Molecular mechanisms of muscular and non-muscular actions of neuromuscular blocking agents in critical illness: a narrative review.

Despite frequent use of neuromuscular blocking agents in critical illness, changes in neuromuscular transmission with critical illness are not well appreciated. Recent studies have provided greater insights into the molecular mechanisms for beneficial muscular effects and non-muscular anti-inflammatory properties of neuromuscular blocking agents. This narrative review summarises the normal structure and function of the neuromuscular junction and its transformation to a 'denervation-like' state in critical illness, the underlying cause of aberrant neuromuscular blocking agent pharmacology. We also address the important favourable and adverse consequences and molecular bases for these consequences during neuromuscular blocking agent use in critical illness. This review, therefore, provides an enhanced understanding of clinical therapeutic effects and novel pathways for the salutary and aberrant effects of neuromuscular blocking agents when used during acquired pathologic states of critical illness.

Anesthetic management with a neuromuscular relaxant and sugammadex in a patient with Prader-Willi syndrome: A case report.

Prader-Willi syndrome is a genetic disorder that is characterized by obesity, characteristic facial features, hypotonia, and sleep apnea. These abnormalities mean that airway management is difficult in such patients. Several previous reports suggest that neuromuscular blocking agents should not be used to reduce airway and respiratory complications in these patients. However, this is not always possible. Here, we report the case of a patient with Prader-Willi syndrome in whom anesthesia for ophthalmic surgery was managed successfully using sugammadex after administration of rocuronium.

Anesthesia for cesarean section in pregnant woman with Guillain Barré syndrome: a case report / Anestesia para cesariana em gestante com síndrome de Guillain Barré: relato de caso / Anestesia para cesárea en gestante con síndrome de Guillain Barré: relato de caso

Background and objectives: Guillain Barré syndrome (GBS) is an autoimmune neurological disease characterized by an acute or subacute demyelinating polyradiculoneuritis. It is an unusual event during pregnancy and a challenge for the anesthesiologist, due to the possibility of impairment of neuromuscular function and occurrence of respiratory complications in the post-operative period. The objective of this paper is to discuss the anesthetic management of a pregnant patient affected by the disease. Case report: Female patient, 30 years old, 38 weeks' pregnant, diagnosed with fetal death that occurred about a day, and with SGB. Cesarean section was performed under general anesthesia, progressing without complications perioperatively. Conclusions: Although it is uncommon, GBS can affect pregnant women and the anesthesiologist may encounter such patients in his (her) daily practice. It is important to understand the peculiarities of GBS to adequately address the patient in the perioperative period, contributing to its better evolution. .

Justificativa e objetivos: A síndrome de Guillain Barré (SGB) é uma doença neurológica autoimune que se caracteriza por uma polirradiculoneurite desmielinizante aguda ou subaguda. É um evento incomum durante a gravidez e um desafio para o anestesiologista pela possibilidade de comprometimento da função neuromuscular e de complicações respiratórias no pós-operatório. O objetivo deste trabalho é discutir o manejo anestésico da paciente gestante afetada pela doença. Relato de caso: Paciente do sexo feminino com 30 anos, gestante de 38 semanas, com diagnóstico de óbito fetal havia um dia e SGB. Foi submetida à cesariana sob anestesia geral, evoluindo sem intercorrências no perioperatório. Conclusões: Apesar de ser incomum, a SGB pode acometer gestantes e o anestesiologista pode se deparar com esse tipo de paciente na sua prática diária. É importante compreender as peculiaridades da SGB para se abordar adequadamente a paciente no perioperatório, contribuindo para a sua melhor evolução. .

Justificación y objetivos: El síndrome de Guillain Barré (SGB) es una enfermedad neurológica autoinmune que se caracteriza por una polirradiculoneuritis desmielinizante aguda o subaguda. Es un evento poco común durante el embarazo y se le considera un reto para el anestesista por la posibilidad de compromiso de la función neuromuscular y de complicaciones respiratorias en el postoperatorio. El objetivo de este trabajo es discutir el manejo anestésico de la paciente gestante afectada por la enfermedad. Caso clínico: Paciente del sexo femenino con 30 años, gestante de 38 semanas, con diagnóstico de óbito fetal hacía un día y SGB. Fue sometida a cesárea bajo anestesia general, evolucionando sin intercurrencias en el perioperatorio. Conclusiones: A pesar de ser poco común, el SGB puede perjudicar a las gestantes y el anestesista puede tener que enfrentarse con ese tipo de paciente en su práctica diaria. Es importante comprender las peculiaridades del SGB para abordar adecuadamente a la paciente en el perioperatorio, contribuyendo así a su mejor evolución. .

