The Effect of Fentayl and Midazolam on the Incidence of Emergence Agitation in Children Following Sevoflurane Anesthesia for Tonsillectomy / 대한마취과학회지

BACKGROUND: It is well known that sevoflurane anesthesia is associated with emergence agitation (EA) in children, and that fentanyl may reduce its incidence. However, in case of midazolam, there have been conflicting reports. Therefore, we measured the effect of midazolam on EA after sevoflurane anesthesia and compared it with that of fentanyl. METHODS: Sixty pediatric patients receiving sevoflurane anesthesia for tonsillectomy was assigned to 3 groups. Saline 0.1 ml/kg (group P), midazolam 0.1 mg/kg (group M), or fentanyl 1 microgram/kg (group F) was administered intravenously 10 minutes before the end of surgery. The incidences of over-sedation (OS) and EA were checked three times at the postanesthesia care unit. RESULTS: Group M had a tendency to show a high incidence of OS, but its incidence of EA was not different from the other groups. In group F, OS and EA were less frequent than in groups P and M. CONCLUSIONS: After sevoflurane anesthesia for tonsillectomy, fentanyl effectively prevented EA, but midazolam elicited OS and was ineffective at preventing EA.

Effects of Ondansetron on the Neuromuscular Block of Vecuronium, Rocuronium or Atracurium in a Rat Phrenic Nerve-Hemidiaphragm Preparation / 대한마취과학회지

BACKGROUND: Ondansetron, a 5-HT3 receptor antagonist, is widely used for the prevention of postoperative nausea and vomiting. However, the interaction of ondansetron with non-depolarizing muscle relaxants have not been reported until now. Therefore we studied the effects of ondansetron on the neuromuscular block of vecuronium, rocuronium or atracurium in vitro. METHODS: A square wave 0.1 Hz supramaximal stimuli was applied to the phrenic nerve-hemidiaphragm preparation of a rat, and the twitch height response was recorded mechanomyographically. We measured cumulative concentration response curves of vecuronium, rocuronium or atracurium alone and after pretreating with ondansetron (1microgram/ml). We also measured the effects of ondansetron. The EC50's and EC90's of these muscle relaxants alone and after pretreatment with ondansetron were calculated using an inhibitory sigmoid Emax model. RESULTS: Ondansetron depressed the twitch height in a dose-dependent manner, and its potency was lower than the muscle relaxants. The EC50 and EC90 of ondansetron were 14.7microgram/ml and 33.4microgram/ml, respectively. Pretreated ondansetron (1microgram/ml) significantly reduced the EC50's and EC90's of vecuronium, rocuronium and atracurium (P<0.05). CONCLUSIONS: Ondansetron itself may have neuromuscular blocking properties, and it significantly enhances the neuromuscular blocks induced by vecuronium, rocuronium or atracurium.

Right Ventricular Perforation by a Pulmonary Artery Catheter / 대한마취과학회지

A 62-year-old woman with two vessel coronary artery disease was scheduled for an off-pump coronary artery bypass graft. Under general anesthesia, a 7.5 Fr pulmonary artery (PA) catheter (AH-05050-H, Arrow, USA) was inserted via an 8.5 Fr introducer in the right internal jugular vein. After several attempts, it was successfully guided into the PA, and the systolic/diastolic/mean pressure was 28/10/16 mmHg at 45 cm insertion. Since the catheter migrated into an overwedged position during the operation, the catheter was withdrawn several centimeter. After a while, a sudden change of PA pressure waveform to plateau was noticed, and then PA pressure fell into 0/0/0 mmHg. The PA catheter tip was seen protruding through the normal-appearing anterior wall of the right ventricle. The catheter was withdrawn to a right atrial position, and the perforation was closed. The operation was finished uneventfully and the patient remained stable for the next 14 days and was discharged home. In this case, withdrawal of the PA catheter probably placed its tip in the origin of the PA, from which it then slipped into and perforated the right ventricle. After withdrawal of a PA catheter to avoid an overwedged position, the balloon of the catheter should be re-advanced into a proper position or be withdrawn to a right atrial position.

