Rocuronio en obesos: ¿debe dosificarse por peso real o por peso ideal? / Rocuronium in obese: should be dosed by actual weight or ideal weight?

RESUMEN

El aumento universal en la prevalencia de obesidad ha causado que los anestesiólogos se vean frecuentemente enfrentados a anestesiar pacientes obesos. Pese a esto aún existen dudas respecto a cómo dosificar las drogas en estos pacientes. La literatura recomienda dosificar el rocuronio en obesos en base al peso ideal (IBW, iniciales del inglés Ideal Body Weight) pero esta sugerencia está basada más bien en la prudencia que en la evidencia. Se decidió explorar con análisis de sobrevida (análisis tiempo-evento), la duración del rocuronio en obesos al ser dosificado por peso ideal (IBW) y por peso real (TBW, iniciales del inglés de peso corporal total). Al administrar el rocuronio en base al peso real (TBW) se observó una prolongación en su duración de acción con un acortamiento de su latencia en relación con la dosificación en base al peso ideal (IBW). Hubo una marcada prolongación de la duración de acción y el índice de recuperación tanto al dosificar por peso real como peso ideal. Debido a esta sensibilidad aumentada al rocuronio en pacientes obesos recomendamos dosificarlo en base al peso ideal, excepto si se necesita intubar rápidamente...

ABSTRACT

The universal increase in prevalence of obesity has caused that anesthesiologist are frequently encountered with anesthetizing obese patients. There stills exists doubt on how to dosage drugs to these patients. Literature recommends dosing rocuronium in the obese based on ideal weight (IBW), being this suggestion based more on prudence than on evidence. Randomized control trial was designed for obese patients scheduled for bariatric surgery to study the pharmacodynamics of rocuronium in this population. Patients were randomly assigned into two groups rocuronium dosage 0.6 mg•kg-1 for real weight (TBW) or rocuronium dosage of 0.6mg•kg-1 for ideal weight (IBW). Ideal weight was calculated according to Lemmens formula. The reference group was the dosage based on IBW. Previous calibration, evaluating the first twitch of train-of-four (T1), we registered onset time, clinical duration, recovery index, level of muscle relaxation to which the first reinforcement was administered and clinical duration of rocuronium reinforcement. A total of 100 patients were part of the study 54 in group TBW and 46 in group IBW. When administering rocuronium based on real weight (TBW) a prolongation in clinical duration was found Medium (IQR*); 79.5 (67 - 105) minutes versus 44.5(33 - 63.5 minutes) in the IBW group (p < 0.001) with a decrease in latency in the TBW group 120 (90-150secs.) versus the IBW group 180 (120 - 270 secs.) (p < 0.001). There were no differences in the recovery index between both levels of dosing. There was a marked prolongation of both clinical duration and recovery index in both groups, as supported in some literature. Based on the evidence, we recommend to dose rocuronium in obese patients based on ideal weight, with the exception of cases were quick intubation is required...