[Anesthesia for cesarean section in pregnant woman with Guillain Barré syndrome: a case report]. / Anestesia para cesariana em gestante com síndrome de Guillain Barré: relato de caso.

BACKGROUND AND OBJECTIVES: Guillain Barré syndrome (GBS) is an autoimmune neurological disease characterized by an acute or subacute demyelinating polyradiculoneuritis. It is an unusual event during pregnancy and a challenge for the anesthesiologist, due to the possibility of impairment of neuromuscular function and occurrence of respiratory complications in the postoperative period. The objective of this paper is to discuss the anesthetic management of a pregnant patient affected by the disease. CASE REPORT: Female patient, 30 years old, 38 weeks' pregnant, diagnosed with fetal death that occurred about a day, and with SGB. Cesarean section was performed under general anesthesia, progressing without complications perioperatively. CONCLUSIONS: Although it is uncommon, GBS can affect pregnant women and the anesthesiologist may encounter such patients in his (her) daily practice. It is important to understand the peculiarities of GBS to adequately address the patient in the perioperative period, contributing to its better evolution.

Postoperative respiratory outcomes in laparoscopic bariatric surgery: comparison of a prospective group of patients whose neuromuscular blockade was reverted with sugammadex and a historical one reverted with neostigmine.

PURPOSE: Bariatric surgery patients are at high risk of perioperative respiratory adverse events. We hypothesized that the use of sugammadex to reverse neuromuscular blockade could improve postoperative respiratory outcomes. METHODS: Prospective observational series of consecutive patients scheduled for laparoscopic bariatric surgery in whom neuromuscular blockade was reverted with sugammadex were compared with a historical matched cohort of patients reverted with neostigmines. The necessity of postoperative mechanical ventilation or pathological changes in postoperative chest X-ray were two of the comparisons done. RESULTS: We enrolled 160 patients in each group (Sugammadex - SG and Historical - HG). Two patients (mean, CI 95%), (1.25, 0.34-4.4) in the SG and five patients in the HG (mean, CI 95%), (3.13, 1.34-7.11) required mechanical ventilation immediately after surgery (p=0.38, chi-square test). Significantly less chest X-ray postoperative changes were observed in the SG: 11 patients (6.9%) versus 26 patients (16.3%) in the HG (Odds ratio OR, CI 95%) (0.36, 0.18-0.8). CONCLUSION: Requirement of mechanical ventilation is not associated to the reversal agent employed. Less pathological postoperative chest X-ray changes were found in the group of patients whose neuromuscular blockade was reverted with sugammadex.

Comparison of the variability of the onset and recovery from neuromuscular blockade with cisatracurium versus rocuronium in elderly patients under total intravenous anesthesia

This study was designed to compare the variability of the onset and offset of the effect of two neuromuscular blocking drugs with different elimination pathways in adult and elderly patients during total intravenous anesthesia (TIVA). After Ethics Committee approval and patients’ informed consent, the drugs were compared in 40 adult and 40 elderly patients scheduled for elective surgery under TIVA with tracheal intubation who were randomized to receive a single bolus dose of 0.15 mg/kg cisatracurium or 0.9 mg/kg rocuronium. The time of onset of maximum depression, duration of action, and recovery index time were measured and recorded for each patient and variability is reported as means ± standard deviation. Time of onset was significantly shorter for rocuronium than cisatracurium for the adult and elderly groups (P = 0.000), but the variability of cisatracurium was significantly greater compared with rocuronium for the same age groups (93.25 vs 37.01 s in the adult group and 64.56 vs 33.75 s in the elderly group; P = 0.000). The duration of the effect in the elderly group receiving rocuronium was significantly longer than in the elderly group receiving cisatracurium, and the variability of the duration was significantly greater in the rocuronium group than in the cisatracurium group. Mean time of recovery was significantly longer for the elderly group receiving rocuronium than for the elderly group receiving cisatracurium (P = 0.022), and variability was also greater (P = 0.002). Both drugs favored good intubating conditions. In conclusion, cisatracurium showed less variability in these parameters than rocuronium, especially in the elderly, a fact that may be of particular clinical interest.