Evaluation of Presynaptic Action of Depolarizing Neuromuscular Blocking Agents with Single Twitch Response in Vitro / 대한마취과학회지

BACKGROUND: This study was performed to evaluate the presynaptic effects of depolarizing neuromuscular blocking drugs by using slow and fast frequencies of indirect stimulation on partial twitch depression in vitro. METHODS: A rat phrenic nerve hemidiaphragm was dissected and was mounted in an organ bath containing an oxygenated Krebs solution. The phrenic nerve was stimulated supramaximally and the twitch response (0.1 Hz) was stabilized for at least 30 minutes. T200/T1 ratio (twitch height of the 200th stimuli divided by that of the first stimuli) at frequencies of 0.2, 0.5, 1.0, and 2.0 Hz using a drug concentration which provided approximately 20% twitch depression at 0.1 Hz was calculated. To compare T200/T1 ratios with TOF ratios, a 2.0 Hz TOF response was measured immediately after the 200th stimuli at either frequency of stimulation. RESULTS: T200/T1 ratios produced by succinylcholine (SCC) and decamethonium (C10) were located between alpha-bungarotoxin (ABX) and hexamethonium (C6), however, significant differences among the four drugs were found at 2.0 Hz. The propensity for a decrease in T200/T1 ratios at 2.0 Hz might differ from this study: C6 > C10 > SCC > ABX. T200/T1 ratios at 2.0 Hz were not different from TOF ratios. CONCLUSIONS: It is concluded that small doses of C10 have a greater presynaptic activity than that of SCC, when the observed effects in this study were compared with the result of ABX acting predominantly at postsynaptic receptors and C6 acting predominantly at presynaptic receptors.

The Effect of 4-Aminopyridine with Anticholinesterases on MgSO4-Rocuronium-Induced Neuromuscular Blockade in Vitro / 대한마취과학회지

BACKGROUND: The aim of this study was to evaluate the effect of 4-aminopyridine (4-AP) combined with anticholiesterase (antiChE) in antagonizing MgSO4-rocuronium-induced neuromuscualr blockade using a rat hemidiaphragm. METHODS: A hemidiaphragm with phrenic nerve was dissected and was mounted in a bath containing oxygenated Krebs solution. The phrenic nerve was stimulated supramaximally and the twitch response (0.1 Hz) was stabilized for at least 30 minutes. After maximal twitch inhibition by IC95 (concentration of 95% twitch inhibition) of rocuronium and MgSO4 20 mg was achieved, antagonistic effects of 1.6, 16 microgram/ml of edrophonium, 0.1, 1.0 microgram/ml of neostigmine, 0.5, 5.0 microgram/ml of pyridostigmine, and 0.8 microgram/ml of 4-AP combined with each of the above mentioned antiChEs were investigated. RESULTS: Whereas antiChE alone at low concentration partially recovered only the twitch response, 4-AP combined with antiChE recovered both the twitch and train-of-four responses significantly. CONCLUSIONS: 4-AP enhances antagonism of a magnesium-rocuronium induced neuromuscular blockade by edrophonium, neostigmine or pyridostigmine in vitro.

The Effect of sium on the Onset Time of Rocuronium-Induced Neuromuscular Blockade in the Isolated Rat Phrenic Nerve-Hemidiaphragm / 대한마취과학회지

