Anesthesia and analgesia
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Anesthesia and analgesia · Dec 1998
Randomized Controlled Trial Clinical TrialIntrathecal bupivacaine reduces pruritus and prolongs duration of fentanyl analgesia during labor: a prospective, randomized controlled trial.
Pruritus is a frequent complication (40%-100%) of intrathecal (IT) fentanyl 25 microg (F) for labor analgesia. The addition of IT bupivacaine 2.5 mg (B) to F has been reported in a nonrandomized series to have a 17.3% incidence of pruritus. This study prospectively evaluated the incidence and distribution of pruritus in laboring parturients receiving IT F + B. Sixty-five laboring parturients were randomly assigned to receive IT F, B, or F + B as part of a combined spinal-epidural technique. Visual analog scores, sensory level, motor strength, and pruritus were recorded before injection and at intervals thereafter. When present, the distribution of pruritus was evaluated. The duration of analgesia was determined as the time from IT drug administration until the patient requested supplemental analgesia. The median duration of analgesia in the F, B, and F + B groups was 62.5, 55.0, and 94.5 min, respectively. Compared with F alone, the combination of F + B led to a decreased frequency of pruritus (36.4% vs 95%). The incidence of facial pruritus (25%) was same in the F + B and F groups; however, the occurrence of pruritus distributed over the rest of the body was significantly more frequent in the F compared with the F + B group. The combination of F + B prolongs the duration of labor analgesia compared with IT F or B alone. F + B also leads to a decreased incidence of pruritus, except in the facial region. ⋯ When administered intrathecally with fentanyl 25 microg in laboring parturients, bupivacaine 2.5 mg attenuates the frequency of pruritus on all parts of the body except the face. This combination also results in a rapid onset and prolonged duration of labor analgesia compared with either drug alone.
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Anesthesia and analgesia · Dec 1998
Randomized Controlled Trial Comparative Study Clinical TrialPreoperative preparation programs in children: a comparative examination.
We sought to determine whether an extensive behavioral preparation program for children undergoing surgery is more effective than a limited behavioral program. The primary end point was child and parent anxiety during the preoperative period. Secondary end points included behavior of the child during the induction of anesthesia and the postoperative recovery period. Several days before surgery, children (n = 75) aged 2-12 yr randomly received either an information-based program (OR tour), an information + modeling-based program (OR tour + videotape), or an information + modeling + coping-based program (OR tour + videotape + child-life preparation). Using behavioral and physiological measures of anxiety, we found that children who received the extensive program exhibited less anxiety immediately after the intervention, in the holding area on the day of surgery, and on separation to the operating room. These findings, however, achieved statistical significance only in the holding area on the day of surgery (44[10-72] vs 32[8-50] vs 9[6-33]; P = 0.02). Similarly, parents in the extensive program were significantly less anxious on the day of surgery in the preoperative holding area, as assessed by behavioral (P = 0.015) and physiological measures (P = 0.01). In contrast, no differences were found among the groups during the induction of anesthesia, recovery room period, or 2 wk postoperatively. We conclude that children and parents who received the extensive preoperative preparation program exhibited lower levels of anxiety during the preoperative period, but not during the intraoperative or postoperative periods. ⋯ The extensive behavioral preoperative program that we undertook had limited anxiolytic effects. These effects were localized to the preoperative period and did not extended to the induction of anesthesia or the postoperative recovery period.
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Anesthesia and analgesia · Dec 1998
Characteristics of tolerance to somatic and visceral antinociception after continuous epidural infusion of morphine in rats.
A continuous epidural infusion of morphine may cause a complicated tolerance to develop, depending on the spinal and supraspinal sites. We designed this study to clarify the characteristics of the tolerance to somatic and visceral antinociception after epidural morphine infusion. Rats received epidural infusion of morphine at the rates of 50 or 100 microg kg(-1) h(-1), or isotonic sodium chloride solution for 7 days. The tail-flick (TF) test and colorectal distension (CD) test were used to measure the somatic and visceral antinociceptive effects, respectively. Nociceptive tests were performed on Days 1, 2, 3, 4, and 7. After 7 days, time-response curves after epidural morphine (10 microg) or intraperitoneal morphine (3 mg) challenge tests were conducted to assess the magnitude of tolerance. Epidurally infused morphine significantly increased percent maximal possible effects (%MPEs) (P < 0.05) in both the TF and CD tests, depending on the concentration of morphine. In the epidural morphine challenge test, increases in %MPEs were significantly attenuated (P < 0.05) in the morphine-infused group compared with the isotonic sodium chloride solution-infused group. The increases in %MPEs in the intraperitoneal challenge test were also attenuated in the morphine-infused group. We conclude that morphine tolerance to both somatic and visceral antinociception develops rapidly during epidural infusion and is based on the development of tolerance at the systemic, as well as the epidural, level. ⋯ A continuous epidural infusion of morphine rapidly induces tolerance to visceral and somatic antinociception in rats. This development is based on the development of tolerance at the systemic, as well as the epidural, level.
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Anesthesia and analgesia · Dec 1998
End-tidal sevoflurane concentration for tracheal extubation and skin incision in children.
We sought to determine minimum alveolar anesthetic concentrations for skin incision (MAC) and for tracheal extubation (MAC(Ex)) for sevoflurane and its associated awakening time and respiratory complications during emergence from sevoflurane anesthesia in children. We studied 40 (20 in each group) unpremedicated pediatric patients ranging in age from 2 to 8 yr. For MAC(Ex) determination, anesthetic induction, tracheal intubation, and maintenance of anesthesia were performed with sevoflurane and N2O in oxygen. However, N2O administration was discontinued at the end of surgery. The ratio of the predetermined end-tidal to inspiratory concentration was maintained at 0.95-1.00 for at least 15 min. The trachea was gently extubated, and smooth tracheal extubation was defined by the absence of gross purposeful muscular movements. In addition, the respiratory complications and awakening time were investigated during emergence from anesthesia for each patient. For MAC determination, anesthesia induction and tracheal intubation were performed with 5% sevoflurane in oxygen. After the predetermined end-tidal sevoflurane concentration had been established and maintained for at least 15 min, skin incision was attempted. Patients' responses to skin incision were described as "no movement" or "movements." The MAC or MAC(Ex) for sevoflurane was 2.22% +/- 0.13% (mean+/-SD) or 1.70%+/-0.12%, and the 95% effective dose (ED95) for smooth extubation was 1.87% (95% confidence limits 1.75%-2.62%), respectively, in children. During emergence from anesthesia, none of patients held their breath or experienced laryngospasm in the current study. One patient in a subgroup at 1.5% coughed before tracheal extubation. All 10 patients with smooth tracheal extubation had hemoglobin oxygen saturation levels of > or =98% in this study. Awakening time was 9.7+/-3.7 min in the subgroup that received 1.75% sevoflurane. In conclusion, the MAC(Ex) and ED95 values of sevoflurane were 1.64% and 1.87%, respectively, in children. The MAC(Ex) to MAC ratio for sevoflurane was 0.8 in children within the same age range and mean age. ⋯ Because tracheal extubation of anesthetized patients may be advantageous in certain clinical situations, we performed this study. The ratio minimum alveolar anesthetic concentrations for skin incision and for tracheal extubation for sevoflurane was 0.8 in children within the same age range and mean age. No patient in the current study had laryngospasm.