Home mechanical ventilation through mask: monitoring leakage and nocturnal oxygenation at home.

BACKGROUND Leakage is common in patients receiving home mechanical ventilation (HMV) via a face mask. Although pressure ventilators have partial compensatory capacity, excessive leakage can compromise the effectiveness of treatment. Home ventilators are equipped with built-in software which provides information on leakage. However, the values of leakage and their effects in routine clinical practice are currently little known. OBJECTIVE To measure leakage in stable patients on nocturnal HMV and its impact on treatment effectiveness. METHODS Consecutive outpatients on HMV were recruited. Nocturnal pulse oximetry was performed at home and leakage was measured using the ventilator's built-in software. We measured: mean SpO(2), percentage of time with SpO(2) <90% (T90), mean leakage (meanL), maximum leakage (maxL), and minimum leakage (minL) during the ventilation session. We estimated ventilator capacity to compensate for leakage according to inspiratory positive airway pressure and divided the patients into two groups: those with leak compensation and those without. RESULTS The study included 41 patients [mean age, 64 years (SD 11.9); 23 (56%) women]. Nocturnal pulse oximetry showed an SpO(2) of 94% (±2.9) and a T90 of 10% (±21.7). Leakage (in l/min) was: meanL, 32.2 (±15.3); maxL, 64.8 (±28.5), and minL, 18.8 (±10.6). Seven cases (17%) had leakage greater than the ventilator compensatory capacity, but no significant difference in SpO(2) or T90 was observed between patients with or without leak compensation. CONCLUSIONS A wide variation between maxL and minL was observed in our series; 17% of cases had higher leakage values than the compensatory capacity of the ventilator, but this did not affect nocturnal oxygenation.