Neuromuscular Pharmacodynamics of Mivacurium in Patients with Major Burns / 대한마취과학회지

BACKGROUND: Burned patients sometimes require rapid onset of neuromuscular paralysis to secure the airway in full stomach patients or to treat laryngospasm. Because of poor lung function and hypermetabolic state, they desaturate quite rapidly. Burned patients are usually resistant to the effects of nondepolarizing relaxants. Mivacurium can be potentially a good alternative for rapid onset of paralysis, since it is metabolized by plasma cholinesterase, an enzyme often decreased in subject with major burns. This prospective study was conducted to define the neuromuscular pharmacodynamic profile of a single bolus dose of mivacurium in adult patients with major burns. METHODS: Adults (M/F = 22/8), aged 44.0 +/- 10.2 years, with total body surface area (TBSA) burn of 35.0 +/- 12.5% were studied at 39.8 +/- 28.9 post burn days. Age and sex matched 30 non-burned patients served as controls. Anesthesia was consisted of propofol and fentanyl infusion with nitrous oxide and oxygen. Mivacurium 0.2 mg/kg was administered as a bolus. Using TOF Watch, neuromuscular block was monitored with T1 response after the initial tetanic stimulation to recruit all muscle fibers. Onset time was defined as the interval from the beginning of drug administration to maximal twitch suppression. Intubation was attempted at 1 minute after the drug administration to simulate the rapid sequence induction with recording of either failure or success of intubation. By allowing spontaneous recovery without reversal drug, recovery profiles of neuromuscular paralysis were also measured. RESULTS: Patients demographics were similar in both groups except for the burn. Onset times and all recovery profiles were significantly prolonged in the burned versus non-burned groups. Attempts at intubation at 1 minute after the drug administration were successful with difficulty in approximately 70% of patients in both groups. CONCLUSIONS: Mivacurium 0.2 mg/kg demonstrated the conflicting dual responses in the burned patients. The prolonged onset time suggests resistance to neuromuscular effects. The prolonged recovery suggests increased sensitivity. This can be partially explained by the acetylcholine receptor proliferation and decreased level of plasma pseudocholinesterase. In view of the prolonged onset time of almost two minutes for maximal paralysis, mivacurium does not appear to be a good drug for rapid onset of paralysis in burns.

Inhibitory Effects of Structurally Different Neuromuscular Blockers on the Serotonin Type 3 Receptor Expressed in Xenopus Oocytes / 대한마취과학회지

BACKGROUND: The serotonin type 3 receptors are diffusely distributed in both the central and the peripheral nervous system. Physiological and pathophysiological processes thought to be mediated by this receptor include nausea and vomiting, peripheral nociception and central antinociception, conditioned aversion response to drugs, anxiety, and cognition. Because of the structural similarity between the nicotinic acetylcholine receptor and the 5HT3 receptor, we investigated the effects of clinically used neuromuscular blockers on the 5HT3 receptor function related with PONV. METHODS: A cDNA clone encoding the full length murine 5HT3a receptor was subcloned into an oocyte expression vector and 50 ng of cRNA transcribed in vitro injected per oocyte. After 24 72 h incubation, oocytes were placed into a recording chamber continuously perfused with frog Ringer's solution and electrophysiological recordings were obtained by the two electrode voltage clamp technique. Serotonin with or without the various drugs were bath applied by a computer controlled solenoid valve. Peak currents induced by the drug applications were measured and dose responses were obtained. RESULTS: The 5HT3 receptor expression in Xenopus oocyte was identified by the pharmacologic tools. Serotonin induced rapid inward currents, and thus was showed dose-dependent: KD = 2.5 micrometer, Hill coefficiency = 2.09. Inhibition by the neuromuscular blockers showed dose-dependence and their inhibitory potency on 5HT3 receptor (IC50) was in order of d-tubocurarine (0.046 micrometer) > vecuronium (16.32 micrometer) > gallamine (1,169 micrometer). CONCLUSIONS: There was a different inhibitory effect of nicotinic cholinergic antagonists, clinically used neuromuscular blockers, on the 5HT3 receptor and a judicious selection of them might contribute to reducing the incidence of PONV clinically.

