An unusual case of acute orchitis following aortic surgery.
Explore the source record for details and available documents.
Acute Disease↗
Biomedical subjects
Cyrus Motamed
Publications and source records attributed to Cyrus Motamed.
Potentiation of mivacurium blockade by low dose of pancuronium: a pharmacokinetic study.
BACKGROUND: Mivacurium is potentiated by pancuronium to a much greater extent than other relaxants. In a previous investigation we suggested that this potentiation could be due to the ability of pancuronium to inhibit plasma cholinesterase activity, but we did not measure plasma concentrations of mivacurium. In the current study we performed a pharmacokinetic analysis by measuring the plasma concentration of mivacurium when preceded by administration of a low dose of pancuronium. METHODS: After induction of general anesthesia with propofol and fentanyl and orotracheal intubation, 10 patients (pancuronium-mivacurium group) received 15 microg/kg pancuronium followed 3 min later by 0.1 mg/kg mivacurium, whereas 10 other patients (mivacurium group) received saline followed by 0.13 mg/kg mivacurium 3 min later. Plasma cholinesterase activity was measured before and 3 and 30 min after pancuronium dosing in the pancuronium-mivacurium group and was measured before and after administration of saline in the mivacurium group. Arterial plasma concentrations of mivacurium and its metabolites were measured at 0.5, 1, 1.5, 2, 4, 10, 20, and 30 min after injection. Neuromuscular blockade was assessed by mechanomyography. RESULTS: Plasma cholinesterase activity decreased by 26% in the pancuronium-mivacurium group 3 min after injection of pancuronium (P < 0.01) and returned to baseline values 30 min later; however, no significant variation was observed in the mivacurium group. The clearances of the two most active isomers (Cis-Trans and Trans-Trans) were lower in the pancuronium-mivacurium group (17.6 +/- 5.1, 14.7 +/- 5.3 ml. min-1. kg-1, respectively) than in the mivacurium group (32.4 +/- 20.2, 24.8 +/- 13.5 ml. min-1. kg-1; P < 0.05). CONCLUSIONS: A subparalyzing dose of pancuronium decreased plasma cholinesterase activity and the clearance of the two most active isomers of mivacurium. Pancuronium potentiates mivacurium more than other neuromuscular blocking agents because, in addition to its occupancy of postsynaptic acetylcholine receptors, it slows down the hydrolysis of mivacurium.
Adolescent↗
Sevoflurane and isoflurane, but not propofol, decrease mivacurium requirements over time.
PURPOSE: Volatile anesthetic agents potentiate neuromuscular blockade, but the magnitude of potentiation appears to be time dependent. The time course of this interaction was studied by measuring mivacurium infusion rates during sevoflurane, isoflurane and propofol anesthesia. METHODS: After informed consent, anesthesia was induced in 48 ASA physical status I-II adults with propofol, fentanyl and mivacurium 0.25 mg.kg(-1) and maintained with N(2)O (60%) and one of the three agents chosen at random: sevoflurane 1.9%; isoflurane 1.2%; or propofol 100-150 microgram.kg(-1).min(-1). Train-of-four stimulation was applied every 15 sec to the ulnar nerve. Neuromuscular blockade was monitored with accelerometry. At 5% recovery of the first twitch (T1), a mivacurium infusion was started and adjusted every five minutes to maintain 90-95% T1 depression. RESULTS: The time to 5% T1 recovery after the initial dose was similar in all groups (13-15 min). Fifteen minutes after the start of the infusion mivacurium requirements were greater (P < 0.05) in the propofol group (7.5 +/- 1.7 microgram.kg(-1).min(-1); mean +/- SD) than in either isoflurane (4.7 +/- 1.6 microgram.kg(-1).min(-1)) or sevoflurane (4.5 +/- 1.5 microgram.kg(-1).min(-1)) group. Then, the rate remained stable for propofol (6.2 +/- 1.4 microgram.kg(-1).min(-1) after 90 min of infusion) while it decreased with isoflurane to 2.9 +/- 1.6 microgram.kg(-1).min(-1) at 90 min (P < 0.05 vs propofol) and to 1.4 +/- 1.0 microgram.kg(-1).min(-1) in the sevoflurane group (P < 0.05 vs propofol and isoflurane). CONCLUSION: Sevoflurane and isoflurane do not prolong the effect of a bolus dose of mivacurium, but potentiation increases with time from 30-105 min of exposure. This interaction is greater with sevoflurane than isoflurane.
Adult↗
Systolic blood pressure, not BIS, is associated with movement during laryngoscopy and intubation.
OBJECTIVE: To compare bispectral index (BIS) values to hemodynamic variations, in order to evaluate adequacy of anesthesia during orotracheal intubation with muscle relaxants. METHODS: Forty-one patients ASA I-II, scheduled for elective peripheral surgery under general anesthesia with tracheal intubation were enrolled in the study. Fentanyl/thiopental followed by vecuronium were used for induction. Onset of relaxation was monitored at the orbicularis occuli (OO) muscle using train-of-four stimulation. Intubation was performed when no response at the OO was detected visually. Intubating conditions were noted. The "isolated forearm" technique was used to detect movement during laryngoscopy/intubation. BIS values, pulse rate (PR), and systolic pressure were recorded before induction, during laryngoscopy/intubation and 60 sec after intubation. RESULTS: Although intubating conditions were clinically adequate for all patients, ten out of 41 had movement of the isolated arm during laryngoscopy/intubation. BIS values were not significantly different for these patients: 67 (55-83) compared to those who had no movement: 60 (35-80), P = 0.6. During laryngoscopy, PR increased for all patients while systolic pressure increased significantly only in patients who moved: 125 (100-136) mmHg vs those who did not: 108 (67-140), P < 0.05. CONCLUSION: Systolic pressure elevations were associated with inadequate anesthesia as evaluated by the "isolated forearm" technique, during laryngoscopy/intubation. BIS values were not different between groups, suggesting that systolic blood pressure may be a better predictor of inadequate anesthesia under the circumstances described.
Adjuvants, Anesthesia↗