Comparison of unilateral antegrade cerebral perfusion at 16 degrees C and 22 degrees C systemic temperature

Unilateral antegrade cerebral perfusion can be performed with minimal manipulations to arch arteries, but whether it provides adequate brain perfusion remains unclear. Some authors believe that this technique can be inadequate without deep hypothermia. We investigated the reliability of unilateral cerebral perfusion at 22 degrees C hypothermia and the advantages of avoiding deep hypothermia.

Study participants were 55 patients who underwent surgery with unilateral cerebral perfusion. Patients were divided into 2 groups; 18 patients underwent surgery at 16 degrees C hypothermia (group I) and 37 patients at 22 degrees C hypothermia (group II). The mean age of the patients was 59 +/- 10 years in group I and 55 +/- 14 years in group II. Supracoronary ascending aorta replacement was performed in 25 and hemiarch replacement in 15 patients. Nine patients underwent surgery for a Bentall procedure. Total arch replacement was performed in 4 patients and total thoracic aorta replacement in 2 patients.

The hospital mortality was 11% in group I and 5.4% in group II (P = .59). Transient neurologic deficits were not detected in any of the patients. The rate of permanent neurologic deficits was 5.9% in group I and 2.8% in group II (P = .54). Although mean aortic cross-clamp and antegrade cerebral perfusion times were not significantly different, mean cardiopulmonary bypass time was longer in group I than group II (174 +/- 38 vs 142 +/- 37 minutes, P = .005). Postoperative bleeding, blood product usage, serum creatinine and hepatic enzyme level changes, inotrope usage, and arrhythmia occurrence were not different between the 2 groups. Mean mechanical ventilation time was longer in group I than group II (24 +/- 17 vs 16 +/- 6 hours, P = .02).

Unilateral antegrade cerebral perfusion at 22 degrees C systemic hypothermia appears to be safe and reliable for brain protection. Advantages of this technique are avoidance of deep hypothermia and reduced cardiopulmonary bypass and mechanical ventilation times in patients undergoing aortic surgery.