BACKGROUND: Magnesium sulfate (MgSO4) is widely used in the treatment of preeclamptic Hyperreflexia. Eclamptic convulsions are almost always prevented by MgSO4 in plasma concentrations of 4 to 7 mEq/L. It is well known that MgSO4 enhances the effect of nondepolarizing neuromuscular blockade. But the onset time of rocuronium is not shortened by MgSO4. METHODS: The effect of magnesium on the onset time of rocuronium-induced neuromuscular blockade was investigated in vitro rat phrenic nerve-hemidiaphragm preparation. The phrenic nerve-hemidiaphragm was dissected and suspended in an organ bath containing modified Krebs' solution and produced single twitch responses under 0.2 ms, 0.1 Hz, electrical stimulation. We added rocuronium until the twitch height decreased more than 95% of the initial level and determined a dose in 95% decrease twitch height as an effective concentration (EC95). After the administration of MgSO4, the onset time of neuromuscular blockade by rocuronium 1 x EC95, 1.5 x EC95, 2 x EC95 was compared with the onset time without MgSO4. RESULTS: EC50 and EC95 of rocuronium was 0.178 and 1.10 mg/dl. After administration of MgSO4, the concentration of Mg2 in the organ bath was 4.38 mEq/L. The onset time of the neuromuscular blockade by 1 x EC95 rocuronium was significantly shortened, but in the case of over 1.5 x EC95, it was not influenced by MgSO4. CONCLUSIONS: The concentration of Mg2 was within the therapeutic range for inhibition of uterine contraction. The onset time of rocuronium-induced neuromuscular blockade was shortened by magnesium but because a high dose of rocuronium was administered for intubation due to low potency and high plasma concentration, the effect of magnesium on the onset time of rocuronium seems to be masked. Therefore clinically, the onset time of rocuronium-induced neuromuscular blockade was not shortened by MgSO4.

The Correlation between Perception and Nociception Thresholds by Selected Current Stimuli in Adults / 대한마취과학회지

BACKGROUND: This study was designed to investigate the correlation between pain and non-pain sensation of the cutaneous nociceptors in healthy adults use 250 Hz and 5 Hz evoking neuroselective sinusoidal current to A delta and C-fiber separately. METHODS: Fifty healthy adult volunteers who have no history of neurological illness were examined. Twenty-five of them were male, and twenty-five were female. Their ages ranged from 20 to 46 years, with a mean equal to 29.5 years old. The thresholds for both current perception and nociceptive perception were measured bilaterally in volar aspect of wrist using a Neurometer CPT/C (Quantitative Sensory Nerve Testing Device). The manual mode for current perception threshold and the staircase method for nociceptive current perception threshold was performed individually. RESULTS: The mean values of the threshold for perception evoked by 250 Hz were 0.30 mA in left and 0.31 mA in right, 0.17 mA in left and 0.14 mA in right at 5 Hz respectively. The mean values of the nociception threshold were 0.52 mA in both site at 250 Hz and from 0.35 mA to 0.32 mA at 5 Hz (Table 1). There were no differences between left and right wrist (Fig. 1). Also a significant positive correlation between current perception and nociception thresholds was found (p<0.05) (Fig. 2, 3). There appeared to be different between genders in perception threshold evoked by 250 Hz and nociception threshold evoked by 5 Hz in left (p<0.05) (Table 2). CONCLUSIONS: There exists a meaningful correlation between both sensations of non-pain and pain perception thresholds obtained from all subjects. The measurement of the current perception threshold is considered to be a unique and valuable resource in evaluation of patient with neurologic condition, as well as in serial evaluation of patient to assess the outcome of therapeutic intervention.

Influence of Various Muscle Relaxants on the Plasma Cholinesterase Activity / 대한마취과학회지

BACKGROUND: The reduction in the plasma cholinesterase (PChE) level results in slow to hydrolysis of succinylcholine (SCC) and mivacurium (MIV). The factors altering the level of the normal enzyme in human could be considered under the several conditions. We investigated in the present study whether the drugs induced decreases in normal PChE activity after administration of various muscle relaxants during anesthesia are evident and how these results should be influenced to the time course of neuromuscular blockade produced by SCC and MIV. METHODS: Young adult patients of ASA class I or II scheduled for elective surgery requiring muscle relaxation were premedicated and anesthesia was maintained with nitrous oxide in oxygen with increment of thiopentone or fentanyl as required. In the neuromuscular monitoring, surface electrodes were applied on the ulnar nerve at wrist. Supramaximal transcutaneous single twitch stimulation (1 Hz) during onset and 0.1 Hz during recovery of neuromuscular blockade induced by various muscle relaxants delivered by a peripheral nerve stimulator was applied. Twitch response of thumb adductor was measured mechanomyographically using 2 kg Load Cell Strain Gauge with thumb piece modification. Recordings were made on a Gould recorder. PChE levels were measured by the modified Garry method after induction of anesthesia and, at 3, 10, 20 and 30 min following administration of 2 x ED95 of pancuronium (PAN), vecuronium (VEC) and atracurium (ATR). Neuromuscular recordings were measured with onset time defined as lag time and manifest time, and recovery time defined as clinical duration, recovery index and total duration. RESULTS: The levels of PChE were significantly reduced after administration of PAN and VEC (p<0.05). Onset times were significantly shorten but recovery time in the group given MIV pretreated by small dose of PAN was significantly prolonged (p<0.05). And there were a evidence to prolong recovery time in the group pretreated by small dose of VEC but not significant. CONCLUSIONS: It is concluded that aminosteroidal derivative neuromuscular blocking agents have presumably evidence induced decreases in PChE activity rather than benzylisoquinolinium derivative neuromuscular blocking agents.

