CPAP applied by a nasal mask is the gold standard treatment of obstructive sleep apnea. Oronasal masks are an alternative interface that can be used, especially in subjects with predominant oral breathing. However, oronasal masks have higher costs, are associated with larger leaks and higher residual apnea-hypopnea index, and in some cases may be ineffective.
Nascimento JA, Carvalho TS, Moriya HT, Fernandes PH, Andrade RG, Genta PR, Lorenzi-Filho G, Nakagawa NK. Body position may influence oronasal CPAP effectiveness to treat OSA. J Clin Sleep Med 2016;12(3):447–448.
CPAP applied by a nasal mask is the gold standard treatment of obstructive sleep apnea (OSA). Oronasal masks are an alternative interface that can be used, especially in subjects with predominant oral breathing.1,2 However, oronasal masks have higher costs, are associated with larger leaks and higher residual apnea-hypopnea index (AHI), and in some cases may be ineffective. This case report was approved by the local ethics committee (CEP-FMUSP 102/13).
REPORT OF CASE
A 60-year-old female had loud snoring with suspected OSA and was referred to the sleep outpatient clinic. She complained of excessive diurnal somnolence (Epworth Sleepiness Scale score = 20). On physical examination, her body mass index was 31 kg/m2. She presented a narrow oral cavity (modified Mallampati class IV) with no significant facial anatomy abnormalities. The patient reported difficulty with nasal breathing; however, nasoendoscopy showed no significant nasal obstruction. A full baseline polysomnography (PSG) showed severe OSA (AHI = 80 events/h, minimal oxygen saturation: MinO2Sat = 58%) that was not dependent on supine position (supine and non-supine AHI = 71 and 88 events/h, respectively). A second PSG for continuous positive airway pressure (CPAP) titration was performed using an oronasal mask. CPAP was titrated up to 16 cm H2O with persistent residual events (residual AHI = 10 events/h and MinO2Sat = 84%), which were present at all CPAP levels tested. All obstructive events occurred at the supine position (Figure 1A). A third PSG study for CPAP titration was performed using a nasal mask and showed abolishment of respiratory events with CPAP at 7 cm H2O (residual AHI = 2 events/h and MinO2Sat = 90%) (Figure 1B). CPAP titration was performed manually by a sleep technician on both CPAP titration nights.
(A) CPAP titration up to 16 cm H2O showed a residual AHI of 10 events/h. The patient slept in lateral-decubitus during most of the night. However, observe that obstructive events returned in supine (arrows) and were not dependent on CPAP level that was titrated up to 16 cm H2O. (B) In contrast, nasal CPAP at 7 cm H2O was effective to abolish respiratory events.
(A) CPAP titration up to 16 cm H2O showed a residual AHI of 10 events/h. The patient slept in lateral-decubitus during most of the night. However, observe that obstructive...
OSA treatment with CPAP was first conceived to be applied by a nasal mask because the pressure through the nose would displace the tongue forward. Early clinical observations showed that oronasal interfaces can be an effective alternative, particularly in patients with nasal issues.1,2 However, there is evidence that the use of oronasal interface is associated with higher therapeutic CPAP level, higher leak and lower effectiveness to treat OSA compared to nasal CPAP.3,4 The present clinical case describes one patient with severe OSA who was not adequately treated with CPAP via oronasal mask despite high CPAP levels, but was successfully titrated with a nasal mask to a relatively low CPAP level, independent of body position. When there was a coincidence of oronasal CPAP during supine position, obstructive events were not abolished, despite titration up to 16 cm H2O. In contrast, when lateral decubitus was adopted by the patient using an oronasal interface, a CPAP of 16 cm H2O was able to control obstructive events, probably by decreasing the collapsibility in the pharynx.5 Therefore, the interaction between supine position and the oronasal interface may have resulted in posterior tongue displacement and airway obstruction. Alternatively, the oronasal interface by itself may have led to airway narrowing through posterior mandible displacement, mouth opening, or failure to improve the transmural pressure gradient between nasal and oral cavities, as well as intermediate palatal position resulting from oronasal breathing.6 In conclusion, this is a unique case reporting the interaction between supine positon and CPAP for OSA treatment applied through an oronasal interface that resulted in persistency of obstructive events.
This was not an industry supported study. Financial support was provided by Fundação de Amparo à Pesquisa do Estado de São Paulo (2013/13598-9) and CNPq (470356/2013-8). The authors have indicated no financial conflicts of interest.