The effect of patient positioning on intraabdominal pressure and blood loss in spinal surgery.

UNLABELLED Intraabdominal pressure (IAP) can influence blood loss during spinal surgery. We examined the relationship of IAP changes to blood loss with a rectal balloon pressure catheter. Forty patients were randomly assigned to narrow (Group 1) or wide (Group 2) pad support widths of the Wilson frame. IAP was measured when the patient was supine after the induction of anesthesia, prone on a gurney, prone on the Wilson frame before and after incision, and then, again supine after tracheal extubation. IAP in the prone position on the Wilson frame before incision (3.6 cm H(2)O) in Group 2 was significantly less than in Group 1 (8.8 cm H(2)O) (P: < 0.05). Intraoperative blood loss per vertebra in Group 2 (190 +/- 65 mL) was significantly less than in Group 1 (381 +/- 236 mL) (P: < 0.05). The correlation between blood loss and IAP in the prone position on the Wilson frame in Group 1 was significant (P: = 0.0022). In conclusion, IAP and intraoperative blood loss were significantly less in the wide, than in the narrow, pad support width of the Wilson frame. Blood loss tended to increase with an increase in IAP in the narrow pad support width of the Wilson frame. IMPLICATIONS The relationship of intraabdominal pressure changes to blood loss were examined with a rectal balloon pressure catheter during spinal surgery. Blood loss tended to increase with an increase in intraabdominal pressure in the narrow pad support width of the Wilson frame.