Ultrasonography for nasogastric tube placement verification: an additional reference

Nasogastric tube (NGT) placement is common for community-dwelling adults who are unable to meet their nutritional requirements orally. The nasogastric tube provides access to the stomach and is indicated for therapeutic purposes, including feeding and medication administration. Although blind insertion of NGTs with initial placement confirmed by the nurse is considered to be safe, incorrect positioning can have serious or fatal consequences (National Patient Safety Agency (NPSA), 2016).

Various methods have been suggested to verify NGT placement, including pH analysis (Holmes, 2012; Boeykens et al, 2014); auscultation test (Simons and Abdallah, 2012); capnography or capnometry (Chau et al, 2011; Miller, 2011); and chest X-ray (Taylor, 2013). A pH value of 1–5.5 for the aspirate is considered in the safe range, and this can be used as the first-line reference to exclude NGT misplacement in the respiratory tract (NPSA, 2011). However, studies have found false-negative pH findings among patients who received acid-reducing medications (Kim et al, 2012; Boeykens et al, 2014). Although the auscultation test allows good assessment of tube placement, it is not reliable in identifying a malposition of the NGT (NHS Improvement, 2016; Anderson, 2019). A few studies have reported that capnography or capnometry helps to confirm NGT placement, but a capnogram alone may not truly reflect tube position and an X-ray is unavoidable (Chau et al, 2011; Ryu et al, 2016). While all these tests have limitations in NGT placement verification, chest X-ray remains the gold standard for NGT placement confirmation (NPSA, 2016).