Inhibitory Effects of Structurally Different Neuromuscular Blockers on the Serotonin Type 3 Receptor Expressed in Xenopus Oocytes / 대한마취과학회지

BACKGROUND: The serotonin type 3 receptors are diffusely distributed in both the central and the peripheral nervous system. Physiological and pathophysiological processes thought to be mediated by this receptor include nausea and vomiting, peripheral nociception and central antinociception, conditioned aversion response to drugs, anxiety, and cognition. Because of the structural similarity between the nicotinic acetylcholine receptor and the 5HT3 receptor, we investigated the effects of clinically used neuromuscular blockers on the 5HT3 receptor function related with PONV. METHODS: A cDNA clone encoding the full length murine 5HT3a receptor was subcloned into an oocyte expression vector and 50 ng of cRNA transcribed in vitro injected per oocyte. After 24 72 h incubation, oocytes were placed into a recording chamber continuously perfused with frog Ringer's solution and electrophysiological recordings were obtained by the two electrode voltage clamp technique. Serotonin with or without the various drugs were bath applied by a computer controlled solenoid valve. Peak currents induced by the drug applications were measured and dose responses were obtained. RESULTS: The 5HT3 receptor expression in Xenopus oocyte was identified by the pharmacologic tools. Serotonin induced rapid inward currents, and thus was showed dose-dependent: KD = 2.5 micrometer, Hill coefficiency = 2.09. Inhibition by the neuromuscular blockers showed dose-dependence and their inhibitory potency on 5HT3 receptor (IC50) was in order of d-tubocurarine (0.046 micrometer) > vecuronium (16.32 micrometer) > gallamine (1,169 micrometer). CONCLUSIONS: There was a different inhibitory effect of nicotinic cholinergic antagonists, clinically used neuromuscular blockers, on the 5HT3 receptor and a judicious selection of them might contribute to reducing the incidence of PONV clinically.

Effects of Aminophylline on the Dose-Response Curve of Vecuronium on Rat Hemidiaphragm Preparation / 대한마취과학회지

BACKGROUND: Aminophylline is an inhibitor of phosphodiesterase; it increase the cAMP and, in turn, the level of acetylcholine at the neuromuscular junction. In doing so, it has an antifatigue action. It antagonizes nondepolarizing neuromuscular blockade in animals, and has been anecdotally noted to do so in humans, as well. We investigated the interaction of aminophylline and vecuronium on the dose response curve in vitro. METHODS: Institutional approval was obtained. Thirty seven male Spague Dawley rats (150~200 g) were divided into four groups (control, aminophylline 2.5, 5.0 and 7.5 microgram/ml). The animal were anesthetized with 40 mg/kg phentobarbital. The left hemidiaphragm with phrenic nerve was dissected and mounted within 5 minutes in bath containing 100 ml Krebs solution at 32oC. The phrenic nerve was stimulated at supramaximal intensity by a Grass S88 stimulator through an SIU5 isolation unit. The twitch height was measured by precalibrated Grass FT03 force displacement transducer and recorded. After stabilization of twitch response, vecuronium was added to the solution to obtained an initial concentration 1.0 microgram/ml with aminophylline 0, 2.5, 5.0, or 7.5 microgram/ml. When a stable 3~5 twitch was obtained after first dose, additional vecuronium was added to the Krebs solution in increments of 0.5 microgram/ml to achieve a more than 90% neuromuscular block. The data were analyzed by repeated measures of ANOVA and kappa2 test. RESULTS: There was a significant increase in the effective dose of vecuronium needed to depress the twitch response in aminophylline 5.0 and 7.5 microgram/ml added groups compared with control group and aminophylline 2.5 microgram/ml group. CONCLUSIONS: We conclude that aminophylline shows decreased sensitivity to vecuronium in the phrenic nerve diaphragm preparation of rats.

