Anesthesia and analgesia
-
Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialSmall-dose propofol by continuous infusion does not prevent postoperative vomiting in females undergoing outpatient laparoscopy.
This study was designed to test the hypothesis that there is a direct prophylactic antiemetic effect of small-dose propofol given by continuous infusion. Sixty female patients undergoing outpatient laparoscopy under general anesthesia were randomized to receive, in a double-blind fashion, either a bolus of 0.1 mg/kg followed by a constant infusion of 1 mg.kg-1.h-1 of propofol or an equivalent volume of 10% Intralipid (placebo) beginning 30 min before induction of anesthesia and continuing until discharge from Stage I postanesthesia care unit (PACU). Anesthesia was induced and maintained in a standard fashion in all patients. ⋯ No significant differences between Intralipid and propofol were found for any of the outcome variables tested. While small-dose propofol is an effective adjuvant in reducing chemotherapy-induced emesis, we were unable to demonstrate any beneficial effect of propofol in reducing postoperative nausea and vomiting when used as the sole prophylactic medication in this patient population. Propofol may have a synergistic effect when administered with other antiemetics, or the specific antiemetic effect of propofol, if it exists, may be dose-dependent and the dose used in this study was below the efficacy threshold.
-
Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialSmall-dose hypobaric lidocaine-fentanyl spinal anesthesia for short duration outpatient laparoscopy. II. Optimal fentanyl dose.
We performed a double-blind, controlled trial to determine the optimal dose of intrathecal fentanyl in small-dose hypobaric lidocaine spinal anesthesia for outpatient laparoscopy. Sixty-four gynecological patients were randomized into three groups, receiving 0, 10, or 25 micrograms fentanyl added to 20 mg lidocaine and sterile water (total 3 mL). Administration was with 27-gauge Whitacre needles and patients sat upright until the block was > T-8. ⋯ Based on these results, we concluded that 25 micrograms intrathecal fentanyl is required when 20 mg lidocaine is used for hypobaric spinal anesthesia (SA) to ensure reliable, durable anesthesia, reduce shoulder-tip pain, and minimize the need for intraoperative supplementation. This dose provides longer postoperative analgesia and does not increase side effects apart from pruritus. SA with small-dose hypobaric lidocaine-fentanyl was found to be a satisfactory technique for outpatient laparoscopy, although postdural puncture headache can occur in some patients.
-
Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialDifferential sensory block after spinal bupivacaine in volunteers.
We performed this study to determine whether differential sensory block to touch, pinprick, and cold after spinal bupivacaine could be used to predict the dermatomal level of block to transcutaneous electrical stimulation (TES) equivalent to surgical stimulation, onset of tourniquet pain, or magnitude of hemodynamic depression. Eight subjects per group were randomized to receive 3.75, 7.5, or 11.25 mg of 0.75% bupivacaine with 8.25% dextrose in a double-blind fashion. Sensory block was assessed with touch, pinprick, cold, TES at T-12, L-2, S-1, and thigh tourniquet pain. ⋯ However, the extent of differential sensory block to touch, pinprick, and cold varied up to 10 dermatomes (2 SD) cephalad to block to TES and up to 7 dermatomes (2 SD) cephalad to the thigh tourniquet at the time of intolerable tourniquet pain. Sensory block to cold did not correlate with hemodynamic depression. Differential sensory block occurs after bupivacaine spinal anesthesia, but is a poor predictor for surgical anesthesia, tourniquet pain, and hemodynamic depression.
-
Anesthesia and analgesia · Jan 1997
Clinical Trial Controlled Clinical TrialRegional brain activity changes associated with fentanyl analgesia elucidated by positron emission tomography.
Recent positron emission tomography (PET) studies have demonstrated areas of pain processing in the human brain. Given the inhibitory effects of opioids on neuronal activity, we predicted that fentanyl's analgesic effects would be associated with suppression of pain-evoked responses in these distinct brain areas. To test this, PET was used to measure cerebral blood flow responses, as reflections of regional neuronal activity, to painful and nonpainful thermal stimuli both in the absence and presence of fentanyl in humans. ⋯ During combined pain stimulation and fentanyl administration, fentanyl significantly augmented pain-related rCBF increases in the supplementary motor area and prefrontal cortex. This activation pattern was associated with decreased pain perception, as measured on a visual analog scale. In contrast to our hypothesis, these data indicate that fentanyl analgesia involves augmentation of pain-evoked cerebral responses in certain areas, as well as both activation and inhibition in other brain regions unresponsive to pain stimulation alone.
-
Anesthesia and analgesia · Jan 1997
Randomized Controlled Trial Clinical TrialEffects of epidural and intravenous buprenorphine on halothane minimum alveolar anesthetic concentration and hemodynamic responses.
There is limited information regarding the effects of epidural or intravenous (i.v.) buprenorphine on minimum alveolar anesthetic concentration (MAC) of volatile anesthetic and hemodynamic responses to tracheal intubation and surgical incision. This study was conducted to find the effects of i.v. and epidural buprenorphine required for postoperative pain relief on halothane MAC and hemodynamic responses to tracheal intubation and surgical incision in 126 female patients. Patients were randomly assigned to the four groups: Group I received i.v. and epidural saline as a control; Group II was given buprenorphine 4 micrograms/kg i.v.; and Groups III and IV received buprenorphine 2 and 4 micrograms/kg epidurally, respectively. ⋯ Systolic blood pressure did not change significantly in Groups II-OR and IV-OR after tracheal intubation and in Group III-Ward and IV-Ward after surgical incision but increased significantly (P < 0.05) in the remaining groups in response to noxious stimuli. Heart rate responses to tracheal intubation and surgical incision were similar to those in systolic blood pressure. These results indicate that preanesthetic administration of epidural or IV buprenorphine required for postoperative analgesia reduces halothane MAC and attenuates hemodynamic responses to tracheal intubation and surgical incision according to the dose, route, and timing of administration.