ANTHROPOMETRIC VARIABLES AS PREDICTORS FOR DURATION OF ACTION OF VECURONIUM-INDUCED NEUROMUSCULAR BLOCK

To identify the best anthropometric predictor for duration of action o f neuromuscular block and to propose a better dosing regimen for vecur onium in obese patients, we studied 67 female patients (body weight 45 -126 kg) anesthetized with thiopental, fentanyl, droperidol, and nitro us oxide. Twelve different anthropometric variables were evaluated as predictors for duration of action. Simple and multiple linear, least-s quares, regression analyses were used. The predictors with the greates t correlation coefficients for duration of action of the vecuronium in duction dose (100 mu g/kg) were percentage of ideal body weight (%IBW) (r(2) = 0.389, P = 0.0001) and body mass index (r(2) = 0.379, P = 0.0 001). Body weight alone was also correlated to duration of action, but the r(2) value was less (r(2) = 0.312, P = 0.0001). The most signific ant predictors of the first supplementary dose of vecuronium (33 mu g/ kg) were the sum of subscapularis and suprailiac skin folds divided by surface area (r(2) = 0.264, P = 0.0001) and %IBW (r(2) = 0.261, P = 0 .0001). We conclude that %IBW, the body mass index, and the sum of sub scapularis and suprailiac skin folds divided by the surface area are t he best predictors of duration of action of a vecuronium neuromuscular block.