Anesthesia and analgesia
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Anesthesia and analgesia · Feb 1996
The influence of carbon dioxide and body position on near-infrared spectroscopic assessment of cerebral hemoglobin oxygen saturation.
Near-infrared spectroscopy may allow continuous and noninvasive monitoring of regional brain hemoglobin oxygen saturation by measuring the differential absorption of infrared light by oxyhemoglobin and deoxyhemoglobin. We have previously examined the correlation between the spectroscopic signal generated by a prototype cerebral oximeter (Invos 3100; Somanetics, Troy, MI), and global brain hemoglobin oxygen saturation calculated from arterial and jugular venous bulb oxygen saturations. Because the technology does not distinguish between arterial and venous hemoglobin saturation, changes in the proportion of cerebral arterial and venous blood volume, which may result from changes in blood flow or venous distending pressure, may confound measurements. ⋯ We found that changes in position did not influence the association between CSfO2 and CScombO2 (r2 = 0.69-0.885) during hypoxic challenge. In a second set of eight volunteers, we studied the influence of hypercapnia and hypocapnia and body position on the association between CSfO2 and CScombO2, and found that they were less well correlated (r2 = 0.366-0.976) in individual patients. Because changes in body position and Paco2 confound the relationship between CSfO2 and CScombO2, changes in CSfO2 can best be assessed if position and Paco2 are constant.
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Anesthesia and analgesia · Feb 1996
Randomized Controlled Trial Clinical TrialOral clonidine premedication reduces postoperative pain in children.
Clonidine is an effective preanesthetic medication in children, providing a preoperative sedative effect. The analgesic properties of the drug have been well documented in adults. The current study was designed to investigate the effect of oral clonidine given preoperatively on postoperative pain in children undergoing minor surgery. ⋯ Postoperative pain was assessed by a blinded observer using an objective pain scale (OPS). Clonidine 4 micrograms/kg provided lower OPS (highest) scores during 12 h after surgery and reduced requirement for postoperative supplementary analgesic (diclofenac suppository) compared with the other two regimens. These data suggest that oral clonidine premedication (4 micrograms/kg) is a possible approach to facilitating postoperative analgesia in children undergoing minor surgery.
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Anesthesia and analgesia · Feb 1996
Randomized Controlled Trial Comparative Study Clinical TrialHemodynamic effects of spinal anesthesia in the elderly: single dose versus titration through a catheter.
Sixty elderly patients (> 70 yr old) undergoing surgery for hip fracture were prospectively studied in order to compare hemodynamic tolerance of titrated doses of hyperbaric bupivacaine using continuous spinal anesthesia (CSA) versus single-dose spinal anesthesia (SDSA). Patients were randomized into two groups (CSA group: n = 30; SDSA group: n = 30). The SDSA patients received 10-15 mg of 0.5% hyperbaric bupivacaine (based on age and height), and the CSA patients received a starting dose of 5 mg of 0.5% hyperbaric bupivacaine, followed after 15 min by optional reinjection of 2.5 mg every 5 min until a T10 level sensory block was reached. ⋯ The mean dose of ephedrine was significantly less in the CSA group (1.8 +/- 0.7 mg, administered to only 37% of patients) than in the SDSA group (19.4 +/- 3.3 mg administered to all patients, P < 0.0001). No late complications related to the spinal anesthesia technique were observed in either group. We concluded that CSA, using small titrated doses of 0.5% hyperbaric bupivacaine, is safe, efficient, and provides better hemodynamic stability than SDSA in elderly patients.
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Anesthesia and analgesia · Feb 1996
Randomized Controlled Trial Clinical TrialTropisetron for the prevention of postoperative nausea and vomiting in women undergoing gynecologic surgery.
The aim of this study was to evaluate the efficacy of tropisetron, a selective 5-hydroxytryptamine type 3 (5-HT3) receptor antagonist, versus placebo in the prevention of postoperative nausea and vomiting in patients undergoing general anesthesia for gynecologic surgery. Ten minutes before induction of general anesthesia, 80 patients received in a double-blind manner a single intravenous (IV) injection of either 5 mg tropisetron or a matching placebo. Anesthesia was induced with thiopental and maintained with nitrous oxide and enflurane in oxygen. ⋯ The incidence of nausea was 30% (12/40) in the tropisetron group and 52% (21/40) in the placebo group (P < 0.05). A total effective antiemetic response showed 26 patients (65%) in the tropisetron group and 16 patients (40%) in the placebo group (P < 0.05). We conclude that tropisetron given IV prior to gynecologic procedures in general anesthesia significantly reduces postoperative nausea and vomiting when compared to placebo without causing any adverse effect.