Incidence of Cesarean Section Following a Continuous Lumbar Epidural Analgesia for Labor Pain / 대한마취과학회지

BACKGROUND: This retrospective study was subjected to evaluate a causal relation in the incidences of Cesarean section with or without epidural analgesia during labor. METHODS: All of the subjects was divided into two groups which consisted of 394 cases wanted epidural analgesia as Epidural group and 2938 cases unwanted it as Non-epidural group. Continuous lumbar epidural analgesia was performed at L3-4 interspace with catheter advancing 3 cm cephalad when cervix was dilated to at least 3~5 cm and then patient was placed lateral decubitus or sitting posture. 0.125% bupivacaine 10 ml was injected initially via the epidural catheter and then followed by a mixture (10 ml) of bupivacaine 16.7 mg and fentanyl 16.7 microgram hourly to be infused continuously. The data were analysed using Pearson's x2 test with p<0.05 taken as a significant difference. RESULTS: The incidence of normal spontaneous vaginal delivery and Cesarean section, the cause of alteration to Cesarean section, and gestational frequency followed by Cesarean section rate showed no significant difference between two groups. The occurrence of neonate below 7 points of Apgar score at one and five minute after Cesarean section was rather more in Non-epidural group (p<0.05) than that in Epidural group. CONCLUSION: It is concluded that the continuous lumbar epidural analgesia with the dose of bupivacaine and fentanyl as mentioned above does not affect to Cesarean section rate during labor, which provides safe and effective for labor pain control.

The Effect of Frequency of Stimulation on Partial Twitch Depression in a Rat Phrenic Nerve Hemidiaphragm Preparation / 대한마취과학회지

Background: This study was designed to determine whether presynaptic receptor blockade could be differentiated from postsynaptic receptor blockade by examining the effect of increasing frequencies of indirect stimulation on partial twitch depression in vitro rat phrenic nerve hemidiaphragm preparations. Methods: After isolating rat phrenic nerve hemidiaphragm preparation, T200/T1 ratio (twitch height of the 200th stimuli divided by that of the 1st stimuli) at frequencies of 0.2, 0.5, 1.0, and 2.0 Hz using a drug concentration which provided approximately 20% twitch depression at 0.1 Hz was calculated. To compare T200/T1 ratios with TOF ratios, 2.0 Hz TOF response was measured immediately after 200th stimuli at either frequency of stimulation. Results: Hexamethonium caused a marked decrease in T200/T1 ratio at 0.5~2.0 Hz of stimulation, whereas alpha-bungarotoxin caused no change in T200/T1 ratios at up to 2.0 Hz of stimulation. The T200/T1 ratios produced by d-tubocurarine, vecuronium, mivacurium, and rocuronium located intermediate between alpha-bungarotoxin and hexamethonium, however significant differences among four drugs were found at 2.0 Hz. The propensity for decrease in T200/T1 ratios at 2.0 Hz might differ from this study: hexamethonium >d-tubocurarine >rocuronium >mivacurium = vecuronium >alpha-bungarotoxin. T200/T1 ratios at 2.0 Hz were not different from TOF ratios. Conclusions: When the observed effects in this study were provided with result of alpha-bungarotoxin acting predominantly at postsynaptic receptors and hexamethonium acting predominantly at presynaptic receptors, the effects of nondepolarizing muscle relaxants at each binding site could be differentiated by examining the T200/T1 ratios at 2.0 Hz.

