Validation of the RightSpot™ device for determination of gastric pH during nasogastric tube placement.
BACKGROUND
The RightSpotpH™ indicator is a new device designed to facilitate pH-based confirmation of nasogastric tube placement while minimizing exposure of the operator to nasogastric contents.


OBJECTIVE
In vivo and in vitro validation of the RightSpotpH™ indicator.


RESULTS
Patients (23) undergoing general anesthesia had placement of a nasogastric tube and gastric pH electrode catheter following endotracheal intubation. Direct intragastric pH was recorded simultaneously with gastric aspirate pH using the RightSpotpH™ indicator as well as an external pH electrode. In vitro validation of the RightSpotpH™ indicator was performed using standard buffer solutions. Electrode catheter-determined intragastric pH was compared to the RightSpotpH™ indicator result (pH greater or less than 4.5) as was aspirate pH using an external pH electrode. The positive predictive value for the RightSpotpH™ indicator was 0.92 (95% CI 0.62-0.99) and negative predictive value was 1.0 (95% CI 0.48-1.0) when compared to the direct catheter intragastric pH determination. This corresponds to a sensitivity of 1.0 and specificity of 0.83. The positive predictive value for the RightSpotpH™ indicator was 1.0 (95% CI 0.29-0.99) and negative predictive value was 0.75 (95% CI 0.19-0.99) when compared to the external pH electrode determination of aspirate. This corresponds to a sensitivity of 0.91 and specificity of 1.0. Blinded in vitro testing of 46 buffer solution samples of pH 2-7 yielded sensitivity and specificity for correct pH discrimination of 1.0 and 1.0.


CONCLUSIONS
The RightSpotpH™ indicator is sensitive and specific for determination of intragastric pH determination as less than or greater than 4.5 as commonly used for nasogastric tube placement.
University of Florida College of Medicine, 1600 Archer Road, Gainesville, Florida, 32610, USA. Charles.lambert@ahss.org.
Charles R
CR
Lambert
David
D
Varlotta
Marjorie
M
Posey
Jadie L
JL
Heberlein
Janice M
JM
Shirley