Prevalencia de bloqueo residual en la Unidad de Cuidados Postanestésicos del Hospital Metropolitano / Prevalence of residual blockade in the Postanesthetic Care Unit of the Hospital Metropolitano

RESUMEN El bloqueo residual se define como la debilidad muscular postoperatoria producida por un antagonismo incompleto de los relajantes neu-romusculares, siendo sus principales complicaciones las respiratorias. Actualmente, el mejor método de evaluación objetiva del bloqueo neuromuscular es el Tren de Cuatro (TOF). El objetivo de este estudio fue describir la prevalencia de bloqueo residual en la Unidad de Cuidados Postanestésicos (UCPA) en pacientes ASA I y ASA II sometidos a cirugía electiva y de emergencia bajo anestesia general en el Hospital Metropolitano. Se realizó un estudio observacional, descriptivo y prospectivo en 211 sujetos, donde mediante el TOF se deter-minó que la prevalencia de bloqueo residual en la UCPA fue del 8,5%, valor que se relacionó con la falta de monitorización de la función neuromuscular, determinando además que el empleo de fármacos que revierten el bloqueo neuromuscular no excluye la presencia de bloqueo residual. Se recomienda el uso rutinario de monitorización de la relajación neuromuscular para prevenir y diagnosticar el bloqueo residual, además de la administración de reversión farmacológica independientemente del tiempo quirúrgico.

ABSTRACT Residual blockade is defined as postoperative muscle weakness caused by incomplete antagonism of neuromuscular relaxants, its main complications being respiratory, currently the best method of objective evaluation of neuromuscular blockade is the Train of Four (TOF). The objective of this study was to describe the prevalence of residual block in the Post Anesthesia Care Unit (UCPA) in patients with ASA I and ASA II undergoing elective and emergency surgery under general anesthesia at the Metropolitan Hospital. An observational, descrip-tive and prospective study was conducted in 211 subjects, where it was determined that the prevalence of residual block in UCPA was 8.5% with TOF, a value that was related to the lack of monitoring of neuromuscular function, also determining that the use of drugs that reverse neuromuscular blockade does not exclude the presence of residual blockade. Routine use of neuromuscular relaxation monitoring is recommended to prevent and diagnose residual block, in addition to drug reversal administration regardless of surgical time.

Feasibility of Perioperative Diaphragmatic Ultrasound in Assessment of Residual Neuromuscular Blockade / 中国医学科学院学报

Objective To evaluate the relationship between diaphragmatic ultrasound and postoperative residual neuromuscular blockade(PRNB). Methods The patients undergoing non-thoracic and abdominal surgery under general anesthesia from August to October in 2019 were randomly enrolled from Peking Union Medical College Hospital.Diaphragmatic ultrasound was acquired pre-operation and post extubation.A 4-15 MHz probe was used to measure diaphragmatic thickness at the intersection point of 8-9 intercostal space with right anterior axillary line at the end of inspiration and expiration during quiet breathing and deep breathing(DB),and the diaphragmatic thickness fraction(DTF)was calculated.A 1-5 MHz probe was used to measure diaphragmatic excursion(DE)at the intersection point of right costal margin with midaxillary line during quiet breathing and DB.Train of four ratio(TOFr)was recorded for neuromuscular monitoring.TOFr,observer assessment of alertness and sedation score at extubation,Aldrete score at postanesthesia care unit,and postoperative pulmonary complication were recorded. Results The PRNB rate was 54.7%.The DTF-DB [31.3(21.1,45.0)vs.38.5(26.6,53.9),P=0.045] and DE-DB(2.9±1.4 vs.4.1±1.0,P<0.001)in PRNB group was lower than those in the group without PRNB.DTF-DB(r=0.351,P=0.002)and DE-DB(r=0.580,P<0.001)were correlated with TOFr. Conclusion Perioperative diaphragmatic ultrasound may be helpful for the diagnosis of PRNB.

