Anesthesia and analgesia
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Anesthesia and analgesia · Feb 1998
Randomized Controlled Trial Comparative Study Clinical TrialFast-track eligibility after ambulatory anesthesia: a comparison of desflurane, sevoflurane, and propofol.
This study was designed to test the hypothesis that using the less soluble volatile anesthetics, desflurane and sevoflurane, as alternatives to propofol for maintenance of anesthesia facilitates the ability of outpatients to achieve postanesthesia care unit (PACU) discharge criteria (i.e., fast-track eligibility) on arrival in the PACU after laparoscopic surgery. One hundred-twenty consenting women undergoing laparoscopic tubal ligation procedures were randomly assigned to one of three treatment groups. After a standardized induction of anesthesia and tracheal intubation sequence, anesthesia was maintained with either desflurane 2%-6%, sevoflurane 0.6%-1.75%, or propofol 50-150 microg x kg(-1) x min(-1) in combination with nitrous oxide 60% in oxygen. Recovery times, postanesthesia recovery scores, and the number and type of therapeutic interventions in the PACU were recorded. Compared with the propofol group, the times to awakening and to achieve a recovery score of 10 were significantly shorter, and the percentage of patients judged fast-track eligible on arrival in the PACU was significantly higher, in the desflurane and sevoflurane groups (90% and 75% vs 26%). In conclusion, compared with propofol, the use of desflurane and sevoflurane for the maintenance of general anesthesia resulted in a higher percentage of patients being judged fast-track eligible after outpatient laparoscopic tubal ligation procedures. ⋯ Bypassing the recovery room by transferring outpatients directly to the step-down unit after ambulatory surgery ("fast-tracking") could result in significant cost-savings. We examined the effects of three different maintenance anesthetics--desflurane, sevoflurane, and propofol--on the fast-track eligibility of outpatients after laparoscopic tubal ligation surgery. Compared with propofol, desflurane and sevoflurane resulted in a higher percentage of outpatients being judged eligible for fast-tracking.
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Anesthesia and analgesia · Feb 1998
Randomized Controlled Trial Clinical TrialSubhypnotic doses of propofol do not relieve pruritus induced by intrathecal morphine after cesarean section.
The purpose of this study was to determine whether subhypnotic doses of propofol effectively relieve pruritus in women who received intrathecal morphine for postoperative analgesia after cesarean delivery. Twenty-nine women who developed pruritus after undergoing an elective cesarean section and receiving intrathecal morphine (0.25 mg) for postoperative analgesia were enrolled in this randomized, prospective, double-blind study. The women were randomly assigned to receive either 1 mL of propofol (n = 17) or 1 mL of placebo (n = 12) I.V. Pruritus was evaluated 5 min after treatment. In the absence of successful treatment, the women received another 1 mL of the same drug. Pruritus was again evaluated 5 min after the second dose. We found that pruritus was successfully treated twice in the propofol group and once in the placebo group (P = not significant). The antipruritic action of propofol lasted for up to 6 h in one woman and 15 min in the other. The one success in the placebo group lasted for 15 min. We conclude that the success rate of propofol in treating pruritus in women who received intrathecal morphine for postoperative analgesia after cesarean delivery is not significantly different from that of placebo. ⋯ Pruritus is a common and bothersome side effect of neuraxial opioids after cesarean section. Subhypnotic doses of I.V. propofol (10 mg) have been used to treat pruritus caused by neuraxial opioids. In this prospective, randomized, double-blind study, we found that propofol does not relieve pruritus in women who underwent cesarean section and received intrathecal morphine sulfate (0.25 mg) for postoperative pain relief.
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Anesthesia and analgesia · Feb 1998
Randomized Controlled Trial Clinical TrialOral clonidine premedication reduces the awakening concentration of isoflurane.
