Evaluating noninvasive ventilation using a monitoring system coupled to a ventilator: a bench-to-bedside study

Abstract

Empirically determined noninvasive ventilation (NIV) settings may not achieve optimal ventilatory support. Some ventilators include monitoring modules to assess ventilatory quality. We conducted a bench-to-bedside study to assess the ventilatory quality of the VPAPIII-ResLink (ResMed, North Ryde, Australia). We tested the accuracy of minute ventilation (MV) and leak calculations given by VPAPIII-ResLink compared to those measured by a bench model at varied leak levels and ventilator settings. We systematically assessed NIV efficacy using this system from 2003 to 2006. Ventilation was considered inadequate if leak (>24 L x min(-1)), continuous desaturation (>30% of the trace) or desaturation dips (>3%) were present. On the bench test, both methods were highly correlated (r = 0.947, p>0.0001 and r = 0.959, p<0.0001 for leak and MV, respectively). We performed 222 assessments in 169 patients (aged 66.42+/-16 yrs, 100 males). Abnormalities were detected on 147 (66%) out of 222 occasions. Leak was the most common abnormality (34.2%) followed by desaturation dips (23.8%). The most effective therapeutic solutions were a chin strap if leak was detected (61.2%) and expiratory positive airway pressure increase for desaturation dips (59.5%). In 15.7% of cases, when abnormalities persisted, a polygraphy was performed. The systematic use of this device enables NIV to be optimised, limiting the indication of sleep studies to complex cases.