Comparison of Different Dosages of Rocuronium on Abdominal Wound Closure / 昆明医科大学学报

Objective To evaluate the effects of different dosages of rocuronium on abdominal wound closure under general anesthesia.Methods Ninety ASA class I or II patients scheduled for elective abdominal surgery under general anesthesia were randomized into three groups with 30 cases each.Each group received rocuronium 1 time of ED95 (0.3 mg/kg),0.5 time of ED95 (0.15 mg/kg),0.2 time of ED95 (0.06 mg/kg) respectively when closing the abdominal wall.TOF recovered to 25%, 75%, 90%, time of eye-opening on command, time of head-lift for more than 5 seconds,extubation time, the rate of upper airways obstruction after extubation and the satisfaction score for the muscle relaxation to general surgeons were recorded.Results TOF values had no significantly different among the three groups before abdominal wound closure (P＞0.05).Compared with group A and group B,time of TOF in group C was significangtly increased after administration of rocuronium (P＜0.05) . Time of TOF recovery to 25%, 75%, 90%in group C were significangtly decreased (P＜0.01).Compared with group A and group B, time of eye-opening on command ,head-lift for more than 5 seconds and extubation time were significantly shorter in group C.There were 8,4,0 patients undwent upper airways obstruction among each group respectively after extubation (P＜0.05).The satisfaction score for muscle relaxation among three groups had no significant difference.Conclusion An additional administration of 0.2 time of ED95 (0.06 mg/kg) rocuronium before abdominal wound closure in abdominal surgery can achieve satisfactory muscle relaxation for surgeons.

Estimation of the effect-site equilibration rate constant using the time-to-peak effect of muscle relaxants measured by train-of-four stimulation during general anesthesia induction / 대한마취과학회지

BACKGROUND: The concept of the effect-site concentration of anesthetic agents is important. The effect compartment model can be explained using the concepts of effect-site concentration and effect-site equilibration rate constant (k e0). This study confirms that the time-to-peak effect (tpe ) can be measured easily in clinical practice by applying a priming dose and train-of-four (TOF) during general anesthesia induction, and k e0 can be calculated from the tpe of the four muscle relaxants that are commonly used in general anesthesia. METHODS: Eighty patients who received general anesthesia were divided into the succinylcholine, rocuronium, atracurium, or vecuronium groups. Priming doses of muscle relaxants were administered. The effects of muscle relaxants were quantified by recording the twitch response of the adductor pollicis muscle after stimulating the ulnar nerve. The tpe was measured at the lowest TOF value. k e0 was calculated from the measured tpe . RESULTS: The k e0 values of the succinylcholine, rocuronium, atracurium, and vecuronium groups were 0.076 (0.030)/min, 0.228 (0.122)/min, 0.062 (0.011)/min, and 0.077 (0.019)/min, respectively. CONCLUSIONS: It is possible to estimate k e0 from the tpe of muscle relaxants using a priming dose and TOF during general anesthesia induction.

What anesthesiologists ask to know and should know about the neuromuscular monitoring: an updated review

The increase in mortality and morbidity associated with the use of muscle relaxants, is associated with a lack of clinical pharmacological knowledge of the drugs, and a lack of understanding the risk of postoperative residual curarization. This is due to the absence of standards for neuromuscular monitoring. Clinicians experienced in neuromuscular monitoring and using muscle relaxants in the clinic may have some queries regarding the monitoring: Why should neuromuscular monitoring be done? Are clinical tests really not effective? Why is it not good when I actually perform neuromuscular monitoring? Would using sugammadex not require neuromuscular monitoring? This review answers most of the questions that many clinicians have, and also forwards the knowledge required of clinicians.