Because clonidine has analgesic and sedative properties, it may influence the awakening concentration or dose of an anesthetic. To investigate the effects of oral clonidine premedication on emergence from isoflurane anesthesia, we studied 61 ASA physical status I or II patients undergoing superficial operations. They were randomly allocated to one of three groups according to the dose of clonidine they received: the clonidine-2.5 group (n = 21), clonidine-5 group (n = 20), and control group (n = 20) received approximately 2.5, 5, or 0 microg/kg oral clonidine, respectively, in addition to 20 mg of famotidine 90 min before general anesthesia induction. Anesthesia was induced by thiamylal 5 mg/kg, and tracheal intubation was facilitated with succinylcholine 1.5 mg/kg I.V. Anesthesia was maintained with a 1.1% end-tidal isoflurane concentration and 67% N2O in oxygen, while ventilation was controlled to maintain end-tidal CO2 tension between 33 and 38 mm Hg. After surgery, N2O was discontinued while the end-tidal isoflurane concentration was maintained at 1.1%. After confirming the end-tidal N2O concentration of 0%, isoflurane was discontinued. The end-tidal isoflurane concentration at the time when patients responded to a standardized verbal command to open their eyes was recorded as MAC-Awake. The MAC-Awake values in the clonidine-5 group (0.22% +/- 0.09% [mean +/- SD]) was significantly less than those in the clonidine-2.5 and control groups (0.28% +/- 0.07% and 0.30% +/- 0.07%, respectively, P < 0.05). The wake-up time, from discontinuance of isoflurane until arousal, was longer in the clonidine-2.5 and clonidine-5 groups than in the control group (17.3 +/- 8.0, 16.9 +/- 7.0, and 10.6 +/- 5.3 min, respectively; P < 0.05). In conclusion, oral clonidine premedication 5 microg/kg decreases the awakening concentration of isoflurane, and arousal from isoflurane anesthesia is prolonged with oral clonidine in a dose of 2.5-5 microg/kg. ⋯ Preanesthetic medication with oral clonidine, 2.5-5 microg/kg, is associated with prolonged recovery from isoflurane anesthesia in adults.
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Anesthesia and analgesia · Feb 1998
Pharmacokinetics and side effects of milrinone in infants and children after open heart surgery.
We investigated the pharmacokinetics and side effects of milrinone in infants and children (< or = 13 yr) after open heart surgery in this prospective, open-label study. Milrinone binding to cardiopulmonary bypass (CPB) circuitry was also examined in out two groups. Children in the small dose group (n = 11) received two 25-microg/kg boluses with a final infusion rate of 0.5 microg kg(-1) x min(-1); those in the large dose group (n = 8) received a 50-microg/kg bolus and a 25-microg/kg bolus with a final infusion rate of 0.75 microg x kg(-1) x min(-1). Blood samples for milrinone concentration were drawn 30 min after each bolus, at steady state, and after discontinuing the milrinone infusion. Pharmacokinetics were evaluated using traditional and nonlinear mixed effects modeling analysis. Milrinone kinetics best fit a two-compartment model. Steady-state plasma levels in the small and large dose groups were within the adult therapeutic range (113 +/- 39 and 206 +/- 74 ng/mL, respectively). The volumes of distribution (Vbeta) in infants (0.9 L/kg) and children (0.7 L/kg) were not different, but infants had significantly lower milrinone clearance (3.8 vs 5.9 mL x kg(-1) x min(-1)). Thrombocytopenia (defined as platelet count < or = 100,000 mm(-3)) occurred in 58%, and the risk increased significantly with duration of infusion. Tachyarrythmias were noted in two patients. Milrinone did not bind to CPB circuitry. We conclude that milrinone is cleared more rapidly in children than in adults. The major complication was thrombocytopenia. ⋯ Most pediatric dosing is based on data published for adults. Infants and children have kinetics that differ from adults. We studied the distribution of I.V. milrinone in infants and children after open heart surgery. Milrinone had a larger volume of distribution and a faster clearance in infants and children than in adults, and dosing should be adjusted accordingly.
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Anesthesia and analgesia · Feb 1998
Pneumoperitoneum as a risk factor for endobronchial intubation during laparoscopic gynecologic surgery.
Patients undergoing gynecological surgery under laparoscopic guidance usually receive general anesthesia with endotracheal intubation and mechanical ventilation. The creation of a pneumoperitoneum and the Trendelenburg position, both of which are used to improve visualization, are associated with cephalad movement of the diaphragm. This may increase the risk of endobronchial intubation. We studied the change in the distance from the tip of the endotracheal tube (ETT) to the carina with a fiberoptic bronchoscope in 30 patients aged 21-40 yr who were undergoing laparoscopic tubal ligation (n = 28) or hysterectomy (n = 2). Measurements were taken in the supine and Trendelenburg positions before and after pneumoperitoneum. The average distance from the ETT to the carina in the supine position was 2.1 +/- 0.8 cm and in the Trendelenburg position was 1.8 +/- 0.8 cm (P = not significant). After insufflation of the abdominal cavity, the mean distance decreased to 0.7 +/- 1.4 cm in the supine position (P < 0.05) and was associated with endobronchial intubation in eight patients. The addition of the Trendelenburg position to an established pneumoperitoneum resulted in minimal displacement (0.54 +/- 1.4 cm, P < 0.05) and one additional endobronchial intubation. We conclude that the insufflation of gas in the abdominal cavity, and not the change in patient position, is the main risk factor for endobronchial intubation in patients undergoing laparoscopic gynecologic surgery. ⋯ This study demonstrated that in anesthetized women, the insufflation of gas into the abdomen during laparoscopy for gynecologic surgery is the main risk factor for migration of the endotracheal tube into a bronchus.