title: Morbidly obese patients are hemodynamically stable during laparoscopic surgery: a thoracic bioimpedance study.
abstract: OBJECTIVE
  Morbid obesity caries an increased risk of cardiovascular morbidity and might be associated with intraoperative hemodynamic instability. Based on clinical observation, we hypothesized that during laparoscopic surgery, morbidly obese patients behave hemodynamically similar to the nonobese patients and remain hemodynamically stable.
  
  
  METHODS
  In a prospective trial, thirty nonobese and tthirty morbidly obese (BMI > or = 35 kg/m(2)) patients scheduled for elective laparoscopic surgery were assigned to receive standard balanced anesthesia. We aimed at equianesthetic levels by keeping the BIS (bispectral index) value between 40-50 throughout surgery. End-tidal isoflurane was measured every 5 min. Noninvasive hemodynamic measurements included cardiac index (CI), mean arterial pressure (MAP) and heart rate (HR), recorded every 5 min and at specific predetermined times. Systemic vascular resistance (SVR) was calculated. Episodes of MAP < or = 60 and MAP > or = 130 mmHg or HR < or = 50 and HR > or = 110 bpm occurring throughout surgery and requiring pharmacological intervention were considered main end-points. Additionally, hemodynamic variables were compared at specific time points and overall throughout surgery. Secondary end-points were CI and SVRI.
  
  
  RESULTS
  Heart rate was higher in obese patients in head-up position (79 +/- 15 mmHg vs. 65 +/- 12 mmHg - P=0.011). SVR was higher in the nonobese group with head-up position (1978 +/- 665 dynes s cm(-5) vs. 1394 +/- 496 dynes s cm(-5) P=0.01). Mean overall intraoperative MAP, HR, CI and SVR were similar. There were no episodes of MAP < or = 60 and > or =130 mmHg or HR < or = 50 and > or =110 bpm in either of the groups.
  
  
  CONCLUSIONS
  Our study confirmed our hypothesis that for the most periods of laparoscopic surgery, obese patients are hemodynamically as stable as their nonobese counterparts.
authors.affiliation: Department of Surgery "B", The Edith Wolfson Medical Center, Holon, Sackler School of Medicine, Tel Aviv, Israel.
authors.forename: Yoela
authors.initials: Y
authors.lastname: Aloni
authors.forename: Shmuel
authors.initials: S
authors.lastname: Evron
authors.forename: Tiberiu
authors.initials: T
authors.lastname: Ezri
authors.forename: Benjamin
authors.initials: B
authors.lastname: Medalion
authors.forename: Michael
authors.initials: M
authors.lastname: Protianov
authors.forename: Peter
authors.initials: P
authors.lastname: Szmuk
authors.forename: Reuven
authors.initials: R
authors.lastname: Zimlichman
authors.forename: Michael
authors.initials: M
authors.lastname: Muggia-Sullam
mesh_terms: D000328:Adult; D050110:Bariatric Surgery / Q000379:methods*; D001794:Blood Pressure; D002302:Cardiac Output; D002307:Cardiography, Impedance / Q000379:methods; D005260:Female; D006339:Heart Rate; D006706:Homeostasis; D006801:Humans; D010535:Laparoscopy / Q000379:methods*; D008297:Male; D009767:Obesity, Morbid / Q000175:diagnosis / Q000503:physiopathology* / Q000601:surgery*; D016896:Treatment Outcome