Hemodynamics in the prone jackknife position during surgery.

We examined the hemodynamic changes occurring with prone jackknife positioning during colorectal surgery. The operative procedure was restorative proctocolectomy with ileal J-pouch anal anastomosis in five patients with adenomatosis coli and six patients with ulcerative colitis and anoabdominal resection of the rectum with colonic J-pouch anal anastomosis in eight patients with rectal cancer. Nineteen patients (10 men and 9 women aged 41 +/- 19 years) were monitored with arterial and Swan-Ganz catheters during positioning. Measurements were obtained in the supine and prone positions (1 minute, 3 minutes), and the jackknife position (1, 3, 5, and 10 minutes), as well as before and after adoption of the Lloyd-Davies position (1, 3, 5, and 10 minutes). Turning the patient from the supine position to the prone position resulted in a significant decrease in the cardiac index (CI). However, following head-down rotation, the CI increased and returned to the value seen in the supine position (p less than 0.05). Heart rate (HR) slowed and mean arterial pressure (MAP) increased in the prone jackknife position. We concluded that the extent of the changes in cardiac function presented no serious problems.