Efeitos neuromusculares e cardiovasculares do pipecurônio: estudo comparativo entre diferentes doses / Efectos neuromusculares y cardiovasculares del pipecuronio: estudio comparativo entre diferentes dosis / Neuromuscular and cardiovascular effects of pipecuronium: a comparative study between different dose

JUSTIFICATIVA E OBJETIVOS: O pipecurônio é um bloqueador neuromuscular não-despolarizante, com propriedades similares as do pancurônio, mas desprovido de efeitos cardiovasculares. Foram avaliados os efeitos neuromusculares, as condições de intubação traqueal e as repercussões hemodinâmicas de duas diferentes doses de pipecurônio. MÉTODO: Pacientes foram distribuídos em dois grupos de acordo com a dose de pipecurônio: Grupo I (0,04 mg.kg-1) e Grupo II (0,05 mg.kg-1). A medicação pré-anestésica consistiu em midazolam (0,1 mg.kg-1) por via muscular, 30 minutos antes da operação. A indução anestésica foi obtida com propofol (2,5 mg.kg-1) precedido de fentanil (5 µg.kg-1) e pipecurônio nas doses de 0,04 e 0,05 mg.kg-1 para os Grupos I e II, respectivamente. Os pacientes foram ventilados com O2 a 100 por cento sob máscara até a redução de 75 por cento da amplitude da resposta a estímulo isolado (1 Hz), quando foram realizadas a laringoscopia e intubação traqueal. O isoflurano (0,5 a 1 por cento) em mistura de O2 e N(2)0 a 50 por cento para a manutenção da anestesia, foi introduzido logo após a intubação traqueal. Os pacientes foram ventilados mecanicamente para manter P ET CO2 entre 32 e 36 mmHg. A farmacodinâmica do pipecurônio foi avaliada por aceleromiografia. RESULTADOS: Os tempos médios e desvios-padrão para o início de ação, duração clínica (T1(25 por cento)) e índice de recuperação (T1(25-75 por cento)) foram: Grupo I (122,10 ± 4,18 s, 49,63 ± 9,54 min e 48,21 ± 6,72 min) e Grupo II (95,78 ± 8,91 s, 64,84 ± 13,13 min e 48,52 ± 4,95 min). O início de ação, a duração clínica e as condições de intubação traqueal foram significativamente diferentes entre os grupos. CONCLUSÕES: O pipecurônio na dose 0,05 mg.kg-1 pode ser usado em procedimentos de longa duração, nos quais é desejável evitar alterações cardiocirculatórias.

BACKGROUND AND OBJECTIVES: Pipecuronium is a non-depolarizing neuromuscular blocker with similar properties to pancuronium, but without cardiovascular effects. Neuromuscular effects, conditions of tracheal intubation, and hemodynamic repercussions of two different doses of pipecuronium were evaluated. METHOD: Patients were divided into two groups according to the dose of pipecuronium: Group I (0.04 mg.kg-1) and Group II (0.05 mg.kg-1). Intramuscular midazolam (0.1 mg.kg-1) was administered 30 minutes before the surgery. Propofol (2.5 mg.kg-1), preceded by fentanyl (5 µg.kg-1) and pipecuronium (0.04 and 0.05 mg.kg-1 for Groups I and II, respectively), was administered for anesthetic induction. Patients were ventilated with 100 percent oxygen via a face mask until a 75 percent reduction in the amplitude of the response to an isolated stimulus (1 Hz) is achieved, at which time laryngoscopy and intubation were carried out. Anesthetic maintenance was achieved with isoflurane (0.5 to 1 percent) with a mixture of 50 percent O2 and N2O. Mechanical ventilation was used to maintain P ET CO2 between 32 and 36 mmHg. The pharmacodynamics of pipecuronium was evaluated by acceleromyography. RESULTS: Mean times and standard deviation for the onset of action, clinical duration (T1(25 percent)), and recovery index (T1(25-75 percent)) were: Group I (122.10 ± 4.18 sec, 49.63 ± 9.54 min, and 48.21 ± 6.72 min), and Group II (95.78 ± 8.91 sec, 64.84 ± 13.13 min, and 48.52 ± 4.95 min). Onset of action, clinical duration, and conditions of tracheal intubation were significantly different for both groups. CONCLUSIONS: Pipecuronium at a dose of 0.05 mg.kg-1 can be used in prolonged procedures in which cardiovascular changes should be avoided.

