Prevalence and consequences of patient–ventilator interactions in a cohort of home-ventilated restrictive and neuromuscular patients: a multicentre study

Aims Analysis of patient-ventilator interactions in patients on chronic home mechanical ventilation can be time consuming, and the consequences of individual interaction on pulmonary gas exchange are not well understood. The objective was to analyse the relationship between interactions and nocturnal oximetry and arterial blood gases. Methods A cross-sectional study was carried out in restrictive and neuromuscular patients who underwent respiratory polygraphy with a system that allowed interactions to be correlated with mean saturation in 5-min periods. Unintentional leaks, periodic decreases in flow and primary patient-ventilator asynchronies were analysed. Each interaction was correlated with mean oxygen saturation measured by pulse oximetry (SpO2) and baseline arterial blood gases obtained at the recruitment visit, and the 5-min SpO2 analysis was individualised for each patient based on their mean +/- sd SpO2 during polygraphy. Results 40 patients were included. There was a correlation between interactions and mean SpO2 in periods with mean accidental leak >20 Lmin-1 (ANOVA test). After exclusion of periods with leakage above this threshold, a relationship was documented between periodic decreases in flow and asynchronies with mean SpO2 in 5-min periods. However, there was no relationship between patient-ventilator interactions and baseline arterial blood gases at recruitment. Conclusion The presence of interactions was associated with a decrease in mean SpO2 when 5-min recordings are analysed. Therefore, it seems advisable to systematically detect and correct patient-ventilator interactions in home mechanical ventilated patients.