Anesthesia and analgesia
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Anesthesia and analgesia · Apr 2000
Anticoagulation for cardiac surgery in patients receiving preoperative heparin: use of the high-dose thrombin time.
Patients receiving heparin infusions have an attenuated activated clotting time (ACT) response to heparin given for cardiopulmonary bypass (CPB). We compared patients receiving preoperative heparin (Group H) to those not receiving heparin (REF group) with respect to ACT, high-dose thrombin time (HiTT), and markers of thrombin generation during CPB. Sixty-five consecutive patients (33 Group H, 32 REF group) undergoing elective CPB were evaluated. ACT and HiTT were measured at multiple time points. Plasma levels of thrombin-antithrombin III complex and fibrin monomer were determined at baseline, during CPB, and after protamine administration. Transfusion requirements and postoperative blood loss were measured and compared. ACT values after heparinization increased less in Group H and were significantly lower than those in the REF group (P < 0.01). HiTT values did not differ significantly between the two groups. Blood loss and transfusion requirements were not significantly different between the two groups. Plasma levels of thrombin-antithrombin III complexes and fibrin monomer also did not differ between groups at any time, despite a lower ACT in Group H after heparinization and during CPB. Our data suggest that thrombin formation and activity are not enhanced in patients receiving heparin therapy, despite a diminished ACT response to heparin. The utility of ACT and the threshold values indicative of adequate anticoagulation for CPB are relatively undefined in patients receiving preoperative heparin. HiTT should be investigated as a safe and accurate monitor of anticoagulation for CPB in patients receiving preoperative heparin therapy. ⋯ The diminished activated clotting time response to heparin, in patients receiving preoperative heparin therapy, poses difficulties when attempting to provide adequate anticoagulation for cardiopulmonary bypass. Current data suggest that heparin resistance is not observed when high-dose thrombin time is used to monitor anticoagulation and that a lower activated clotting time value in these patients may be safe.
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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 AnalysisLocal anesthetic infiltration for postoperative pain relief after laparoscopy: a qualitative and quantitative systematic review of intraperitoneal, port-site infiltration and mesosalpinx block.
In a systematic review, we evaluated randomized controlled trials (RCTs) of peripheral local anesthetics (LA) compared with placebo or no treatment in the control of postoperative pain after laparoscopic surgery. A total of 41 trials with data from 2794 patients were considered appropriate for analysis. Of these 41 RCTs, 13 evaluated intraperitoneal LA after cholecystectomy, four RCTs assessed intraperitoneal LA after other procedures, eight RCTs evaluated port-site infiltration after various procedures, 12 RCTs evaluated mesosalpinx or fallopian tube block after sterilization, and four RCTs considered combined LA regimens. Outcome measures were pain scores, analgesic consumption, and time to first analgesic request. Efficacy was estimated by significant difference (P < 0.05), as reported in the original reports, and by calculation of the weighted mean difference of visual analog scale pain scores between treatment groups. Improved pain relief was observed in seven of the 13 RCTs of intraperitoneal LA after cholecystectomy and in four RCTs of other procedures. A statistically significant weighted mean difference of -13 mm visual analog scale (95% confidence intervals [CI]: -20 to -6) in favor of the treatment groups was observed after cholecystectomy. Three of eight trials of port-site infiltration showed significant differences but questionable clinical importance and validity in two; weighted mean difference was not statistically significant between treatment groups (95% CI -9 to 1). All RCTs of mesosalpinx or fallopian tube block after sterilization showed improved pain relief with a statistically significant weighted mean difference of -19 mm (95% CI -25 to -14) in favor of treatment groups. Data of combined regimens were positive, however, sparse. We conclude that there was evidence for a statistically significant but clinically questionable, important effect of intraperitoneal LA for postoperative pain control. There was evidence for a significant but short-lasting effect of mesosalpinx/fallopian tube block after sterilization, but there was a lack of evidence for any important effect of port-site infiltration. Data from combined regimens were too sparse for conclusions. ⋯ A systematic review summarizes, through transparent methodology, available information from randomized, controlled trials to produce the best available evidence-based estimate of a "true" clinical effect of an intervention. This systematic review confirms intraperitoneal and mesosalpinx local anesthetic block, not port-site infiltration, to have some impact on postoperative pain after laparoscopy.