JUSTIFICATIVA Y OBJETIVOS: El pipecuronio es un bloqueador neuromuscular no despolarizador, con propiedades similares a las del pancuronio, pero desprovisto de efectos cardiovasculares. Se evaluaron los efectos neuromusculares, condiciones de intubación traqueal y las repercusiones hemodinámicas de de los diferentes dosis de pipecuronio. MÉTODO: Los pacientes fueron distribuidos en de los grupos de acuerdo a la dosis de pipecuronio: Grupo I (0,04 mg.kg-1) y Grupo II (0,05 mg.kg-1). La medicación preanestésica consistió en midazolam (0,1 mg.kg-1) por vía muscular, 30 minutos antes de la operación. La inducción anestésica se obtuvo con propofol (2,5 mg.kg-1) precedido del fentanil (5 µg.kg-1) y del pipecuronio en las dosis de 0,04 y 0,05 mg.kg-1 para los Grupos I y II, respectivamente. Los pacientes se ventilaron con O2 a 100 por ciento bajo máscara hasta la reducción de un 75 por ciento de la amplitud de la respuesta al estímulo aislado (1 Hz), cuando fueron realizadas la laringoscopía y la intubación traqueal. El isoflurano (0,5 a 1 por ciento) en mezcla de O2 y N(2)0 a un 50 por ciento para el mantenimiento de la anestesia, fue introducido a continuación de la intubación traqueal. Los pacientes fueron ventilados mecánicamente para mantener el P ET CO2 entre 32 y 36 mmHg. La farmacodinámica del pipecuronio se evaluó por aceleromiografía. RESULTADOS: Los tiempos promedios y desviaciones estándar para el inicio de acción, duración clínica (T1(25 por ciento)) e índice de recuperación (T1(25-75 por ciento)) fueron los siguientes: Grupo I (122,10 ± 4,18 seg, 49,63 ± 9,54 min y 48,21 ± 6,72 min) y Grupo II (95,78 ± 8,91 seg, 64,84 ± 13,13 min y 48,52 ± 4,95 min). El inicio de acción, la duración clínica y las condiciones de intubación traqueal fueron significativamente diferentes entre los grupos. CONCLUSIONES: El pipecuronio, en la dosis 0,05 mg.kg-1 puede ser usado en procedimientos de larga duración donde se desee evitar alteraciones ca...

Efeito do priming na redução da latência do pipecurônio, novo bloqueador neuromuscular não-despolarizante / Effect of priming in shortening onset of pipecuronium, a new nondepolarizing neuromuscular blocker

JUSTIFICATIVA E OBJETIVOS: Uma das mais importantes propriedades dos bloqueadores neuromusculares é o rápido início de ação, possibilitando intubação traqueal precoce. A administração de pequena dose de bloqueador não-despolarizante antes da dose plena é sabidamente redutora da latência da maioria dos bloqueadores neuromusculares utilizados. O brometo de pipecurônio é um agente aminoesteróide de longa duração com grande estabilidade cardiovascular, porém, com início de ação tardio. O objetivo desse estudo foi avaliar o efeito do priming do pipecurônio em pacientes adultos submetidos a cirurgias eletivas sob anestesia geral. MÉTODO: Foram estudados 33 pacientes adultos de ambos os sexos, com idade entre 20 e 65 anos, estado físico ASA I ou II, submetidos a cirurgias eletivas sob anestesia geral. Foram excluídos do estudo pacientes com insuficiência renal ou hepática, neuromiopatia, uso concomitante de drogas que influenciem a sua farmacocinética ou pacientes com histórico familiar de hipertermia maligna. Foram divididos em dois grupos: Grupo 1 onde foi utilizado o priming com 0,01 mg.kg-1 e três minutos depois completada a dose de 0,08 mg.kg-1 e o Grupo 2, sem dose priming (Grupo Controle). O relaxamento neuromuscular foi controlado pela aceleromiografia (Aparelho TOF-Guard) e no momento em que T1 < 10 por cento era realizada a laringoscopia. A análise estatística foi feita pelos testes T para amostras independentes e a normalidade pelo Shapiro Wilks. RESULTADOS: Os grupos foram homogêneos e observou-se que o tempo para T1 < 10 por cento no Grupo 1 foi de 161,4 ± 13,7 segundos e no Grupo 2 foi 217,8 ± 23,4 segundos, com p < 0,001, havendo diferença estatística significativa entre os grupos. CONCLUSÕES: Os resultados do estudo mostraram diferença estatística significativa entre os grupos com e sem priming, indicando que o pipecurônio também tem latência reduzida, assim como os demais bloqueadores neuromusculares conhecidos.

