Cortrak feeding tube safety: Criteria for interpreting lung misplacement

Pneumothorax occurs in 0.52% of blind tube placements, with 97% occurring in-procedure. Post-procedure pH or x-ray checks cannot prevent these, but CO₂ checks or guided tube placement can. Cortrak guided tube placement is widespread, but manufacturer guidance to interpret lung placement is subjective.

Develop objective criteria to differentiate lung from oesophageal tube placement from measurements and patterns in Cortrak traces.

Paired comparison of lung and oesophageal Cortrak traces using a retrospective analysis of prospectively collected data in critically ill patients.

From 126 paired traces, lung position, versus oesophageal, was indicated by deviation from the sagittal midline further from the receiver and by a greater angle and distance. No lung trace moved deep to shallow and returned to the midline then turned left compared with 99.2% of oesophageal traces; 56.3% of traces had some degree of artefact caused by receiver misalignment and required interpretation to account for this.

Differences in trace measurements give early warning of lung placement, and absence of an oesophageal pattern is definitive. Manufacturer guidance describing Cortrak trace is subjective, lacking advice on how to interpret or correct for artefacts. This could fail to prompt a 'lung warning' and/or lead to unnecessary withdrawal of oesophageal placements; both risk trauma.

The objective criteria developed enable detection of lung placement. If regulatory authorities mandate their use in independently accredited training, Cortrak would be a safe method to confirm tube position.