Anesthesia and analgesia
-
Anesthesia and analgesia · Jan 1999
Randomized Controlled Trial Clinical TrialThe safety and effectiveness of remifentanil as an adjunct sedative for regional anesthesia.
We assessed the sedative potential of continuous infusions of remifentanil with a validated composite alertness scale in 160 patients (ASA physical status I or II) undergoing hip replacement surgery with spinal block (n = 61) or hand surgery using brachial plexus block (n = 93). They were randomized to receive one of the following initial dose regimens in double-blinded fashion: placebo or 0.04, 0.07, or 0.1 microg x kg(-1) x min(-1) remifentanil subsequently titrated to effect. Additional midazolam IV was allowed for adequate sedation as required. The combined analysis of both surgery groups revealed a dose-related increase in achievement of sedation level > or =2 within 15 min of the start of the study drug infusion; all remifentanil dose comparisons with placebo reached significance (P < 0.001). The remifentanil 50% effective dose for a composite sedation level > or =2 within 15 min of the start of drug infusion was estimated as 0.043 microg x kg(-1) x min(-1) (95% confidence interval 0.01, 0.059). The requirement for midazolam decreased with increasing remifentanil dose compared with placebo (P < 0.001). The median time to return to alertness after the end of infusion was 10-12 min in the remifentanil groups and 5 min in the placebo group. Significant incidences of nausea, pruritus, sweating, and respiratory depression were reported during remifentanil infusions compared with placebo. The data suggest that remifentanil may be useful for supplementation of regional anesthesia, provided that ventilation is carefully monitored. ⋯ In this dose-finding, placebo-controlled study, remifentanil infusions were used to provide sedation during spinal and brachial plexus regional anesthesia. The 50% effective dose for achievement of sedation was 0.043 microg x kg(-1) x min(-1). Return to alertness occurred after 10-12 min (median time). Remifentanil infusions can be used to supplement regional anesthesia, but this requires careful monitoring of ventilation.
-
Anesthesia and analgesia · Jan 1999
Randomized Controlled Trial Clinical TrialCost analysis of target-controlled infusion-based anesthesia compared with standard anesthesia regimens.
With the development of new computer-assisted target-controlled infusion (TCI) systems and the availability of short-acting anesthetics, total IV anesthesia (TIVA) has become increasingly popular. The aim of this study was to compare costs of TCI-based anesthesia with two standard anesthesia regimens. Sixty patients undergoing elective laparoscopic cholecystectomy were randomly divided into three groups. Group 1 (TIVA/TCI) received TIVA using a propofol-based TCI system and continuous administration of remifentanil; Group 2 (isoflurane) underwent inhaled anesthesia with isoflurane, fentanyl, and N2O; Group 3 (standard propofol) received fentanyl and N2O and a continuous infusion of propofol using a standard delivery system. Maintenance doses for anesthetics were adjusted according to the patient's need. Isoflurane consumption was measured by weighing the vaporizer by using a precision weighing machine. Duration of surgery and of anesthesia was similar in the three groups. Time from stopping administration of anesthetics until tracheal extubation (6+/-2 min) and stay in the postanesthesia care unit (PACU; 70+/-12 min) were shorter in Group 1 than in the Groups 2 (15+/-3 and 87+/-13 min, respectively) and 3 (10+/-4 and 81+/-14 min, respectively) (P < 0.05). Episodes of postoperative nausea and vomiting in the PACU and on the surgical ward were less common in Group 1 than in the other two groups. Intraoperative costs were higher in Group 1 ($62.19/patient; $0.55/min of anesthesia) than in Groups 2 ($16.97/patient; $0.13/min of anesthesia) and 3 ($34.68/patient; $0.32/min of anesthesia). Cost for discarded anesthetic drugs accounted for almost 18% of total intraoperative costs in Group 1. We conclude that TIVA/TCI anesthesia using propofol/remifentanil was associated with the highest intraoperative costs but the fewest postoperative side effects. An overall cost-effectiveness analysis of new anesthetic regimens must balance the direct cost of anesthetics and beneficial effects leading to improved patients' comfort. ⋯ In today's climate of cost-consciousness, careful economic evaluation of new anesthetic regimens is necessary. A target-controlled infusion (TCI)-based total IV anesthesia (TIVA) regimen using propofol and remifentanil was compared with a standard propofol anesthesia regimen and an inhaled anesthetic technique using isoflurane. Target-controlled infusion/total IV anesthesia was associated with the largest intraoperative costs but allowed the most rapid recovery from anesthesia, was associated with fewest postoperative side effects, and permitted earlier discharge from the postanesthesia care unit.
-
Anesthesia and analgesia · Jan 1999
Randomized Controlled Trial Clinical TrialEpidural analgesia with local anesthetics after abdominal surgery: earlier motor recovery with 0.2% ropivacaine than 0.175% bupivacaine.