Effects of cisatracurim on cardiovascular system and histamine release in comparison to atracurium and pipecuronium

The aim of this work was to evaluate the hemodynamic change profile and assessment of histamine release associated with cisatracurium administration in both young adults and elderly patients, both experimentally and clinically, in comparison with the parent drug, atracurium, and with a cardiovascular stable relaxant, pipecuronium. The clinical study was done on 120 patients who were assigned into two groups according to their age. Each group was further subdivided into three subgroups [n=20] who randomly received only one of the three neuromuscular blockers; pipecuronium, atracurium and cisatracurium. The hemodynamic changes over time were measured and manifestations of histamine release were assessed. The experimental study was done to study the effect of gradually increasing doses of pipecuronium, atracurium, and cisatracurium on isolated rabbit heart and the possible histamine release. In the clinical study, there were either clinically or statistically significant cardiovascular changes in the mean heart rate or in the mean values of systolic, diastolic and mean blood pressure following cisatracurium or pipecuronium in both age groups. In contrast, atracurium showed an elevation in the mean HR in one age group [young adults] and a reduction in the mean values of systolic, diastolic and mean blood pressure in the elderly group in comparison to the other groups. Histamine release signs shown with the atracurium-receiving patients were comparable and statistically significant from those of the nearly absent signs in the cisatracurium-receiving patients. In patients receiving pipecuronium, these signs were completely absent. In the experimental study, cisatracurium in a dose 32xED50 resulted in apparent increase in the correction of the ventricles. Atracurium in a lesser dose [16xED50] produced a similar effect. These responses were abolished completely after the injection of H-2 antagonist up to 64xED50 of pipecuronium failed to produce any change in ventricular contraction. In conclusion, cisatracurium in the clinically used doses appears to have much less or may be devoid of histamine release than atracurium and so it has a cardiovascular stability as pipe curonium

Unanticipated Difficult Intubation in a Patient with an Asymptomatic Epiglottic Cyst / 대한마취과학회지

Although an epiglottic cyst is often asymptomatic and harmless to the patient, discovery of a large epiglottic cyst after induction of anesthesia is a potentially life-threatening problem for the patient and provides a challenge for the anesthesiologist in airway management. We experienced a case of unanticipated difficult mask ventilation and intubation as a result of an asymptomatic epiglottic cyst. A 37-year-old woman presented for elective removal of a brain tumor. She had normal mouth opening and neck extension; no masses or distortions of the tongue or neck were observed. She was premedicated with 0.2 mg glycopyrrolate intramuscularly. Anesthesia and paralysis were induced with 250 mg thiopental, fentanyl 100ng and pipecuronium 6 mg. It was noted that ventilation of the lungs via mask was difficult. Despite insertion of an oropharyngeal airway, ventilation proved to be more difficult. Intubation was attempted. Direct laryngoscopy revealed a 2 cm cyst arising from the epiglottis. The cyst completely obscured the view of the epiglottis and larynx, preventing intubation despite multiple attempts by three anesthesiologists. We consulted an otolaryngologist and awakened the patient. During further questioning in the post anesthesia care unit she admitted to a several-years of dysphagia. Next day, she was admitted to the operation room for removal of an epiglottic cyst. She was intubated using fiberoptic bronchoscope guided awake intubation, and the remainder of anesthetia and the operation proceeded uneventfully. The pathology report confirmed the finding of a 2.5 X 1.5 X 1.5 cm epidermal cyst.

Effect of pipecuronium and pancuronium on intracranial pressure and cardiovascular parameters in patients with supratentorial tumours.