The Effect of Oral Clonidine on the Duration of Vecuronium / 대한마취과학회지

BACKGROUND: As of alpha2-agonist, clonidine reduces generalized sympathetic outflow in nervous system and also reduces acetylcholine release at cholinergic terminals presynaptically. So clonidine premedication is possibly able to decrease muscle contraction and prolong the duration of neuromuscular blockers. Therefore, the aim of our current study is to investigate the effect of oral clonidine on the duration of vecuronium. METHODS: Forty patients (ASA I or II) sheduled for elective low abdominal or extrimities operation were randomly divided into 2 groups. Clonidine group (n=20) received 5 microgram/kg oral clonidine at 90 min before operation. Control group (n=20) received nothing. Neuromuscular transmission was measured with relaxograph. After injection of vecuronium 0.1 mg/kg, we measured onset time (the time from injection of vecuronium to decrease to the 25% of baseline value, duration 1 (the time interval between injection and recovery of the first twitch to 25% of the baseline value), and duration 2 (the time interval between second injection of 0.02 mg/kg vecuronium and recovery of the first twitch to 25% of the baseline value). RESULTS: There were no statistical differences between control and clonidine group in onset time (2.6 +/- 0.6 min vs 2.7 +/- 0.5 min), duration 1 (37.5 +/- 8.9 min vs 40.3 +/- 8.6 min) and duration 2 (22.0 +/- 6.8 min vs 24.4 +/- 6.1 min). CONCLUSIONS: Five microgram/kg of oral clonidine premedication did not prolong the duration of vecuronium.

Vecuronium Administration for Endotracheal Intubation: The Priming Method vs. Intravenous Infusion Method / 대한마취과학회지

BACKGROUND: Priming significantly shortened the onset of neuromuscular blockade(NMB), but also results in a high incidence of side effects. This study was designed to determine the effect of infusion priming method on the side effects, intubation condition, and onset of NMB compared with divided priming method. METHOD: The effects of different priming method of vecuronium on onset time and endotracheal intubation condition were investigated. 40 patients were studied in two parts. In control part, 20 patients were allocated into two groups(n=10 in each group) receving 10, 20 g/kg vecuronium as a priming dose, followed by a intubating dose(0.1 mg/kg-priming dose) 3 min later; the other part, 20 patients were allocated into two groups(n=10 in each group) receving 0.2 mg/kg/hr vecuronium continuous intravenous infusion, followed by a intubating dose(0.1 mg/kg-total infusion dose) 3, 5 min later. Onset time is calculated by single twitch stimulation test from injection of the intubating dose to maximum depression of the single twitch. Intubatin condition was appreciated based on vocal cord reflex, coughing, and jaw relaxation and scored. RESULTS: The times to fade out on the single twitch of the intravenous infusion priming group were shorter than control priming group. There was no difference between control priming group and infusion priming group to evaluate the intubation conditions. Side effects in the continuous infusion group were lesser than control priming group. CONCLUSION: This results suggest that the use of continuous infusion method is one of the promising methods to shorten the neuromuscular blockade and to provide more comfort to the patients.

Incidence of Sore Throat after Tracheal Intubation and Postoperative / 대한마취과학회지

BACKGROUND: Sore throat is one of the most common complications of intubation. There are many factors that affect the incidence of sore throat and the succinylcholine-induced myalgia. Our study is to reveal the influences of these factors on the postoperative sore throat and the succinylcholine-induced myalgia. METHODS: One thousand and seven patients in ASA class I or II undergoing elective surgery under general anesthesia were studied, except patients undergoing brain surgery, open heart surgery, operation in oro-, naso-pharynx and larynx, and uncooperated psychiatric. We checked age, sex, patient controlled analgesia and nasogastric tube, size and kind of tube, operation position, duration of intubation and anesthetic agent. At 24~38 hours after operation, the patients were questioned about pre- and postoperative sore throat, or myalgia. RESULTS: Sore throat after endotracheal intubation developed more frequently in woman (32.8%) than man (25.9%). The older the patients, the lower the incidence of sore throat (p<0.05). The longer the anesthesia duration, the lower the incidence of sore throat (p<0.05). Succinylcholine, patient controlled analgesia, nasogastric tube, endotracheal tube, operation position, maintenance anesthetic agents and the amount of smoking did not affect the incidence of sore throat. The incidence of succinylcholine-induced myalgia was lower in elderly or patients who were administered nondepolarizing muscle relaxant. CONCLUSIONS: The incidences of sore throat and myalgia were 29% and 15%, respectively. There were significant differences in incidence of sore throat and myalgia depending on the gender, age, duration of operation, but the controllable factors which reduce the incidence of sore throat were not found. Nondepolarizing muscle relaxants could reduce the occurrence of postoperative myalgia.

