Reversal of Deep Pipecuronium-Induced Neuromuscular Block With Moderate Versus Standard Dose of Sugammadex: A Randomized, Double-Blind, Noninferiority Trial.

BACKGROUND: Certain surgical interventions may require a deep neuromuscular block (NMB). Reversal of such a block before tracheal extubation is challenging. Because anticholinesterases are ineffective in deep block, sugammadex 4 mg/kg has been recommended for the reversal of rocuronium- or vecuronium-induced deep NMB. However, this recommendation requires opening 2 vials of 200 mg sugammadex, which results in an increase in drug costs. Therefore, we sought a less expensive solution for the induction and reversal of deep NMB. Although the optimal dose of sugammadex for antagonism of deep block from pipecuronium has not been established, data pertaining to moderate block are available. Accordingly, we hypothesized that sugammadex 2 mg/kg would be a proper dose to reverse deep pipecuronium block, enabling us to avoid cost increases. In the present study, we compared sugammadex 2 mg/kg with the standard dose of 4 mg/kg for reversal of deep block from pipecuronium. METHODS: This single-center, randomized, double-blind, 2 parallel-arms, noninferiority study comprised 50 patients undergoing general anesthesia with propofol, sevoflurane, fentanyl, and pipecuronium. Neuromuscular monitoring was performed with acceleromyography (TOF-Watch SX). Noninferiority margin was specified beforehand as an increase in reversal time of no >10% (corresponding to 1 minute for the primary outcome). When the block spontaneously recovered to posttetanic count 1, the patients randomly received sugammadex 2 or 4 mg/kg, and the time from the injection to the train-of-four (TOF) ratio of 1.0 was measured. Primary outcome was the time to achieve the normalized TOF ratio of 0.9 in a particular patient. Residual or recurrent postoperative NMB was additional end point. RESULTS: Each patient recovered to the normalized TOF ratio of 0.9. In the 2 mg/kg group, reversal time was 1.73 ± 1.03 minutes (95% confidence interval [CI], 1.33-2.13; n = 25), and in the 4 mg/kg group, reversal time was 1.42 ± 0.63 minutes (mean ± standard deviation) (95% CI, 1.17-1.67; n = 25). The mean difference in reversal times between the 2 groups was 0.31 minutes (95% CI, -0.18 to 0.8), and the upper limit of CI was below the noninferiority margin of 1 minute. Postoperative block did not occur. CONCLUSIONS: The effect of sugammadex 2 mg/kg was noninferior to that of 4 mg/kg in reversing posttetanic count-1 degree pipecuronium block. Sugammadex reversal of deep pipecuronium block appears to be effective.

Low-dose ketamine combined with pentobarbital in a miniature porcine model for a cardiopulmonary bypass procedure: a randomized controlled study.

BACKGROUND AND OBJECTIVE: Porcine anaesthesia remains a great problem for cardiac surgery research and especially with cardiopulmonary bypass procedures. This study was designed to develop a suitable anaesthesia model in which miniature pigs could be induced smoothly and be maintained stably during and after a cardiopulmonary bypass procedure. METHODS: Thirty-one miniature pigs were randomly divided into two groups and induced using ketamine and pentobarbital (K-P group, n = 15) or pentobarbital (P group, n = 16) alone, respectively. Animals in group K-P were induced with intramuscular injections of ketamine 5 mg kg and pentobarbital 20 mg kg body weight, and those in group P were induced with pentobarbital 30 mg kg alone. After intubation and intravenous catheterization, group K-P was maintained by continuous infusion of ketamine and pentobarbital, and pentobarbital was withdrawn after cardiopulmonary bypass started. Group P received a continuous infusion of pentobarbital throughout the operation. In addition, both groups were injected hourly with midazolam and pipecuronium bolus to achieve optimal surgical conditions. RESULTS: All of the group K-P animals survived for 24 h postoperatively. Five of the group P animals died from anaesthesia-related respiratory and cardiac arrest: three after induction and two after extubation. The animals in group K-P had more stable haemodynamics and arterial blood gas indices than animals in group P. Furthermore, the percentage of animals achieving satisfactory anaesthetic effects was significantly higher in group K-P than in group P. CONCLUSION: Combination anaesthesia with low-dose ketamine and pentobarbital demonstrated superior haemodynamic and respiratory indices in comparison with pentobarbital. The combination regimen can achieve both hypnosis and analgesia effects with stable circulatory parameters.