A prospective, randomised, single blind study was conducted to evaluate and compare the intracranial pressure (ICP) and cardiovascular effects of pipecuronium (PPC) and pancuronium (PNC) in 20 patients undergoing supratentorial surgery. Patients were randomly divided into two groups. Patients in Group I (n = 10) received pancuronium (0.1 mg kg(-1)) and in Group II (n = 10) pipecuronium (0.07 mg kg(-1)) for intubation. Intracranial pressure (ICP), heart rate (HR), systolic, diastolic and mean arterial pressures (SAP, DAP, MAP), central venous pressure (CVP), nasopharyngeal temperature and arterial blood gases (ABG) were monitored at the following time periods: before induction (0 minutes); 3 minutes after thiopentone and muscle relaxant; immediately after intubation; and 4, 6, 8, 10, 20 and 30 minutes following intubation. The rise in intracranial pressure at intubation was significantly greater in group I (21.10+/-3.97 torr, 122.59%) when compared to group II patients (1.80+/-0.70 torr, 10.04%) (p<0.0 1). Cardiovascular parameters also showed a significantly greater degree of rise in group I when compared to group II patients. Heart rate increased by 29+/-6.32 beats min(-1) (33.52%) and systolic arterial pressure by 11.60+/-7.37 torr (9.47%) in group I. These parameters did not change significantly in group II. No significant alterations were observed in the other measured parameters in either of the two groups.

Neuromuscular blockade profile of pipec - uronium in patients with liver cirrhosis

This study aimed to evaluate the neuromuscular blockade profile of pipecuronium in 20 patients suffering from hepatic cirrhosis and divided equally into two groups [a control healthy group and hepatic group submitted to operations to relieve portal hypertension]. All patients were subjected to general anesthesia induced by thiopentone sodium 5 mg/kg, followed by pipecuronium 0.06 mg/kg to facilitate endotracheal intubation and maintained by N2O: O2 [2: 1] and halothane 0.5-1.0% with 0.01 mg/kg of pipecuronium as maintenance relaxation doses. Endotracheal intubation was successfully performed when TI ratio reached 10% and TOF ratio approximately reached 0% as traced by Datex relaxograph. The onset of action of pipecuronium, duration of clinical relaxation of bolus dose and total dose requirements were measured

ST-Segment Displacement during Isoflurane and Enflurane Anesthesia / 대한마취과학회지

BACKGROUND: Isoflurane and enflurane have different activity on the cytoplasmic calcium movements of a cardiac muscle cell and a vascular smooth muscle cell. Isoflurane is less depressive in cardiac contraction, and more potent in vasodilation than enflurane. This study is to elucidate the effects of these anesthetics on the ST-segment displacement. METHODS: The anesthesia was induced by the intravenous injection of thiopental (6 mg.kg 1) and pipecuronium (0.1 mg.kg 1). The patients (n=80) undergoing tympanoplasty were randomly allocated to two groups for the maintenance METHODS: Group I was inhaled with isoflurane (1~2%), O2 (2 L.min 1), and N2O (2 L.min 1), Group II, enflurane (1.5~2.5%), O2 and N2O. Continuous electrocardiographic recordings with Holter monitor were made during anesthesia. The recordings were scanned on an Avionics Electrocardioscanner with particular emphasis on ST-segment changes. The criteria describe an episode as ST-segment displacement greater than or equal to 0.1 mV measured 80 ms from J-point lasting for more than 1 minutes. Mean heart rate was calculated. Results were categorized as induction, maintenance, and emergence, and inferred from unpaired t-test, x2-test, and Mann-Whitney U test with p<0.05 considered significant. RESULTS: Enflurane had higher incidence of ST-segment depression during induction, more maximally depressed ST-segment during maintenance and slower heart rate during induction and maintenance than isoflurane. CONCLUSION: It could be suggested that enflurane make stronger influence on the ST-segment depression than isoflurane. However, the clinical significance remains to be studied.

Uso de bloqueantes neuromusculares y su monitoreo en pediatría / Use of neuromuscular blocking agents and its monitoring in pediatrics

El actual arsenal farmacológico, en cuanto a relajantes musculares ha hecho necesario la constante actualización y desarrollo de técnicas para las indicaciones adecuadas y el correcto control de los mismos. El aumento de la utilización de estos fármacos en pediatría, sobre todo los relajantes musculares no despolarizantes ha facilitado la tarea médica del anestesiólogo, obligándolo a una constante actualización en el conocimiento sobre el desarrollo de estos fármacos y el monitoreo clínico e instrumental sobre el paciente.

