Paid for by Oventus Medical
Even a small increase in nasal resistance can mean big trouble for patients on positive airway pressure or oral appliance therapies.
The importance of the nose to successful use of sleep apnea therapy cannot be overstated.
The nose normally contributes up to 50% of the total airway resistance.1 There are numerous factors that contribute to increased nasal resistance, including anatomical factors such as septal deviation, enlarged turbinates, and valvular collapse, as well as external causes such as allergic rhinitis. So when the nose is obstructed in any way, flow is impeded—with resulting difficulty in nasal breathing.
Flow is exquisitely sensitive to even small changes in nasal airway size. This is because flow is related to the 4th power of the radius of a tube (the nasal passage being the tube). If the usable airway is halved in size, flow decreases 16-fold.2
Jerrold A. Kram, MD, FCCP, FAASM, medical director of the California Center for Sleep Disorders, says greater awareness is needed of the nose’s role in the adoption and use of CPAP and oral appliance therapy for obstructive sleep apnea. The nose is an often-overlooked factor in successful implementation and use of sleep apnea therapies.
Incorporating review of nasal symptoms, such as the NOSE scale,3 and rigorous followup has the potential to improve patients’ therapeutic success. A new therapy option exists that may create an opportunity for successful treatment.
Robyn Woidtke, MSN, RN, RPSGT, CCSH, sr. manager, dental-sleep initiatives, Oventus: Can you briefly describe the role of the nose?
Kram: In addition to assisting with speech and housing smell receptors in the mucous membranes, the major function of the nose is the conduction of air into the lungs and to filter, warm, and humidify the air.
Woidtke: What happens to breathing and the airway when the nose has restricted breathing?
Kram: When the functional size of the nose is compromised, the airflow is reduced and becomes turbulent. This increases airway resistance. The increase in nasal airway resistance can lead to mouth breathing.4 Upper airway resistance increases during oral breathing, which may increase the collapsibility of the airway during sleep.5
Woidtke: In your opinion, how would this impact a patient’s ability to use traditional therapy for the treatment of sleep apnea?
Kram: The inability of the patient to breath through their nose—leading to subsequent mouth breathing—can lead to abandonment of sleep apnea therapy, in addition to side effects such as dry mouth and dental issues.6
Woidtke: What percentage of your patients have this issue?
Kram: The literature cites around 50% of patients experience nasal issues with the use of CPAP.7 Our experience is similar and becomes a particular issue if a patient wants to use an oral appliance.
Woidtke: Does the use of full face masks and heated humidification eliminate nasal problems?
Kram: Recent literature has alerted us that full face masks push the mandible posteriorly, which has the potential to increase apnea severity; subsequently, an increase in CPAP pressure is needed. Higher pressure and the size of the mask often lead to PAP intolerance.
We have used heated humidification to mimic the role of the nose with the belief it would benefit patients. In some studies this has led to improved adherence, but many patients don’t experience improvement.8
Woidtke: Nasal steroids are often used to combat the patient’s inability to breathe through the nose. Are there any consequences to using nasal steroids on a long-term basis?
Kram: In a recent metaanalysis, the use of nasal steroids showed some benefits to long-term therapy adherence, but it did not reach statistical significance.9 There are few long-term consequences of using nasal steroids, but there are reports of mucosal thinning and nose bleeds.
Woidtke: What is an alternative approach for patients who report an inability to use their CPAP or oral appliance due to nasal issues?
Oventus O2Vent W
Kram: Oventus O2Vent™ introduces a new modality of treating patients. The device acts as a mandibular advancement device (MAD) but also incorporates an airway channel. This channel mimics the cross-section of the average patient’s nose and bypasses nasal obstruction by providing an oral airway—which eliminates resultant increase in nasal resistance.
Woidtke: Do you see promise in prescribing this type of product in patients who have nasal issues?
Kram: Yes. Patients breathe through their nose to the extent that they can. But when they can’t, air can be rerouted by bypassing the nasal obstruction in a manner to mimic the nose.
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References
1. Lin SJ, Meyers AD, Danahey DG, et al. Nasal Aerodynamics. Medscape. 2015 May 14. Available at https://emedicine.medscape.com/article/874822-overview.
2. Airway Resistance. Johns Hopkins School of Medicine’s Interactive Respiratory Physiology. 1995. Available at http://oac.med.jhmi.edu/res_phys/Encyclopedia/AirwayResistance/AirwayResistance.HTML
3. Stewart MG, Witsell DL, Smith TL, et al. Development and validation of the Nasal Obstruction Symptom Evaluation (NOSE) scale. Otolaryngol Head Neck Surg. 2004 Feb;130(2):157-63.
4. McNicholas WT. The nose and OSA: variable nasal obstruction may be more important in pathophysiology than fixed obstruction. Eur Respir J. 2008 Jul;32(1):3-8.
5. Suzuki M, Furukawa T, Sugimoto A, et al. Relationship between oral flow patterns, nasal obstruction, and respiratory events during sleep. J Clin Sleep Med. 2015 Aug 15; 11(8):855–60.
6. Bachour A, Maasilta P. Mouth breathing compromises adherence to nasal continuous positive airway pressure therapy. Chest. 2004 Oct;126(4):1248-54.
7. Michels Dde S, Rodrigues Ada M, Nakanishi M, et al. Nasal involvement in obstructive sleep apnea syndrome. Int J Otolaryngol. 2014:717419.
8. Lasters F, Mallegho C, Boudewyns A, et al. Nasal symptoms in patients with obstructive sleep apnea and their impact on therapeutic compliance with continuous positive airway pressure. Acta Clin Belg. 2014 Apr;69(2):87-91.
9. Charakorn N, Hirunwiwatkul P, Chirakalwasan N, et al. The effects of topical nasal steroids on continuous positive airway pressure compliance in patients with obstructive sleep apnea: a systematic review and meta-analysis. Sleep Breath. 2017;21:3.
