Leak Compensation During Volume Guarantee With the Dräger Babylog VN500 Neonatal Ventilator

To investigate how compensating for endotracheal tube leaks by targeting the leak-compensated tidal volume affects measured physiologic and ventilator variables during neonatal mechanical ventilation.

Retrospective observational study.

A level III Neonatal ICU.

We enrolled 30 neonates who were ventilated using synchronized intermittent positive pressure mode with volume guarantee and had at least 12 hours of continuous detailed recording of ventilation variables.

Infants were treated using the Dräger VN500 ventilator (Dräger, Lübeck, Germany), which uses a proprietary algorithm to measure and compensate for endotracheal tube leaks. Eleven were ventilated without leak compensation and 19 with leak compensation.

Detailed ventilation data were collected and analyzed at 1 Hz, with intermittent blood gas values. The percentage of leak was less than 20% in 73% of leak-compensated inflations, and the volume of the leak compensation was less than 1 mL/kg in 97.3% of inflations. Between the two groups, ventilation variables were comparable, except the percentage of leak that was significantly (p = 0.005) higher in the recordings with leak compensation. Without leak compensation, the mean expired tidal volume was maintained very close to the set level up to 50% leak, but with leaks greater than 50%, it declined progressively. With leak compensation, the mean leak-compensated expired tidal volume was well maintained even with leak greater than 90% although with large variability. Without leak compensation, the difference between the maximum allowed inflating pressure and the peak inflating pressure decreased progressively as the leak increased. This did not occur with leak compensation. The median PCO2 was slightly higher with leak compensation.

During volume guarantee ventilation with a Dräger VN500 ventilator, without leak compensation the expired tidal volume declined after 50% leak. With leak compensation, the tidal volume was maintained even with a large leak. With leak compensation, there was a more stable peak inflating pressure, although the PCO2 was slightly higher.