The aim of this prospective, randomized, double-blinded study was to compare pain relief, side effects, and ability to ambulate during epidural anesthesia with ropivacaine 0.2% plus sufentanil versus bupivacaine 0.175% plus sufentanil after major gastrointestinal surgery. Epidural catheters were inserted at T8-11, and 30 microg of sufentanil with 15 mL of ropivacaine 0.75% (Group 1, n = 42) or bupivacaine 0.5% (Group 2, n = 44) was injected. General anesthesia was induced, a continuous epidural infusion (5 mL/h) was then begun with 1 microg/mL sufentanil plus ropivacaine 0.2% (Group 1) or bupivacaine 0.175% (Group 2). Postoperatively, the infusion rate was adjusted to individual requirements. Patients were also able to receive additional 2-mL bolus doses every 20 min. Demographic data (except for gender and height), analgesia, drug dosage, and side-effects, including motor blockade (Bromage score), were similar in both groups, but mobilization recovered more quickly in Group 1. Gender, age, ASA physical status, duration of surgery, and intraoperative blood loss had no effect on mobilization. We conclude that epidural analgesia is effective and safe with both regimens. There is not necessarily a correlation between the Bromage score and the desired outcome of mobilization. The ability to walk postoperatively is hastened if ropivacaine is used instead of bupivacaine. ⋯ Regarding pain relief and side effects, epidural analgesia with ropivacaine 0.2% and sufentanil 1 microg/mL yields pain scores and pain intensity comparable to those for the well evaluated combination of bupivacaine 0.175% and sufentanil 1 microg/mL. However, earlier recovery of the ability to walk unassisted in patients receiving the combination of ropivacaine and sufentanil may result in their earlier rehabilitation.
-
Anesthesia and analgesia · Jan 1999
Randomized Controlled Trial Clinical TrialThe effects on resting ventilation of intravenous infusions of morphine or sameridine, a novel molecule with both local anesthetic and opioid properties.
Sameridine has both local anesthetic and partial mu-opioid receptor agonistic properties. The aim of this single-blinded, randomized, three-way cross-over study of 12 subjects was to investigate the effects on resting ventilation of two doses of sameridine: 0.15 mg/kg (S-Small) and 0.73 mg/kg (S-Large) compared with 0.10 mg/kg morphine. Each drug was infused IV over 20 min. Ventilation was measured by pneumotachography and in-line capnography, and sedation was rated by the subjects using a visual analog scale (VAS). Plasma was collected and analyzed for sameridine and morphine. At the end of drug infusion, minute ventilation (VE) and tidal volume (VT) were reduced in the S-Large group, and VE was reduced in the morphine group. End-tidal CO2 increased in both groups (P < 0.05), but respiratory rates remained unchanged. In the S-Small group, no ventilatory changes were recorded. In the S-Large group, the median sedation score was 6.8 cm with corresponding values in the morphine and S-Small groups of 3.3 and 2.5 cm, respectively. There was a relationship between the plasma concentration of sameridine and the depression of ventilation. We conclude that sameridine influences resting ventilation and that this effect is directly related to plasma concentrations of sameridine. From a ventilatory aspect, a clinical dose of sameridine with both local anesthetic and opioid properties seems safe. ⋯ Sameridine, a molecule with both local anesthetic and analgesic properties, impaired resting ventilation after a large IV dose (0.73 mg/kg), more so than 0.10 mg/kg IV morphine. A clinical dose of sameridine (0.15 mg/kg) did not have any effects on ventilation.
-
Anesthesia and analgesia · Jan 1999
Randomized Controlled Trial Clinical TrialConcentration of lidocaine affects intensity of sensory block during lumbar epidural anesthesia.
We investigated the effects of a twofold difference in concentration and volume of lidocaine on lumbar epidural block using a cutaneous current perception threshold (CPT) quantitative sensory testing device. Twenty ASA I patients scheduled for elective gynecological surgery were randomly divided into two equal groups to receive either 20 mL of 1% lidocaine or 10 mL of 2% lidocaine through an epidural catheter inserted at the L1-2 interspace. CPTs at 2000-, 250-, and 5-Hz stimulation and sensation to light touch, temperature, and pinprick at ipsilateral dermatomes V, T9, and L2 were measured before and every 5 min until 60 min after the epidural lidocaine. Epidural anesthesia with both solutions produced a significant increase in all CPTs at dermatomes T9 and L2. Alterations in CPTs were similar for both groups at T9 but were significantly greater in patients given 2% lidocaine than in those given 1% lidocaine at L2. There were no differences in the upper level of sensory block to cold, pinprick, and touch between the two groups. We conclude that lumbar epidural anesthesia with 10 mL of 2% lidocaine produces more intense blockade of both large- and small-diameter sensory nerve fibers than that with 20 mL of 1% lidocaine. ⋯ The effects of local anesthetic concentration and volume on the quality of epidural anesthesia have not been adequately investigated. The results of the present study suggest that the concentration affects the intensity of sensory block during epidural anesthesia with lidocaine.