Neuromuscular and cardiovascular effects of pipecuronium. A comparative study between different doses.

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 x kg(-1)) and Group II (0.05 mg x kg(-1)). Intramuscular midazolam (0.1 mg x kg(-1)) was administered 30 minutes before the surgery. Propofol (2.5 mg x kg(-1)), preceded by fentanyl (5 microg x kg(-1)) and pipecuronium (0.04 and 0.05 mg x kg(-1) for Groups I and II, respectively), was administered for anesthetic induction. Patients were ventilated with 100% oxygen via a face mask until a 75% 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%) with a mixture of 50% 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%)), and recovery index (T1(25-75%)) 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 x kg(-1) can be used in prolonged procedures in which cardiovascular changes should be avoided.

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...

Single transpulmonary thermodilution in off-pump coronary artery bypass grafting: haemodynamic changes and effects of different anaesthetic techniques.

BACKGROUND: Off-pump coronary artery bypass grafting (OPCAB) can be associated with severe cardiovascular changes, thus requiring advanced haemodynamic monitoring. Our aim was to investigate the feasibility of transpulmonary single thermodilution (STD) combined with pulse-contour analysis, a newly introduced method for cardiovascular monitoring, for assessment of changes in haemodynamics during different anaesthetic techniques in OPCAB. METHODS: Thirty-six patients scheduled for elective OPCAB were randomized to receive anaesthesia either with midazolam, propofol or isoflurane, in addition to fentanyl and pipecuronium. After catheterization of the femoral artery, haemodynamic parameters were assessed using STD and pulse-contour analysis. The measurements were performed after induction of anaesthesia, during surgery and at 2, 4 and 6 h post-operatively. RESULTS: At the end of surgery, the global ejection fraction decreased by 29% and 19% in the midazolam and the propofol groups, respectively, (P < 0.05) but remained unchanged in the isoflurane group. Moreover, in the isoflurane group, the left ventricular contractility index was higher and the mean arterial pressure (MAP) and the systemic vascular resistance index (SVRI) decreased in comparison with pre-operative values. Post-operatively, the cardiac index (CI) and the cardiac function index (CFI) increased in all groups (P < 0.05). The peri-operative requirement for ephedrine and nitroglycerin increased in the propofol and the midazolam groups, respectively (P < 0.05). CONCLUSION: During OPCAB, STD and pulse-contour analysis displayed changes in preload, myocardial function and afterload that gave valuable guidance for the conduct of anaesthesia, fluid management, and the administration of vasoactive agents. As assessed using STD, isoflurane within the present dose range appears to maintain myocardial performance and vascular tone better than midazolam or propofol.

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.

[New russian myorelaxant vero-pipecuronium (pipecuronium bromide) used for the anesthetic management of operations on the thorax and abdomen organs]. / Novyi otechestvennyi miorelaksant vero-pipekuronii (pipekuronii bromid) v anesteziologicheskom obespechenii operatsii na organakh grudnoi i briushnoi polosti.

The experience of clinical use of the new Russian myorelaxant of the non-depolarizing action vero-pipecuronium (pipecuronium bromided) manufactured by "Veropharm" is described. Vero-pipecuronium was found to ensure splendid and good conditions for the intubation of the trachea and to maintain reliably myorelaxation. The recommended doses and availability of an antidote (prozerine) provide for a sufficiently controllable myorelaxation. Vero-pipecuronium does not virtually exert any effect on the parameters of hemodynamics and can be successfully used in patients with a high anesthetic risk including heart surgeries. Thus, Russian vero-pipecuronium has now an effective and safe myorelaxant manufactured inside the country, whose parameters are not inferior to those of pipecuronium bromide (arduan) manufactured by "Gedeon Richter", Hungary. Since the described drug is made in Russia, one can hope it will be highly effective both economically and pharmacologically.

[Correction of cardiorespiratory disorders in laparoscopic cholecystectomy]. / Korrektsiia kardiorespiratornykh narushenii pri laparoskopicheskoi kholetsistéktomii.

