Limiting ventilator-associated lung injury in a preterm porcine neonatal model

Purpose: Preterm infants are prone to respiratory distress syndrome (RDS), with severe cases requiring mechanical ventilation for support. However, there are no clear guidelines regarding the optimal ventilation strategy. We hypothesized that airway pressure release ventilation (APRV) would mitigate lung injury in a preterm porcine neonatal model. Methods: Preterm piglets were delivered on gestational day 98 (85% of 115 day term), instrumented, and randomized to volume guarantee (VG; n = 10) with low tidal volumes (5.5 cm(3) kg(-1)) and PEEP 4 cmH(2)O or APRV (n = 10) with initial ventilator settings: P-High 18 cmH(2)O, P-Low 0 cmH(2)O, T-High 1.30 s, T-Low 0.15 s. Ventilator setting changes were made in response to clinical parameters in both groups. Animals were monitored continuously for 24 hours. Results: Themortality rates between the two groups were not significantly different (p > 0.05). The VG group had relatively increased oxygen requirements (FiO2 50% +/- 9%) compared with the APRV group (FiO2 28% +/- 5%; p > 0.05) and a decrease in PaO2/FiO(2) ratio (VG 162 +/- 33 mmHg; APRV 251 +/- 45 mmHg; p < 0.05). The compliance of the VG group (0.51 +/- 0.07 L.cmH(2)O(-1)) was significantly less than the APRV group (0.90 +/- 0.06 L.cmH(2)O(-1); p < 0.05). Conclusion: This study demonstrates that APRV improves oxygenation and compliance as compared with VG. This preliminary work suggests further study into the clinical uses of APRV in the neonate is warranted. (C) 2017 Elsevier Inc. All rights reserved.