Gastric intramucosal pH-guided therapy in patients after elective repair of infrarenal abdominal aneurysms: is it beneficial?

Objective: To determine if gastric intramucosal pH (pHi)-guided therapy reduces the number of complications and length of stay in the intensive care unit (ICU) or the hospital after elective repair of infrarenal abdominal aortic aneurysms.

Design: Prospective, randomized study.

Setting: Surgical intensive care unit (SICU) of a University Hospital.

Patients: Fifty-five consecutive patients randomized to group 1 (pHi-guided therapy) or to group 2 (control).

Interventions: Patients of group 1 with a pHi of lower than 7.32 were treated by means of a prospective protocol in order to increase their pHi to 7.32 or more.

Measurements And Results: pHi was determined in both groups on admission to the SICU and thereafter at 6-h intervals. In group 2, the treating physicians were blinded for the pHi values. Complications, APACHE II scores, duration of endotracheal intubation, fluid and vasoactive drug treatment, treatment with vasoactive drugs, length of stay in the SICU and in the hospital and hospital mortality were recorded. There were no differences between groups in terms of the incidence of complications. We found no differences in APACHE II scores on admission, the duration of intubation, SICU or hospital stay, or hospital mortality. In the two groups the incidence of pHi values lower than 7.32 on admission to the SICU was comparable (41% and 42% in groups 1 and 2, respectively). Patients with pHi lower than 7.32 had more major complications during SICU stay (p < 0.05), and periods more than 10 h of persistently low pHi values (< 7.32) were associated with a higher incidence of SICU complications (p < 0.01).

Conclusions: Low pHi values (< 7.32) and their persistence are predictors of major complications. Treatment to elevate low pHi values does not improve postoperative outcome. Based on these data, we cannot recommend the routine use of gastric tonometers for pHi-guided therapy in these patients. Further studies are warranted to determine adequate treatment of low pHi values that results in beneficial effects on the patient's postoperative course and outcome.