Anesthesia and analgesia
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Anesthesia and analgesia · Sep 1999
Randomized Controlled Trial Comparative Study Clinical TrialThe relative potency of oral transmucosal fentanyl citrate compared with intravenous morphine in the treatment of moderate to severe postoperative pain.
Pharmacokinetic studies have shown that oral transmucosal absorption of fentanyl is relatively rapid compared with gastrointestinal absorption, and it results in increased bioavailability. We designed this study to establish the relative potency of oral transmucosal fentanyl citrate (OTFC) compared with i.v. morphine in 133 postoperative patients. The morning after surgery, patients randomly received one dose of either OTFC (200 or 800 microg) and a placebo i.v. injection or i.v. morphine (2 or 10 mg) and an oral transmucosal placebo unit. Pain intensity, pain relief, time to meaningful pain relief, and time to remedication were recorded. Median time to onset of relief was approximately 5 min for all groups. Over the first hour, little difference among treatment groups was seen for pain intensity and pain relief. By 2 h after study drug administration, 800 microg of OTFC and 10 mg of i.v. morphine generally produced similar analgesia, which was better than the smaller doses. Duration of analgesia with the larger doses (800 microg of OTFC and 10 mg of morphine) was similar and longer that produced by the smaller doses. The larger doses of OTFC and morphine produced better and more sustained analgesia than 200 microg of OTFC or 2 mg of morphine. ⋯ The relative potency of oral transmucosal fentanyl citrate (OTFC) to i.v. morphine was 8-14:1. In this postoperative setting, OTFC produced rapid pain relief similar to that produced by i.v. morphine. The larger doses of OTFC (800 microg) and morphine (10 mg) produced better and more sustained analgesia than 200 microg of OTFC or 2 mg of morphine.
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Anesthesia and analgesia · Sep 1999
Randomized Controlled Trial Comparative Study Clinical TrialComparison of ropivacaine 0.2% and lidocaine 0.5% for intravenous regional anesthesia in volunteers.
A longer acting local anesthetic such as ropivacaine may offer advantages over lidocaine for IV regional anesthesia (IVRA). The objective of this investigation was to determine whether the use of ropivacaine improves the quality and duration of IVRA. In a randomized, double cross-over design, 10 volunteers received lidocaine 0.5% or ropivacaine 0.2% for IVRA of the upper extremity on two separate days with a standard double-cuff technique. Sensation to pinprick, response to tetanic stimuli, and tourniquet pain were assessed on a 0-10 verbal numeric score scale at 5-min intervals throughout the period of tourniquet inflation. Motor function was evaluated by grip strength. After release of the second (distal) cuff, pinprick sensation, motor strength, and systemic side effects were evaluated at 3, 10, and 30 min. No significant differences were observed for onset times of anesthesia and times to proximal (38 +/- 3 and 36 +/- 3 min) or distal (34 +/- 13 and 36 +/- 13 min) tourniquet release after the administration of ropivacaine and lidocaine, respectively. However, postdeflation hypoalgesia and motor blockade were prolonged with ropivacaine, and postdeflation light-headedness, tinnitus, and drowsiness were more prominent with lidocaine. We conclude that ropivacaine may be an alternative to lidocaine for IVRA. It may result in prolonged analgesia and fewer side effects after tourniquet release. ⋯ In this study, volunteers received lidocaine 0.5% or ropivacaine 0.2% for IV regional anesthesia on two study days. Ropivacaine and lidocaine provided similar surgical conditions. However, after release of the distal tourniquet, prolonged sensory blockade and fewer central nervous system side effects were observed with ropivacaine.
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Anesthesia and analgesia · Sep 1999
Comparative StudyThe effect of olprinone compared with milrinone on diaphragmatic muscle function in dogs.
We compared the effect of olprinone with milrinone on the contractility of fatigued diaphragms in dogs. Animals were divided into four groups of 10 each. In each group, diaphragmatic fatigue was induced by intermittent supramaximal bilateral electrophrenic stimulation at a frequency of 20 Hz applied for 30 min. After producing fatigue, Group I received only maintenance fluids; Group II was given a bolus injection (50 microg/kg) followed by continuous infusion (0.5 microg x kg(-1) x min(-1)) of milrinone; Group III was infused with olprinone (10 microg/kg initial dose plus 0.3 microg x kg(-1) x min(-1) maintenance dose); Group IV was infused with nicardipine (5 microg x kg(-1) x min(-1)) during olprinone administration. After the fatigue-producing period in each group, transdiaphragmatic pressure (Pdi) at low-frequency (20 Hz) stimulation decreased from the prefatigued values (P < 0.05), whereas there was no change in Pdi at high-frequency (100-Hz) stimulation. In Groups II and III, during study drug infusion, Pdi at both stimuli increased from fatigued values (P < 0.05). The increase in Pdi was larger in Group III than in Group II (P < 0.05). In Group IV, the augmentation of Pdi by olprinone was abolished in the fatigued diaphragm with an infusion of nicardipine. We conclude that olprinone is more effective than milrinone for the improvement of contractility in he fatigued diaphragm and that the potentiating mechanism of olprinone may be closely related to the transmembrane calcium movement. ⋯ Diaphragmatic fatigue may contribute to the development of respiratory failure. Compared with milrinone, olprinone improves the contractility in fatigued diaphragm in dogs.
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Anesthesia and analgesia · Sep 1999
Randomized Controlled Trial Comparative Study Clinical TrialPeribulbar anesthesia with either 0.75% ropivacaine or a 2% lidocaine and 0.5% bupivacaine mixture for vitreoretinal surgery: a double-blinded study.
No study has evaluated the efficacy of ropivacaine in peribulbar block for ophthalmic surgery. The purpose of this prospective, randomized, double-blinded study was to compare ropivacaine and a lidocaine-bupivacaine mixture in peribulbar anesthesia. Sixty ASA physical status I or II patients scheduled for elective vitreoretinal surgery were randomized to receive a peribulbar block with 8 mL of either 0.75% ropivacaine (ropivacaine group, n = 30) or a 1:1 mixture of 2% plain lidocaine and 0.5% plain bupivacaine (lido-bupivacaine group, n = 30). Time required for onset of surgical anesthesia, quality of postoperative analgesia, incidence of side effects, and analgesic consumption were recorded. Surgical block was achieved after 8 +/- 5 min in the lido-bupivacaine group and after 10 +/- 5 min in the ropivacaine group (P = 0.23). A 3-mL supplemental injection 15 min after block placement was required in 6 patients in the lido-bupivacaine group (20%) and in 10 patients in the ropivacaine group (33%) due to inadequate motor block (P = 0.38). On Postoperative Day 1, 26 patients in the ropivacaine group (87%) reported no pain at the verbal rating score, compared with 18 patients in the lido-bupivacaine group (60%) (P = 0.005). We conclude that 0.75% ropivacaine may be a suitable choice when performing peribulbar anesthesia for vitreoretinal surgery. ⋯ Quick onset of block with prolonged postoperative analgesia is an important goal in regional anesthesia for ophthalmic surgery. Evaluating clinical properties of 0.75% ropivacaine and a 1:1 mixture of 2% lidocaine and 0.5% bupivacaine for peribulbar anesthesia, we demonstrated that ropivacaine has an onset similar to that of the lidocaine-bupivacaine mixture and provides a better quality of postoperative analgesia.