Reversal Effects of Neostigmine, Edrophonium and 4-aminopyridine of Verapamil Pretreatment on Pipecuronium Induced Neuromuscular Blockade in Rat-Hemidiaphragm / 대한마취과학회지

BACKGROUND: It has been shown that L-type calcium channel blockers increase the muscle relaxation effects of non-depolarizing neuromuscular blocking agents whereas the potentiated neuromuscular blocking effects by L-type calcium channel blocker are resistant to reversal by neostigmine. The aims of this study were 1) to see whether the pretreatment of L-type calcium channel blocker, such as verapamil, aggravates the pipecuronium-induced muscle relaxation, 2) if so, to see whether these effects are reversed by anticholinesterase, such as neostigmine and edrophonium or potassium channel blocker, such as 4-aminopyridine. METHODS: The rat-phrenic nerve-hemidiaphragms (n=60) were prepared. Twenty microgram of pipecuronium was administered to all organ bath. All samples were divided into two groups according to the administration of 10uM of verapamil i.e. verapamil pretreated, non-pretreated group. The amounts of administered pipecuronium were gradually increased by 4ug until the force of twitch decreased to 10% of control value in both groups. Each group was subdivided into three groups according to the administration of 0.75 M of neostigmine, 12.4 uM of edrophonium or 40uM of 4-aminopyridine. RESULTS: The dose of pipecuronium required for the decrease of contractile force to 10% of control value was less in verapamil pretreated group than in non-pretreated group. And, the decrease of contractile force in both groups was more effectively reversed by 4-aminopyridine than neostigmine and edrophonium. CONCLUSIONS: Verapamil potentiates the pipecuronium-induced neuromuscular blockade and 4-aminopyridine is more effective to reverse verapamil pretreated, pipecuronium induced neuromuscular blockade.

The Neuromuscular Blocking Effect of Mivacurium in Isolated Rat Phrenic-Hemidiaphragm with Long-term Phenytoin Pretreatment / 대한마취과학회지

BACKGROUND: Long-term phenytoin therapy induces resistance to the neuromuscular blocking effects of metocurine, atracurium, doxacurium, and pipecuronium. This study examine neuromuscu-lar blocking effect and recovery of mivacurium in isolated rat phrenic-hemidiaphragm with two-weeks phenytoin pretreatment. METHOD: After the administration of 14 days of phenytoin 40 mg/kg, administered intraperitoneally twice daily (n=10), ED90, antagonism of neostigmine and 4-aminopyridine on the electrically evoked twitch response and train-of-four (TOF) stimulation were compared to control groups in isolated rat phrenic-hemidiaphragm preparation. RESULTS: ED90 was significantly greater in the phenytoin group than in the control group (319 +/- 39.5 g vs. 209.5 +/- 52.2 g, respectively). After the administration of neostigmine 0.75 M, the recovery of the single twitch and TOF ratio were significantly lesser in the phenytoin group than in the control group (single twitch; 19.6 +/- 6.6% vs. 69.2 +/- 9.4%, TOF ratio; 0.258 +/- 0.149 vs. 0.543 +/- 0.1, respectively). After the administration of 4-aminopyridine 40uM, the recovery of the single twitch and TOF ratio were no significant differrence between the phenytoin group and the control group (twitch; 118.1 +/- 25.3% vs. 122.6 +/- 24.8%, TOF ratio; 0.937 +/- 0.051 vs. 0.949 +/- 0.067, respectively). CONCLUSION: Long-term phenytoin therapy induces resistance to the neuromuscular blocking effects of mivacurium.

Cardiovascular Effects of Pancuronium, Vecuronium and Pipecuronium during High-Dose Fentanyl Anesthesia in Neonates, Infants and Children / 대한마취과학회지