Postoperative Sore Throat and Hoarseness : Influence of the Method of Anesthesia Induction and Time for Extubation / 대한마취과학회지

BACKGROUND: Tracheal intubation for general anesthesia often leads to trauma of the airway mucosa, resulting in postoperative sore throat and hoarseness. Numerous studies have investigated the factors as contributing causes, but the influence of method of anesthesia induction and time for extubation of the endotracheal tube has not been systematically examined. The aim of this study was to establish the effects of the methods of anesthesia induction and timing of extubation on postoperative sore throat and hoarseness. METHODS: Eighty patients with ASA physical status 1 or 2 were randomly divided into four groups. Group 1 patients (n=20) recieved succinylcholine 1.0 mg/kg for intubation and early extubated ; group 2 patients (n=20) recieved succinylcholine 1.0 mg/kg for intubation and lately extubated ; group 3 patients (n=20) recieved pancuronium 0.1 mg/kg for intubation and early extubated ; group 4 patients (n=20) recieved pancuronium 0.1 mg/kg for intubation and lately extubated. All patients were interviewed 6, 24, 48, and 72 hrs after operation by an anesthesiologist in a double-blind manner. RESULTS: The incidence of sore throat at postoperative 6 and 24 hrs were decreased in group 3 compaired with group 1, 2, and 4 (p<0.05), respectively. The severity of sore throat at postoperative 6 hrs were decreased in group 3 compared with group 1, 2 and 4 (p<0.05), and that of postoperative 24 hrs were decreased in group 3 compared with group 1 and 2 (p<0.05), respectively. The severity of hoarseness at postoperative 6 hrs were decreased in group 3 compared with group 2 (p<0.05). CONCLUSIONS: We suggest that postoperative sore throat and hoarseness may be developed more when extubation was perfomed lately than early. Therefore, early extubation provide advantage in terms of reducing sore throat and hoarseness in limited cases of anesthesia.

Continuous Intravenous Infusion of Propofol and Succinylcholine Supplemented with Nitrous Oxide in Short Duration of Microlaryngeal Surgery Comparison with Thiopental/Enflurane-N2O and Succinylcholine Infusion / 대한마취과학회지

BACKGROUND: Anesthetic technique for laryngeal microscopic surgery should be focused on rapid recovery of deep anesthesia and full muscle relaxation. This study was taken to evaluate the effect of continuous infusion of propofol and succinylcholine for this kind of anesthetic goal. METHODS: Forty patients scheduled for laryngeal microscopic surgery of short duration(15 min) were randomly allocated into two groups. Anesthesia was induced and maintained with either propofol(2.5 mg/kg followed by a continuous infusion of 0.1 mg/kg/min) in group P or with thiopental (5.0 mg/kg) and inhalation of 1~2 vol % enflurane for maintenance of anesthesia in group T/E. Succinylcholine(1 mg/kg followed by continuous infusion of 0.1 mg/kg/min) was administered to facilitate tracheal intubation and maintain neuromuscular blockade. RESULTS: No significant difference of duration of anesthesia appeared between two groups. Additional doses of succinylcholine were needed in 10% of group P and 30% of group T/E (p<0.05). In group P, time to response to suction catheter(136+/-54 vs 232+/-116 sec), time to eye open spontaneously or to verbal commands (368+/-142 vs 549+/-165 sec) and time to extubation (454+/-117 vs 647+/-181 sec) were significantly shorter comparing to group T/E. The quality of awakening was more favorable in group P(p<0.05). Laryngeal suspension induced bradycardia in 15% of group P and in 5% of group T/E. Both group P and group T/E (10% vs 30%) needed esmolol infusion to control the blood pressure during surgical procedure. CONCLUSIONS: Rapid recovery of anesthesia and muscle relaxation can be expected after continuous infusion of propofol(2.5 mg/kg followed by 0.1mg/kg/min) and succinylcholine(1 mg/kg followed by 0.1 mg/kg/min) supplemented with 50% N2O in 50% O2 for short duration of laryngeal microscopic surgery.