Carboxyperitoneum and traditional forced ventilation of the lungs have a negative impact on external respiration function during laparoscopic operations, leading to impairment of the ventilation device, pressure rise in airways, and decrease in oxygen diffusion and carbon dioxide release. This leads to accumulation of carbon dioxide in the blood and tissue with a trend to development of acidosis of mixed origin. Cardiovascular changes during laparoscopic cholecystectomy manifest by hypertension and tachicardia in the presence of increased central venous pressure and total peripheral vascular resistance, decreased stroke and cardiac indexes, decreased right-ventricular diastolic function, increased pressure in the pulmonary artery, and deceleration of venous bloodflow in the inferior and superior venae cavae. The most rational variant of forced ventilation of the lungs in laparoscopic cholecystectomy is high-frequency injection ventilation, which appreciably attenuates the negative effect of carboxyperitoneum on central hemodynamics, gas exchange, and external respiration function. The optimal variant of total anesthesia in laparoscopic cholecystectmy is endotracheal combined narcosis with diprivane and fentanide. The key factor in the choice of forced ventilation protocols is the maintenance of adequate gas exchange in the lungs in the presence of the lowest possible mean pressure in the airways.

[The characteristics of the action of nondepolarizing myorelaxants during operations on children with thermal injuries]. / Osobennosti deistviia nedepoliarizuiushchikh miorelaksantov vo vremia operatsii u detei s termicheskoi travmoi.

Effects of nondepolarizing myorelaxants pancuronium, arduan, and tracrium were studied during surgery in 347 children with thermal injuries aged from several months to 15 years. Nondepolarizing myorelaxants are drugs of choice for providing myoplegia in children operated on for thermal injuries. The optimal initial dose of these agents in children with burns is 30-50% higher than the recommended dose and depends on the size of the lesion. For controllable myoplegia, the doses of subsequent injections are to be 1.-5-2 times lowered in comparison with the initial dose. The effects of pancuronium and arduan depend on the hepatorenal function. Tracrium ensures sufficient controllable myorelaxation in children with burns even in cases with hepatorenal dysfunction.

Pipecuronium revisited: dose-response and maintenance requirement in infants, children, and adults.

STUDY OBJECTIVE: To compare dose-response relationship and maintenance requirement of pipecuronium in anesthetized infants, children, and adults. DESIGN: Prospective, consecutive sample trial. SETTING: Operating room at a university hospital. PATIENTS: 15 infants (1-11 months), 15 children (3-10 years), and 15 adults (35-50 years) of ASA physical status I and II. INTERVENTIONS: Anesthesia was induced and maintained with N2O:O2 2:1 and 1 minimum alveolar concentration end-tidal halothane. The neuromuscular function was recorded by adductor pollicis electromyogram evoked by a train-of-four ulnar nerve stimulation at 20 second intervals. An individual cumulative log-probit dose-response curve was established and maintenance requirement of pipecuronium determined. Between-group comparisons were made by analysis of variance and Scheffe F-test. MEASUREMENTS AND MAIN RESULTS: Dose-response curves were parallel with a dose-requirement of pipecuronium similar in infants and adults (ED95 of 40-42 micrograms/kg) and greater in children (ED95 of 52 micrograms/kg). After 30 minutes of surgical neuromuscular block, pipecuronium was required in each age group at a rate of 0.6 to 0.7 individual ED95 doses per hour to maintain an 85% to 95% neuromuscular block. CONCLUSIONS: Bolus dose requirement of pipecuronium is greatest in children. Maintenance requirement is related to potency in each age group studied.

[Features of anesthesia in surgical removal of insulinoma]. / Osobennosti provedeniia narkoza pri operativnom udalenii insulinomy.

Presence of endocrine disorders, malfunction of liver and kidneys requests special approach application concerning general anaesthetic use in patients with the hormone producing insulinomas. There were 44 patients examined, in whom tumor was removed. Sodium hydroxybutyrate application while introducing anaesthesia promoted the haemodynamics stabilization. Arduan dosage ought to be reduced because of it possible cumulation in blood due to hepatorenal disorders existing in this patients. The dominance of the blood glucagon at the end of operation and the glucagon-insulin coefficient shift causes the tachycardia and the shock index increase. The proposed direct binasal stimulation of respiration after the anaesthesia conduction promoted rapid muscle tone and respiratory movements restoration in patients.

