[Neostigmine-induced neuromuscular blockade in the corrugator supercilii muscle]. / Bloqueo neuromuscular inducido por neostigmina en el músculo Corrugator supercilii.

OBJECTIVE: To investigate whether a single dose of neostigmine, administered when the adductor pollicis muscle presents 2 twitches in train-of-four (TOF) stimulation, can reduce the TOF ratio in the corrugator supercilii muscle. PATIENTS AND METHODS: We designed a case-control study of patients between 18 and 65 years of age classified ASA 1-2. We used 2 accelerometers--1 for the cubital nerve/thumb adductor muscle and 1 for the facial nerve/corrugator supercilii muscle. Neuromuscular blockade was induced with 0.6 mg x kg(-1) of rocuronium, and 40 microg x kg(-1) of neostigmine was administered at the third twitch in the TOF in the thumb adductor. If the TOF ratio in the corrugator supercilii fell by 10% or more at that time, the patient was classified as a case. We recorded the age, sex, weight, height, body mass index, duration of the procedure, and TOF ratio in the corrugator supercilii muscle when the neostigmine was administered. RESULTS: Ten cases and 10 controls were enrolled. No significant differences between cases and controls were found in any variables except the mean (SD) TOF ratio in the corrugator supercilii muscle: 70.9% (17.8%) in cases and 35.3% (7.8%) in controls (P < .001). CONCLUSIONS: In our patients, administration of neostigmine after the appearance of the third twitch in TOF stimulation of the thumb adductor was associated with a reduction in the TOF ratio in the corrugator supercilii. The similarity between blockades of the corrugator muscle, the diaphragm, and the larynx is of clinical interest.

Bloqueo neuromuscular inducido por neostigmina en el músculo Corrugator supercilii / Neostigmine-induced neuromuscular blockade in the corrugator supercilii muscle

Objetivo: Investigar si una dosis de neostigmina administrada cuando el adductor pollicis presenta dos respuestas al tren de cuatro estímulos (TOF), puede producir una atenuación del cociente del TOF en el músculo corrugator supercilii (CS). Pacientes y métodos: Se diseñó un estudio casos-control con pacientes ASA I-II entre 18 y 65 años. Se utilizaron dos acelerómetros: nervio cubital/músculo aductor del pulgar y nervio facial/músculo CS. El bloqueo neuromuscular se indujo con rocuronio 0,6 mg Kg–1. Cuando el TOF ratio en el aductor del pulgar mostraba tres respuestas se administró neostigmina (40 μg Kg–1). Si en ese momento el TOF ratio en el CS disminuía 10 o más puntos se clasificaba como “caso”. Se midieron las variables edad, sexo, peso, talla, índice de masa corporal (IMC), duración y TOF ratio en el CS cuando se administró neostigmina. Resultados: Se incluyeron 10 casos y 10 controles. No hubo diferencias significativas excepto en el TOF ratio en el CS (media, [DE]): 70,9% (17,8%) en los casos frente a 35,3% (7,8%) en los controles (p < 0,001). Conclusiones: En nuestros pacientes administrar neostigmina tras la aparición de la tercera respuesta al TOF en el aductor del pulgar se asoció con un descenso del TOF ratio en el CS. La similitud del bloqueo del corrugator con el diafragma y la laringe tiene interés sobre la relevancia clínica del fenómeno(AU)

Objective: To investigate whether a single dose of neostigmine, administered when the adductor pollicis muscle presents 2 twitches in train-of-four (TOF) stimulation, can reduce the TOF ratio in the corrugator supercilii muscle. Patients and methods: We designed a case-control study of patients between 18 and 65 years of age classified ASA 1-2. We used 2 accelerometers—1 for the cubital nerve/thumb adductor muscle and 1 for the facial nerve/corrugator supercilii muscle. Neuromuscular blockade was induced with 0.6 mg·kg–1 of rocuronium, and 40 μg·kg–1 of neostigmine was administered at the third twitch in the TOF in the thumb adductor. If the TOF ratio in the corrugator supercilii fell by 10% or more at that time, the patient was classified as a case. We recorded the age, sex, weight, height, body mass index, duration of the procedure, and TOF ratio in the corrugator supercilii muscle when the neostigmine was administered. Results: Ten cases and 10 controls were enrolled. No significant differences between cases and controls were found in any variables except the mean (SD) TOF ratio in the corrugator supercilii muscle: 70.9% (17.8%) in cases and 35.3% (7.8%) in controls (P<.001). Conclusions: In our patients, administration of neostigmine after the appearance of the third twitch in TOF stimulation of the thumb adductor was associated with a reduction in the TOF ratio in the corrugator supercilii. The similarity between blockades of the corrugator muscle, the diaphragm, and the larynx is of clinical interest(AU)