Influence of Decamethonium on the Neuromuscular Blocking Action of d-Tubocurarine in the Rat Phrenic Nerve Hemidiaphragm Preparation / 대한마취과학회지

BACKGROUND: To elucidate the mechanism of interaction between depolarizing and nondepolarizing muscle relaxants, train-of-four (TOF) fade during onset of neuromuscular blockade of d-tubocurarine (dTC) with or without decamethonium (C10) was evaluated in a rat phrenic nerve hemidiaphragm preparation. METHODS: Phrenic nerve hemidiaphragm preparations from 250~300 g Sprague Dawley rats (n=20) were suspended in a Krebs solution bubbled with 5% CO2 in O2 at 32oC. Phrenic nerves were stimulated with supramaximal stimuli of 0.2 ms duration at 0.15 Hz single twitch and 2 Hz TOF by a Grass S88 stimulator and the contractions of the hemidiaphragm were detected by a Grass FT03 force transducer then recorded. Estimation of ED50 for the dose response data were performed by a linear regression. The statistical significance of the results was determined by Wilcoxon Rank Sum test. p<0.05 was considered significant. RESULTS: Mean ED50 values of dTC and C10 calculated from the dose response relations were 7.76 microgram/ml and 0.65 microgram/ml respectively. Compared to adminstration of 2xED50 of dTC alone, TOF ratios at 75% and 50% of twitch height were markedly decreased by combination of ED50 of C10 and ED50 of dTC with statistic significance (67 +/- 1.9% vs. 46 +/- 3.1% and 36 +/- 2.5% vs. 7 +/- 2.5%). Conclusion: If fade in response to TOF stimulation represents a prejunctional effect, the results from this study suggests that the presynaptic action of C10 has some role in the mechanism of the interaction between dTC and C10 in the rat.

The Effects of Esmolol on Neuromuscular Action of Succinylcholine or Mivacurium / 대한마취과학회지

Background: Esmolol is rapid hydrolyzed by plasma esterase but may inhibit plasma cholinesterase activity based on its structure. This study was designed to evaluate the interactions between esmolol and succinylcholine or mivacurium which are metabolized by plasma cholinesterase and to determine the inhibitory effect of esmolol on human plasma cholinesterase. Methods: Neuromuscular effects of succinylcholine (1.0 mg/kg) and mivacurium (0.15 mg/kg) with or without esmolol (0.5 mg/kg or 1.0 mg/kg) were compared in 57 adult patients (ASA class I) during O2-N2O-isoflurane anesthesia. Neuromuscular block was monitored by recording the compound electromyogram of the hypothenar muscle resulting from supramaximal train of four stimuli applied to the ulnar nerve. Also plasma cholinesterase activity was measured before and 5, 10 minutes after injection of esmolol. Results: Time from injection to onset of over 95% block, clinical duration from injection to 25% recovery of control twitch, and recovery index defined as from 25% to 75% twitch recovery of succinylcholine or mivacurium were not altered by pretreatment of esmolol. Plasma cholinesterase activity was not decreased after injection of esmolol 0.5 mg/kg, but decreased by 5% after injection of 1.0 mg/kg (p<0.05). Conclusions: It is unlikely that neuromuscular blocking effects of succinylcholine and mivacurium are prolonged by administration of clinical doses of esmolol (0.5~1.0 mg/kg) due to inhibition of plasma cholinesterase activity in human.

Effects of Pseudocholinesterase, Anticholinesterase, and 4-Aminopyridine to the Mivacurium-induced Neuromuscular Block on Rat Diaphragm / 대한마취과학회지

