Uso de Bloqueadores Neuromusculares em Pacientes com Miastenia Gravis. Relato de Dois Casos
Neuromuscular Blockers in Myasthenia Gravis Patients. Report of Two Cases
Maria Cristina Simões de Almeida
Resumo
Justificativa e Objetivos - Existe uma grande diversidade na gravidade da Miastenia Gravis, assim como na dose e resposta aos bloqueadores neuromusculares (BNM). O objetivo deste relato é apresentar dois casos de bloqueio neuromuscular prolongado com cisatracúrio e mivacúrio, em pacientes com Miastenia Gravis. Relato dos Casos - Caso nº 1 - Paciente masculino, 55 anos, 82 kg, com história de Miastenia Gravis submetido a timectomia por via transesternal, sob anestesia geral com propofol, alfentanil, isoflurano e óxido nitroso. Para intubação traqueal foi utilizado cisatracúrio (1,2 mg). Após 3:45 h de cirurgia, a reversão com neostigmina foi considerada insatisfatória e o paciente teve que permanecer intubado por duas horas. Somente após este período a descurarização foi considerada satisfatória (T4/T1 em 0,9) e o paciente foi extubado. Caso nº 2 - Paciente do sexo feminino, 42 anos, 59 kg, submetida à histerectomia por via vaginal sob anestesia combinada (peridural e geral). Foi feita monitorização da transmissão neuromuscular antes da injeção de mivacúrio (0,2 mg.kg-1) e notou-se intensa fadiga. Após 3:30 h a relação T4/T1 estava 0,15, havendo resposta a injeção de neostigmina (0,05 g.kg-1). Posteriormente foi diagnosticada Miastenia Gravis. Conclusões - O uso de monitores de transmissão neuromuscular não deve ficar restrito aos pacientes miastênicos, pois a diversidade das respostas aos BNM é comum nos pacientes normais.
Palavras-chave
Abstract
Background and Objectives - Myasthenia Gravis may present a great diversity of degrees of severity, neuromuscular blocker (NMB) dose requirements and responses. This report aimed at presenting two cases of prolonged neuromuscular block with cisatracurium and mivacurium in Myasthenia Gravis patients. Case Reports - Case 1 - Male patient, 55 years old, 82 kg, with history of Myasthenia Gravis and submitted to transsternal thymectomy under general anesthesia with propofol, alfentanil, isoflurane and nitrous oxide. Cisatracurium (1.2 mg) was used for tracheal intubation. After 3:45 h of surgery, reversion with neostigmine was considered unsatisfactory and patient had to remain intubated for two more hours, when decurarization was considered satisfactory (T4/T1 in 0.9) and the extubation performed. Case 2 - Female patient, 42 years old, 59 kg, submitted to vaginal hysterectomy under combined anesthesia (epidural and general). Neuromuscular transmission was monitored before mivacurium injection (0.2 mg.kg-1) and an intense fatigue was noticed. At the end of the surgery (3:30 h) T4/T1 ratio was in 0.15. There was a satisfactory response to neostigmine injection (0.05 g.kg-1). Myasthenia Gravis was diagnosed in the postoperative period. Conclusions - The use of neuromuscular transmission monitors should not be limited to myasthenic patients because the diversity of NMB responses is common in normal patients.
Keywords
References
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