Mivacurium is mainly metabolized by plasma cholinesterase, whereas atracurium is removed by Hofman elimination. The purpose of this study was to compare the infusion rate of atracurium and mivacurium in maintaining surgical relaxation, and to compare their recovery indices between parturients and non-pregnant women. Muscle relaxation was maintained by the continuous infusion of relaxants to retain the first response of train-of-four (TOF) at 5% of control. When mivacurium was used, Bolus-T5 (duration from the end of mivacurium bolus injection to 5% single twitch recovery) was measured. After discontinuing the infusion, the recovery index was measured. The infusion rate of mivacurium, not atracurium, was significantly lower in parturients and Bolus-T5 of parturients was significantly longer than that of non-pregnant women. There was no significant difference in the recovery indices of both relaxants. The authors concluded that the infusion rate of mivacurium in maintaining muscle relaxation in parturients should be reduced compared to the rate in non-pregnant women and measuring Bolus-T5 may be helpful in determining the infusion rate to maintain muscle relaxation.
Adult ; Atracurium/therapeutic use ; Atracurium/administration & dosage* ; Cesarean Section* ; Comparative Study ; Female ; Human ; Injections, Intramuscular ; Isoquinolines/therapeutic use ; Isoquinolines/administration & dosage* ; Neuromuscular Nondepolarizing Agents/therapeutic use ; Neuromuscular Nondepolarizing Agents/administration & dosage* ; Pregnancy

OBJECTIVETo compare the dose requirements of continuous infusion of rocuronium and atracurium throughout orthotopic liver transplantation (OLT) in humans.

METHODSTwenty male patients undergoing liver transplantation were randomly assigned to two comparable groups of 10 patients each to receive a continuous infusion of rocuronium or atracurium under intravenous balanced anesthesia. The response of adductor pollicis to train-of-four (TOF) stimulation of unlar nerve was monitored. The infusion rates of rocuronium and atracurium were adjusted to maintain T1/Tc ratio of 2%~10%. The total dose of each drug given during each of the three phases of OLT was recorded.

RESULTSRocuronium requirement, which were (0.468+/-0.167) mg/(kg.h) during the paleohepatic phase, decreased significantly during the anhepatic phase to (0.303+/-0.134) mg/(kg.h) and returned to the initial values at the neohepatic period ((0.429+/-0.130) mg/(kg.h)); whereas atracuruim requirements remained unchanged during orthotopic liver transplantation.

CONCLUSIONSThis study showed that the exclusion of the liver from the circulation results in the significantly reduced requirement of rocuronium while the requirement of atracurium was not changed, which suggests that the liver is of major importance in the clearance of rocuronium. A continuous infusion of atracurium with constant rate can provide stable neuromuscular blockade during the three stages of OLT.

Adult ; Aged ; Androstanols ; administration & dosage ; pharmacokinetics ; Atracurium ; administration & dosage ; pharmacokinetics ; Humans ; Infusions, Intravenous ; Intraoperative Period ; Liver ; metabolism ; Liver Transplantation ; Male ; Middle Aged ; Neuromuscular Nondepolarizing Agents ; administration & dosage ; pharmacokinetics

PURPOSE: We investigated the effect of muscle relaxants (atracurium) on the outcomes of intermittent exotropia surgery under general anesthesia, with a focus on resection procedures. METHODS: Thirty four patients who underwent recession and resection (R&R) were divided into two groups: atracurium usage (group A, n=18) and no atracurium usage (group B, n=16). Patients were divided into two subgroups according to the amount of resection of the medial rectus (MR): less than 5 mm (group 1, n=13) or 5 mm and greater (group 2, n=21). Deviation angles were compared between groups and subgroups. Surgical outcome was defined as successful if distant deviation angles were equal to or less than 10 prism diopters. RESULTS: The overall postoperative deviation angles did not show statistically significant differences between groups A and B. However, in patients with larger MR resections (> or = 5 mm), the 1 week postoperative distant deviation was significantly larger in group A (1.8+/-2.6 PD) than in group B (-1.6+/-4.6 PD, p=0.048 by t-test). The overall undercorrection rate at 3 months postoperatively for group A was 16.7%, which was higher than that of group B (6.3%), and the difference was even larger in subgroups with larger MR resections (> or =5 mm): 18.2% in group A and 0% in group B. CONCLUSIONS: Patients who underwent R&R procedures under general anesthesia with a muscle relaxant tended to be less corrected than those without muscle relaxant, especially in the early postoperative period and with a larger MR resection equal to or greater than 5 mm. However, there was no significant difference in the later postoperative period.
Anesthesia, Inhalation ; Atracurium/*administration & dosage ; Child ; Child, Preschool ; Exotropia/*physiopathology/*surgery ; Female ; Humans ; Injections, Intravenous ; Male ; Muscle Relaxation ; Neuromuscular Nondepolarizing Agents/*administration & dosage ; Oculomotor Muscles/*physiopathology ; Ophthalmologic Surgical Procedures ; Treatment Outcome

