The aims of the study were (1) to describe the respiratory events during noninvasive positive pressure ventilation (NPPV) and, (2) to analyze the clinical consequences.
Nocturnal polygraphic (PG) recordings were performed in stable patients. Respiratory events were scored using the SomnoNIV Group definitions [1]. The consequences of an event i.e. a fall of ≥ 3% of pulse oximetry (SpO2) and/or a ≥ 30% decrease in pulse rate amplitude (respiratory autonomic micro-arousals: RAM) were described.
PG tracings of 27 patients (13 boys, age range 1-18) were analysed: neuromuscular disease (n=7), obstructive sleep apnea (n=8) and lung disease (n=12). Unintentional leaks, partial or total upper airway obstruction without reduction of ventilatory drive, a decrease in ventilatory drive, mixed events, and patient ventilator asynchronies were observed in 61%; 37%; 28%; 7%; 53% of the patients, respectively. These events were associated with a decrease of SpO2 in 21%; 37%; 18%; 4%; 12% of the patients respectively, and with a RAM in 38%; 27%; 8%; 3%; 32% of the patients respectively. The mean number of type of events per patient was 1.8±1.1. For a given patient, there was a predominant event representing 87 ± 10% of total time with respiratory events. The median duration spend in respiratory event was 39% (range 0.7 to 92%) of total recording time. Of the patients with a minimal nocturnal SpO2 >90% and a PtcCO2 <50mmHg, 12 (44%) had at least one respiratory event.
Respiratory events are common in stable children treated with long term NPPV and can be associated with desaturations and/or RAM.
1. Gonzalez J et al. Thorax 2011.