O004 Accuracy of ventilator data to optimise NIV for respiratory failure

Abstract Background Following advancements in home mechanical ventilation device (HMVD) technology, incorporating summarised ventilator (sumVent) indices including the apnoea hypopnea index (AHI) and tidal volume (Vt) for the optimisation of non-invasive ventilation (NIV) therapy in chronic respiratory failure (CRF) is recommended. To date, there has been no evaluation of how these data compare with laboratory polysomnography (labPSG) for the titration of NIV. The aim was to compare the differences in AHI and residual hypercapnia between labPSG versus sumVent data and to examine the effect on clinical usage and mortality. Methods A prospective cohort of 60 individuals with CRF were established on NIV. After 3-months, participants underwent labPSG NIV titration. SumVent 30-day AHI and mean Vt were compared to NIV PSG AHI and paCO2 for assessing ventilation adequacy. Subsequent mortality and clinical contact data were collected over a 3-year period. Results Comparative analysis with Bland–Altman plots of NIV PSG AHI (>10events/hour (n = 25)) with SumVent AHI demonstrated a mean difference (MD) 14.9events/hour (standard deviation (SD)8.1events/hr) with an associated elevated patient ventilator asynchrony (PVA) index (n = 25) mean 36.5events/hr (SD 71events/hr). SumVent Vt demonstrated poor correlation with residual hypercapnia (Pearson coefficient R = -0.06, p=.68). 10 individuals died. 70% of these individuals’ sumVent Vt was within the target range (6-10 mL/kg/min) versus 63% who survived (Χ2 2.14, p=.14). Conclusion There were significant differences between the PSG and sumVent AHI which may be due to PVA. Additionally, relying upon sumVent Vt may fail to identify residual hypercapnia which was associated with mortality in this study.