Anesthesia and analgesia
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Comparative Study Clinical TrialResistive-heating and forced-air warming are comparably effective.
Serious adverse outcomes from perioperative hypothermia are well documented. Consequently, intraoperative warming has become routine. We thus evaluated the efficacy of a novel, nondisposable carbon-fiber resistive-heating system. Twenty-four patients undergoing open abdominal surgery lasting approximately 4 h were randomly assigned to warming with 1) a full-length circulating water mattress set at 42 degrees C, 2) a lower-body forced-air cover with the blower set on high, or 3) a three-extremity carbon-fiber resistive-heating blanket set to 42 degrees C. Patients were anesthetized with a combination of continuous epidural and general anesthesia. All fluids were warmed to 37 degrees C, and ambient temperature was kept near 22 degrees C. Core (tympanic membrane) temperature changes among the groups were compared by using factorial analysis of variance and Scheffé F tests; results are presented as means +/- SD. Potential confounding factors did not differ significantly among the groups. In the first 2 h of surgery, core temperature decreased by 1.9 degrees C +/- 0.5 degrees C in the circulating-water group, 1.0 degrees C +/- 0.6 degrees C in the forced-air group, and 0.8 degrees C +/- 0.2 degrees C in the resistive-heating group. At the end of surgery, the decreases were 2.0 degrees C +/- 0.8 degrees C in the circulating-water group, 0.6 degrees C +/- 1.0 degrees C in the forced-air group, and 0.5 degrees C +/- 0.4 degrees C in the resistive-heating group. Core temperature decreases were significantly greater in the circulating-water group at all times after 150 elapsed minutes; however, temperature changes in the forced-air and resistive-heating groups never differed significantly. Even during major abdominal surgery, resistive heating maintains core temperature as effectively as forced air. ⋯ Efficacy was similar for forced-air and resistive heating, and both maintained intraoperative core temperature far better than circulating-water mattresses. We thus conclude that even during major abdominal surgery, resistive heating maintains core temperature as effectively as forced air.
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Clinical TrialPostoperative analgesia in children undergoing myringotomy and placement equalization tubes in ambulatory surgery.
We enrolled 120 children undergoing bilateral myringotomy and tube placement in this prospective, randomized, observer-blinded study. Patients were randomized into one of four groups: Group 1 (control) was plain acetaminophen 10 mg/kg orally, Group 2 was acetaminophen 10 mg/kg with 1 mg/kg of codeine orally, Group 3 was transnasal butorphanol 25 micro g/kg given immediately after the induction of anesthesia, and Group 4 was ketorolac 1 mg/kg given IM immediately after the induction of anesthesia. All children received oral midazolam (0.6 mg/kg) before surgery. A nurse blinded to the analgesic technique used assessed the child's behavior at the induction of anesthesia and in the postanesthesia care unit using a 4-point scale. Analgesic effectiveness was determined by assessing the child's pain at 5-min intervals using a modified 10-point objective pain scale. In the postanesthesia care unit, rescue pain medication was administered for an objective pain scale >or=4 or a behavior score >or=3. Our data suggest that IM ketorolac is a promising analgesic to be used in this surgical population. Time to first rescue analgesic was longest in the ketorolac group, and there was no associated postoperative vomiting or nausea. IM ketorolac given during surgery was the best analgesic regimen for these procedures. ⋯ We compared four different analgesics in the management of pain after placement of pressure equalization tubes during myringotomy in children and demonstrated that ketorolac or butorphanol provided superior analgesia when compared with acetaminophen with codeine or plain acetaminophen. Children who received ketorolac versus butorphanol had less vomiting in the 24 h after surgery.
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Clinical TrialEffect-site concentration of propofol for recovery of consciousness is virtually independent of fentanyl effect-site concentration.
Fentanyl reduces the amount of propofol necessary to prevent responses to surgical stimuli. However, opioids have relatively little effect on consciousness. We, therefore, tested the hypothesis that fentanyl minimally alters the effect-site concentration of propofol associated with awakening. Fifty women having gynecologic laparotomy with propofol anesthesia were randomly allocated into the following target effect-site fentanyl concentrations: 0.8, 1.0, 1.4, 2.0, and 3.0 ng/mL. Fentanyl was continued at the designated rate through the initial postoperative phase. The propofol effect-site concentration associated with eye opening in response to verbal command was regarded as the awakening concentration. The estimated propofol effect-site concentrations at awakening did not differ significantly among the groups and were 1.9 +/- 0.5 micro g/mL with a fentanyl effect-site concentration of 0.8 ng/mL; 1.6 +/- 0.4 micro g/mL with 1.0 ng/mL of fentanyl; 1.6 +/- 0.2 micro g/mL with 1.4 ng/mL of fentanyl; 1.7 +/- 0.4 micro g/mL with 2.0 ng/mL of fentanyl; and 1.6 +/- 0.34 micro g/mL with 3.0 ng/mL of fentanyl (mean +/- SD). Seventy percent of the subjects in the 0.8 ng/mL fentanyl group spontaneously complained of pain, whereas none of the patients in the 2 or 3 ng/mL groups did. Five (56%) of 9 women in the 3 ng/mL group had a postoperative respiratory rate <6 breaths/min. Heart rate in one of these women decreased to <40 bpm. These data suggest that the optimal fentanyl effect-site concentration in patients recovering from gynecologic laparoscopy is between 1.4 and 2.0 ng/mL. ⋯ The effect-site concentration for propofol at awakening was virtually independent of the fentanyl effect-site concentration over the range of 0.8 to 3.0 ng/mL; however, 0.8 ng/mL of fentanyl was associated with inadequate postoperative analgesia, and 3.0 ng/mL of fentanyl was associated with respiratory toxicity. The optimal postoperative fentanyl effect-site concentration during recovery from propofol general anesthesia for laparotomy thus appears to be near 2 ng/mL.