BACKGROUND: Prolongation of the neuromuscular block of mivacurium can occur when there is a genetic deficiency of the enzyme or in the presence of anticholinesterase (AntiChE) which inhibit the activity of the enzyme. The aim of this study was to determine the efficacies of cholinesterase, AntiChE (neostigmine, pyridostigmine), and 4-aminopyridine in reversing mivacurium block, using the phrenic nerve-diaphragm preparation of a rat. METHODS: Forty-eight Sprague-Dawley rats (200~300 g) were anesthetized with peritoneal injection of 2.5% thiopental 5~10 ml. After a stable twitch and train-of-four responses were established for at least 30 minutes in each preparation, incremental dose of mivacurium was added to obtain 90~95% inhibition of control twitch height. The effects of 0.1 and 1.0 u/ml of horse pseudocholinesterase (pChE, Sigma), 0.1 and 1.0 g/ml of neostigmine, 0.2 and 2.0 g/ml of pyridostigmine, and 1.6, 16 g/ml of 4-aminopyridine (P.B.I) on reversal of mivacurium block were tested. The effects of 0.1 g/ml of neostigmine, or 0.2 g/ml of pyridostigmine with and without 0.1 or 1.0 u/ml of pChE following mivacurium were also tested. RESULTS: In reversing mivacurium block, single twitch and TOF ratios were recovered completely with pChE but not with antiChEs or 4-aminopyridine (p<0.05). Second set of experiments showed that antiChE mixed with pChE had a tendency to recover faster (p<0.05). The comparable recovery patterns of pChE 0.1u/ml alone and neostigmine 0.1 g/ml with pChE 0.1u/ml in our study, indicated that neostigmine would prolong the mivacurium block especially in the presence of hereditary or acquired defects of pChE activity. CONCLUSION: The authors conclude that pChE 1.0 u/ml with and without antiChE were equally effective in reversing neuromuscular block of mivacurium. If these results can be extrapolated to human, it is unlikely that mivacurium block is potentiated by antiChE that may slow its metabolism.

Effects of Succinylcholine on the Recovery of Vecuronium-induced Neuromuscular Block / 대한마취과학회지

BACKGROUND: Succinylcholine is commonly used for tracheal intubation during induction of anesthesia and followed by a nondepolarizing neuromuscular blocking drug for intraoperative muscle relaxation. We have determined whether the effect of succinylcholine used for endotracheal intubation on the recovery of vecuronium-induced neuromuscular block offers many changes in time course of neuromuscular block. METHOD: Forty ASA class 1 or 2 adult male patients were studied. Patients were premedicated with nalbuphine 10 mg and glycopyrrolate 0.2 mg and after induction of anesthesia with thiopental, anesthesia was maintained with 1~2% enflurane, and 50% nitrous oxide in oxygen. Twitch responses of adductor pollicis were measured acceleromyographically using 0.2 ms, 2 Hz, train of four (TOF) stimulation of ulnar nerve every 15 seconds. The patients were allocated randomly to following four groups; Ten patients received vecuronium 0.1 mg/kg only (group 1), remained thirty patients received succinylcholine 1.0 mg/kg first and vecuronium 0.1 mg/kg was administered at 0% (group 2, n=10), 25% (group 3, n=10), 75% (group 4, n=10) recovery of first twitch from succinylcholine-induced neuromuscular block respectively. RESULT: Clinical duration, recovery index, and TOF ratio of vecuronium were not significantly different between groups. CONCLUSION: Succinylcholine for endotracheal intubation during induction of anesthesia does not affect time course of action of vecuronium-induced neuromuscular block. The cause of this result suspect that the effect of succinylcholine might be masked by large dose of vecuronium (2XED95). Clinically, it is unlikely that prior administered succinylcholine 1 mg/kg influence the recovery of vecuronium-induced neuromuscular block.

Neuromuscular Blocking Action of Neostigmine Methylsulfate / 대한마취과학회지

BACKGROUND: Although the neuromuscular blocking properties of neostigmine have been known for many years, few assessment of this effect has been described in man. The aim of this study is to determine the effect of neostigmine on neuromuscular transmission in the absence of muscle relaxants. METHODS: ASA I, twenty unpremedicated patients who had given their informed consent were administered neostigmine 2.0 mg and atropine 0.5 mg under propofol, fentanyl, and O2-N2O(67%) anesthesia. Train-of-four responses were measured electromyographically using 0.2 msec, 2 Hz of supramaximal ulnar nerve stimulation every 20 sec. RESULTS: There was no alteration in the train-of-four ratio, but the first twitch height decreased significantly after administration of neostigmine(P<0.05). Fasciculations were noted in the face and arms. Heart rate was decreased significantly to compare with preinjection value(P<0.05) while mean arterial pressure was not changed. CONCLUSIONS: It is concluded that even in clinical doses neostigmine may produce a depolarizing neuromuscular blockade, probably from the consequence of excessive accumulation of acetylcholine in the neuromuscular junction.

