Intraoperative fluid replacement and postoperative creatine phosphokinase levels in laparoscopic bariatric patients

Morbid obesity and bariatric surgery are both risk factors for the development of postoperative rhabdomyolysis (RML). RML results from injury to skeletal muscle, and a serum creatine phosphokinase (CK) level >1,000 IU/L is considered diagnostic of RML. The aim of this study was to determine if intraoperative intravenous fluid (IVF) volume affects postoperative CK levels following laparoscopic bariatric operations.

Prospective, single blinded, and randomized trial was conducted.

Patients scheduled to undergo laparoscopic sleeve gastrectomy, adjustable gastric band, or Roux-en-Y gastric bypass operations were randomized into two groups. Subjects in Group A received 15 ml/kg total body weight (TBW) of IV crystalloid solution during surgery, while subjects in Group B received 40 ml/kg TBW. Preoperative and postoperative CK and creatinine levels and intra- and postoperative urine output were monitored and recorded.

Forty-seven patients were assigned to Group A and 53 patients to Group B. Group B patients had significantly higher urine output in the operating room, in the post-anesthesia care unit (PACU), and on postoperative days 0 and 1. Group B patients also had significantly lower serum creatinine level in the PACU and a trend towards lower creatinine levels on postoperative days 0, 1, and 2. There were no statistical differences in CK levels at any time between the two groups. Four patients in Group A and three patients in Group B developed postoperative RML.

Conservative (15 ml/kg) versus liberal (40 ml/kg) intraoperative IVF administration did not change the incidence of RML in patients undergoing laparoscopic bariatric operations. Since the occurrence of RML in this patient population is relatively high, postoperative CK levels should be routinely obtained in patients at special risk.