Goal-directed fluid optimization using plethysmography variability index in laparoscopic bariatric obese patients: is it the answer?

Objective
The aim of the study was to compare effect of goal-directed fluid replacement using plethysmography variability index (PVI) guidance versus liberal fluid regimen in elective laparoscopic bariatric surgery on pulmonary oxygenation and gastrointestinal, cerebral, and renal function.
Materials and methods
This randomized-controlled trial included 60 consecutive patients who were 20–40 years of age with BMI greater than 40 scheduled for elective laparoscopic bariatric surgery between June 2010 and December 2011. Patients were randomized into ‘liberal fluid’ (LF) or ‘goal-directed’ (GD) fluid infusion group. All patients received 500 ml lactated Ringer's solution then 1–2 ml/kg/h in the GD group or 6–8 ml/kg/h in the LF group. A 5-min bolus infusion of 200 ml of 6% hydroxyl ethyl starch was administered, if PVI goes above 14, urine output less than 0.5 ml/kg/h, heart rate greater than 100/min, or decreased systolic blood pressure less than 20% of baseline value. This colloid bolus was repeated until 20 ml/kg is reached then lactated Ringer's solution was used for further boluses. The primary outcome measures were length of hospital stay, postoperative hypoxemia assessed by PO/FiO ratio, and serum lactate level.
Results
Intraoperatively, lactate level and volumes of infused Ringer's lactate and hydroxyl ethyl starch were significantly lower in the GD group ( < 0.001). PVI was significantly higher in the GD group ( < 0.001). Intraoperatively, lactate level and urine output were significantly lower in the GD group ( < 0.001). Postoperatively, the GD group showed significantly lower urine output ( < 0.001) and shorter time to recovery ( < 0.001) to first bowel movement ( < 0.001) and to resume normal diet ( < 0.001). Hypoxemia, diuresis, and fatigue were significantly more frequent in the LF group. No significant difference was seen in other postoperative complications.
Conclusion
Goal-directed, PVI-guided intraoperative fluid replacement significantly improved clinical outcome compared with liberal fluid intake. PVI guidance provides a sensitive and accurate determinant of fluid responsiveness and allowed for lower fluid intake. We recommend GD intraoperative fluid replacement with PVI and arterial blood gases (ABG) guidance in morbidly obese patients undergoing laparoscopic bariatric surgery.