Anesthesia and analgesia
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Anesthesia and analgesia · Nov 1993
Monitoring of intraoperative motor-evoked potentials under conditions of controlled neuromuscular blockade.
Motor-evoked potentials were recorded after electrical spinal cord stimulation in 19 patients undergoing neurosurgical or orthopedic procedures. Anesthesia was maintained with nitrous oxide, opioids, and inhaled anesthetics. Vecuronium was infused sufficient to eliminate 90% of twitch tension. ⋯ Intraoperative deterioration of motor-evoked potentials occurred in one patient who had a postoperative neurologic deficit. This study demonstrates the feasibility and utility of intraoperative motor tract monitoring using direct spinal cord stimulation. Controlled neuromuscular blockade permits recording of compound muscle action potentials while eliminating patient motor activity that could interfere with surgery.
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Anesthesia and analgesia · Nov 1993
Reliability of a new generation transesophageal Doppler device for cardiac output monitoring.
A new generation continuous-wave transesophageal Doppler (TED) device for cardiac output (CO) monitoring (Accucom 2, Datascope), which displays aortic blood flow velocity in real time, was evaluated by 140 simultaneous comparisons with thermodilution (TD) in 16 patients early after coronary artery bypass surgery. The aim was to determine whether this technologic advancement improves the accuracy of COTED assessment. Absolute COTED values showed a considerable scatter as compared to COTD [COTED = 1.77 + 0.75. ⋯ The agreement between delta COTD and delta COTED improved (P < 0.05) when the aortic diameter changes induced by changes in mean arterial pressure were considered [delta COTEDMAPC = 1.10 + 0.95.delta COTD (%), r = 0.87, n = 124]. Compared with previous results, the reliability of the second generation device to monitor relative CO changes was considerably improved. Provided that the aortic blood flow velocity signal was stable and free from any disturbances, the second generation TED device may be regarded acceptable for CO trend monitoring in sedated, paralyzed patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Nov 1993
Effects of nitric oxide synthase inhibition on regional cerebral blood flow and vascular resistance in conscious and isoflurane-anesthetized rats.
Nitric oxide is an important regulator of the regional cerebral vascular tone. We compared the magnitude of nitric oxide-related changes in the vascular tone by studying the regional cerebral blood flow (rCBF) and vascular resistance in conscious and isoflurane-anesthetized rats by using a nitric oxide synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME). In the conscious group (n = 12), after cannulation of a femoral artery and two veins under isoflurane anesthesia, rats were allowed to remain awake for 90 min. ⋯ Regional vascular resistance was determined by the ratio of mean arterial blood pressure and rCBF which was measured by [14C]iodoantipyrine. L-NAME significantly increased mean arterial blood pressure in both the conscious (123 to 158 mm Hg) and anesthetized (82 to 144 mm Hg) rats. Regional vascular resistance increased significantly in all 12 brain regions studied with the average value increasing from 1.19 +/- 0.33 mm Hg.mL-1 x min x 100 g to 2.22 +/- 0.48 (P < 0.0001) in the conscious and from 0.78 +/- 0.27 to 1.61 +/- 0.48 (P < 0.0001) in the isoflurane-anesthetized rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Nov 1993
Randomized Controlled Trial Clinical TrialLeg warming minimizes core hypothermia during abdominal surgery.
The efficacy of leg skin warming in preventing hypothermia and shivering was evaluated in two separate prospective, randomized trials in patients undergoing abdominal surgery. In the first trial, 22 patients were randomized to receive no hypothermia prevention (control group) or active warming with an electric warming blanket (electric blanket group). In the second trial 33 patients were randomized to receive no hypothermia prevention (control group) or forced-air warming (Bair Hugger group) or forced-air warming with insulation of the air blanket from the environment (insulated Bair Hugger group). ⋯ In the second trial, core temperature was 35.1 +/- 0.2 degrees C at the end of surgery in the control group, 36.3 +/- 0.1 degrees C in the Bair Hugger group (P < 0.01) and 37.1 +/- 0.1 degrees C in the insulated Bair Hugger group (P < 0.01 versus control; P < 0.05 versus Bair Hugger). Shivering occurred in one patient of each warmed group and in seven of the control group (P < 0.05). Skin-surface warming limited to the legs provides sufficient heat (ranging 34 to 43 watts) to counterbalance heat losses during abdominal surgery.
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Anesthesia and analgesia · Nov 1993
Randomized Controlled Trial Clinical TrialMinimum effective combination dose of epidural morphine and fentanyl for posthysterectomy analgesia: a randomized, prospective, double-blind study.
Recent studies have produced conflicting results regarding whether the addition of epidural fentanyl improves postoperative analgesia from epidural morphine. Therefore, we prospectively determined the dose-response relationship and the minimum effective combination dose of epidural morphine and fentanyl (fentanyl given after morphine) for posthysterectomy analgesia. We studied 120 patients undergoing radical abdominal hysterectomy. ⋯ For 4 mg of morphine, the same conclusion was drawn, except that vomiting occurred more frequently with addition of 100 micrograms of fentanyl (P < 0.05). Among fentanyl groups, there was no significant difference in pain scores, duration of analgesia, and analgesic requirements. Therefore, we conclude that epidural fentanyl given after morphine improves early postoperative analgesia from epidural morphine, and the minimum effective combination dose is morphine 2 mg/fentanyl 50 micrograms for posthysterectomy surgery analgesia.