Anesthesia and analgesia
-
Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialThe efficacy of intravenous 0.15 versus 0.25 mg/kg intraoperative morphine for immediate postoperative analgesia after remifentanil-based anesthesia for major surgery.
We evaluated the effect of perioperative administration of two doses of morphine for postoperative analgesia after remifentanil-based anesthesia. The prospective, randomized study included 245 patients from 33 centers. All patients were scheduled for abdominal or urological surgery lasting more than 1 h. General anesthesia used remifentanil as the perioperative opioid (1 microg/kg as a bolus then, 0.5 microg/kg as a continuous infusion). A morphine bolus of 0. 15 mg/kg (0.15-mg group) or 0.25 mg/kg (0.25-mg group) was administered 30 min before the end of surgery. In the postanesthesia care unit, pain scores for patients were evaluated by using behavioral pain scores of 1-3, verbal pain scores of 0-3, and visual analog scale scores of 0-10). Postoperative analgesia was obtained by a morphine titration (3 mg every 5 min). Demographic and surgery characteristics were similar in both groups. The delay for first demand of morphine was similar in the 0.15-mg and the 0.25-mg groups (26 [9-60] and 30 [10-60] min, respectively). The frequency of morphine titration was similar in both groups (75% and 66%, respectively). The amount of morphine used in the postanesthesia care unit was smaller in the 0.25-mg group (0.16 [0.0-1.25] vs 0.10 [0.0-0.56] mg/kg; P = 0.008). In the 0.25-mg group, the behavioral pain score was lower at 15 min, the verbal pain score was lower at 60 min (P < 0.001), and similar at 30 min. The visual analog scale pain score at 30 min and 60 min was similar in both groups. The incidence of minor side effects was similar in both groups. However, three cases of postoperative respiratory depression occurred in the 0.25-mg group compared with no cases in the 0.15-mg group. In conclusion, perioperative administration of morphine alone does not provide entirely adequate immediate postoperative pain control after remifentanil-based anesthesia in major surgery. ⋯ The administration of 0.15 or 0.25 mg/kg perioperative morphine during remifentanil-based anesthesia for major surgery does not preclude additional morphine administration in the postanesthesia care unit. The larger dose of 0.25 mg/kg slightly improves postoperative analgesia; however, it may be responsible for postoperative respiratory depression.
-
Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialA comparison of epidural analgesia with 0.125% ropivacaine with fentanyl versus 0.125% bupivacaine with fentanyl during labor.
We previously found that the extent of an epidural motor block produced by 0.125% ropivacaine was clinically indistinguishable from 0.125% bupivacaine in laboring patients. By adding fentanyl to the 0. 125% ropivacaine and bupivacaine solutions in an attempt to reduce hourly local anesthetic requirements, we hypothesized that differences in motor block produced by the two drugs may become apparent. Fifty laboring women were randomized to receive either 0. 125% ropivacaine with fentanyl 2 microg/mL or an equivalent concentration of bupivacaine/fentanyl using patient-controlled epidural analgesia (PCEA) with settings of: 6-mL/hr basal rate, 5-mL bolus, 10-min lockout, 30-mL/h dose limit. Analgesia, local anesthetic use, motor block, patient satisfaction, and side effects were assessed until the time of delivery. No differences in verbal pain scores, local anesthetic use, patient satisfaction, or side effects between groups were observed; however, patients administered ropivacaine/fentanyl developed significantly less motor block than patients administered bupivacaine/fentanyl. Ropivacaine 0.125% with fentanyl 2 microg/mL produces similar labor analgesia with significantly less motor block than an equivalent concentration of bupivacaine/fentanyl. Whether this statistical reduction in motor block improves clinical outcome or is applicable to anesthesia practices which do not use the PCEA technique remains to be determined. ⋯ By using a patient-controlled epidural analgesia technique, ropivacaine 0.125% with fentanyl 2 microg/mL produces similar analgesia with significantly less motor block than a similar concentration of bupivacaine with fentanyl during labor. Whether this statistical reduction in motor block improves clinical outcome or is applicable to anesthesia practices which do not use the patient-controlled epidural analgesia technique remains to be determined.
-
Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Clinical TrialIs an infusion pump necessary to safely administer remifentanil?
We sought to determine if remifentanil could be administered as safely and effectively from an IV drip as from a calculator pump, because not all anesthesiologists have access to a calculator pump. Forty healthy adults undergoing outpatient knee arthroscopy were premedicated with midazolam, 2 mg. Total IV anesthesia was induced with propofol by bolus (2 mg/kg) and maintained by a continuous infusion of propofol and remifentanil. On a randomized, double-blinded basis, they received, IV, either remifentanil (50 microg/mL) by syringe from an infusion pump or from a bag of saline containing remifentanil 20 microg/mL through a minidrip set. The remifentanil infusion syringe pump rate was 0.4 microg. kg(-1). min(-1) until skin incision and then 0.2 microg. kg(-1). min(-1), whereas that from the bag/minidrip set was set to approximate the delivery rate from the pump. Both a syringe pump and bag/minidrip set infusion were administered to each patient but only one contained remifentanil, that one being determined in a randomized, double-blinded manner. There were no differences in demographic data, time to recovery of open eyes, response to command, ability to speak (approximately 7 min), total dose and time of administration of propofol and remifentanil, the incidence of intraoperative hypotension and bradycardia, and postoperative shivering. We demonstrated that remifentanil can be administered as safely and effectively from a bag with a minidrip set as from a syringe in a calculator infusion pump, provided the anesthesiologist is paying attention to the drip rate from the bag. ⋯ Because remifentanil is rapidly degraded in the body, it can be safely and effectively administered from a bag through a minidrip set. We showed that there was no difference with this less expensive method of administration than from the more precise method of a calculator infusion pump.
