The purpose of our study was to prospectively study the splanchnic response to hypothermic and tepid cardiopulmonary bypass (CPB) using alpha-stat management of arterial blood gas tensions. Twenty-four patients for elective CABG surgery were allocated randomly to tepid (35-36°C) or hypothermic (30°C) bypass groups. Measurements were made at four times: (1) baseline, (2) stable during CPB (inflow temperature=nasopharyngeal temperature) 30°C for hypothermic patients, bypass +20 min for tepid patients, (3) 10 min before the end of bypass, (4) after bypass, skin closure. Both groups demonstrated a significant reduction in gastric intramucosal pH (pH(im)) from time 1 to time 4 and there was no difference in the incidence of a low pH(im) between the tepid and cold groups (4/12 vs 3/12; ns) at time 4. pH(im) was significantly lower in the tepid group at time 3 (P = 0.03) but this discrepancy may have been because of an artefactually high pH(im) in the cold group. There was a significantly higher incidence of postoperative non-cardiac complications in patients who had a low pH(im) at time 4 (P = 0.0008) Therefore, we conclude that although the temperature during CPB had a transient effect on pH(im) it is unlikely to be a major determinant in the pathogenesis of gut mucosal hypoperfusion after bypass.
- Gastrointestinal tract, mucosal perfusion
- Gastrointestinal tract, pH
- Heart, cardiopulmonary bypass
- Surgery, cardiovascular
- Temperature, effect
ASJC Scopus subject areas
- Anesthesiology and Pain Medicine