Hypovolemia after traditional preoperative care in patients undergoing colonic surgery is underrepresented in conventional hemodynamic monitoring

Hypovolemia after bowel preparation as well as capnoperitoneum (CP) may compromise hemodynamic function during laparoscopic colonic surgery. A fall in arterial pressure after induction of anesthesia is often answered by generous fluid administration, which might impair "fast-track" rehabilitation. Intraoperative assessment of the needed infusion volume is difficult because of a lack of data regarding the volume status in these patients. Nineteen patients scheduled for laparoscopic colonic surgery after bowel preparation were prospectively monitored using the PULSION COLD Z-021 system and central venous catheter. Intrathoracic blood volume index (ITBVI), mean arterial pressure (MAP), cardiac index (CI), central venous pressure (CVP), and heart rate (HR) were measured after induction of anesthesia (M1), during CP in head-down position with an intraabdominal pressure (IAP) of 20 mmHg (M2) and 12 mmHg (M3). Although MAP (87 mmHg), HR (64 min(-1)), and CVP (8 mmHg) were within normal ranges at the induction of surgery, ITBVI (834 ml m(-2)), and CI (2.66 l m(-2)) were decreased, indicating a relative hypovolemia. CP with 12 mmHg increased ITBVI (p