Atropine is more efficient than ZM241385 to reduce a drastic level of fade caused by cisatracurium at 50 Hz / Atropina é mais eficiente que ZM241385 para reduzir o intenso nível de fadiga causada por cisatracurium a 50 Hz

The effects of atropine (non selective muscarinic antagonist) and ZM241385 (A2A receptors antagonist) in the cisatracurium-induced drastic (100%) level of fade at 50 Hz (10 s) (100% Fade) were compared in the phrenic nerve-diaphragm muscle preparations of rats indirectly stimulated at a physiological tetanic frequency (50 Hz). The lowest dose and the instant cisatracurium caused 100% Fade were investigated. Cisatracurium induced 100% Fade 15 min after being administered. Atropine reduced the cisatracurium-induced 100% Fade, but the administration of ZM241385 separately, or combined with atropine, did not cause any effect in the cisatracurium-induced 100% Fade. Data indicate that the simultaneous blockage of M1 and M2 muscarinic receptors on motor nerve terminal by atropine is more efficient than the blockage of presynaptic A2A receptors for a safer recovery of patients from neuromuscular blockade caused by cisatracurium.

Os efeitos de atropina e ZM241385 (antagonistas de receptores A2A) no drástico (100%) nível de fadiga (100% Fadiga) produzido pelo cisatracúrio a 50 Hz (10 s) foram comparativamente investigados em preparações nervo frênico músculo diafragma isolado de ratos indiretamente estimuladas com a frequência fisiológica tetanizante de 50 Hz. A menor dose e o instante no qual cisatracúrio causou 100% Fadiga foram pesquisados. O cisatracúrio induziu 100% Fadiga 15 min depois de ser administrado. A atropina reduziu a fadiga de 100% causada pelo cisatracúrio, mas ZM241385, ou a administração combinada de atropina com ZM241385, não causou qualquer efeito na 100% Fadiga produzida pelo cisatracúrio. Os dados indicam que o bloqueio simultâneo dos receptores muscarínicos M1 e M2 no terminal nervoso motor pela atropina é mais eficiente do que o bloqueio dos receptores pré-sinápticos A2A no auxilio da recuperação mais segura do bloqueio da transmissão neuromuscular causada por cisatracúrio.

Late recurarization in the post-anesthetic care unit after total thyroidectomy: A case report

Residual paralysis, recurarization is defined as a remnant effect of neuromuscular blocking after surgery that can cause postoperative complications. Clinical complications of recurarization include dyspnea, gastric content aspiration, and atelectasis. Therefore, complete recovery of muscle strength at the end of surgery is a significant factor for patient safety. We report a case of a 53-year-old woman who presented with residual paralysis after total thyroidectomy. To improve her condition, we injected sugammadex intravenously in the post-anesthetic care unit. After that, we observed her for 1 hour and her muscle strength gradually recovered. She did not have any symptoms on the next day and was discharged on the 5th post-operative day.

Uso de rocuronio en terapia electroconvulsiva, una alternativa segura? Reporte de casos / Rocuronium use in electroconvulsive therapy, a safe alternative? Case reports

Introducción: en la actualidad el uso de la terapia electroconvulsiva (TEC) ha aumentado como alternativa terapéutica en varias patologías. El uso de TEC modifcado ayuda a disminuir los efectos fsiológicos y los efectos adversos del tratamiento; el objetivo del presente estudio es determinar la seguridad del uso de rocuronio en la terapia electroconvulsiva. Materiales y métodos: se realizó un estudio prospectivo de una serie de casos en los que intervinieron 47 terapias electroconvulsivas, se usó como relajante neuromuscular rocuronio a dosis de 0.3 mg/ kg, el tiempo promedio para realizar la descarga eléctrica fue de 5 minutos. Se administra neostigmina y atropina como agente de reversión de la parálisis. Resultados: el análisis de los casos dan resultados descriptivos, el promedio de la relación TOF obtenido luego de 20 minutos del uso de neostigmina y atropina fue de 88.7%, lo que no asegura un retorno a la ventilación espontánea. Conclusiones: el uso de rocuronio en terapia electroconvulsiva es seguro siempre y cuando se lo convine con Sugamadex, ya que este garantiza una reversión del bloqueo neuromuscular confable y minimiza los posibles efectos adversos de los bloqueadores nueromusculares no despolarizantes.

