Choosing an Oronasal Mask to Deliver Continuous Positive Airway Pressure May Cause More Upper Airway Obstruction or Lead to Higher Continuous Positive Airway Pressure Requirements than a Nasal Mask in Some Patients: A Case Series.
The choice of mask interface used with continuous positive airway pressure (CPAP) therapy can affect the control of upper airway obstruction (UAO) in obstructive sleep apnea (OSA). We describe a case series of four patients with paradoxical worsening of UAO with an oronasal mask and the effect of changing to a nasal mask.



We retrospectively reviewed the case histories of 4 patients and recorded patient demographics, in-laboratory and ambulatory CPAP titration data, CPAP therapy data, type of mask interface used and potential confounding factors.



The 4 cases (mean ± SD: age = 59 ± 16 y; BMI = 30.5 ± 4.5 kg/m(2)) had a high residual apnoea-hypopnea index (AHI) (43 ± 14.2 events/h) and high CPAP pressure requirements (14.9 ± 6.6 cmH2O) with an oronasal mask. Changing to a nasal mask allowed adequate control of UAO with a significant reduction in the average residual AHI (3.1 ± 1.5 events/h). In two of the four cases, it was demonstrated that control of UAO was obtained at a much lower CPAP pressure compared to the oronasal mask (Case one = 17.5 cmH2O vs 12cmH2O; Case two = 17.9 cmH2O vs 7.8 cmH2O). Other potential confounding factors were unchanged. There are various physiological observations that may explain these findings but it is uncertain which individuals are susceptible to these mechanisms.



If patients have OSA incompletely controlled by CPAP with evidence of residual UAO and/or are requiring surprisingly high CPAP pressure to control OSA with an oronasal mask, the choice of mask should be reviewed and consideration be given to a trial of a nasal mask.



A commentary on this article appears in this issue on page 1209.
Adelaide Institute for Sleep Health - a Flinders Centre of Research Excellence and Sleep and Respiratory Medicine, Repatriation General Hospital, Southern Adelaide Local Health Network, Daws Road, Daw Park, South Australia, Australia.
Justin R
JR
Ng
Adelaide Institute for Sleep Health - a Flinders Centre of Research Excellence and Sleep and Respiratory Medicine, Repatriation General Hospital, Southern Adelaide Local Health Network, Daws Road, Daw Park, South Australia, Australia.
Vinod
V
Aiyappan
Adelaide Institute for Sleep Health - a Flinders Centre of Research Excellence and Sleep and Respiratory Medicine, Repatriation General Hospital, Southern Adelaide Local Health Network, Daws Road, Daw Park, South Australia, Australia.
Jeremy
J
Mercer
Adelaide Institute for Sleep Health - a Flinders Centre of Research Excellence and Sleep and Respiratory Medicine, Repatriation General Hospital, Southern Adelaide Local Health Network, Daws Road, Daw Park, South Australia, Australia.
Peter G
PG
Catcheside
Adelaide Institute for Sleep Health - a Flinders Centre of Research Excellence and Sleep and Respiratory Medicine, Repatriation General Hospital, Southern Adelaide Local Health Network, Daws Road, Daw Park, South Australia, Australia.
Ching Li
CL
Chai-Coetzer
Adelaide Institute for Sleep Health - a Flinders Centre of Research Excellence and Sleep and Respiratory Medicine, Repatriation General Hospital, Southern Adelaide Local Health Network, Daws Road, Daw Park, South Australia, Australia.
R Doug
RD
McEvoy
Adelaide Institute for Sleep Health - a Flinders Centre of Research Excellence and Sleep and Respiratory Medicine, Repatriation General Hospital, Southern Adelaide Local Health Network, Daws Road, Daw Park, South Australia, Australia.
Nick
N
Antic
D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000209:etiology*; D045422:Continuous Positive Airway Pressure / Q000295:instrumentation* / Q000379:methods / Q000706:statistics & numerical data*; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008397:Masks / Q000009:adverse effects*; D008875:Middle Aged; D009666:Nose; D009960:Oropharynx; D017286:Polysomnography; D012189:Retrospective Studies; D020181:Sleep Apnea, Obstructive / Q000628:therapy*
CPAP; OSA; equivalence of interfaces; nasal mask; oronasal