Anesthesia and analgesia
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Clinical TrialThe absence of acute tolerance during remifentanil infusion in volunteers.
The development of acute opioid tolerance in humans remains controversial. We tested the hypothesis that continuous remifentanil infusion leads to rapid development of opioid tolerance. Twenty healthy male volunteers were enrolled onto a randomized, placebo-controlled, double-blinded, cross-over design study to receive a 3 h continuous infusion of remifentanil (0.08 microg x kg(-1) x min(-1)) or saline. Test procedures included determination of pain perception thresholds and pain tolerance thresholds to heat and cold and neuroselective sine wave constant current at 5 Hz and 250 Hz. Test procedures were performed at baseline and then repeated at 25, 55, 85, 115, and 160 min (heat/cold) and at 35, 65, 95, 125, and 170 min (electrical current) during infusion. No significant decrease of the pain threshold devolutions between 55 and 180 min after the start of infusion of remifentanil could be detected. In conclusion, no development of acute opioid tolerance was observed during constant remifentanil infusion of 3 h in volunteers. ⋯ The opioid remifentanil was applied to 20 volunteers at a constant concentration for 3 h while pain thresholds to temperature and current were repeatedly assessed. Our aim was to study whether thresholds decrease over time because of the rapid development of opioid tolerance. No development of rapid opioid tolerance was observed.
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Anesthesia and analgesia · May 2002
Review Case ReportsDystonic reaction to propofol attenuated by benztropine (cogentin).
Neuroexcitatory movements associated with propofol anesthesia are well recognized. Here we report on the successful use of benztropine (2 mg) to abolish abnormal dystonic movements after propofol anesthesia. Forty-five case reports are reviewed, and a treatment strategy for abnormal movements during propofol anesthesia is provided.
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Clinical TrialThe efficacy of premedication with celecoxib and acetaminophen in preventing pain after otolaryngologic surgery.
Non-opioid analgesics are often used to supplement opioids for the management of perioperative pain. In this randomized, double-blinded, placebo-controlled study, we examined the effects of acetaminophen and a cyclooxygenase type-2 inhibitor, celecoxib, when administered alone or in combination, before elective otolaryngologic surgery in 112 healthy outpatients. Subjects were assigned to 1 of 4 study groups: Group 1, placebo (vitamin C, 500 mg per os [PO]); Group 2, acetaminophen 2000 mg PO; Group 3, celecoxib 200 mg PO; or Group 4, acetaminophen 2000 mg and celecoxib 200 mg PO. All patients received a standardized anesthetic technique. During the postoperative period, pain was assessed using a 10-point verbal rating scale. Recovery times, the need for rescue analgesics, side effects, and patient satisfaction scores were also recorded. The combination of acetaminophen and celecoxib was significantly more effective than placebo in reducing postoperative pain. Celecoxib, when administered alone or in combination with acetaminophen, improved patients' satisfaction with their postoperative analgesia. With the combination of acetaminophen and celecoxib, an additional expenditure of $6.16 would be required to obtain complete satisfaction with postoperative pain management in one additional patient who would not have been completely satisfied if he/she had received the placebo. However, oral celecoxib or acetaminophen alone was not significantly more effective than placebo in reducing postoperative pain when administered before surgery. We conclude that oral premedication with a combination of acetaminophen (2000 mg) and celecoxib (200 mg) was highly effective in decreasing pain and improving patient satisfaction after outpatient surgery. ⋯ Oral premedication with a combination of acetaminophen (2000 mg) and celecoxib (200 mg) was effective in decreasing pain and improving patient satisfaction after otolaryngologic surgery. However, acetaminophen (2000 mg) or celecoxib (200 mg) alone was not significantly more effective than placebo in reducing postoperative pain.
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Comparative Study Clinical TrialEnvironmental monitoring of sevoflurane and nitrous oxide using the cuffed oropharyngeal airway.
