Effects of inhaled nitric oxide and high-frequency ventilation in rabbits with meconium aspiration

Aim: To evaluate effects of inhaled nitric oxide (iNO) in experimental meco nium aspiration treated with high-frequency (HFV) or conventional mechanica l ventilation (CMV). Ventilated adult rabbits had meconium instilled intrat racheally resulting in respiratory failure as evidenced by more than 50% re duction of dynamic lung compliance (Cdyn) and increase in mean oxygenation index (OI) from 1 to 16. The animals were then allocated to 2 groups treate d without (control) or with iNO at 20 ppm (NO). In each group the animals w ere initially ventilated with CMV or HFV mode for 3 h and then in a crossov er fashion with HFV or CMV for another 3h (CMV --> HFV, HFV --> CMV), respe ctively. In the first 3 h of treatment, the animals subjected to HFV-CMV in the control, and those with both HFV-CMV and CMV-HFV in the NO group had s ignificantly reduced OI. in the subsequent 3 h, the animals in the control group with CMV-HFV did not improve in OI and those with HFV-CMV had deterio rated. In the NO group with both CMV-HFV and HFV-CMV moderate improvement o f OI was observed. Platelet aggregation capability and counts were signific antly decreased and bleeding time prolonged in animals receiving iNO treatm ent. These results suggest that both HFV alone and a combined treatment of iNO with either CMV or HFV are more effective in improving blood oxygenatio n than that of CMV in this animal model. The influence of iNO an platelet a ggregation should be considered. Copyright (C) 1999 S. Karger AG. Basel.