Introduction: to relate a clinical case in OR of a pulmonary surgery for review the management of hypoxia in unipulmonar ventilation and with this realize that we could have catastrophic consequences. Clinic case: male patient, 46 years of age with a history of several episodes of hemoptysis underwent left upper lobectomy, presenting episode of intraoperative massive hemoptysis. Algorithm of hypoxia in one lung ventilation was followed nevertheless maintains prolonged hypoxia with important consequences of hypoxic encephalopathy. Conclusion: every anesthesiologist that have in OR a pulmonary surgery must have the knowledge of hypoxia in unipulmonar ventilation management.

Change in the effect of rocuronium after pneumatic tourniquet release in patients undergoing unilateral total knee arthroplasty

BACKGROUND: A pneumatic tourniquet is commonly used in orthopedic surgery. However, neuromuscular blocking agent can be sequestered in the isolated limb and be reabsorbed into the systemic circulation after tourniquet release, potentially delaying extubation. To investigate the change in the train-of-four (TOF) ratio after tourniquet release and correlate the TOF ratio change with the extubation time. METHODS: Forty patients undergoing unilateral total knee arthroplasty were enrolled. Before and after the pneumatic tourniquet release, 10 measurements of the TOF ratio were averaged and compared. Additionally, we investigated the correlation between the percentage change in the TOF ratio before and after tourniquet release and the extubation time. RESULTS: Among the 40 patient subjects, 30 showed a TOF ratio before tourniquet release and 10 showed only a TOF count. Of the 30 patients with a TOF ratio, 21 showed a TOF ratio increase after tourniquet release and 9 showed a TOF decrease; both increase and decrease were statistically significant (P < 0.001 and P = 0.008, respectively). The extubation time showed a weak negative correlation with the percentage change in the TOF ratio after tourniquet release (P = 0.004). CONCLUSIONS: In orthopedic surgery using a pneumatic tourniquet, neuromuscular function monitoring may be required to monitor the change in the effect of neuromuscular blocking agent before and after tourniquet release, which may help to improve anesthesia safety.

The study of proper depth of muscle relaxant in posterior fossa surgery under total intravenous anesthesia / 临床麻醉学杂志

Objective To investigate the proper depth of muscle relaxant without affecting elec-trophysiological monitoring in patients undergoing posterior fossa surgery under total intravenous an-esthesia (TIVA).Methods Forty patients selected for posterior fossa surgery were randomly divided into two groups A and B.Group A:no muscle relaxants were administered after anesthesia induction until the EMG was completed.Group B:muscle relaxants maintained in range of TOF 2%-25% dur-ing electrophysiological monitor.TIVA were used to all patients and BIS was maintained in range of 40-60.Two electrophysiological data were applied during the electrophysiological monitoring:sponta-neity EMG and evoked EMG.EMG amplitude was recorded at different TOF value.Operation time and the dosages of propofol,sufentanil,rocuronium bromide were recorded.Also,the SBP,DBP,HR at perioperational period and facial nerve function before surgery,one week and six months after sur-gery were recorded.Results The electrophysiological monitoring completed successfully in all pa-tients.The total amount of propofol in group A significantly increased than those in group B(P <0.05).Three patients in group A had body movement during the operation.Four cases in group B couldn??t perform electrophysiological monitor when the TOF had three signals.There were no differ-ence between the two groups in SBP,DBP,HR and facial nerve function.Conclusion Maintaining TOF value in range of 2%-25% under non-depolarizing muscle relaxant during CPA surgery doesn??t affect intraoperative nerve electrophysiological monitor and prevent body movement,total dose of sed-ative anesthetics is also decresed.