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Clinical TrialThe efficacy of celecoxib premedication on postoperative pain and recovery times after ambulatory surgery: a dose-ranging study.
Recently, the Food and Drug Administration increased the celecoxib dosage recommendation from 200 mg to 400 mg for acute pain management. No studies have directly compared the analgesic efficacy of different doses of celecoxib for the prevention of postoperative pain. In this prospective, double-blinded, placebo-controlled study, we compared oral celecoxib 200 mg to 400 mg when administered for premedication of outpatients undergoing minor ear-nose-throat surgery. A total of 93 healthy outpatients were assigned to 1 of 3 study groups: control (placebo; n = 30), celecoxib 200 mg (n = 30), or celecoxib 400 mg (n = 33). The study drug was given orally 30-45 min before surgery, and all patients received a standardized general anesthetic technique. During the postoperative period, pain scores (0-10), recovery times, the need for rescue analgesics, quality of recovery (0-100), patient satisfaction with pain management (0-100), and side effects were recorded. Pain was assessed at 30-min intervals using a verbal rating scale, with 0 = no pain to 10 = worst pain imaginable, in the postanesthesia care unit and day surgery unit recovery areas and at 24 h after surgery. Celecoxib 400 mg was significantly more effective than 200 mg (and placebo) in reducing postoperative pain. Both celecoxib 200 mg and 400 mg were more effective than placebo in reducing the postoperative fentanyl requirement (74 +/- 67 micro g and 56 +/- 62 micro g versus 120 +/- 86 micro g, respectively). The larger dose of celecoxib significantly reduced the percentage of patients with severe pain at discharge (6% versus 37% and 30% in the celecoxib 200 mg and control groups, respectively). The median number of doses of oral analgesic medication after discharge was also significantly reduced in the celecoxib 400 mg group (0 versus 2 and 2 in the celecoxib 200 mg and control groups, respectively). However, no differences were found among the three study groups with respect to recovery times and secondary outcome variables (e.g., patient satisfaction and quality of recovery). We conclude that oral premedication with celecoxib 400 mg was more effective than 200 mg in reducing severe postoperative pain and the need for rescue analgesic medication in the postoperative period. ⋯ Oral premedication with celecoxib 400 mg was more effective than 200 mg in reducing postoperative pain and the need for rescue analgesic medication in the early postoperative period. However, neither dose of celecoxib was more effective than a placebo in facilitating the recovery process after outpatient surgery.
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Anesthesia and analgesia · Jun 2003
Randomized Controlled Trial Clinical TrialSympathetic and vascular consequences from remifentanil in humans.
We explored the possible mechanisms of hypotension during the administration of sedation-analgesia doses of remifentanil in young (ASA physical status I) volunteers (n = 24). Cardiorespiratory and sympathetic variables were collected at baseline and at plasma concentrations of remifentanil (2 and 4 ng/mL). Monitoring included electrocardiogram, heart rate (HR), direct blood pressure, muscle sympathetic nerve activity, and forearm blood flow (FBF). A cold pressor test (1-min hand immersion in ice water) quantified analgesia effectiveness (visual analog scale, 0-100). Visual analog scale to the cold pressor test (62 at baseline) decreased to 27 and 18 during remifentanil infusions. Respiratory rate decreased and end-tidal carbon dioxide (ETCO(2)) increased with increasing doses of remifentanil; HR, direct blood pressure, muscle sympathetic nerve activity, SpO(2) remained unchanged, but FBF increased compared with placebo. In a second study (n = 7), timed respiration was used to maintain ETCO(2) during remifentanil, but FBF still increased. In a third study (n = 11), direct effects of remifentanil on vascular tone were determined with progressive infusions from 1 to 100 micro g/h into the brachial artery; FBF increased significantly from 3.5 to 4.3 mL/min per 100 mL of tissue (approximately 13%-18% increase). Sedative doses of remifentanil resulted in analgesia but no changes in neurocirculatory end-points except FBF. Direct effects of remifentanil on regional vascular tone may play a role in promoting hypotension. ⋯ Remifentanil occasionally has been associated with hypotension, the mechanism of which is unclear. This study found that remifentanil directly causes the forearm arterial vasculature to dilate.