[Gastric pH changes during and after extracorporeal circulation. What is its clinical meaning?]
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A Paccagnella1, M Calò, M Baiocchi
1II Servizio di Anestesia e Rianimazione, Ospedale S. Maria de' Battuti, Treviso.
Insights
Gastric pH (pHm) did not significantly change during cardiopulmonary bypass. Post-surgery, pHm showed correlations with blood oxygen and hemoglobin, but its prognostic value in cardiac surgery remains uncertain.
Area of Science:
- Anesthesiology
- Critical Care Medicine
- Gastroenterology
Background:
- Cardiopulmonary bypass (CPB) is a critical procedure in cardiac surgery.
- Monitoring physiological parameters during and after CPB is essential for patient outcomes.
- Gastric pH (pHm) has been proposed as a potential indicator of visceral perfusion.
Purpose of the Study:
- To investigate the relationship between gastric pH (pHm) and various blood perfusion indices in patients undergoing CPB.
- To assess the utility of pHm as a prognostic marker in elective cardiac surgery.
Main Methods:
- A prospective study involving 19 patients undergoing elective cardiac surgery.
- Gastric pH was continuously monitored using a nasogastric probe.
- Data collected included pHm, transcutaneous oxygenation (PtcO2), hemodynamic parameters, temperature, and blood gases during CPB and postoperatively.
Main Results:
- No significant variations in pHm were observed during the CPB procedure.
- Post-surgery, significant correlations were found between pHm and PaO2 (p < 0.001), hemoglobin (p < 0.001), and blood pH (p < 0.05).
- No statistical correlation was found between pHm and hemodynamic variations.
Conclusions:
- Despite observed changes in vascular resistance and oxygenation during CPB, pHm did not correlate with these parameters.
- The prognostic significance of pHm in elective cardiac surgery patients cannot be confirmed at this time.
- Further research is needed to determine if pHm variations can serve as a reliable marker of visceral perfusion.
Objective:
To determine the relationship between gastric pH (pHm) and several other indices of blood perfusion in patients undergoing cardiopulmonary bypass (CPB). To evaluate the importance of pHm as a prognostic index for elective cardiac surgery.
Design:
Prospectives study.
Setting:
Cardiac surgery ICU of a Regional Hospital in Italy.
Patients:
Nineteen patients were sequentially studies in a 4-month period.
Method:
Before anesthetic induction, a pH probe incorporated in the tip of a nasogastric tube (GrapHprobe SH, GrapHometer, Zinetics Medical, USA) was inserted in the stomach. Results, collected during the CPB and in the postoperative period until 1 hour after extubation, were compared to the peripheral tissue perfusion and oxygenation data (transcutaneous: PtcO2), hemodynamic variations (Swan-Ganz catheter), pharyngeal temperature, and blood gases.
Results:
No significant variations of pHm were reported during the study. Significant relations were found only after surgery between pHm and PaO2 (p < 0.001), hemoglobin (p < 0.001), and blood pH (p < 0.05). No statistical correlations were reported between pHm and hemodynamic variations.
Conclusions:
Although a significant variation of peripheral and pulmonary vascular resistance and transcutaneous oxygenation was reported throughout the study, no correlations were found to pHm. At present it is not possible to confirm the importance of pHm as a prognostic index for elective cardiac patients, even though it is necessary to examine whether the additional data of pHm variation could be considered a true marker of visceral perfusion.