Incidencia de parálisis muscular residual con el uso de relajantes musculares no despolarizantes de duración intermedia / Incidence of residual muscular paralysis produced by nondepolarizing neuromuscular blockers

Objetivo: El objetivo de este estudio fue analizar la incidencia de parálisis muscular residual producida por bloqueadores neuromusculares no despolarizantes en la Unidad de Cuidados Postanestésicos (UCPA)del Hospital Miguel Pérez Carreño, Caracas, Venezuela. Material y Métodos: Se incluyeron 246 pacientes en los que se midió la relación T4/T1 al momento del ingreso a la unidad, a los tres y a los cinco minutos. El criterio para considerar un paciente sin bloqueo residual fue una relación T4/T1 > 0,9. Además se monitorizó la saturación de oxígeno, variables demográficas, características de la cirugía y la anestesia, y uso o no de reversión. Resultados: El promedio de edad fue de 36,45 años, con un peso de 62,85 kg. La incidencia de parálisis residual en la UCPA fue 51,2 por ciento para el momento de llegada a la unidad, de 47,6 por ciento a los tres minutosy de 46,7 por ciento al quinto minuto, siendo los pacientes de mayor edad los más afectadas (p= 0,002). Cuando se comparó la utilización de reversión con la presencia de relajación residual no se encontró diferencia estadísticamente significativa (p = 0,516). Conclusión: La incidencia de parálisis muscular residual en la UCPA es alta en nuestro centro (51 por ciento), similar a lo que reporta la literatura a nivel mundial; los pacientes más afectados fueron los de mayor edad y el uso de reversión no excluyó la presencia de esta entidad.

Objective: The outcome of this study was to analyze the incidence of residual muscular paralysis produced by nondepolarizing neuromuscular blockers in the PostAnesthetic Care Unit (PACU) of the Doctor Miguel Pérez Carreño Hospital, Caracas, Venezuela. Methods: 246 patients were included. T4/T1 ratio was measured at the moment of arriving to the postoperative unit, 3 and 5 minutes later. Criteria for consideringno residual effects was a T4/T1 > 0,9. Moreover, oxygen saturation was monitored. Demographic variables,characteristics of surgery and anesthesia and the usage or not of reversion drugs were noted. Results: The average of age was 36,45 years, with an average weight of 62,85 kg. The incidence of residual muscularparalysis in the PACU was 51,2 percent at the time of arriving, and 47,6 percent and 46,7 percent at the 3rd and 5th minutes respectively, being the more aged patients the most affected (p = 0,002). When compared the usage ofreversion with the presence of residual muscular paralysis no difference statistically significant was found(p = 0,516). Conclusion: The incidence of residual muscular paralysis in PACU at our center was high (51 percent) and similar to the one reported in worldwide literature; the most affected were the more aged patients and the use of reversion did not exclude the presence of this entity.

Comparison of recovery times from deep neuromuscular blockade between single bolus and continuous infusion of rocuronium

BACKGROUND: To prevent sudden unexpected movement of patients during surgery, muscle relaxants are used to maintain intense neuromuscular blockade.They are administered by intermittent bolus or continuous infusion.Rocuronium is often used for continuous infusion because it is known to lack cumulative effects. The purpose of this study was to compare recovery times from intense neuromuscular block to reappearance of muscle twitches after 0.1 Hz single twitch stimulation. MATERIALS AND METHODS: Seventy five patients were randomized to one of 3 groups.Patients in group 1 were administered a single bolus of rocuronium; groups 2 and 3 were given continuous infusion of rocuronium for 1 and 2 h, respectively.During anesthesia, neuromuscular blockade was monitored by TOF-watch(R) and regulated so as not to exceed more than 5 (PTC) during the infusion. After infusion, PTC was counted every 5 min until single twitch heights had reappeared and the time till the twitch reappeared was calculated. RESULTS: There was a good correlation between the time it took to observe a PTC and the first response of TOF time in each group.In a parallelism test, there were no significant differences. There were also no significant differences in recovery times from PTC to the reappearance of a single twitch between groups. CONCLUSIONS: There are no significant differences in recovery times-from deep neuromuscular blockade to reappearance of single twitch-regardless of the infusion time.When a PTC occurs during deep neuromuscular blockade, it may predict the remaining time of reappearance of a single twitch response.