The Effect of Neostigmine on the Train-of-four Ratio during the Recovery from Vecuronium- or Atracurium-induced Neuromuscular Blockade / 대한마취과학회지

BACKGROUND: The train-of-four(TOF) fade known as expression of prejuntional receptor binding was useful for evaluating the residual neuromuscular blockade(NMB). The present study was undertaken to investigate the effect of the neostigmine(Neo) on TOF ratio during the recovery from vecuronium(V) or atracurium(A) induced NMB under the general anesthesia. METHODS: Forty healthy adult patients were randomly divided into 4 groups as follows; spontaneous recovery from V-induced NMB(V-C group) or A-induced NMB(A-C group), reversed recovery with Neo at 20% recovery of control first twitch height(T) from V-induced NMB(V-R group) or A-induced NMB(A-R group). TOF ratio at 25 and 75% recovery of T and recovery index(RI) defined as time from 25 to 75% recovery of T were measured. RESULTS: TOF ratios at 25 and 75% recovery of T were 3.7 & 35.8%(V-C group), 8.4 & 46.9%(A-C group), 3.7 & 48.7%(V-R group) and 15.2 & 55.6%(A-R group) respectively(P>0.05). RI were 19.2 min(V-C group), 19.5 min(A-C group), 3.5 min(V-R group), and 5.6 min(A-R group) respectively (P<0.05). CONCLUSIONS: RI were significantly shortened in reversed recovery groups with Neo than spontaneous recovery groups (P<0.05). However TOF ratio at 75% recovery of T1 were not significantly different between spontaneous recovery and reversed recovery groups.

The Effects of Furosemide on the Recovery from Neuromuscular Blockade Induced by Vecuronium / 대한마취과학회지

BACKGROUND: The interactions between furosemide and muscle relaxants is controversial. In this study, the effects of furosemide on the recovery from neuromuscular blockade induced by vecuronium were investigated in thirty ASA class 1 or 2 adult patients undergoning elective orthopedic surgery under the general aneshtesia with O2-N2O-enflurane. METHODS: Furosemide was administered intravenously at 20% spontaneous recovery of first twitch height of TOF(T1) under the neuromuscular monitoring using Relaxograph?(Datex Co. Finland) as follows: placebo in control group, 5mg in group 1 and 20mg in group 2. Recovery index(RI) defined as the time from 25% to 75% recovery of T1, urinary output during this period and serum K+ levels at 10% and 75% recovery of T1 were measured. RESULTS: RI was shortened significantly in group 1 (11.2+/-3.4 min.) and group 2 (14.9+/-2.7 min.) compared with control group (19.3+/-4.0 min.)(P<0.05). The urinary output was significantly greater in the groups received furosemide than that in the control group(P<0.05), but serum K+ levels were not significantly changed after administration of furosemide. CONCLUSIONS: Furosemide facilitates recovery of neuromuscular blockade induced by vecuronium.