Effect of Administration of Vecuronium or Rocuronium on Recovery from Pancuronium and Vice Versa in Isolated Forearm / 대한마취과학회지

BACKGROUND: It is important to consider the sequential administration of long- and short-acting non-depolarizing muscle relaxants. The purpose of this study is to evaluate the interaction between non-depolarizing muscle relaxants under isolated forearm test. METHODS: Ethics committee approval for all the volunteers (n=12) experiments was obtained. Pancuronium, 0.3 mg in 20 mL saline, was injected into one forearm; and vecuronium, 0.3 mg in 20 mL saline, was injected simultaneously into the other forearm in 6 volunteers. Three minutes later both tourniquets were released. Following spontaneous recovery in each forearm to 50% of the control twitch, the tourniquet was reinflated and the dose of drug of the same dilution used in the contralateral forearm was then injected (i. e., vecuronium following pancuronium in one forearm and pancuronium following vecuronium in the other forearm). Tourniquet was again released after 3 minutes and spontaneous recovery was allowed to occur. Interactions between pancuronium (0.3 mg) and rocuronium (2.0 mg) in 6 volunteers were also evaluated in a same method. RESULTS: Prior administration of pancuronium significantly prolonged the recovery rate from subsequent rocuronium (23.9 vs. 32.1 min, p<0.05), and rocuronium significantly shortened the recovery rate of pancuronium (32.4 vs. 25.9 min, p<0.05). There was simple additive interaction between pancuronium and vecuronium. CONCLUSION: The possible mechanism of these phenomena may be due to interaction of drug with acetylcholine receptors in the neuromuscular junction rather than due to residual plasma drug concentration.

The Comparison of the TOF Ratios between Electromyograph and Accelerograph following Vecuronium Administration / 대한마취과학회지

The present study was firstly undertaken in an attempt to compare simultaneously EMG(electromyography) and two new ACC(accelerography) reponses in the both hand following vecuronium administration in 26 ASA 1 or 2 adult patients undergoing general anesthesia. In the three NMT monitors, stimulating electrodes are applied similarly over the ulnar nerve on the volar side of the wrist, but the evoked EMG(Relaxograph, Datex Co.) responses obtained from the hypothenar muscles, TOFGUARD(Biometer Co.) responses from adductor pollicis and ParaGraph(Utah Med. Prod. Co.) responses from both muscles of hypothenar and thenar muscle of the hand respectively. Following induction of anesthesia with thiopental sodium(5 mg/kg) and vecuronium(0.08 mg/kg) intravenously, endotracheal intubation was facilitated and anesthesia was maintained with a mixture of enflurane(1~2%) and N2O(50%) . After loss of consciousness, the assessment of the neuromuscular blockade was started. We compared simultaneously TR(train-of-four ratio) responses of EMG at the one hand, and two new ACC named TOF-GUARD and ParaGraph at the other hand respectively during evoked recovery from vecuronium induced neuromuscular blockade. The result was the greater depression of TR response in TOF-GUARD and the lesser depression of TR response in ParaGraph than those in EMG. But test for parallelism did not show a statistically significant difference between the slope of these regression lines. Conclusively, the regression line for TR seems to be tend to give an impression that two new ACC named TOF-GUARD and ParaGraph would be suitable in the assessment of neuromuscular blockade in clinical anesthesia.

