Cortrak tube placement part 2: guidance to avoid misplacement is inadequate

Electromagnetic (EM)-guided tube placement has been successfully used to pre-empt lung misplacement, but undetected misplacements continue to occur. The authors conducted an audit to investigate whether official Cortrak or local guidance enabled differentiation of gastrointestinal (GI) from lung traces. X-ray, pH or an EM trace beyond the gastric body were used to independently confirm gastric position. The authors undertook 596 nasointestinal (NI) tube placements, of which 361 were primary GI placements and 41 lung misplacements. Official guidance that in GI traces a midline deviation is absent cannot differentiate GI from lung traces because deviation is common in both. However, when comparing a trace in the same patient, midline deviation during lung misplacement always occurred >18 cm above the horizontal line compared with only 33% of the subsequent GI deviation (p<0.0001). Official guidance could lead to aborted GI placements or undetected lung placements. EM-guided placement must have an expert-led understanding of the 3D trace pattern, artefact correction and appraised practical experience differentiating GI from lung placement. The authors invite Halyard Health to update guidance in view of these findings.