E25 - Comparison of Mask and Binasal Prongs for Delivery of Non-invasive Ventilation to Foals

Abstract: Background Non-invasive ventilation (NIV) can be used to provide respiratory support to foals, but current methods have been associated with hypercapnia. Objectives Comparison of NIV delivered by binasal prongs or mask to healthy, sedated foals with pharmacologically induced respiratory insufficiency. Animals Six healthy foals, < 5 weeks old. Methods Randomized cross-over study. Six foals were blocked in pairs, with one foal in each pair randomly allocated to mask, the other to binasal prongs, for NIV. Foals were sedated and placed in lateral recumbency, with inspired/expired and blood gas analysis, spirometry and ventilator variables collected at the end of each 10 minute intervention window of, sequentially, unassisted respiration through mask/prongs, supplementary oxygen delivered through mask/prongs, and NIV at two different pressures, with and without supplementary oxygen. After a recovery interval of ≥3 days, respiratory support was repeated with the reciprocal patient-device interface. Results Binasal prongs were well tolerated and required less manual positioning or monitoring than the mask. Similar benefits to oxygenation and respiratory mechanics were observed with both patient-device interfaces. Partial pressure of carbon dioxide (PaCO2) was significantly lower with binasal prongs (P≤0.022, Figure 1) during O2 supplementation and at all NIV settings. Increased leak was observed during NIV with binasal prongs, but the observed leak (mean 5.3 L/min, 95% CI 2.9 – 7.6 L/min) was within acceptable limits for human patients. Conclusions and clinical importance Nasal prongs were well tolerated, effected similar benefits on respiratory function, and appeared to ameliorate hypercapnia observed in previous studies of NIV in foals.