Changes in occipital capillary perfusion pressures during coronary artery bypass graft surgery.

This study compared tissue interface pressures (TIPs) on the occiput of 25 volunteer patients undergoing coronary artery bypass graft (CABG) surgery. Pressures were measured using the Gaymar pressure gauge and electropneumatic sensor before and after induction of anesthesia, after the patient was placed on the cardiopulmonary bypass pump, every 30 minutes throughout the procedure, immediately after the patient came off the pump, and before the incision was closed. Significant differences were found over time on mean TIPs and mean arterial pressures (MAPs). Pre-induction mean TIP was significantly higher than TIPs recorded on-pump, post-pump, and prior to closure. The highest average MAPs were at pre-induction; these were significantly higher than MAPs recorded at all other times. The TIPs recorded during surgery were high enough to put the patient at risk for circulation impairment and pressure ulcer development. Therefore, we recommend repositioning patients' heads regularly during surgery and assessing skin postoperatively for alopecia and pressure ulcers.