Validation of the RightLevelpH Detector for Monitoring Gastric pH

Abstract

Background: The RightLevelpH indicator is a new device designed to measure the pH of gastric aspirate obtained via a nasogastric tube while minimizing exposure of the operator.

Objective: To validate the RightLevelpH indicator in vivo and in vitro.

Methods: With general anesthesia, 20 patients had placement of a nasogastric tube and a gastric pH electrode catheter after endotracheal intubation. Direct intragastric pH was recorded simultaneously with gastric aspirate pH by using the RightLevelpH indicator and by using an external pH electrode. Measurements were made every 30 minutes until removal of the nasogastric tube as indicated clinically. In vitro validation of the RightLevelpH indicator was performed by using standard buffer solutions.

Results: The pH of clear buffer solutions was linearly related to pH determined by the RightLevelpH indicator (R(2) = 0.99; P < .001). The pH of gastric aspirate determined with an external pH electrode was linearly related to the gastric aspirate pH determined by using the RightLevelpH indicator (R(2) = 0.92; P < .001). Intragastric pH determined with the catheter electrode was also linearly related but more loosely correlated with gastric aspirate pH determined by using an external pH electrode (R(2) = 0.52; P < .001) and by the RightLevelpH indicator (R(2) = 0.55; P < .001).

Conclusions: The RightLevelpH indicator provides accurate measurements of the pH of gastric aspirate in patients.