Changes in Acetylcholine Receptors and Functional Characterization in Muscle by TOF Stimulation in Rat Experimental Autoimmune Myasthenia Gravis (EAMG) Model / 대한마취과학회지

BACKGROUND: The aim of study is to investigate the initial functional changes of muscle in rats induced to have myasthenia gravis, experimental autoimmune myasthenia gravis (EAMG). The authors investigated the functional changes of muscle evaluated by mechanomyography (MMG) and the expression of acetylcholine receptors (AChRs). METHODS: After the institutional approval, 39 male Lewis rats were randomly allocated into study. 26 animals were immunized to induce EAMG by Torpedo AChR (T-AChR) emulsified with complete Freund's adjuvant (CFA) and phosphate buffer saline (PBS)/bovine serum albumin (BSA) 0.01% at the base of tail, and received booster immunizations twice by T-AChR with incomplete Freund's adjuvant (IFA) and PBS/BSA 0.01% at all different site on the upper back. 13 animals were sham immunized as control group by the same method of EAMG except T-AChR. Clinical EAMG scores were examined. Anti T-AChR and anti rat-AChR (R-AChR) antibodies (Ab) were compared by using (125)I-alpha-bungarotoxin ((125)I-alpha-BuTx) radioimmunoassay. Under the anesthesia, neuromuscular functions were monitored by MMG using single twitch (ST) and TOF. AChRs were quantitated using (125)I-alpha-BuTx. RESULTS: Overall weight gain and final body mass, muscle force (ST), specific muscle force of ST, TOF fade ratio and AChRs were reduced in EAMG score 3 compared to control (P < 0.0001). Anti T-AChR Ab and anti R-AChR Ab were increased in score 3 EAMG (P < 0.0001). CONCLUSIONS: EAMG score 3 rats showed characteristic neuromuscular functions as depressed initial ST and its specific force, initial TOF fade and increased anti AChR Abs. Those above characteristics had significant correlations with the clinical EAMG scores. AChRs were significantly down-regulated according to their functional characteristics and clinical EAMG scores.

Anesthetic Management in a Patient with Charcot-Marie-Tooth Disease: A case report / 대한마취과학회지

A 35-year old woman was scheduled to undergo a total hystectomy due to uterine myoma. She had been diagnosed with Charcot-Marie-Tooth disease 2 years ago. In addition, she had previously received a Cesarean section under epidural anesthesia 10 years ago and reported a prolonged motor blockade at that time. General anesthesia was induced with propofol 120 mg in a divided dose and the intubating condition was achieved with vecuronium 3 mg. Anesthesia was maintained with 1.5-2.5% enflurane with air and O2. During surgery, the body temperature and end tidal concentration of CO2 were maintained within the normal range. Despite the continuous monitoring of the train-of-four (TOF) response, no more muscle relaxants were required during surgery and the patient recovered without a delay in awakening. In the management of patients with Charcot-Marie-Tooth disease, it is desirable to evaluate the patient carefully, select the appropriate anesthetics and adjust the dosage of the drug according to the patients requirements.

Prejunctional Phenomenon during Succinylcholine Onset in Cats / 대한마취과학회지

BACKGROUND: Succinylcholine (Sch) has been generally reported not to produce tetanic stimulation fade on train of four in phase I block, except phase II block. But, the prejunctional phenomenon of Sch during onset is rarely reported these days, and so we investigated whether the prejunctional phenomenon of Sch during onset exists in cats. METHODS: We checked train of four ratios (TOF-R) and tetanic fade ratios (TF-R) by using a nerve stimulator before and after 50microgram/kg of Sch less than ED95 was administered, and during recovery in anesthetized cats. We analyzed TOF-R and TF-R before drug administration as a control and during onset and recovery time in order to estimate the statistic significance of fade. RESULTS: TOF fade and tetanic stimulation during the onset of Sch appeared like those in the partial block of nondepolarizing neuromuscular blockades TOF-R and TF-R during Sch onset compared with those in control and recovery time of Sch had statistical significance (P <0.05). CONCLUSIONS: The prejunctional phenomenon appeared only during Sch onset in cats and then disappeared during recovery to the control level.