BACKGROUND: High dose fentanyl for cardiac surgery in neonates, infants and children can cause severe bradycardia and chest wall rigidity that result in decreased cardiac output and oxygen desaturation due to fixed stroke volume in pediatric patients. To ameliorate the effects of fentanyl, it is common to administer neuromuscular blocking drugs with wanted cardiovascular side effects. This study was designed to compare the cardiovascular variables and oxygen saturation among different muscular relaxants in high dose fentanyl anesthesia. METHODS: Thirty pediatric cardiac patients were allocated randomly into three muscle relaxant groups treated with 0.2 mg/kg pancuronium (n=10), 0.2 mg/kg vecuronium (n=10) or 0.2 mg/kg pipecuronium (n=10) after receiving an initial bolus dose of 25 g/kg of fentanyl. Changes of heart rate (HR), mean arterial blood pressure (MAP), rate-pressure-product (RPP) and oxygen saturation (SpO2) were observed. The same cardiovascular variables were also observed 1 and 2 minutes after the second bolus dose of 25 g/kg fentanyl and compared to the results among muscle relaxants. RESULTS: HR, MAP and RPP decreased significantly (p<0.05) 1 and 2 minutes after injection of the 1st fentanyl, which returned to levels above the control value after administration of pancuronium, vecuronium or pipecuronium. Among muscle relaxants, pancuronium caused the most rapid and significantly high level compared to the control value in HR and MAP. Next was pipecuronium and then vecuronium. In clinical setting, SpO2 was decreased after the 1st fentanyl injection and increased after the injection of muscle relaxants, but not significant statistically. CONCLUSION: In view of hemodynamic changes, pancuronium is most efficient and rapid in returning the hemodynamic variables that was decreased after high dose fentanyl anesthesia in neonates, infants and children whose cardiac output was dependent on HR due to relatively fixed stroke volume.

Optimum Dose of Pipecuronium with a Intravenous Bolus Injection for Endotracheal Intubation in Adults / 대한마취과학회지

BACKGROUND: Studies in animals suggest that pipecuronium dose not induce hemodynamic chan-ges related to histamine release or to an effect on the autonomic nervous system. Therefore the effects of bolus administration of large doses of pipecuronium, up to 0.20 mg/kg, on the intubation condition, onset and duration of neuromuscular blockade, heart rate and blood pressure were studied during fentanyl- nitrous oxide anesthesia. METHOD: Forty adults were randomly assigned to receive a bolus injection of either 0.05, 0.10, 0.15, 0.20 mg/kg of pipecuronium. Neuromuscular blockade was measured using mechanomyographic activity of the adductor pollicis muscle after supramaximal stimulation of the ulnar nerve. Four subgroups of 10 patients received pipecuronium doses of 0.05, 0.10, 0.15 and 0.20 mg/kg, respectively, as an intubating dose. RESULTS: The times of onset and clinical duration (mean sem) after each dose were as follows: 0.05 mg/kg, 2.98 0.42 and 41.5 2.42 min; 0.10 mg/kg, 1.54 0.06 and 82.9 7.48 min; 0.15 mg/kg, 1.41 0.14 and 124.8 13.1 min; 0.20 mg/kg, 1.12 0.05 and 187.1 12.8 min. The intubation condition, time of onset and duration after doses of 0.05 mg/kg were significantly different from values after the higer doses. The duration was increased with dose-increments. No dose-related changes in heart rate or blood pressure were observed. CONCLUSION: The authors conclude that dose of 0.10 mg/kg and over has good intubation condition clinically and large bolus dose of pipecuronium can be safely used with a significantly prolonged duration of action without hemodynamic change.

Comparison of cardiovascular and neuromuscular properties of pancuronium, doxacurium and pipecuronium during induction of anesthesia for open heart surgery

This study compared hemodynamic and neuromuscular properties of pancuronium, doxacurium and pipecuronium during induction of anesthesia in 45 patients undergoing open valvular heart surgery. Anesthesia was induced with fentanyl 10 mg.kg-1 and thiopentone 23 mg.kg-1. Each patient received twice the ED95 of either pancuronium [0.15 mg.kg-1, n=15] or doxacurium [0.05 mg.kg-1, n=15] or pipecuronium [0.1 mg.kg-1 n=15]. Hemodynamic measurements were recorded before induction of anesthesia, before intubation, immediately after intubation and five minutes post-intubation. Pancuronium significantly increased heart rate and mean arterial blood pressure, but this decrease was not statistically significant and heart rate was nearly stable. On the other hand, there was minimal change in heart rate and mean arterial blood pressure with pipecuronium. Other hemodynamic parameters did not change. The time from muscle relaxant administration to 95% suppression of the first twitch of train of 4 stimuli was significantly longer for doxacurium than that for pancuronium and pipecuronium. Therefore, pipecuronium seems to be more satisfactory neuromuscular blocker than either pancuronium or doxacurium for induction of anesthesia for open heart surgery

