title: In non-obese patients, duration of action of rocuronium is directly correlated with body mass index.
abstract: BACKGROUND
  Administration of neuromuscular blocking agents using a dose calculated on actual body weight carries a risk of prolonged duration of action in obese patients whose body mass index (BMI) is > 30 kg · m(-2). In the present study, we hypothesized that there could be a correlation between BMI and the duration of action of rocuronium administered according to actual body weight in non-obese patients, in particular, overweight (BMI 25-30 kg · m(-2)) and underweight patients (BMI < 18.5 kg · m(-2)).
  
  
  METHODS
  Sixteen female patients (BMI 15-30 kg · m(-2), aged 45-60 yr) scheduled for elective surgery under total intravenous anesthesia were included in this study. Rocuronium 0.9 mg · kg(-1) was administered, and adductor pollicis train-of-four responses following ulnar nerve stimulation were monitored every minute with acceleromyography. The times from the injection of rocuronium until spontaneous recovery of first twitch to 5% (5% Duration) and 25% (25% Duration) of baseline were measured, and the correlation with BMI was analyzed.
  
  
  RESULTS
  A significant correlation between 5% Duration and BMI (r(2) = 0.56; P < 0.001) was found by linear regression analysis. A significant correlation was also found between 25% Duration and BMI (r(2) = 0.49; P = 0.003).
  
  
  CONCLUSIONS
  In adult female patients with a BMI in the range of 15-30 kg · m(-2), the duration of action of rocuronium increases with BMI when the drug is administered on the basis of mg per actual kg body weight.
authors: Department of Anesthesiology, Graduate School of Medical Sciences, Kumamoto University Hospital, Kumamoto University, 1-1-1 Honjyo, Cyuoku, Kumamoto-City, Kumamoto 860-8556, Japan. mfujimoto-kmm@umin.ac.jp
authors: Masafumi
authors: M
authors: Fujimoto
authors: Chiyoko
authors: C
authors: Tanahira
authors: Masaaki
authors: M
authors: Nishi
authors: Tatsuo
authors: T
authors: Yamamoto
mesh_terms: D000732:Androstanols / Q000008:administration & dosage* / Q000494:pharmacology; D000762:Anesthesia Recovery Period; D015992:Body Mass Index; D001835:Body Weight; D004305:Dose-Response Relationship, Drug; D054796:Drug Dosage Calculations; D017558:Elective Surgical Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D019148:Neuromuscular Blockade / Q000379:methods*; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage* / Q000494:pharmacology; D050177:Overweight; D000077123:Rocuronium; D013851:Thinness; D013997:Time Factors
chemical_list: D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium