Continuous intravenous heparin infusion prevents peri-operative thromboembolic events in bariatric surgery patients.

Background: The pharmacokinetics of subcutaneous heparin administration in the obese patient are unpredictable. Peak levels are slowly reached and the effects are not rapidly reversible. Low-dose, continuous, intravenous heparin is easily reversed, is more efficacious and is cost-effective.

Methods: From November 2000 until July 2005, 822 consecutive patients were administered continuous intravenous unfractionated heparin at 400 U/hr (9,600 U/day) starting in the preoperative holding area and maintained until discharge. All clinically significant events were documented.

Results: 634 laparoscopic gastric bypass, 10 revisions and 188 Lap-Band procedures were performed. The mean age was 43+/-11 years (15-74) and mean BMI was 45.2+/-7.1 (30-86). There was only one (0.12%) clinically evident thromboembolic event in the entire cohort (after a gastric bypass). Anti-Xa levels and prothrombin time were followed in a group of 40 patients and were found to be normal in all. Bleeding that required transfusion occurred in 1.3% of patients. In 41 patients (5%), heparin therapy was terminated or temporarily held due to need for extensive adhesiolysis or acute drop in hematocrit, with-or-without other evidence of postoperative bleeding. Average estimated blood loss during surgery was 36 cc (5-500 cc). One patient was inadvertently administered excessive doses of heparin due to a pump error without significant sequelae.

Conclusions: Continuous low-dose intravenous heparin therapy is associated with an extremely low incidence of thromboembolic events and a low risk for perioperative hemorrhage. Intravenous heparin also has the benefits of being inexpensive and rapidly reversible.