cesarean section are highly variable. Two suggested sources of this variability are prior use of epinephrine-containing solutions, which may enhance both analgesia and side effects of morphine, and prior use of 2-chloroprocaine, which may inhibit epidural morphine analgesia. To examine these proposed sources of this variability we performed two studies. ⋯ In the second study, designed to test the effect of 2-chloroprocaine, 30 women received 7 mL of either 2% 2-chloroprocaine or lidocaine for epidural catheter testing, followed by 0.5% bupivacaine for epidural anesthesia. Compared to lidocaine testing, 2-chloroprocaine decreased the duration of epidural morphine analgesia (median 16 h with 2-chloroprocaine vs 24 h with lidocaine; P less than 0.05) without altering the incidence of side effects. The authors conclude that addition of epinephrine to local anesthetic does not increase the incidence of side effects or the analgesic effect from epidurally administered morphine. 2-Chloroprocaine, even when administered in small doses remote to the time of morphine injection, interferes with the duration of epidural morphine analgesia.
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Anesthesia and analgesia · Aug 1991
Hemodynamic effects of desflurane/nitrous oxide anesthesia in volunteers.
We determined the cardiovascular effects of 0.91, 1.34, and 1.74 MAC of desflurane/nitrous oxide anesthesia (60% inspired nitrous oxide contributed 0.5 MAC at each level) in 12 healthy, normocapnic male volunteers. Desflurane/nitrous oxide anesthesia decreased systemic blood pressures, cardiac index, stroke volume index, systemic vascular resistance, and left ventricular stroke work index, and increased pulmonary arterial pressures and central venous pressure in a dose-dependent fashion, while heart rate was 10%-12% and mixed venous oxygen tension was 2-4 mm Hg higher at all MAC levels than at baseline (awake). Desflurane/nitrous oxide anesthesia modestly increased left ventricular end-diastolic cross-sectional area (preload) and decreased velocity of left ventricular circumferential fiber shortening, systolic wall stress (afterload), and area ejection fraction; this combination of changes indicates myocardial depression. ⋯ After 7 h of anesthesia, regardless of the background gas, somewhat less cardiovascular depression and/or modest stimulation was apparent: cardiac index, area ejection fraction, and velocity of left ventricular circumferential fiber shortening recovered to or toward awake values, whereas heart rate was further increased. Evidence of circulatory insufficiency did not develop in any volunteers during the study. Segmental left ventricular function was normal at baseline, and no segmental wall-motion abnormalities, ST-segment change, or dysrhythmias developed.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Aug 1991
Effects of dexmedetomidine, a novel imidazole sedative-anesthetic agent, on adrenal steroidogenesis: in vivo and in vitro studies.
Inhibition of steroidogenesis may be produced perioperatively by imidazole compounds, such as the hypnotic agent etomidate, with potentially serious consequences for patient morbidity and mortality. Dexmedetomidine, ([+]4-[1-[2,3-dimethylphenyl]-ethyl]-1H-imidazole), another imidazole compound with anesthetic like properties, is now being used perioperatively. Therefore, we investigated the effects of dexmedetomidine on steroidogenesis as well as on binding to glucocorticoid receptors in a series of in vitro and in vivo animal studies. ⋯ At dexmedetomidine concentrations greater than 10(-7) M, a dose-dependent inhibition of corticosterone release was detected in response to ACTH stimulation in vitro. At these high dexmedetomidine concentrations, [3H]dexamethasone binding was not affected. In the in vivo dog experiments, basal cortisol levels decreased and the cortisol response to ACTH was blunted 3 h after dexmedetomidine administration.(ABSTRACT TRUNCATED AT 250 WORDS)