Anesthesia and analgesia
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialNeostigmine combined with bupivacaine, clonidine, and sufentanil for spinal labor analgesia.
We previously found that spinal clonidine prolongs labor analgesia when combined with spinal bupivacaine and sufentanil. We sought to determine whether the addition of spinal neostigmine to these drugs would further enhance labor analgesia. By use of a combined spinal/epidural technique, 36 patients were randomized to receive a hyperbaric spinal injection of bupivacaine 2.5 mg plus clonidine 50 microg and sufentanil 10 microg with or without neostigmine 10 microg. Pain, maternal hemodynamics, fetal heart rate, nausea, pruritus, sedation, motor block, sensory levels to pinprick, and maternal oxygen saturation were assessed at regularly specified intervals after spinal injection until additional analgesia was requested. The duration of spinal analgesia was similar between groups (215 +/- 60 min in the Control group versus 205 +/- 62 min in the Neostigmine group). Likewise, pain scores, the duration of labor, Apgar scores, and side effects were similar between groups except that patients administered neostigmine experienced significantly more nausea and vomiting (53% vs 7%, P = 0.01). We conclude that spinal neostigmine 10 microg produces severe nausea and does not potentiate the duration of spinal analgesia in laboring women from spinal bupivacaine, clonidine, and sufentanil. ⋯ Spinal neostigmine 10 microg as an adjunct to spinal bupivacaine, clonidine, and sufentanil produces severe nausea and fails to potentiate analgesia in laboring women.
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Anesthesia and analgesia · Dec 2001
Randomized Controlled Trial Clinical TrialEarly pregnancy does not reduce the C(50) of propofol for loss of consciousness.
Requirements for inhaled anesthetics decrease during pregnancy. There are no published data, however, regarding propofol requirements in these patients. Because propofol is often used for induction of general anesthesia when surgery is necessary in early pregnancy, we investigated whether early pregnancy reduces the requirement of propofol for loss of consciousness using a computer-assisted target-controlled infusion (TCI). Propofol was administered using TCI to provide stable concentrations and to allow equilibration between blood and effect-site (central compartment) concentrations. Randomly selected target concentrations of propofol (1.5-4.5 microg/mL) were administered to both pregnant women (n = 36) who were scheduled for pregnancy termination and nonpregnant women (n = 36) who were scheduled for elective orthopedic or otorhinolaryngologic surgery. The median gestation of the pregnant women was 8 wk (range, 6-12 wk). Venous blood samples for analysis of the serum propofol concentration were taken at 3 min and 8 min after equilibration of the propofol concentration. After a 10-min equilibration period of the predetermined propofol blood concentration, a verbal command to open their eyes was given to the patients twice, accompanied by rubbing of their shoulders. Serum propofol concentrations at which 50% of the patients did not respond to verbal commands (C(50) for loss of consciousness) were determined by logistic regression. There was no significant difference in C(50) +/- SE of propofol for loss of consciousness between the Nonpregnant (2.1 +/- 0.2 microg/mL) and Pregnant (2.0 +/- 0.2 microg/mL) groups. These results indicate that early pregnancy does not decrease the concentration of propofol required for loss of consciousness. ⋯ The C(50) of propofol for loss of consciousness in early pregnancy did not differ from that in nonpregnant women, indicating that there is no need to decrease the propofol concentration for loss of consciousness when inducing general anesthesia for termination of pregnancy.
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Anesthesia and analgesia · Dec 2001
Risk factors for ischemic optic neuropathy after cardiopulmonary bypass: a matched case/control study.
Visual loss (acuity or field) secondary to ischemic optic neuropathy (ION) is a rare but devastating complication of cardiac surgery involving cardiopulmonary bypass (CPB). We determined clinical features and risk factors for ION by a retrospective time-matched, case-control study. ION was identified in 17 (0.06%) patients out of 27,915 patients who underwent CPB between January 1, 1976, and December 31, 1994. For each ION patient, two patients who underwent CPB exactly 2 wk before the ION patient were selected as controls. Data were analyzed by using conditional logistic regression with the 1:2 matched-set feature of 17 cases and 34 controls. Two-tailed P values < or =0.05 were considered significant. From bivariate analysis, smaller minimum postoperative hemoglobin concentration (odds ratio [OR] = 1.9, P = 0.047) and the presence of atherosclerotic vascular disease (OR = 7.0, P = 0.026) were found to be independently associated with ION after CPB, as were smaller minimum postoperative hemoglobin concentration (OR = 2.2, P = 0.027) and preoperative angiogram within 48 h of surgery (OR = 7.2, P = 0.042). In ION patients, 13 (76.5%) of 17 experienced a minimum postoperative hemoglobin value of < 8.5 g/dL, whereas only 14 (41.2%) of 34 control patients experienced values < 8.5 g/dL. ⋯ Patients with clinically significant vascular disease history or preoperative angiogram may be at increased risk for ischemic optic neuropathy after cardiac surgery, especially if the hemoglobin remains low in the postoperative period.
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Anesthesia and analgesia · Dec 2001
The impact of longer-than-average anesthesia times on the billing of academic anesthesiology departments.
Academic anesthesiology departments provide clinical services for surgical procedures that have longer-than-average surgical times and correspondingly increased anesthesia times. We examined the financial impact of these longer times in three ways: 1) the estimated loss in revenue if billing were done on a flat-fee system by using industry-averaged anesthesia times; 2) the estimation of incremental operating room (OR) sites necessitated by longer anesthesia times; and 3) the estimated potential gain in billed units if the hours of productivity of current anesthesia time were applied to surgical cases of average duration. Health Care Financing Administration average times per anesthesia procedure code were used as industry averages. Billing data were collected from four academic anesthesiology departments for 1 yr. Each claim billed with ASA units was included except for obstetric anesthesia care. All clinical sites that do not bill with ASA units were excluded. Base units were determined for each anesthesia procedure code. The mean commercial conversion factor (US$45 per ASA unit) for reimbursement was used to estimate the impact in dollar amounts. In all four groups, anesthesia times exceeded the Health Care Financing Administration average. The loss per group in billed ASA units if a flat-fee billing system were used ranged from 18,194 to 31,079 units per group, representing a 5% to 15% decrease (estimated billing decrease of US$818,719 to US$1,398,536 per group). The number of excess OR sites necessitated by longer surgical and anesthesia times ranged from 1.95 to 4.57 OR sites per group. The potential gain in billed units if the hours of productivity of current anesthesia time were applied to surgical cases of average duration was estimated to be from 13,273 to 21,368 ASA units. Longer-than-average anesthesia and surgical times result in extra hours or additional OR sites to be staffed and loss of potential reimbursement for the four academic anesthesiology departments. A flat-fee system would adversely affect academic anesthesiology departments. ⋯ We examined the economic impact of longer-than-average anesthesia times on four academic anesthesiology departments in three ways: the estimated loss in revenue under a flat-fee system, the excess operating room sites staffed, and the potential gain in revenue if the surgeries were of average length. These results should be considered both in productivity measurements and strategies for operating room management.
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Anesthesia and analgesia · Dec 2001
Case ReportsGeneralized tonic-clonic activity after remifentanil administration.
This is the first report of seizure-like activity in an adult who received remifentanil. This report confirms that opioid administration can be associated with generalized tonic-clonic seizure-like activity. It is suggested that this reaction could be referred to as the "opioid-seizure syndrome."