Anesthesia and analgesia
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Anesthesia and analgesia · May 2002
The effects of age on neural blockade and hemodynamic changes after epidural anesthesia with ropivacaine.
We studied the influence of age on the neural blockade and hemodynamic changes after the epidural administration of ropivacaine 1.0% in patients undergoing orthopedic, urological, gynecological, or lower abdominal surgery. Fifty-four patients were enrolled in one of three age groups (Group 1: 18-40 yr; Group 2: 41-60 yr; Group 3: > or=61 yr). After a test dose of 3 mL of prilocaine 1.0% with epinephrine 5 microg/mL, 15 mL of ropivacaine 1.0% was administered epidurally. The level of analgesia and degree of motor blockade were assessed, and hemodynamic variables were recorded at standardized intervals. The upper level of analgesia differed among all groups (medians: Group 1: T8; Group 2: T6; Group 3: T4). Motor blockade was more intense in the oldest compared with the youngest age group. The incidence of bradycardia and hypotension and the maximal decrease in mean arterial blood pressure during the first hour after the epidural injection (median of Group 1: 11 mm Hg; Group 2: 16 mm Hg; Group 3: 29 mm Hg) were more frequent in the oldest age group. We conclude that age influences the clinical profile of ropivacaine 1.0%. The hemodynamic effects in older patients may be caused by the high thoracic spread of analgesia, although a diminished hemodynamic homeostasis may contribute. ⋯ Analgesia levels after the epidural administration of 15 mL of ropivacaine 1.0% increase with increasing age. This is associated with an increased incidence of hypotension in the elderly, although an effect of age on the hemodynamic homeostasis may have contributed. It appears that epidural doses should be adjusted for elderly patients.
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Anesthesia and analgesia · May 2002
Randomized Controlled Trial Clinical TrialCaudal clonidine prolongs analgesia from caudal S(+)-ketamine in children.
We performed a prospective randomized double-blinded study to test preservative-free S(+)-ketamine alone or in combination with clonidine for intra- and postoperative caudal blockade in pediatric surgery over a 24-h period. Fifty-three children (1-72 mo) scheduled for inguinal hernia repair were caudally injected with either S(+)-ketamine 1 mg/kg alone (Group K) or with additional clonidine (Group C1 = 1 microg/kg; Group C2 = 2 microg/kg) during sevoflurane anesthesia via a laryngeal mask. Intraoperative monitoring included heart rate, blood pressure, and pulse oximetry; postoperative monitoring included a pain discomfort scale and a sedation score. No additional analgesic drugs were required during surgery. The mean duration of postoperative analgesia was 13.3 +/- 9.2 h in Group K, 22.7 +/- 3.5 h in Group C1, and 21.8 +/- 5.2 h in Group C2 (P < 0.0001, Group K versus other groups). Groups C1 and C2 received significantly fewer analgesics in the postoperative period than Group K (15% and 18% vs 63%; P < 0.01). The three groups had similar postoperative sedation scores. We conclude that the combination of S(+)-ketamine 1 mg/kg with clonidine 1 or 2 microg/kg for caudal blockade in children provides excellent analgesia without side effects over a 24-h period. ⋯ Caudally administered preservative-free S(+)-ketamine combined with 1 or 2 microg/kg clonidine provides excellent perioperative analgesia in children and has minimal side effects.
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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.