Anesthesia and analgesia
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Anesthesia and analgesia · May 1999
Randomized Controlled Trial Clinical TrialIntraperitoneal lidocaine decreases intraoperative pain during postpartum tubal ligation.
We conducted a randomized, double-blinded, placebo-controlled trial to evaluate the effectiveness of intraperitoneal lidocaine, IM morphine, or both drugs together for pain relief in postpartum tubal ligation. Eighty postpartum patients scheduled to have tubal sterilization were randomly divided into four groups to receive IM isotonic sodium chloride solution (1 mL) and intraperitoneal instillation of 80 mL of isotonic sodium chloride solution (Group P); IM morphine (10 mg in 1 mL) and intraperitoneal instillation of 80 mL of isotonic sodium chloride solution (Group M); IM injection of isotonic sodium chloride solution and intraperitoneal instillation of 0.5% lidocaine in 80 mL (Group L); and both IM morphine and intraperitoneal lidocaine instillation (Group ML). The minilaparotomy was performed after local infiltration with 15 mL of 1% lidocaine. A numerical rating score was used to rate pain on a 0-10 scale during the surgical procedures. The mean pain scores were 1.2 in Group L and 0.8 in Group ML. These pain scores were significantly lower than those in Groups P and M, which were 5.5 and 6.0, respectively (P < 0.001). ⋯ Pain relief was inadequate in patients undergoing postpartum tubal ligation under local anesthesia, even after the administration of IM morphine. Instilling lidocaine into the abdominal cavity, however, effectively decreased intraoperative pain in these patients.
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Anesthesia and analgesia · May 1999
Randomized Controlled Trial Clinical TrialThe effects of subanesthetic concentrations of sevoflurane and nitrous oxide, alone and in combination, on analgesia, mood, and psychomotor performance in healthy volunteers.
We studied the effects of subanesthetic concentrations of sevoflurane and nitrous oxide, alone and in combination, on analgesia, mood, and psychomotor performance in human volunteers. We hypothesized that nitrous oxide and sevoflurane would produce both opposing and potentiating effects within the same study. Over the course of three sessions, 20 subjects inhaled 0%, 0.2%, or 0.4% end-tidal sevoflurane for a 68-min period that was divided into four 17-min blocks. During either the second or fourth block, 30% end-tidal nitrous oxide was added to the concentration of sevoflurane being inhaled. Pain response, psychomotor performance, and mood were evaluated during the second and fourth blocks. Pain ratings were higher when sevoflurane and nitrous oxide were administered together than when nitrous oxide was administered alone, which indicates that sevoflurane attenuated the analgesic effects of nitrous oxide. Sevoflurane increased self-reported ratings of sleepiness, and the addition of nitrous oxide decreased these ratings. Nitrous oxide potentiated psychomotor impairment that was induced by sevoflurane. The combination of sevoflurane and nitrous oxide produced both opposing and potentiating effects within the same study. The results suggest that nitrous oxide and sevoflurane may act through different neurochemical mechanisms on some end points, such as analgesia and sleepiness. ⋯ Healthy volunteers inhaled subanesthetic concentrations of sevoflurane and nitrous oxide. Sevoflurane made nitrous oxide less effective as an analgesic, and nitrous oxide made sevoflurane less effective as a sedative. The two drugs may work at cross purposes on different end points of anesthesia.
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Anesthesia and analgesia · May 1999
Randomized Controlled Trial Comparative Study Clinical TrialThe effect of intravenous lactated Ringer's solution versus 0.9% sodium chloride solution on serum osmolality in human volunteers.
Animal studies have shown that large volumes of IV lactated Ringer's solution (LR) decrease serum osmolality, thereby increasing cerebral water. These studies have led to recommendations to limit LR to avoid cerebral edema in neurosurgical patients. Eighteen healthy human volunteers aged 20-48 yr received 50 mL/kg LR over 1 h on one occasion and 0.9% sodium chloride (NS) on another. Venous samples were taken at baseline (T1), at infusion end (T2), and 1 h after T2 (T3). Time until first urination was noted. With LR, serum osmolality decreased by 4+/-3 mOsm/kg from T1 to T2 and increased insignificantly with NS. At T3, osmolality returned almost to baseline in the LR group. Blood pH increased from T1 to T2 with LR by 0.04+/-0.04 and decreased with NS by 0.04+/-0.04. These pH changes persisted at T3. Subjective mental changes occurred only with NS. Abdominal discomfort was more common with NS. Time until first urination was longer with NS (106+/-11 min) than with LR (75+/-10 min) (P < 0.001). In healthy humans, an infusion of large volumes of LR, but not NS, transiently decreased serum osmolality, whereas acidosis associated with NS persisted and urinary output was slower with NS. ⋯ Large volumes of lactated Ringer's solution administered to healthy humans produced small transient changes in serum osmolality. Large volumes of sodium chloride did not change osmolality but resulted in lower pH.
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Anesthesia and analgesia · May 1999
Distress during the induction of anesthesia and postoperative behavioral outcomes.
We determined whether children who are extremely anxious during the induction of anesthesia are more at risk of developing postoperative negative behavioral changes compared with children who appear calm during the induction process. Children (n = 91) aged 1-7 yr scheduled for general anesthesia and elective outpatient surgery were recruited. Using validated measures of preoperative anxiety and postoperative behaviors, children were evaluated during the induction of general anesthesia and on Postoperative Days 1, 2, 3, 7, and 14. Using a multivariate logistic regression model, in which the dependent variable was the presence or absence of postoperative negative behavioral changes and the independent variables included several potential predictors, we demonstrated that anxiety of the child, time after surgery, and type of surgical procedure were predictors for postoperative maladaptive behavior. The frequency of negative postoperative behavioral changes decreased with time after surgery, and the frequency of negative postoperative behavioral changes increased when the child exhibited increased anxiety during the induction of anesthesia. Finally, we found a significant correlation (r) of 0.42 (P = 0.004) between the anxiety of the child during induction and the excitement score on arrival to the postanesthesia care unit. We conclude that children who are anxious during the induction of anesthesia have an increased likelihood of developing postoperative negative behavioral changes. We recommend that anesthesiologists advise parents of children who are anxious during the induction of anesthesia of the increased likelihood that their children will develop postoperative negative behavioral changes such as nightmares, separation anxiety, and aggression toward authority. ⋯ Anesthesiologists who care for children who are anxious during the induction of anesthesia should inform parents that these children have an increased likelihood of developing postoperative negative behavioral changes.
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Anesthesia and analgesia · May 1999
Comparative StudyComparison between the European and North American protocols for diagnosis of malignant hyperthermia susceptibility in humans.
We compared the diagnostic outcome of in vitro contracture tests for diagnosis of malignant hyperthermia susceptibility performed according to the European Malignant Hyperthermia Group protocol and the North American Malignant Hyperthermia Group protocol. The aim of the study was to compare the two major diagnostic tests of malignant hyperthermia susceptibility to have basic data for a common worldwide protocol. We evaluated 156 patients and 17 control individuals. The accordance in diagnostic outcome was 87%. The diverging outcomes between the two protocols were found in a group of patients reacting in few muscle strips and close to the cutoff limits. A 100% accordance in diagnostic outcome was found in individuals with contractures in at least five of six tested muscle strips. In both protocols, contractures close to the cutoff limits in a few muscle strips in scientific studies should be considered as unknown results. ⋯ We compared the two major protocols for investigating malignant hyperthermia susceptibility. There was 87% accordance in diagnostic outcome. The diverging outcomes were seen in individuals with less reproducible test results near the cutoff limits. In scientific studies, such results should be considered as unknown.