A B S T R A C T
Background: Blind placement of a nasogastric feeding tube is a common nursing
procedure. Confirmation of the correct position in the stomach is warranted to avoid
serious complications such as misplacement in the lung. Testing pH of aspirate from a tube
is one of the techniques to confirm the tip position. The purpose of this study was to
evaluate the auscultatory method and pH measurement with a pH cut-off point of 5.5 after
tube insertion and to compare this with the ‘gold standard’: an abdominal X-ray.
Also the feasibility of the pH method was evaluated.
Materials and methods: Large prospective observational study in a general hospital. In
adult hospitalised patients, the positioning of 331 feeding tubes was tested using two
different methods to predict tube position in the stomach.
Results: In 98.9% (n = 178) of aspirate samples with a pH 5.5, the tube was located in the
stomach. If an aspirate could be obtained, the results of pH measurements showed a
sensitivity of 78.4% and a specificity of 85.7%. Obtaining aspirate initially after placement
was possible in approximately half of cases but after taking additional measures (including
administration of air into the tube, side-positioning of the patient and re-aspiration after
one hour) this increased to 81.6%. The sensitivity of the auscultatory method was 79%
while the specificity was 61%.
Conclusions: A pH of 5.5 from tube aspirate is adequate to check the position of the tube
in the stomach. Additional measures improve the success to obtain an aspirate from the
tube. The auscultatory method is unreliable.