Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2000
Pediatric evaluation of the bispectral index (BIS) monitor and correlation of BIS with end-tidal sevoflurane concentration in infants and children.
The bispectral index (BIS) has been developed in adults and correlates well with clinical hypnotic effects of anesthetics. We investigated whether BIS reflects clinical markers of hypnosis and demonstrates agent dose-responsiveness in infants and children. In an observational arm of this study, BIS values in children undergoing general anesthesia were observed and compared with similar data collected previously in a study of adults. In a second arm of the study, a range of steady-state end-tidal concentrations of sevoflurane was administered and corresponding BIS documented. Data were examined for differences between infants (0-2 yr) and children (2-12 yr). No difference was seen in BIS values in children before induction, during maintenance, and on emergence compared with adult values. There was no difference in BIS between infants and children at similar clinical levels of anesthesia. In children and infants, BIS was inversely proportional to the end-tidal concentration of sevoflurane. The sevoflurane concentration for a BIS = 50 (95% confidence interval) was significantly different: 1. 55% (1.40-1.70) for infants versus 1.25% (1.12-1.37) for children. Although validation with specific behavioral end points was not possible, BIS correlated with clinical indicators of anesthesia in children as it did in adults: as depth of anesthesia increased, BIS diminished. BIS correlated with sevoflurane concentration in infants and children. The concentration-response difference between infants and children was consistent with data showing that minimum alveolar concentration is higher in children less than 1 yr of age. ⋯ The use of bispectral index (BIS) during general anesthesia improves the titration of anesthetics in adults. The data from this study suggest that the same equipment and method of electroencephalogram analysis may be applied to infants and children.
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Anesthesia and analgesia · Apr 2000
Randomized Controlled Trial Multicenter Study Comparative Study Clinical TrialA randomized, double-blinded study of remifentanil versus fentanyl for tonsillectomy and adenoidectomy surgery in pediatric ambulatory surgical patients.
We compared, in a double-blinded manner, the anesthetic maintenance and recovery properties of remifentanil with a clinically comparable fentanyl-based anesthetic technique in pediatric ambulatory surgical patients. Anesthesia was induced with either halothane or sevoflurane and nitrous oxide and oxygen. Patients were randomized (computer generated) to receive either remifentanil or fentanyl in a blinded syringe with nitrous oxide and oxygen in one of four possibilities: halothane/remifentanil, halothane/fentanyl, sevoflurane/remifentanil or sevoflurane/fentanyl. In patients receiving remifentanil, a placebo bolus was administered, and a continuous infusion (0.25 microg. kg(-1). min(-1)) was begun. In patients receiving fentanyl, a bolus (2 microg/kg) was administered followed by a placebo continuous infusion. The time from discontinuation of the anesthetic to extubation, discharge from the postanesthesia care unit (PACU), and discharge to home, as well as pain scores, were assessed by a blinded nurse observer. Systolic blood pressure and heart rate were noted at selected times, and adverse events were recorded. Remifentanil provided faster extubation times and higher pain-discomfort scores. PACU and hospital discharge times were similar. There were no statistical differences among the groups for adverse events. There were statistically, but not clinically, significant differences in hemodynamic variables. We noted that continuous infusions of remifentanil were intraoperatively as effective as bolus fentanyl. Although patients could be tracheally extubated earlier with remifentanil, this did not translate to earlier PACU or hospital discharge times. In addition, remifentanil was associated with higher postoperative pain scores. The frequent incidence of postoperative pain observed in the postoperative recovery room suggests that better intraoperative prophylactic analgesic regimens for postoperative pain control are necessary to optimize remifentanil's use as an anesthetic for children. ⋯ This is a study designed to examine the efficacy and safety of a short-acting opioid, remifentanil, when used in pediatric patients. The frequent incidence of postoperative pain observed in the postoperative recovery room suggests that better intraoperative prophylactic analgesic regimens for postoperative pain control are necessary to optimize remifentanil's use as an anesthetic for children.
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Anesthesia and analgesia · Apr 2000
Meta AnalysisPrevention of pain on injection with propofol: a quantitative systematic review.
The best intervention to prevent pain on injection with propofol is unknown. We conducted a systematic literature search (Medline, Embase, Cochrane Library, bibliographies, hand searching, any language, up to September 1999) for full reports of randomized comparisons of analgesic interventions with placebo to prevent that pain. We analyzed data from 6264 patients (mostly adults) of 56 reports. On average, 70% of the patients reported pain on injection. Fifteen drugs, 12 physical measurements, and combinations were tested. With IV lidocaine 40 mg, given with a tourniquet 30 to 120 s before the injection of propofol, the number of patients needed to be treated (NNT) to prevent pain in one who would have had pain had they received placebo was 1.6. The closest to this came meperidine 40 mg with tourniquet (NNT 1.9) and metoclopramide 10 mg with tourniquet (NNT 2.2). With lidocaine mixed with propofol, the best NNT was 2.4; with IV alfentanil or fentanyl, it was 3 to 4. IV lidocaine before the injection of propofol was less analgesic. Temperature had no significant effect. There was a lack of data for all other interventions to allow meaningful conclusions. The diameter of venous catheters and speed of injection had no impact on pain. ⋯ IV lidocaine (0.5 mg/kg) should be given with a rubber tourniquet on the forearm, 30 to 120 s before the injection of propofol; lidocaine will prevent pain in approximately 60% of the patients treated in this manner.