Parálisis residual posoperatoria tras anestesia general sin monitorización neuromuscular objetiva: un estudio observacional en el Hospital Regional Docente de Cajamarca, Perú / Postoperative residual paralysis after general anesthesia without objective neuromuscular monitoring: An observational study at the Regional Cajamarca Hospital, Perú

Objetivo: Determinar la incidencia y severidad de la parálisis residual en pacientes sin monitorización neuromuscular intraoperatoria. Materiales y métodos: Se realizó un estudio prospectivo y observacional en 236 pacientes adultos ASA I-III intervenidos bajo anestesia general sin monitorización neuromuscular intraoperatoria. A su llegada a la Unidad de Cuidados Post-Anestesia (UCPA) se realizó la monitorización neuromuscular mediante aceleromiografía del músculo aductor del pulgar. La incidencia de parálisis residual con TOF ratio (TOFr) < 0,9 y TOFr < 0,7 fueron valorados. Resultados: La incidencia de parálisis residual en la UCPA con TOFr < 0,9 fue de 81,36% (IC 95%: 76,39-86,33) y con TOFr < 0,7 fue de 33,9% (IC 95%: 27,86-39,94). La neostigmina fue utilizada para revertir el bloqueo neuromuscular solamente en el 48,3% de los casos. La incidencia de parálisis residual con TOFr < 0,7 fue significativamente mayor entre los que no recibieron antagonistas del bloqueo neuromuscular y los que sí lo recibieron (42,62% vs. 24,56%, p=0.003). Conclusiones: La incidencia y severidad de la parálisis residual posoperatoria en pacientes sin monitorización neuromuscular fue elevada en nuestra institución, probablemente favorecida por una dosificación no guiada de los relajantes musculares, la escasa utilidad de los criterios subjetivos para valorar la recuperación de la función neuromuscular y la falta de reversión rutinaria del bloqueo neuromuscular.

Objective: To determine both the incidence and severity of residual paralysis in patients not undergoing intraoperative neuromuscular monitoring. Material and Methods: A prospective observational study was performed in 236 ASA I-III adult subjects who underwent surgery under general anesthesia without intraoperative neuromuscular monitoring. When patients were brought to the Post-Anesthesia Care Unit (PACU), neuromuscular monitoring was performed using acceleromiography of the adductor muscle of the thumb. The incidence of residual paralysis with TOF ratio (TOFr) values <0.9 and <0.7 was assessed. Results: The incidence of residual paralysis in the PACU with TOFr <0.9 was 81.36% (95% CI: 76.39%-86.33%) and with TOFr <0.7 was 33.9% (95% CI: 27.86%-39.94%). Neostigmine was used to revert neuromuscular blockade only in 48.3% of all cases. The incidence of residual paralysis with TOFr<0.7 was significantly higher in those subjects who did not receive neuromuscular blockade antagonists compared with those who did (42.62% vs. 24.56%, p= 0.03). Conclusions: Both the incidence and severity of residual postoperative paralysis in patients without neuromuscular monitoring was notoriously high in our institution, likely favored by a non-guided dosing of muscle relaxant agents, as well as due to low usefulness of subjective criteria for assessing recovery of neuromuscular function and the lack of routine reversion of neuromuscular blockade.

Complicación respiratoria en el postoperatorio tardío en un paciente con distrofia miotónica tipo I. Reporte de un caso / Respiratory complication in the late postoperative period in a patient with type I myotonic dystrophy. Case report

Myotonic dystrophy is an uncommon disease, characterised by disorders of the muscle membrane. Its clinical manifestations are muscle weakness, difficulty at initiating movements and delayed muscle relaxation. Carriers of this disease are very sensitive to anaesthetic drugs. Residual neuromuscular blockade is common among these patients, leaving them at risk of various postoperative complications. Proper neuromuscular blockade reversal is therefore crucial. We report the case of an 18-year-old male with myotonic dystrophy type I (Steinert's disease), who was admitted for a complicated hydatid cyst. He required a laparotomy, which was done under general anesthesia with no intraoperative incidents. He was extubated at the end of the procedure, with 94% response at the train-of-four (TOF) and adequate spontaneous ventilation. No reversal for neuromuscular blockade was given. The patient evolved favourably during the postoperative phase. However, in the later postoperatory period the patient presented severe respiratory complications. Proper anaesthetic management of these patients, as described in the literature, includes the use of non-depolarising muscle relaxants, monitoring of muscle relaxation and reversal of neuromuscular blockade. The combination of rocuronium and sugammadex appears to convey the optimum reversal required for these cases.

Las distrofias miotónicas son enfermedades poco comunes, caracterizadas por trastornos a nivel de la membrana muscular. Clínicamente se manifiestan por debilidad muscular progresiva, dificultad al iniciar movimientos y retardo en la relajación muscular. Los portadores de este grupo de enfermedades tienen una marcada sensibilidad a los fármacos anestésicos. Es habitual que presenten bloqueo neuromuscular residual, arriesgándose a sufrir diversas complicaciones postoperatorias. Por ello, es importante realizar una reversión adecuada de la relajación muscular en estos pacientes. Presentamos el caso de un paciente masculino de 18 años, con distrofia miotónica de Steinert tipo I, que ingresa para laparotomía por quiste hidatídico hepático complicado. Recibió anestesia general sin incidentes. Es extubado con una respuesta al tren-de-cuatro (TOF) de 94% y ventilación espontánea adecuada. No se realiza reversión del bloqueo neuromuscular y evoluciona favorablemente en el postoperatorio inmediato. Sin embargo, en el período postoperatorio tardío, presenta complicaciones respiratorias severas. El adecuado manejo de estos pacientes, según lo recomendado en la literatura, requiere el uso de relajantes no-depolarizantes, monitorización y reversión del bloqueo neuromuscular, siendo probablemente la combinación de rocuronio y sugammadex, la más adecuada para estos fines.

Neuromuscular blockade and pharmacokinetic-pharmacodynamic modeling

A major goal in pharmacokinetic-pharmacodynamic (PK/PD) modeling of neuromuscular blockade (NMB) is to quantitatively estimate the dose-response relationship.Our PK/PD model consists of three submodels:PK, link kinetics, and PD.A virtual effect compartment in which the drug concentration is in equilibrium with the observed concentration is used to extract the kinetic component (keo) from the pharmacodynamic data alone.Parameters of this model are keo, Ce(50), and gamma.The underlying structural pharmacokinetics and pharmacodynamics for NMB have been well understood, and new novel PK/PD models have been substituted for the gold standard PK/PD model for NMB.The purpose of this review was to describe progress in the field of PK/PD modeling of NMB from the first model, a simultaneous PK/PD model developed by Sheiner et al in the 1970s, to some of the more complicated models.Specific PK/PD models, which accurately described the behaviors of rocuronium, mivacurium, atracurium, and cisatracurium, include the recirculatory model, the peripheral link model, the peripheral elimination model, and a nonparametric model for link kinetics.