[The problem of airtightness during the use of a laryngeal mask under conditions of carboperitoneum and muscle relaxation]. / Problema germetizma pri ispol'zovanii laringeal'noi maski v usloviiakh karboperitoneuma i miorelaksatsii.

This study was aimed at assessing the airtightness of the airways during the use of a laryngeal mask (LM) under conditions of myoplegia and traditional forced ventilation of the lungs (FVL) with carboperitoneum (CP) during laparoscopic cholecystectomy (LCE). A total of 146 anesthesias for LCE were carried out using LM (n = 86) or endotracheal tube (ETT) (n = 60). The groups did not differ by the demographic characteristics or concomitant diseases. After premedication and induction of anesthesia it was maintained with N2O:O2--2/1 (Fi O2 = 0.3), fractionated administration of fentanyl (0.1-0.2 mg), and pipecuronium bromide (0.06 mg/kg). A gastric tube was inserted. Two variants of FVL were used: 1) permanent minute respiration volume (MRV) was maintained and 2) MRV was increased in order to maintain the Et CO2 at a constant level. The amount of gastric contents was measured and its pH assessed. Regurgitation and aspiration was assessed (in 33 patients) using methylene blue in gelatin capsules administered orally 10 min before anesthesia. Gas exchange was monitored by the Datex Capnomac-Ultima and by check-ups of acid base balance in the arterial capillary blood, hemodynamics was monitored by noninvasive Criticon Dynamap monitor. Manual FVL with inhalation P no more than 10 cm H2O completely prevented the entry of gas narcotic mixture into the stomach. Application of LM under conditions of total myoplegia and FVL with inhalation P of 23-25 cm H2O provided a satisfactory airtightness of the LM-airways contact without audible (appreciable) leaking of gas narcotic mixture. Leakage of gas narcotic mixture during LM application under total myoplegia and carboperitoneum (with CO2 pressure in the abdominal cavity 12 cm Hg) is no more than 6%, which indicates that LM is a reliable air guide providing good airtightness of the LM-airways contact even under conditions of increased abdominal pressure. No cases of regurgitation and aspiration were observed.

The onset of pipecuronium following application of the priming principle.

Pipecuronium bromide, a long acting non-depolarizing neuromuscular blocking agent was administered to four groups of 10 patients using the priming technique. The effects of the combination of two different priming doses (0.01 or 0.015 mg kg-1) given at two different time intervals (3 or 4 min) before the 'main' intubating dose (0.07 or 0.065 mg kg-1) were investigated. Onset times were recorded and the intubation conditions were scored and compared with a group of patients receiving the same total amount of pipecuronium (0.08 mg kg-1) in a single bolus injection. Intubating conditions at 90 s after administration of the intubating dose were found to be significantly improved in all primed groups but the onset times, evaluated using the response of the adductor pollicis muscle to a single twitch stimulation, were similar to that observed after the single bolus injection. The optimal priming combination is considered to be 0.01 mg kg-1 of pipecuronium followed 3 to 4 min later by 0.07 mg kg-1.

Is rocuronium an exception to the relation between onset and offset? A comparison with pipecuronium.

A general relation between the rate of onset and rate of recovery from non-depolarizing blockade has been demonstrated, with recovery consistently about ten times slower than onset. This observation has led to the suggestion that non-depolarizing agents share a common mechanism of action. Rocuronium, a recently introduced steroidal non-depolarizing agent, is claimed to have a very rapid onset but an intermediate duration and appears to test this hypothesis. To investigate this paradox we have calculated the rates of onset and recovery of rocuronium using the isolated human forearm and compared them with those of pipecuronium. The mean ratio of recovery time/onset time for rocuronium was 31.3, which is significantly greater than that for pipecuronium, 11.6 (P < 0.01). Whilst pipecuronium conforms to the same general relation between onset and offset described previously for other non-depolarizing agents, rocuronium appears to have a disproportionately rapid rate of onset for its rate of recovery. This suggests that onset, recovery, or both onset and recovery, from rocuronium blockade occur in a different manner to that of other non-depolarizing agents.

