Research studies in healthy populations may require enteric applications to deliver
test meals/pharmaceuticals or to obtain intestinal secretion products. Use of radiological
methods for controlling tube position and for insertion is widely accepted for both
patients and healthy volunteers. However, radiological methods remain controversial
[1]. They carry radiation burden, which depends on the experience of the investigator
and on anatomic conditions. Their use in healthy volunteers should therefore follow
careful ethical consideration, and alternative methods should be sought if necessary.
In critically ill patients, sonographically guided enteric feeding tube position placement
at the bedside has already been successfully employed [2]. Hence, in this prospective study we investigated the use of ultrasonography to
confirm correct intraduodenal tube placement on three occasions in 18 healthy volunteers
(m/f 0.8; age (mean ± SD) 27.8 ± 5.4 years; BMI 22.27 ± 1.88 kg/m2 ), leading to a total of 54 tube insertions. After an overnight fast and ingestion
of 180 mL water, a polyurethane enteric feeding tube (diameter 2.6 mm, length 120
cm) was blindly inserted in right decubitus position. The manoeuvre was performed
under continuous aspiration of gastrointestinal juice. The required location of the
tube was verified by bedside measurement of aspirated fluid pH (pH 6.9 ± 0.9). Transabdominal
ultrasound (3.75-MHz Probe) visualized the enteral tube from the pylorus to the second
part of the duodenum (mediolateral of the gallbladder and upper transverse section
in front of the inferior vena cava), both in upright and supine positions (Figure
[1]). Visual detection was enhanced by injection of 10 mL air followed by 10 mL saline
(Figure [2]). In 98 % of all insertions the tube was localized in the second part of the duodenum
by ultrasonography. We believe ultrasonography is a feasible alternative to radiological
methods for monitoring postpyloric tube placement, and is preferable for studies in
populations of healthy volunteers.
Figure 1 Pars III duodeni marked by arrowheads in the middle below the left liver lobe. Arrow
indicates the feeding tube.
Figure 2 Injected hand-shaken air bubbles generate stronger scattering signals within the feeding
tube (arrow).
Endoscopy_UCTN_Code_TTT_1AO_2AK