OBJECTIVETo evaluate the impact of gender differences on the dose-effect relationship of cisatracurium.

METHODSEighty ASA class I or II patients (40 male and 40 female patients) undergoing elective abdominal surgeries received a single-dose intravenous injection of midazolam and fentanyl. The male and female patients were subdivided into 4 equal groups to receive a intravenous bolus of 20, 30, 40, or 50 µg/kg of cisatracurium. The neuromuscular block was measured using a neuromuscular transmission monitor, and the responses were defined in terms of the percentages of maximum suppression in T1 of TOF of the adductor pollicis muscle. According to log-probit transformation of the data of the dose and response, the dose-response curve of cisatracurium was established through linear regression. The onset time of vecuronium was also observed.

RESULTSThe ED95 value of cisatracurium in male patients was 67.4±4.4 µg/kg, significantly higher than that in female patients (48.7±1.0 µg/kg, P<0.05). No significant variation in the onset time was found in the 4 dose groups of either male or female patients (P>0.05).

CONCLUSIONFemale patients are more sensitive to cisatracurium than male patients.

Abdomen ; surgery ; Adolescent ; Adult ; Anesthesia, General ; Atracurium ; administration & dosage ; analogs & derivatives ; pharmacology ; Dose-Response Relationship, Drug ; Elective Surgical Procedures ; Female ; Humans ; Male ; Neuromuscular Blockade ; methods ; Neuromuscular Blocking Agents ; administration & dosage ; pharmacology ; Pharmacological Phenomena ; physiology ; Sex Factors ; Young Adult

OBJECTIVETo compare the effects of sevoflurane and propofol-remifentanil anesthesia on neuromuscular blockade produced by continuous cisatracurium infusion.

METHODSForty ASA I or II patients undergoing selective surgery were randomly divided into sevoflurane and propofol-remifentanil anesthesia groups (n=20). Neuromuscular blockade was monitored using train-of-four (TOF) stimulation by recording the contraction force of the adductor pollicis muscle with a muscle relaxation monitor. A bolus dose of cisatracurium of 0.15 mg/kg was administered to facilitate endotracheal intubation, followed by continuous infusion adjusted manually to maintain the first twitch (T1) < or = 5% of the control level. The following variables were recorded including the infusion rate, total amount of cisatracurium, spontaneous recovery index (RI), and the time interval from termination of infusion cisatracurium to recovery of TOF ratio (TOFR) to 0.9.

RESULTSWith the maintenance of a 95%-99% neuromuscular blockade, the infusion rate was significantly lower in sevoflurane group than in propofol-remifentanil group (P<0.05), and stabilized in both groups after 120 min. No significant differences were found in RI or the time to TOFR of 0.9 between the two groups (P>0.05).

CONCLUSIONDuring the maintenance of stable neuromuscular blockade by continuous cisatracurium infusion, both sevoflurane and propofol-remifentanil anesthesia can time-dependently enhance the effect of cisatracurium without producing significant differences in the recovery properties.

