P070 Oronasal masks are associated with increased airway collapsibility and increased therapeutic CPAP requirements

Introduction Continuous positive airway pressure (CPAP) delivered via oronasal masks are associated with lower adherence, higher residual AHI and CPAP requirement in comparison to nasal masks. Mechanisms contributing to increased CPAP requirement are not well understood. This physiological study aimed to assess the effect of mask type on upper airway anatomy and collapsibility. Methods 13 OSA patients, underwent a sleep study during which they wore both nasal and oronasal mask for half the night each (order randomized). CPAP was manually titrated to determine therapeutic pressure. Passive upper airway collapsibility was assessed using the Pcrit technique. Participants then underwent an MRI wearing both the nasal and oronasal mask. Cine MRI was used to dynamically assess cross-sectional area of the retroglossal airway across the respiratory cycle with each mask interface. Scans were repeated at 4cmH2O, as well as at the nasal and oronasal therapeutic pressures. Results The oronasal mask was associated with both higher therapeutic pressure requirements (∆M±SEM; +2.6±0.5, p<0.001) and higher Pcrit (+2.4±0.5cmH2O, p=0.001) compared to the nasal mask. The change in therapeutic pressure between masks was strongly correlated with the change in Pcrit (r2= 0.73, p=0.003). Preliminary MRI analyses indicate robust increases in cross-sectional area associated with increasing pressure. After controlling for pressure and breath-phase, the retroglossal area was larger when using a nasal compared to an oronasal mask (+12.42±5.87mm2, p=0.03). Conclusions These preliminary findings suggest that oronasal masks worsen the collapsibility of the airway which likely contributes to the need for an elevated therapeutic pressure relative to nasal masks.

CPAP - The choice of the mask does matter

We present a case of a patient with uncorrected Obstructive Sleep Apnea (OSA) despite good CPAP compliance with an oronasal mask who was referred to our tertiary care multidisciplinary sleep unit. We present here our systematic and comprehensive re-evaluation of the case, accompanied by an image of the polysomnography recordings that exemplify each step in the process, which concludes with a change to nasal CPAP and a transition to BPAP treatment. Keywords: obstructive sleep apnea; CPAP; BPAP; oronasal mask; nasal mask.

NIV Is not Adequate for High Intensity Endurance Exercise in COPD

Noninvasive ventilation (NIV) during exercise has been suggested to sustain higher training intensity but the type of NIV interface, patient-ventilator asynchronies (PVA) or technological limitation of the ventilator may interfere with exercise. We assessed whether these parameters affect endurance exercise capacity in severe COPD patients. In total, 21 patients with severe COPD not eligible to home NIV performed three constant workload tests. The first test was carried out on spontaneous breathing (SB) and the following ones with NIV and a nasal or oronasal mask in a randomized order. PVA and indicators of ventilator performance were assessed through a comprehensive analysis of the flow pressure tracing raw data from the ventilator. The time limit was significantly reduced with both masks (406 s (197–666), 240 s (131–385) and 189 s (115–545), p < 0.01 for tests in SB, with oronasal and nasal mask, respectively). There were few PVA with an oronasal mask (median: 3.4% (1.7–5.2)) but the ventilator reached its maximal generating capacity (median flowmax: 208.0 L/s (189.5–224.8) while inspiratory pressure dropped throughout exercise (from 10.1 (9.4–11.4) to 8.8 cmH2O (8.6–10.8), p < 0.01). PVA were more frequent with nasal mask (median: 12.8% (3.2–31.6), p < 0.01). Particularly, the proportion of patients with ineffective efforts > 10% was significantly higher with nasal interface (0% versus 33.3%, p < 0.01). NIV did not effectively improve endurance capacity in COPD patients not acclimated to home NIV. This was due to a technological limitation of the ventilator for the oronasal mask and the consequence either of an insufficient pressure support or a technological limitation for the nasal mask.

The Importance of Mask Type and Mask Materials in Sleep Apnea Patients

Mask is an important prognostic factor in patient�s compliance to positive airways pressure. As there are a lot�s of factors that contribute to a good interface choosing the right mask remains a challenge. The aim of this study was to evaluate the importance of mask and mask materials in treatment compliance to positive airway pressure in a sample of Romanian patients hospitalized for sleep study. Other factors that may have influence on the compliance were also evaluated (severity of sleep apnea, the presence of symptoms, comorbidities and the type of device used (CPAP or BiPAP). 107 patients with newly diagnosed sleep apnea were included. They received positive airways pressure treatment with nasal or oronasal mask depending on their own preference and tolerance and they were followed for one year. After one year 70% of 107 patients were still on positive airway pressure treatment (CPAP or BiPAP). There seemed to be no difference between the two masks when looking at the whole group. When analyzing the subgroups, however there seemed to be a preference for the nasal mask in patients who were treated with CPAP and oronasal mask in patients treated with BiPAP, suggesting that the associated conditions (COPD) might play an more important role than the mask itself. The materials did not influence the compliance.