Clinical Study of the Onset Time of Rocuronium / 대한마취과학회지

BACKGROUND: Rocuronium, a new nondepolarizing muscle relaxant, has been reported to develop a rapid onset of action and may be suitable as a component of a rapid-sequence induction of anesthesia. Therefore we have compared rocuronium with pancuronium and vecuronium about the onset time, intubation time, and tracheal intubating conditions. METHOD: Thirty patients were divided into three groups, who were receiving intravenously pancuronium 0.14 mg/kg, vecuronium 0.1 mg/kg and rocuronium 0.6 mg/kg respectively for tracheal intubation during induction of anesthesia. The onset time(Time from drug administration to zero count of PTC) and intubation time were checked using train of four responses of the adductor pollicis muscle after ulnar nerve stimulation(2 Hz, 40mA) every 10 seconds. The intubation conditions were recorded by a "blinded" assessor as excellent, good, fair or not possible. RESULT: The onset time of pancuronium, vecuronium and rocuronium was, 125.0+/-10.0, 256.0+/-18.4 and 90.0+/-22.1 sec. respectivly. The time of intubation was 94.0+/-12.6, 95.3+/-7.9, and 77.0+/-10.6sec.(pancuronium,vecuronium & rocuronium respectively). The onset time of rocuronium was significantly faster than the other two nondepolarizing muscle relaxants. The tracheal intubation with rocuronium was possible earlier than pancuronium or vecuronium but no statistical significance was observed and the condition of intubation was excellent compare to others in all ten patients. CONCLUSION: Rocuronium may have advantages over existing non-depolarizing neuromuscular blocking agents with faster rate of development of neuromuscular block with excellent intubation condition after administraction of a dose 0.6 mg/kg(ED 95 x 2).

Clinical Study of the Onset Time of Rocuronium / 대한마취과학회지

BACKGROUND: Rocuronium, a new nondepolarizing muscle relaxant, has been reported to develop a rapid onset of action and may be suitable as a component of a rapid-sequence induction of anesthesia. Therefore we have compared rocuronium with pancuronium and vecuronium about the onset time, intubation time, and tracheal intubating conditions. METHOD: Thirty patients were divided into three groups, who were receiving intravenously pancuronium 0.14 mg/kg, vecuronium 0.1 mg/kg and rocuronium 0.6 mg/kg respectively for tracheal intubation during induction of anesthesia. The onset time(Time from drug administration to zero count of PTC) and intubation time were checked using train of four responses of the adductor pollicis muscle after ulnar nerve stimulation(2 Hz, 40mA) every 10 seconds. The intubation conditions were recorded by a "blinded" assessor as excellent, good, fair or not possible. RESULT: The onset time of pancuronium, vecuronium and rocuronium was, 125.0+/-10.0, 256.0+/-18.4 and 90.0+/-22.1 sec. respectivly. The time of intubation was 94.0+/-12.6, 95.3+/-7.9, and 77.0+/-10.6sec.(pancuronium,vecuronium & rocuronium respectively). The onset time of rocuronium was significantly faster than the other two nondepolarizing muscle relaxants. The tracheal intubation with rocuronium was possible earlier than pancuronium or vecuronium but no statistical significance was observed and the condition of intubation was excellent compare to others in all ten patients. CONCLUSION: Rocuronium may have advantages over existing non-depolarizing neuromuscular blocking agents with faster rate of development of neuromuscular block with excellent intubation condition after administraction of a dose 0.6 mg/kg(ED 95 x 2).

Effect of Esmolol on Serum Potassium Changes Induced by Succinylcholine / 대한마취과학회지

BACKGROUND: The purpose of this study was to determine whether esmolol augmented the increase in serum K+ following administration of succinylcholine. METHODS: Forty patients were randomly divided esmolol group (n=20) and control group (n=20). The esmolol group received a 1 minute rapid infusion of 500 mcg/kg/min followed by a continuous infusion of 200 mcg/kg/min for 4 minutes before administration of succinylcholine. Serum potassium level, mean arterial blood pressure and pulse rate were measured prior to induction(baseline) and 1, 3, 5, 10, 15, 30, 45, 60, 75, 90 minutes after administration of succinylcholine. RESULTS: Serum potassium level was significantly higher in esmolol group after 3 and 15 minutes after succinylcholine than control group. Mean arterial blood pressure was not significantly different between two groups except 10 minute but the pulse rate significantly lower 1, 3, 5, 10 and 15 minutes in esmolol group than control group. CONCLUSIONS: Esmolol does not significantly elevate serum potassium level in clinical use(1 minute infusion of 500 mcg/kg/min followed by infusion of 200 mcg/kg/min for 4 minutes) after administration of succinylcholine. So succinylcholine can be used safely in the presence of beta-1-selective adrenergic blockade. And esmolol can attenuate more effectively increase of pulse rate than mean arterial pressure.