Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1995
Randomized Controlled Trial Comparative Study Clinical TrialCerebral physiologic effects of burst suppression doses of propofol during nonpulsatile cardiopulmonary bypass. CNS Subgroup of McSPI.
Central nervous system (CNS) complications are common after cardiac surgery. Death due to cardiac causes has decreased, but the number of deaths due to CNS injury has increased. As a first stage in the evaluation of its cerebral protection potential, we evaluated the cerebral physiologic effects of burst suppression doses of propofol during nonpulsatile cardiopulmonary bypass. ⋯ Pharmacologic burst suppression with propofol produced a statistically significant reduction in CBF, cerebral oxygen delivery (DO2), and cerebral metabolic rate (CMRO2) at each measurement interval (P < 0..05 vs control). Cerebral arterial venous oxygen difference (C(a-v)O2), and jugular bulb venous oxygen saturation (SJvO2) were not statistically different between groups, indicating maintenance of cerebral metabolic autoregulation (coupling). The reduction in CBF and CMRO2, prominent during the normothermic phases of cardiopulmonary bypass (CPB), indicates a potential for propofol to reduce cerebral exposure to the embolic load during CPB.
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Anesthesia and analgesia · Sep 1995
Randomized Controlled Trial Comparative Study Clinical TrialComparison of ondansetron and droperidol in the prevention of nausea and vomiting after inpatient minor gynecologic surgery.
Ondansetron and droperidol are both effective in the prevention of postoperative nausea and vomiting (PONV). In this randomized, double-blind study, 80 inpatients scheduled for minor gynecologic surgery received either ondansetron 8 mg intravenously (i.v.) or droperidol 2.5 mg i.v. 5 min prior to induction of isoflurane-narcotic anesthesia. PONV was absent in 68% of the patients after ondansetron and in 88% after droperidol (P < 0.05). ⋯ After ondansetron and droperidol, the incidence of severe drowsiness, restlessness, anxiety, or dizziness was 5% and 28%, respectively (P < 0.01). Thus after minor gynecologic surgery, droperidol 2.5 mg i.v. was superior to ondansetron 8 mg i.v. in the prevention of PONV. However, relative to ondansetron, droperidol entailed an average 1-h delay in recovery from anesthesia.
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Anesthesia and analgesia · Sep 1995
Randomized Controlled Trial Comparative Study Clinical TrialElectromyographic comparison of obturator nerve block to three-in-one block.
Obturator nerve block during spinal, epidural, or general anesthesia without muscle relaxants has been recommended for transurethral surgery to prevent thigh adductor muscle contractions during operative electrocautery. We investigated the effectiveness of direct obturator and 3-in-1 nerve motor blocks in 44 patients undergoing transurethral surgery during spinal anesthesia with isobaric bupivacaine. Patients were randomly assigned to receive 3-in-1 block with 40 mL (n = 13) or 50 mL (n = 11) of 1.5% lidocaine plus epinephrine, or direct obturator nerve block with 10 mL of 2% lidocaine plus epinephrine (n = 20). ⋯ Peak lidocaine plasma levels of 1.6 +/- 0.2 micrograms/mL (range 1.0-2.8 micrograms/mL) were reached 60-90 min after the block in those patients receiving 50 mL of local anesthetic. The 3-in-1 technique fails to predictably result in effective motor block of the obturator nerve and thus may not prevent inadvertent thigh adductor muscle contractions during transurethral surgery. A direct approach to the obturator nerve is significantly more effective in producing motor block, and even when given in larger than recommended dosages it results in subtoxic peak plasma lidocaine concentrations.
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Anesthesia and analgesia · Sep 1995
Isoflurane and sevoflurane produce a dose-dependent reduction in the shivering threshold in rabbits.
All general anesthetics markedly impair thermoregulatory responses; nonetheless, sufficient hyperthermia or hypothermia will trigger most protective reflexes. Shivering, however, remains an exception among thermo-regulatory responses: it is common during postanesthetic recovery, but is rare at typical anesthetic concentrations. This observation suggests that general anesthesia impairs shivering far more than other thermoregulatory defenses. ⋯ Four of the six rabbits given 0.3 MAC isoflurane shivered at a mean core temperature of 36.2 +/- 0.6 degrees C, and two of these rabbits failed to shiver at a minimum core temperature of 35.0 degrees C. However, no rabbit given 0.4 MAC isoflurane shivered, even at minimum core temperatures of 35.0 degrees C. All of the rabbits given 0.2 MAC sevoflurane shivered at a mean core temperature of 36.6 +/- 0.7 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)
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Anesthesia and analgesia · Sep 1995
Temperature corrected thrombelastography in hypothermic patients.
Thrombelastograms and other coagulation studies are performed at 37 degrees C, regardless of the patient's body temperature. This prospective study of 45 patients undergoing orthotopic liver transplantation was conducted to evaluate the effect on the thrombelastogram performed at the patient's actual body temperature compared with a control thrombelastogram heated in the standard fashion to 37 degrees C. Thrombelastograms were obtained after the induction of anesthesia and at various times throughout the operation when clinically indicated. ⋯ The variables of the thrombelastogram measured were: r (reaction time in minutes), r + K (coagulation time in minutes), alpha (coagulation rate in degrees), and MA (maximum amplitude in millimeters). Whenever the patient's body temperature was less than 37 degrees C, statistically significant prolongation of the reaction time, coagulation time, and decrease in the clot formation rate occurred compared with control variables at 37 degrees C. Overall means were as follows: r for control, 8.24 +/- 0.28 min; r for temperature corrected, 9.32 +/- 0.27 min; r + K for control, 15.4 +/- 0.65 min; r + K for temperature corrected, 17.5 +/- 0.81 min; and alpha for control, 39.8 +/- 1.22 degrees; alpha for temperature corrected, 37.7 +/- 1.23 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)