Neuromuscular and Cardiovascular Effects of Rocuronium during Propofol, Fentanyl, N2O/O2, Isoflurane Anesthesia / 대한마취과학회지

The neuromuscular blocking and cardiovascular effects of rocuronium (Roc) have been compared with succinylcholine (Scc), mivacurium (Miv) and vecuronium (Vec). Thirty six healthy adult patients were randomly assigned to receive Roc (0.6 mg/kg), Scc (1.0 mg/kg), Miv (0.16 mg/kg) and Vec (0.08 mg/kg) during induction with propofol and fentanyl. The 3M surface electtodes (Red Dot, Ag/AgC1) were applied over the ulnar nerve at the wrist and supramaximal transcutaneous stimulation from a peripheral nerve stimulator (Innervator, Fisher & Paykel, New Zealand) using a 0.2 ms square wave pulses in duration at 0.1 Hz were applied. The twitch response of the thumb adductor was measured mechanomyographically using 2 kg load cell strain gauge (Model No. 505H, RS Component, Ltd, U.K.) with a thumb piece modification. Recordings were made on a Gould TA 240 Easy Graf Thermal Array Recorder with a 6600 series transducer signal. The time from injection of muscle relaxant to complete depression of control twitch height (onset), the time from injection to 25% recovery of control twitch height (clinical duration, CD) and recovery indices (RI, time from 25% to 75% recovery of control twitch height) were measured, and the cardiovascular effects; heart rate (HR) and mean arterial pressure (MAP), were determined before and after injection of muscle relaxants. Onset times for patients, receiving Roc, Scc, Vec and Miv were 65.0+/-13.5 s, 54.0+/-5.2 s, 191.+/-58.0 s and 201.3+/-37.6 s. CDs were 33.6+/-6.6 min, 8.4+/-2.1 min, 21.6+/-4.8 min and 13.0+/-2.2 min. RIs were 12.9+/-4.3 min, 5.5+/-1.2 min, 10.9+/-3.8 min and 6.9+/-1.3 min. There were no significant changes of HR, however MAP were decreased significantly from 2 min after injection of Roc. Consequently, onset time of Roc were faster than that of Miv or Vec and slower than that of Scc but not significant. However, CD and RI of Roc were significantly longer than those of the others, with minimum cardiovascular effects.

The Rebleeding of Ruptured Intracranial Aneurysm during Induction of Anesthesia / 대한마취과학회지

The intraoperative rupture of an intracranial aneurysm can dramatically interrupt the fine operative procedure and jeopardize the patient's chance for meaningful survival. A sudden increase of the arterial pressure and intracranial pressure during laryngoscopy and intubation is potentially dangerous and may lead to fresh bleeding from an aneurysm in patient with recent subarachnoidal hemorrhage due to aneurysmal rupture. But aneurysmal rupture during induction occurs rarely. Recently we experienced rebleeding due to sudden increased arterial blood pressure during laryngoscopy and intubation in 39 years old female patient who was scheduled for clipping of ruptured intracranial aneurysm on 11th day after ictus. And she died of cerebral death on 6th postoperative day. Here we discuss the incidence, prognosis, diagnosis, management and prophylaxis of the aneurysmal rupture during induction with a brief review of the literature.

Comparison of Pharmacokinetic Affinity of Various Non-depolarizing Neuromuscular Blocking Agents in the Isolated Foream / 대한마취과학회지

It is well known that the plasma concentration is important in determining the rate of recovery from neuromuscular block. However, nondepolarizing neuromuscular blockade are retained at the neuromuscular junction and are not readily displaced in response of changes in plasma drug concentration, for instance, the neuromuscular block induced by mivacurium appears to considerably outlast the theoretical plasma half-life of the drug and is continued long after the plasma level has fallen to subparalytic levels due to rapid metabolism by pseudocholinesterase. It has been suggested that although plasma concentration may be the key determinant of recovery from neuromuscular block, recovery will depend upon the dissociation from the affinity of drug in the effect compartrnent and not upon its plasma concentration. In an attempt to confirm these evidences, we have investigated the response of changes in neuromuscular block after releasing tourniquet at 50% twitch depression using the isolated forearm experiment with various neuromuscular blocking agents. The results of this study demonstrated the further increase of block after early toumiquet release in the isolated forarm in all agents; 66+/-14% in vecuronium, 90+/-9% in atracurium, 92+/-7% in pancuronium, and 73+/-18% in mivacurium Conclusively, the further block continued to increase in spite of the negligible plasma drug concentration after early tourniquet release may be caused by more in affinity of drugs in binding sites than plasma drug concentration. Therfore, it is evident that both the affinity of drug to the receptor and the plasma drug concentration have influenced on the recovery from the neuromuscular block.