Restricted Fluid Regimen in Open Abdominal Bowel Surgery

This is a randomized, prospective controlled trial in patients (ASA I-III) undergoing open
abdominal surgical procedures in a single center. This study will be done in two phases. The
first phase is designed to evaluate and prove the safety of restricted fluid regimens in
maintaining tissue perfusion using a central venous oximetric catheter and arterial blood
gas analysis. In the second phase of the study, we plan to mimic the usual clinical practice
without the central venous oximetric catheter and arterial lines (invasive monitors) and the
postoperative total morbidity will be compared between the liberal and restricted fluid
regimens.

In the first phase of the study, 90 patients coming in for open bowel surgery will be
randomized to three groups using a random number generator. All patients will receive a
standard bowel prep regimen (Go-Lyte-half a liter the night before surgery). Group A will
receive current standard of care (liberal fluid therapy), Group B and C will receive
restricted fluid regimens. All patients will receive 500 cc of intravenous fluids (lactated
ringers in Group A and B, 6% hetastarch in Group C) in the preoperative holding area to
correct preoperative fluid deficits due to fasting and bowel preparation. Patients younger
than 18 years, ASA IV or V, pregnant patients, those with coagulopathy, renal insufficiency,
unstable angina, unstable congestive heart failure, and those with contraindication to
central venous pressure catheter insertion will be excluded from the study.

After instituting anesthesia monitors, patients will be anesthetized with a standard
anesthetic regimen. An arterial line and a central venous catheter with oximetric capability
will be inserted in all three groups. A baseline blood gas will be drawn to note the base
excess, lactate levels and the hematocrit at the start of surgery. Parameters like heart
rate, blood pressure, central venous pressure, mixed venous oxygen saturation and arterial
oxygen saturation and urine output will be continuously monitored. Both the regimens will be
started in the operating room and continued into the postoperative period until they resume
their oral intake. Patients in the liberal group will receive (10ml/kg/hr) the current
standard of care for bowel surgery whereas those in the restricted group will receive
4ml/kg/hour. Post induction hemodynamic instability will be treated with ephedrine and
phenylephrine at the discretion of the anesthesiologist in charge.

Intraoperative treatment of tachycardia, hypotension in both the groups will be treated
using a standard fluid regimen algorithm (appendix A). All patients will receive the same
postoperative fluid regimens as the current standard of care. Postoperative morbidity
evaluation (appendix B) will be done at patient's discharge from the hospital. The data
entry will be prospectively done during their hospital stay. The accuracy of the data will
be checked by one of the study investigators.

Inclusion Criteria:

- ASA physical status I-III patients coming in for open abdominal bowel surgery

Exclusion Criteria:

- Coagulopathy,

- Pregnancy,

- Renal insufficiency,

- Contraindications for placing a central line,

- ASA IV and V,

- Age less than 18years