Gastric Intramucosal Perfusion during Descending Aortic Repair under Femoro-Femoral Bypass

The changes in gastric mucosal perfusion during distal aortic perfusion with femoro-femoral bypass (F-F bypass) were assessed by air-automated gastric tonometry. A prospective study was performed in six patients who underwent descending aortic surgery for aortic aneurysm under F-F bypass with mild hypothermia (34 degrees C). Gastric intramucosal pH (pHi) and PaCO2-PgCO2 gap (PCO2 gap) were measured. Data are presented as means and standard deviations and analyzed by using one-way analysis of variance followed by Scheffe test. Perioperative variables of hepatorenal functions are also evaluated. The PCO2 gap significantly increased during F-F bypass (3.0 +/- 2.1 mm Hg at control, 14.2 +/- 5.5 mm Hg during F-F bypass; p = 0.004), indicating abnormal gastric mucosal perfusion during F-F bypass. Significantly low pHi was found at weaning from F-F bypass (7.35 +/- 0.05 at control, 7.21 +/- 0.10 at weaning; p = 0.009), which might be related to progressing systemic metabolic acidosis. No impairment of hepatorenal functions was observed after the surgery. Distal perfusion with F-F bypass during descending aortic surgery could impair the gastric mucosal perfusion, but may have little effect on postoperative visceral dysfunction.