Predicting Recovery from Deep Neuromuscular Block by Rocuronium During Sevoflurane versus Propofol Anesthesia / 대한마취과학회지

BACKGROUND: The use of volatile anesthetics for the maintenance of anesthesia can enhance the action and prolong the duration of non-depolarizing muscle relaxants. The objective of this study was to establish the relation between the post tetanic count (PTC) and the time to reappearance of the first response (T1) by train-of-four (TOF) nerve stimulation following rocuronium 0.6 mg/kg (ED95 X 2) during sevoflurane versus propofol anesthesia. METHODS: Fifty adult patients were randomized to one of two groups, which had anesthesia maintained with sevoflurane or propofol. During sevoflurane or propofol anesthesia, neuromuscular block was monitored by mechanography using TOF stimulation every 12 s. At 6 min intervals, a tetanic stimulation (50 Hz) was applied for 5 s, which was preceded and followed by a 15 s period of 1 Hz single stimulation until the reappearance of T1. RESULTS: First responses to PTS appeared earlier in the propofol group (12.5 +/- 5.2 min) than in the sevoflurane group (16.6 +/- 7.4 min), and first responses to TOF stimulation also occurred significantly sooner in the propofol group (24.8 +/- 5.1 min) than in the sevoflurane group (32.6 +/- 8.9 min). The interval between the appearance of PTC and T1 was shorter in the propofol than in the sevoflurane group. CONCLUSIONS: We conclude that sevoflurane prolonged recovery from deep neuromuscular block by rocuronium as compared to propofol. The PTC method can be used to predict the time to first response to TOF nerve stimulation during intense rocuronium induced neuromuscular blockade.

Interaction between Mivacurium and Nitroglycerin / 대한마취과학회지

BACKGROUND: The neuromuscular blocking effects of a nondepolarizing neuromuscular blocker (NDNM) during a nitroglycerin (NTG) infusion were significantly potentiated and prolonged. NTG reduced the requirement of a NDNM in surgical patients. We investigated the influence of a NTG single bolus injection on a mivacurium nuromuscular blockade. METHODS: We studied 36 adult surgical patients, ASA physical status I or II, between 15 and 53 years old. Neuromuscular monitoring was measured by TOF-GUARD (Biometer Co., Denmark). Anesthesia was induced by thiopental sodium 3-5 mg/kg and fentanyl 3 microgram/kg, and maintained with 3 L/min N2O, 2 L/min O2 and 1 vol.% isoflurane. Patients were randomly assigned to 3 groups: 1) Control group (mivacurium 0.16 mg/kg), 2) N100 group (mivacurium 0.16 mg/kg, NTG 100 microgram), 3) N200 group (mivacurium 0.16 mg/kg, NTG 200 microgram). We measured the train-of-four (TOF) response from the beginning of recovery to the complete regaining of muscle twitch. RESULTS: NTG produced a prolongation of the neuromuscular blocking effect by mivacurium. T1 (contro group: 12.1 +/- 0.5, N100 group: 15.8 +/- 0.4 and N200 group: 11.6 +/- 0.4 min), T25 (16.4 +/- 0.4, 20.5 +/- 0.5 and 14.9 +/- 1.0 min), T75 (22.5 +/- 0.9, 29.4 +/- 0.7 and 20.1 +/- 1.0 min), T95 (27.3 +/- 0.6, 39.6 +/- 0.7 and 24.6 +/- 1.5 min) and the recovery index (6.1 +/- 0.6, 9.0 +/- 0.4 and 5.3 +/- 0.7 min) were significantly prolonged in the N100 and N200 groups (P < 0.05). CONCLUSION: These results suggest that a NTG bolus injection prolonged the neuromuscular blocking effect of mivacurium, dose relatively.

