Anesthesia and analgesia
-
Anesthesia and analgesia · May 1993
Randomized Controlled Trial Clinical TrialEffects of alfentanil on the hemodynamic and catecholamine response to tracheal intubation.
A randomized, placebo-controlled study was conducted in 60 ASA Class I, II, and III patients to determine the dose response of alfentanil in moderating the cardiovascular and catecholamine response to tracheal intubation (INT). Patients were randomly allocated into one of four groups to receive either 15 micrograms/kg alfentanil (A15), 30 micrograms/kg alfentanil (A30), 45 micrograms/kg alfentanil (A45), or normal saline (control), given intravenously (i.v.) before induction of anesthesia. One minute after administration of 4.0 mg/kg thiopental and 1.5 mg/kg succinylcholine i.v., tracheal intubation was performed using direct laryngoscopy. ⋯ In the control group, epinephrine and norepinephrine serum concentrations increased by 152 +/- 52% and 58 +/- 62%, respectively, following INT (different from A30 and A45, P < 0.05). However, up to a dose of 30 micrograms/kg (A30), a dose-dependent decrease in the maximum percent changes of both epinephrine and norepinephrine occurred in response to INT. A larger dose of alfentanil was no more efficacious as the catecholamine response to tracheal intubation was not significantly different when comparing the A45 and A30 groups.(ABSTRACT TRUNCATED AT 250 WORDS)
-
Anesthesia and analgesia · May 1993
Randomized Controlled Trial Comparative Study Clinical TrialComparison of an ephedrine infusion with crystalloid administration for prevention of hypotension during spinal anesthesia.
This study was designed to compare the efficacy of an ephedrine infusion with crystalloid administration for reducing the incidence of hypotension during spinal anesthesia. Fifty-four ASA I patients scheduled for postpartum tubal ligations under spinal anesthesia were randomly allocated to receive either 15 mL/kg of crystalloid (crystalloid group) or an ephedrine infusion (infusion group). Spinal anesthesia was performed using 70-90 mg of hyperbaric 5% lidocaine. ⋯ The incidence of hypotension was 15/27 (55%) in the crystalloid group and 6/27 (22%) in the infusion group (P < 0.05). There was no significant difference between the groups in relation to the level of anesthesia or maximal heart rate, and hypertension did not occur in either group. We conclude that a prophylactic ephedrine infusion is effective for minimizing and managing hypotension associated with spinal anesthesia and compares favorably with crystalloid administration in this patient population in terms of efficacy and incidence of side effects.
-
Anesthesia and analgesia · May 1993
Comparative StudyThe effect of fentanyl, sufentanil, and alfentanil on cerebral arterioles in piglets.
The effect of fentanyl, sufentanil, and alfentanil on cerebral arterioles was determined in 17 halothane-anesthetized newborn piglets. A closed cranial window was inserted over the parietal cortex, and changes in the luminal diameter of pial arterioles were measured by intravital microscopy as increasing concentrations of opioid (10(-9)-10(-5) M) were suffused over the cortical surface. ⋯ Naloxone alone had no effect at concentrations < or = 10(-5) M, suggesting that endogenous opioids contribute little to resting cerebrovascular tone. These results indicate that fentanyl, sufentanil, and alfentanil produce cerebral vasoconstriction by action at an opioid receptor and that their vasoconstrictive potency appears to differ from their analgesic potency.
-
Anesthesia and analgesia · May 1993
Sedative doses of propofol increase beta activity of the processed electroencephalogram.
The effects of sedative infusions of propofol on the processed electroencephalograms (EEG) of eight healthy male volunteers were studied. EEG data for aperiodic analysis were collected during three 5-min periods: before propofol, during propofol infusion, and 30 min after termination of the infusion. After an initial dose of 1 mg/kg, subjects received a propofol infusion titrated to produce a standard level of conscious sedation. ⋯ The change in total power was accompanied by a change in the distribution of power within the EEG spectrum, as the fraction of activity in the beta-band (12-35 Hz) increased during the infusion from 23% +/- 3% to 44% +/- 5% (P < 0.05). Thirty minutes after the infusion was terminated, the distribution of activity within the EEG spectrum had reverted to pre-propofol patterns. The similarity of EEG effects seen with sedative doses of propofol and benzodiazepines suggests that these drugs may share some neurochemical effects.
-
The purpose of this study was to investigate the incidence of technical problems encountered when performing continuous spinal anesthesia and the influence of catheter tip position on block height following injection of a hypobaric spinal anesthetic. Twenty-nine elderly patients undergoing hip surgery were studied. Lumbar puncture was performed with an 18-gauge Tuohy needle at the L3-4 (or L2-3) interspace. ⋯ Although threading difficulties were encountered in 4/28 cases, there was a 100% success rate in catheter insertion. One catheter displacement into the epidural space was noted. Twenty of twenty-eight catheters took a cephalad direction, 6 remained coiled in a horizontal position, and 2 took a caudal direction.(ABSTRACT TRUNCATED AT 250 WORDS)