Technical feasibility and ex vivo validation of a nasogastric tube-integrated potentiometric sensor for continuous intragastric pH monitoring.

BACKGROUND

Gastrointestinal dysfunction is a common manifestation of critical illness, yet it is often under-recognized in routine care. In critically ill patients, impaired splanchnic perfusion and stress-mediated physiological responses can cause fluctuating changes in gastric acidity, which may contribute to stress-related mucosal disease (SRMD). Despite the importance of gastric pH in this context, acid-suppressive therapy is generally prescribed empirically, without direct physiological monitoring to guide treatment.

OBJECTIVE &

METHODS

To address this clinical blind spot, we developed a standard nasogastric (NG) tube featuring a built-in, miniaturized electrochemical pH sensor. We evaluated its accuracy in simulated gastric fluids across a pH range of 3 to 10. We then validated the device ex-vivo using actual gastric aspirates from intensive care patients, comparing our sensor's readings against standard pH indicator paper.

RESULTS

The integrated sensor demonstrated excellent analytical reliability during laboratory and simulated gastric fluid testing. It provided rapid (∼300 ms) and stable readings for over 24 h under controlled experimental conditions. When tested on the ICU patient samples, the sensor's measurements strongly correlated with traditional pH paper (r ≥ 0.90), showing a mean bias of approximately 0.4 pH units compared with pH indicator paper.

CONCLUSION

Continuous intragastric pH monitoring via a sensor-integrated NG tube is technically feasible and demonstrates acceptable analytical agreement in ex vivo patient samples. This technology provides a foundation for transitioning from empirical treatment to personalized, data-driven acid-suppression strategies in the ICU.