Positioning of Diaphragm Electrical Activity Catheter in Premature Infants.

BACKGROUND

Neurally-adjusted ventilatory assist (NAVA) is a mode of ventilation that uses the electrical activity of the diaphragm (EAdi) to synchronize and to control delivered pressure. EAdi is measured with a naso-/orogastric feeding tube, containing an array of sensors. Proper placement of the EAdi catheter is critical for optimal synchronization and support. Positioning the catheter requires (1) predicting the insertion distance and (2) verification using a dedicated positioning window on the ventilator, based on electrocardiogram (ECG) and EAdi signals. In preterm infants, no study has shown that the ventilator method results in proper positioning of the feeding tube tip in the stomach. We aimed to evaluate the position of the EAdi sensors (by the catheter positioning window) with the feeding tube tip position (measured by radiographs).

METHODS

This was a multi-center (5 sites), prospective study. Eligibility: infants with weight 400-2,000 g and either had or were planning to have an EAdi catheter placed. Screenshots of the positioning window and radiographs were taken.

RESULTS

Sixty-seven infants were included. Median study weight was 1,250 g (interquartile range 1,026-1,448 g). The ventilator's positioning window revealed that all insertions were suitable with respect to the diaphragm/sensors position. Radiographs indicated 92% of insertions had the tip of the catheter appropriately in the body of the stomach. In 5 infants, the catheter tip was either touching the greater curvature of the stomach or near the pylorus.

CONCLUSIONS

In our cohort, EAdi catheter insertion using guidance from the ECG/EAdi signals of the electrode array provided a safe method for tube positioning, with regard to both enteral feeding and obtaining appropriate EAdi signals for optimal ventilator support.