RESUMO
BACKGROUND AND OBJECTIVES: Myasthenia gravis is an autoimmune disease marked by high titers of immunoglobulin G antibodies, which accelerate destruction of cholinergic receptors and interfere with neuromuscular transmission. This study aimed to determine whether neuromuscular function under a rocuronium block is different from function under a vecuronium block patients with myasthenia gravis and to describe extubation conditions in the operating room or the intensive care unit. MATERIAL AND METHODS: Randomized, single-blind clinical trial enrolling patients with myasthenia gravis type IIa and IIb according to the classification of Osserman. The patients were randomized to groups receiving a vecuronium or rocuronium block. We recorded arterial oxygen saturation, capnogram, heart rate, noninvasive blood pressure, electrocardiogram, and neuromuscular function by accelerometry. During surgery 25% of the total dose of the neuromuscular blocking agent was administered. Maintenance was with a continuous infusion of propofol and fentanyl. All patients were extubated according to clinical criteria, confirmed by train-of-four ratio (T4/T1). RESULTS: The mean (SD) time elapsed before recovery of 25% of neuromuscular function was 53.1 (1.9) min in the rocuronium group and 56.2 (0.8) min in the vecuronium group (P = .01). Time elapsed before recovery of 90% of function was 71.3 (2.7) min in the rocuronium group and 96.3 (1.2) min in the vecuronium group (P = .001). Twenty-eight of the 30 patients in the rocuronium group (93.3%) were extubated with recovery of 89.1% (0.5%) of twitch response and a T4/T1 ratio of 0.83. The difference between groups was statistically significant (P = .01). In no case was it necessary to administer a maintenance dose or reverse the block. CONCLUSIONS: The rocuronium block had a better profile than the vecuronium block in this study. With this blocking agent we were able to circumvent respiratory depression, with its immediate consequences, and thus meet the main clinical criterion when anesthetizing patients with myasthenia gravis.
Assuntos
Androstanóis/uso terapêutico , Miastenia Gravis , Bloqueio Neuromuscular , Fármacos Neuromusculares não Despolarizantes/uso terapêutico , Timectomia , Brometo de Vecurônio/uso terapêutico , Adulto , Feminino , Humanos , Masculino , Rocurônio , Método Simples-CegoRESUMO
We report the use of sugammadex to reverse a rocuronium block in a man who had received a kidney transplant 4 years earlier. The patient was admitted for gastric non-Hodgkins lymphoma and bleeding that required surgery. Arterial hypertension, tachycardia, and frequent ventricular extrasystoles were detected. Anesthetic induction was accomplished with propofol, fentanyl, and rocuronium; intubation was uneventful. We monitored pulse oximetry, capnography, heart rate, electrocardiography, arterial pressure (invasive), cardiac output, end-systolic volume, bispectral index, temperature, and neuromuscular function. Anesthesia was maintained with an infusion of propofol, fentanyl, and rocuronium guided by train-of-four (TOF) ratio. Total diuresis was 1100 mL. The operation lasted 4.5 hours. Recovery of neuromuscular response was spontaneous until the second TOF twitch, after which we injected 2 mg/kg of sugammadex. A TOF ratio of 0.94 was recorded 158 seconds after injection of the reversal agent. The patient was extubated without complications. Sugammadex can be used in patients with a transplanted kidney, provided the glomerular filtration rate has recovered sufficiently to allow full excretion of the sugammadex-rocuronium complex.
Assuntos
Transplante de Rim , gama-Ciclodextrinas/uso terapêutico , Adulto , Humanos , Masculino , Bloqueio Neuromuscular , SugammadexRESUMO
INTRODUCTION: Myasthenia gravis is an autoimmune disease characterized by the presence of circulating IgG antibodies, which interact with acetylcholine receptors and interfere with neuromuscular transmission. OBJECTIVES: To compare neuromuscular function when mivacurium is used in patients with myasthenia gravis and patients with no impairment of transmission at the neuromuscular synapse. MATERIAL AND METHOD: Prospective study of 40 patients in two groups. Group I (n = 20) consisted of patients with no impairment of neuromuscular transmission who underwent sternotomy or mediastinoscopy and who received 2 ED95 of mivacurium. Group II (n = 20) were patients with myasthenia gravis who underwent transsternal thymectomy and received 0.5 ED95 of mivacurium (50 micrograms/Kg). The neuromuscular function of all patients was monitored by accelerometry of the thumb adductor. RESULTS: All demographic variables except sex were similar in the two groups. Time to maximal block, duration of block and the recovery at T1 25-75 were significantly greater in group II (250 +/- 10 s, 29.1 +/- 2.4 min and 8.1 +/- 1.5 min, respectively) than in group I (188 +/- 13 s, 21.2 +/- 0.4 min and 7.1 +/- 0.2 min in group I). Maintenance doses were given more often in group I. At the end of surgery and before recovery from mivacurium, the mean twitch height in group II was 89.3 +/- 0.5%, such that tracheal tubes were removed from 95% of the patients without complications. The mean time until extubation in group II was 17.8 +/- 1.3 min and was related to the extension of the blocks. The differences were statistically significant (p < 0.05). CONCLUSIONS: The anesthetic effect of mivacurium was twice as great in myasthenic patients, in whom it behaved like an intermediate-level non-depolarizing muscle relaxant. Mivacurium can reduce prolonged mechanical ventilation in patients who are myasthenic or pharmacologically immunosuppressed and at risk of sepsis arising in the respiratory tract.