Adolescent ; Adult ; Aged ; Anesthetics, General ; administration & dosage ; pharmacology ; Anesthetics, Intravenous ; Atracurium ; administration & dosage ; analogs & derivatives ; pharmacology ; Drug Synergism ; Elective Surgical Procedures ; Female ; Humans ; Infusions, Intravenous ; Male ; Methyl Ethers ; administration & dosage ; pharmacology ; Middle Aged ; Neuromuscular Blocking Agents ; administration & dosage ; pharmacology ; Piperidines ; administration & dosage ; pharmacology ; Propofol ; administration & dosage ; pharmacology ; Young Adult

The Prader-Willi syndrome (PWS) is a rare disorder characterized by infantile hypotonia, subsequent obesity with hyperphagia. Hypogonadism, cryptorchidism, delayed psychomotor development, short status, strabismus, myopia, scoliosis, kyphosis and temperature regulation abnormality are other features. The cause of this syndrome is unknown, but a disturbance in the hypothalamus has been postulated because of the various manifestation of the syndrome. The major genetic mechanism giving rise to PWS is a paternal deletion of about the same size in the 15q11-q13 region, that occurs in 70% of the cases. The principal problems related to anesthesia are those that are secondary to the patient's hypoglycemia, skeletal muscle hypotonia and obesity. An 20-month-old boy with PWS was scheduled for surgical correction of bilateral undescended testes. The trachea was intubated with the aid of succinylcholine 7.5 mg intravenous injection. Muscle relaxation was facilitated with intermittent intravenous administration of atracurium (total dose 8 mg). No prolonged effect of muscle relaxants was observed during anaesthesia. High grade fever (38-39 degrees C) was present during anaesthesia.
Administration, Intravenous ; Anesthesia ; Atracurium ; Cryptorchidism ; Fever ; Humans ; Hyperphagia ; Hypoglycemia ; Hypogonadism ; Hypothalamus ; Infant ; Injections, Intravenous ; Kyphosis ; Male ; Muscle Hypotonia ; Muscle Relaxation ; Muscle, Skeletal ; Myopia ; Obesity ; Prader-Willi Syndrome* ; Scoliosis ; Strabismus ; Succinylcholine ; Trachea

BACKGROUND: If general anesthesia is used for cesarean section, important considerations include minimizing the duration of general anesthesia. One may think that skin incision should be started immediately after endotracheal intubation. If so, intra-operative awareness and perception of pain may occur due to light anesthesia. Allowing skin incision to be started 5 min after intubaton while administering 50% nitrous oxide and isoflurane 0.75%, we investigated the changes of BIS (bispectral index), and Apgar scores. METHODS: The investigation was carried out on 33 full-term ASA 1 or 2 patients underwent elective cesarean section under general anesthesia. If any fetal abnormalities were found, we excluded those cases. Premedication was omitted. After rapid sequence induction with sodium thiopental 4 mg/kg, succinylcholine 1 mg/kg, we made skin incision immediately after intubation in control group (n = 18) and 5 min after intubation in experimental group while administering 50% nitrous oxide and isoflurane 0.75%. Muscle relaxation was maintained with intravenous administration of atracurium 0.5 mg/kg. We measured BIS, mean arterial pressure (MAP), heart rate in 1 min interval from preinduction period to delivery and recorded Apgar scores 1 and 5 min after delivery, skin incision to delivery time and uterine incision to delivery time. And we counted the number of patients whose BIS values had been below 60 and 70 from skin incision to delivery in each group. RESULT: Apgar scores recorded 1 and 5 min after delivery did not show significant differences between control and experimental group. During the periods of abdominal wall traction, uterine incision and delivery, BIS values of experimental group were significantly lower than control group and moreover, tended to remain below 60 while those of control group during the same periods tended to be above 60 (P < 0.05). The number of patients of experimental group, whose BIS values had been below 60 from skin incision to delivery, was twice as much as that of control group (P < 0.05), but in case of BIS value below 70, there was no significant difference between control and experimental group. During the periods of skin incision and abdominal wall traction, the MAP's of experimental group were significantly lower than control group (P < 0.05). In cases of heart rate, skin incision to delivery time and uterine incision to delivery time, there were no significant differences between control and experimental group. CONCLUSION: Allowing the skin incision to be started 5 min after intubation while administering 50% nitrous oxide and isoflurane 0.75%, BIS values remained below 60 from abdominal wall traction to delivery, and anesthetics-induced fetal depression did not occur.
Abdominal Wall ; Administration, Intravenous ; Anesthesia ; Anesthesia, General ; Arterial Pressure ; Atracurium ; Cesarean Section* ; Depression ; Female ; Heart Rate ; Humans ; Intubation* ; Intubation, Intratracheal ; Isoflurane ; Muscle Relaxation ; Nitrous Oxide ; Pregnancy ; Premedication ; Skin ; Sodium ; Succinylcholine ; Thiopental ; Traction