mucosa to the tip of the nasogastric tube (Burnham, 2000).
In those cases where no aspirate could initially be
obtained, slow aspiration was repeated several times. If
this was successful, a few drops of the aspirate were placed
on a pH testing strip intended to test human gastric
aspirate. (Merck1 pH indicator strip/pH 2.0–9.0,) with a
colour 0.5 pH units scale. When the pH was found to
be 5.5, it was assumed that the end of the nasogastric
tube was correctly situated in the stomach. When the
results showed a pH 6.0, the characteristics (colour and
consistency) of the aspirate were registered. Subsequently,
20–30 ml of air was administered through the tube and a
stethoscope was used to listen for a whooshing sound
below the diaphragm. If a whooshing sound could be
heard, a subjective distinction was made between a loud
whooshing sound, some degree of whooshing sounds
(inconclusive) and no whooshing sound (see Fig. 1).
Another important aspect of the data collection was the
presence or absence (no intake in the previous 4 h) of
proton pump inhibitors (PPIs) or H2 receptor antagonists.
After including a first group of patients (n = 59) we
concluded that it also would be of value to register if they
had a meal or drinks before placement. Fasting was defined
as no intake of solid food 4 h before intubation, 2 h for
liquids and one hour for enteral medications.