[A new instrument for neuromuscular transmission monitoring: the accelerometer Tofguard. Comparative study of isometric force transduction in the assessment of pipecuronium dose-response relationship]. / Un nuovo strumento per il monitoraggio della trasmissione neuromuscolare: l'accelerometro Tofguard. Studio comparativo nei confronti della trasduzione isometrica di forza nella valutazione della relazione dose effetto per il pipecuronium.

Pipecuronium effective doses 50,90,95 (ED50, ED90, ED95) have been obtained with the cumulative dosage method studying the influences of two different anesthetic techniques (TIVA vs isoflurane), of the patients age, of two different monitoring techniques, force transduction vs accelerometry, both evaluated by T1/TC ratio, ratio between Ist muscular response following the muscle relaxant and the values obtained before its injection, and TOFR, ratio between 4th and Ist response of every train. 33 patients, 55 years average age, 66 kgs average weight, ASA 1&2, scheduled for elective operations were anesthetized with propofol-fentanyl-N2O; tracheas were intubate under topical analgesia; maintenance of anesthesia included propofol and fentanyl or isoflurane 1 MAC. Neuromuscular monitoring included the simultaneous measurement of force of thumb adduction (FT 10 Grass) and its acceleration (Tofguard); neuromuscular blockade was evaluated by T1/TC and TOFR. Pipecuronium was administered in small decreasing boluses until 95% of T1/TC depression. Under force monitoring, ED50, ED90, ED95 values were 19, 28, 33 micrograms/kg respectively with T1/TC, being slightly lower with TOF stimulation (15, 24, 26 micrograms/kg); ED's were not influenced by anesthesia and were inversely related to age. Under accelerometry, EDs were always lower (16,27 e 27 micrograms/kg) under T1/TC, while with tof their values were similar to those derived from force measurements. ED's values obtained with T1/TC, either with force than accelerometry, while accelerometry was more sensitive than force for all ED's. EDs values, both under T1/TC than TOF, either with force transduction than accelerometry, resulted highly correlated each other, indicating a substantial agreement between the two mechanical methods of monitoring. It is concluded that the new instrument Tofguard offers the same reliability than force transduction, with the advantages of being smaller, portable and able to calculate directly the depth of neuromuscular blockade.

Left ventricular regional wall motion and haemodynamic changes following bolus administration of pipecuronium or pancuronium to adult patients undergoing coronary artery bypass grafting.

The objective of this study was to compare the haemodynamic and myocardial effects of pipecuronium and pancuronium in patients undergoing coronary artery bypass grafting (CABG) during benzodiazepine/sufentanil anaesthesia. Twenty-seven ASA III-IV patients received lorazepam (1-3 mg) po and midazolam ( < 0.1 mg.kg-1) i.v. before induction of anaesthesia with sufentanil (3-8 micrograms.kg-1) was administered to facilitate tracheal intubation. According to random allocation, each patient received either pipecuronium (150 micrograms.kg-1) or pancuronium (120 micrograms.kg-1) after sternotomy but before heparinization. Mean arterial pressure, central venous pressure (CVP), pulmonary artery pressure (PAP), ST segment position and ECG (leads III, V5, AVF) were monitored continuously throughout the procedure. Thermodilution determinations of CO in triplicate were made immediately before, and at two and five minutes after muscle relaxant administration. Multiplane transoesophageal echocardiography (TEE, midpapillary short axis views of the left ventricle) images were continuously recorded from ten minutes before until ten minutes after muscle relaxant administration and graded by two experienced echocardiographic readers. Heart rate, MAP and CO increased after administration of pancuronium (by 13.6 beats.min-1, 10.8 mmHg and 1.0 L.min-1 respectively) but not after pipecuronium (P < 0.05). Evidence of myocardial ischaemia was not detected in any patients using ECG ST segment analysis or TEE assessment of left ventricular wall motion. We conclude that pancuronium caused increases in HR, MAP and CO but that neither pancuronium nor pipecuronium caused myocardial ischaemia.