title: Morphine after tubal ligation with bupivacaine: dosage versus body weight.
abstract: OBJECTIVE
  We investigated whether there was a statistically significant difference in patient need for postoperative analgesia based on adjusted body weight between heavier and lighter women who underwent laparoscopic tubal ligation with bupivacaine injection at the skin incision.
  
  
  METHODS
  We examined 49 records of women who underwent laparoscopic tubal ligation at Oklahoma State University Medical Center between 2000 and 2005 and received an injection of bupivacaine at the surgical site during the procedure. Postsurgical morphine was measured as doses per kilogram of body weight against total body weight and as total milligrams per kilogram of body weight against total body weight. A regression was performed for each measurement.
  
  
  RESULTS
  Heavier women required significantly fewer total milligrams of morphine per kilogram of body weight and fewer total doses of morphine per kilogram of body weight than lighter women (2-tailed P = .0035 and P = .0018, respectively).
  
  
  CONCLUSIONS
  Our data may suggest that lipophilic bupivacaine injected at a surgical site is held in place better and works for a longer period when more fat is present.
authors.affiliation: Women's Health Care, Ada, Oklahoma, USA.
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Roehl
authors.affiliation: Department of Physiology, Oklahoma State University Center for Health Sciences and College of Osteopathic Medicine and Surgery, Tulsa, Oklahoma, USA.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Breese McCoy
authors.affiliation: Department of Statistics, Oklahoma State University, Stillwater, Oklahoma, USA.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Payton
authors.affiliation: Department of OB/GYN Anesthesia, PC, Swedish Medical Center, Englewood, Colorado, USA.
authors.forename: LouAnn C
authors.initials: LC
authors.lastname: Witter
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage; D001835:Body Weight; D002045:Bupivacaine / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008026:Ligation; D008875:Middle Aged; D009020:Morphine / Q000008:administration & dosage*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000175:diagnosis / Q000188:drug therapy*; D013246:Sterilization, Tubal / Q000379:methods*; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D002045:Bupivacaine
keywords: Bupivacaine; Morphine; Postoperative analgesia; Tubal ligation