-
Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialReversal of rapacuronium block during propofol versus sevoflurane anesthesia.
We studied the antagonism of rapacuronium with edrophonium-atropine during propofol- or sevoflurane- based anesthesia in 60 healthy outpatients. After the induction of anesthesia with standardized doses of propofol and fentanyl, rapacuronium 1.5 mg/kg was administered to facilitate tracheal intubation. Patients were randomized to receive either a propofol infusion (100 microg. kg(-1). min(-1)) or sevoflurane (1.0%, end-tidal) in combination with nitrous oxide 66% for maintenance of anesthesia. Neuromuscular block was monitored by using electromyography at the wrist and reversed with edrophonium 1.0 mg/kg and atropine 0.015 mg/kg when the first twitch (T(1)) response of the train-of-four (TOF) stimulation recovered to 25% of the baseline value. The clinical duration of action (i.e., time to 25% T(1) recovery) was similar during both propofol (13.1 +/- 3.6 min) and sevoflu-rane (13.7 +/- 4.4 min) anesthesia. The time from 25% T(1) recovery to TOF ratio of 0.8 was also similar with propofol (3.4 +/- 2.1 min) and sevoflurane (5.9 +/- 8.7 min) (P > 0.05). Although none of the patients in the propofol group required more than 9 min to achieve a TOF ratio of 0. 8, two patients receiving sevoflurane required 31 min and 37 min. Adequate antagonism of rapacuronium block with edrophonium can be achieved within 10 min during propofol anesthesia. However, more prolonged recovery may occur in the presence of sevoflurane. ⋯ We studied the reversal of rapacuronium-induced block with edrophonium and found that the residual rapacuronium block can be readily antagonized during propofol-based anesthesia. However, reversal of rapacuronium appears to be less predictable during sevoflurane-based anesthesia.
-
Anesthesia and analgesia · Mar 2000
Randomized Controlled Trial Comparative Study Clinical TrialThe incidence of right upper-lobe collapse when comparing a right-sided double-lumen tube versus a modified left double-lumen tube for left-sided thoracic surgery.
Lung deflation for left-sided thoracic surgery can be accomplished by using either a left- or right-sided double-lumen endotracheal tube (L-DLT or R-DLT). Anatomic variability of the right mainstem bronchus and the possibility of right upper-lobe obstruction have discouraged the routine use of R-DLT. There are, however, situations in which it is preferable to avoid manipulation/intubation of the left main bronchus, requiring placement of a R-DLT. We compared the modified L-DLT with the R-DLT to determine whether R-DLTs can be used during left-sided thoracic surgery without an increased risk of right upper-lobe collapse. Forty patients requiring left lung deflation were randomly assigned to one of two groups. Twenty patients received a modified L-DLT BronchoCath((R)) (Mallinckrodt Medical Inc., St. Louis, MO), and 20 received a R-DLT BronchoCath((R)). The following variables were studied: 1) time required to position each tube until satisfactory placement was achieved; 2) number of times fiberoptic bronchoscopy was required to readjust tube position; 3) number of malpositions after initial tube placement; 4) time required for left lung collapse; 5) incidence of right upper-lobe collapse from an intraoperative chest radiograph obtained in a lateral decubitus position; 6) overall surgical exposure; and 7) tube acquisition cost. Median time required for initial tube placement was greater in the R-DLT group (3.4 min) versus the L-DLT (2.1 min); P = 0.04. Overall tube cost was also larger for the R-DLT group (US $1819.40) versus the L-DLT group (US $1107.75). The incidence of malpositions, (five versus two), need for fiberoptic bronchoscopy, time for adequacy of left lung collapse, and incidence of intraoperative right upper-lobe collapse (0) did not significantly differ between R-DLT and L-DLT groups. We conclude that R-DLTs can be used for left-sided thoracic surgery without an increased risk of right upper-lobe collapse. Our data suggest that R-DLTs may be more prone to intraoperative dislodgment/malposition than L-DLTs; however, in all cases, correction of malposition was easily achieved. ⋯ In this study, right-sided double-lumen tubes (R-DLTs) were compared with modified left-sided double-lumen tubes in patients requiring one-lung ventilation for left-sided thoracic surgery. The incidence of right upper-lobe collapse was assessed intraoperatively by a chest radiograph which showed no collapse of the right upper lobe in all patients who received R-DLTs or left-sided double-lumen tubes. Therefore, we conclude that R-DLTs present no increased risk of complications for left-sided thoracic surgery and should not be abandoned.