The Study of Priming with Vecuronium and Atracurium on Young and Elderly Patients / 대한마취과학회지

BACKGROUND: Succinylcholine is the muscle relaxant of choice for rapid endotracheal intubation, but may produce many side effects such as hyperkalemia, myalgia, increase intraocular pressure. Nondepolarizing muscle relaxants were used instead of succinylcholine, still late onset time was be dangerous. For this reason, priming principle was reported and applied to rapid intubation using nondepolarizing muscle relaxation. We studied the effect of priming with vecuronium and atracurium on elderly and young patients. METHODS: We were randomly assigned 40 patients and observed the effects of priming doses of vecuronium (0.01 mg/kg) and atracurium (0.05 mg/kg). Ten young (20-35 yrs) and ten elderly (65-75 yrs) patients were each placed in vecuronium and atracurium group. Arterial blood gas analysis and train of four (TOF) were determined before priming. All tests were performed again 4 min after vecuronium and 3 min after atracurium. We asked for symptoms and signs of muscle weakness. RESULTS: In arterial blood gas analysis and TOF ratio were decreased in both groups. There is no significant difference between two groups in all tests. PaO2 and TOF ratio were reduced more in elderly patients, significantly (P<0.05). Symptoms and signs of muscle weakness such as ptosis, dizziness, diplopia, swallowing difficulty and respiratory difficulty in elderly patients were more frequent than in young patients. CONCLUSIONS: Priming doses of vecuronium and atracurium produced greater decrease in muscle strength, PaO2 and TOF ratio in the elderly than in their younger counterparts. So using priming method in elderly patients, we need adequate pre-oxygenation and thorough monitoring before endotracheal intubation.

Neuromuscular Blocking Effect of Vecuronium in Electric Burned Patients for Endotracheal Intubation / 대한마취과학회지

BACKGROUND: In inducing anesthesia for burn patients, nondepolarizing muscle relaxant (NDMR) is usually used, because succinylcholine, a widely used muscle relaxant may cause hyperkalemia. It is well known that because burn patients show resistance to NDMR, a high dose of NDMR is needed for them. In this study, we wanted to know whether there is significant difference of the relaxation effect between 0.1 mg/Kg and 0.15 mg/Kg dose's of vecuronium, and between burn and unburn patients. METHODS: Subjects are 40 male patients having 1 or 2 ASA physical status (20 are burn patients and the other 20 are unburn patients). We divided them into 4 groups; 1) Group BI (burn patients, vecuronium 0.1 mg/Kg) 2) Group BII (burn Pts, vecuronium 0.15 mg/Kg) 3) Group UBI (unburn Pts, vecuronium 0.1 mg/Kg) 4) Group UBII (unburn Pts, vecuronium 0.15 mg/Kg). Average onset times (time from injection of vecuronium to zero first twitch height (T1)) were measured and intubating condition were scored on 0 to 4 scale. RESULTS: The onset time of vecuronium and distribution of intubation scores didn't show statistical differences among 4 groups. CONCLUSION: The onset time of vecuronium and intubating condition in burn patients dosen't show a difference from unburn patient.

Effects of Atracurium in the Patients with Myasthenia Gravis Undergoing Thymectomy / 대한마취과학회지

BACKGROUND: Myasthenia gravis is an autoimmune neuromuscular disorder that shows increased sensitivity to nondepolarizing muscle relaxants. Atracurium is eliminated by Hofmann elimination and ester hydrolysis. We studied the onset and duration of atracurium in patients with myasthenia gravis. METHODS: Ten patients undergoing thymectomy for myasthenia gravis and ten patients of ASA Class I-II without liver, kidney and neuromuscular disease for orthopedic surgical procedures were assigned. Anesthesia was induced with thiopental (4~5 mg/kg) and maintained with inhalation of N2O:O2 (1:1) and enflurane (1.0~2.0 vol%). Atracurium (0.5 mg/kg) was given as a muscle relaxant and then intubation was performed after twitch response was depressed more than 80%. Neuromuscular relaxation was assessed by TOF (T1) at the adductor pollicis with supramaximal stimulation of ulnar nerve at 2 Hz every 12 seconds. The onset and the duration of 5, 25, 50, 75% recovery time of T1 and the recovery index were recorded. RESULTS: Onset of block was shortened and recovery time of 5, 25, 50, 75% and recovery index were prolonged in patients with myasthenia gravis. Conlusions: In patients with myasthenia gravis, atracurium induced rapid onset time and prolonged recovery time of 5, 25, 50, 75% and recovery index.