Rocuronio en obesos: ¿Debe dosificarse por peso real o peso ideal?

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 0.6 mg·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 (T 1 ), we registered onset time, clinical duration, recovery index, level of muscle relaxation to which the first reinfor cement 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 (90-150 secs.) 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. * IQR = interquartile range.