We compared exposure to sevoflurane (SEV) and nitrous oxide (N(2)O) during ventilation using the cuffed oropharyngeal airway (COPA) with waste gas exposure using a conventional face mask (FM) without any additional airways or face straps and with the laryngeal mask airway (LMA). Trace concentrations of SEV and N(2)O were assessed by using a direct reading spectrometer during 33 surgical procedures under general anesthesia. Measurements were made at the patients' mouths and in the anesthesiologists' breathing zones. Mean +/- SD concentrations of SEV and N(2)O measured at the patients' mouths were comparable in the COPA (SEV, 8.1 +/- 12.2 ppm; N(2)O, 213.3 +/- 289.2 ppm) and LMA (SEV, 18.5 +/- 25.8 ppm; N(2)O, 283.4 +/- 361.0 ppm) groups but differed significantly from the FM group (SEV, 46.5 +/- 19.6 ppm; N(2)O, 750.7 +/- 308.3 ppm). These values resulted in a comparable contamination of the anesthesiologists' breathing zones (SEV, 0.5 +/- 0.2 ppm; N(2)O, 5.7 +/- 4.8 ppm) for the COPA group, compared with the LMA group (SEV, 1.0 +/- 0.9 ppm; N(2)O, 12.2 +/- 14.3 ppm). This differed significantly from the FM group (SEV, 2.2 +/- 0.9 ppm; N(2)O, 37.5 +/- 14.3 ppm). We conclude that the use of the COPA during short surgical interventions has an occupational safety comparable to that of the LMA and that both resulted in less contamination through waste anesthetic gases. Therefore, the COPA may be a valuable alternative to the conventional FM. ⋯ In this study, we have shown that the occupational exposure to waste anesthetic gases is comparable when using the cuffed oropharyngeal airway (COPA) and the laryngeal mask airway and is increased when using the face mask. Therefore, the COPA may be a valuable alternative to the conventional face mask during short surgical procedures.
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Clinical TrialIsoflurane requirements during combined general/epidural anesthesia for major abdominal surgery.
We evaluated the effects of bupivacaine on the requirements for thiopental and isoflurane during combined general/epidural anesthesia. Sixty patients scheduled for colon resection were randomly distributed into six groups that received, before the induction of anesthesia, an epidural (T9-10) bolus (8 mL) followed by an infusion (8 mL/h) of saline (Groups 1 and 4), bupivacaine 0.0625% plus fentanyl 2 microg/mL (Groups 2 and 5), or bupivacaine 0.125% plus fentanyl 2 microg/mL (Groups 3 and 6). We evaluated the amount of thiopental needed to abolish the eyelid reflex and the percentage of isoflurane required to maintain the bispectral index (BIS) between 50 and 60 (Groups 1-3) or the mean arterial blood pressure (MAP) within 20% of basal values (Groups 4-6). All groups required similar doses of thiopental (5 mg/kg); the time of evaluation, but not epidural treatment, had a significant effect (P < 0.0001) on BIS and MAP. After tracheal intubation, MAP and BIS increased by 18% and 49%, respectively (P < 0.05). In the bupivacaine groups, isoflurane requirements similarly decreased by 35% (P < 0.03). For BIS and MAP, the epidural treatment (P < 0.02) and type of evaluation (P < 0.03) had a significant effect; MAP was lower (P < 0.05) with 0.125% bupivacaine. We conclude that epidural bupivacaine does not alter the thiopental dose, but it decreases isoflurane requirements by 35%. This study demonstrates that both doses of bupivacaine and fentanyl induce similar isoflurane-sparing effects. However, patients receiving 0.125% bupivacaine showed lower values of MAP when compared with controls, and thus bupivacaine 0.0625% should be favored during combined anesthesia. ⋯ In patients undergoing colon resection under combined anesthesia, isoflurane requirements were assessed by changes in blood pressure or bispectral index. Epidural bupivacaine at concentrations of 0.125% or 0.0625% (each with 2 mg/mL of fentanyl) induced the same sparing of isoflurane (35%). The smaller dose produced less hypotension and should be favored.