Performance of Leak Compensation in All-Age ICU Ventilators During Volume-Targeted Neonatal Ventilation: A Lung Model Study

BACKGROUND: Volume-targeted ventilation is increasingly used in low birthweight infants because of the potential for reducing volutrauma and avoiding hypocapnea. However, it is not known what level of air leak is acceptable during neonatal volume-targeted ventilation when leak compensation is activated concurrently.

METHODS: Four ICU ventilators (Servo-i, PB980, V500, and Avea) were compared in available invasive volume-targeted ventilation modes (pressure control continuous spontaneous ventilation [PC-CSV] and pressure control continuous mandatory ventilation [PC-CMV]). The Servo-i and PB980 were tested with (+) and without (−) their proximal flow sensor. The V500 and Avea were tested with their proximal flow sensor as indicated by their manufacturers. An ASL 5000 lung model was used to simulate 4 neonatal scenarios (body weight 0.5, 1, 2, and 4 kg). The ASL 5000 was ventilated via an endotracheal tube with 3 different leaks. Two minutes of data were collected after each change in leak level, and the asynchrony index was calculated. Tidal volume (V_T) before and after the change in leak was assessed.

RESULTS: The differences in delivered V_T between before and after the change in leak were within ±5% in all scenarios with the PB980 (−/+) and V500. With the Servo-i (−/+), baseline V_T was ≥10% greater than set V_T during PC-CSV, and delivered V_T markedly changed with leak. The Avea demonstrated persistent high V_T in all leak scenarios. Across all ventilators, the median asynchrony index was 1% (interquartile range 0–27%) in PC-CSV and 1.8% (0–45%) in PC-CMV. The median asynchrony index was significantly higher in the Servo-i (−/+) than in the PB980 (−/+) and V500 in 1 and 2 kg scenarios during PC-CSV and PC-CMV.

CONCLUSIONS: The PB980 and V500 were the only ventilators to acclimate to all leak scenarios and achieve targeted V_T. Further clinical investigation is needed to validate the use of leak compensation during neonatal volume-targeted ventilation.