[Intramucosal intraoperative gastric pH (pHi) during cardiac surgery] surgery]

Area of Science:

• Cardiovascular Surgery
• Physiology
• Critical Care Medicine

Background:

• Monitoring intramucosal pH (pHi) is crucial for assessing tissue perfusion during cardiopulmonary bypass.
• Standard pH (pHs) is often used as a surrogate, but its reliability during hypothermic extracorporeal circulation (ECC) requires evaluation.
• Postoperative outcomes, such as APACHE III scores, can be influenced by intraoperative physiological status.

Purpose of the Study:

• To evaluate intramucosal pH (pHi) and standard pH (pHs) monitoring during heart surgery with ECC and moderate hypothermia.
• To analyze the correlation between pHi and pHs during surgery.
• To investigate the relationship between intraoperative pH measurements and postoperative APACHE III scores.

Main Methods:

• Studied 16 patients undergoing coronary bypass or valve replacement surgery with ECC and moderate hypothermia.
• Measured arterial pH (pHa), pHi, and pHs at baseline (T0), during ECC (T1), and after ECC (T2).
• Recorded APACHE III scores 18 hours postoperatively.

Main Results:

• No significant differences were found between pHi and pHs.
• pHi was significantly higher during ECC with hypothermia (T1) compared to baseline (T0).
• pHi and pHs showed significant correlation throughout the study period; no correlation was observed between intraoperative pH levels and postoperative APACHE III scores.

Conclusions:

• Splanchnic hypoxia (pHi < 7.32) was not observed in patients with cardiac output > 0.4 during heart surgery with moderate hypothermia.
• Standard pH (pHs) is a reliable indicator of intramucosal pH (pHi) in this setting.
• Early postoperative APACHE III scores are not related to intraoperative pHi or pHs levels.