Neuromuscular Blocking and Cardiovascular Effects of Pipecuronium Comparing with Pancuronium and Vecuronium / 대한마취과학회지

BACKGROUND: Pipecuronium bromide is a long-acting steroidal neuromuscular blocking drug. This study was designed to evaluate the neuromuscular-blocking action and the cardiovascular effects of pipecuronium in patients under O2-N2 O-enflurane anesthesia, by comparing with those of pancuronium and vecuronium. METHODS: Fifty-one adult patients (ASA class 1 or 2) were randomly received pipecuronium 0.1 mg/kg (n=17), pancuronium 0.12 mg/kg (n=17), or vecuronium 0.1 mg/kg (n=l7) as a single intravenous bolus dose. Anesthesia was induced with thiopental 5 mg/kg, followed by one of the muscle relaxants. Patients were then given O2 (2 L/min) - N2O(2 L/min)-enflurane(1.8 vol%) by face mask. Trachea was intubated, and anesthesia was maintained with O2 (2 L/min)- N2O(2 L/min)-enflurane(1-2.5 vol%) during whole study period. Neuromuscular blocking effect was assessed by response of the adductor pollicis muscle in 2Hz train-of-four(TOF) stimulation of ulnar nerve every 20 seconds. The times from administration of initial dose to loss and reappearance of four twitches to TOF were measured. Systolic and diastolic blood pressure(SAP,DAP) and heart rate(HR) were noninvasively measured. RESULTS: The onset times of pipecuronium, pancuronium, and vecuronium were 278+/-99, 268+/-67, and 208+/-56 seconds, respectively. The duration of action of pipecuronium, pancuronium, and vecuronium were 148+/-99, 145+/-35, and 52+/-12 minutes, respectively. SAP and DAP with pancuronium were significantly greater than those with pipecuronium or vecuronium I minute after the administration. No significant difference in SAP and DAP was found until 5 minutes after the administration among the agents. HR was increased significantly until 20 minutes after the administration of pancuronium. CONCLUSION: Pipecuronium is a long-acting drug suitable for longer operations in which cardiovascular stability is required.

The Effects of Magnesium on Pipecuronium-induced Neuromuscular Blockade and its Reversal in the Isolated Rat Phrenic Nerve-Hemidiaphragm / 대한마취과학회지

BACKGROUND: Magnesium sulfate (MgSO4) is widely utilized in the treatment of preeclamptic hyperreflexia. It is well known that magnesium enhances nondepolarizing neuromuscular blockade. Eclamptic convulsions are almost always prevented by magnesium in plasma concentrations of 4 to 7 mEq/L. METHODS: The effects of various concentration of magnesium on the potency and reversibility of pipecuronium were investigated in vitro rat phrenic nerve-hemidiaphragm. The phrenic nerve-hemidiaphragm was dissected and suspended in organ bath containing modified Krebs' solution. Forty samples were divided into 4 groups (n=10 in each group). Group I was studied at the physiologic magnesium concentration(2.4 mEq/L, control group). Group II, III, IV were studied at the concentration of 4, 5.5, and 7 mEq/L, respectively. In each group, we added pipecuronium until twitch height decreased more than 90% of initial level. To compare the recovery, we added neostigmine and calcium, and then, measured TOF ratio. RESULTS: The amounts of added pipecuronium were 73.8+/-15.2 microgram (mean+/-S.D.) in Group I, 38.1+/-5.0 microgram in Group II, 33.0+/-4.1 microgram in Group III and 16.1+/-1.7 microgram in Group IV. The amounts of pipecuronium in Group II, III, IV were significantly less than Group I. After the addition of neostigmine, the values of TOF ratio were under 0.6 in all groups. But after the addition of calcium, all groups were recovered with TOF ratio over 0.85 except Group I. CONCLUSIONS: This study indicated that the increased magnesium concentration potentiated pipecuronium-induced neuromuscular blockade and at higher level, it was more apparent. Neostigmine was not significantly effective to reverse the pipecuronium-induced neuromuscular blockade potentiated with magnesium. But calcium was significantly effective.