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Sleep Apnea Research Group


  Nasal Airway and CPAP Outcomes


Abnormalities on Nasal Exam Associated with Decreased CPAP Tolerance and Use

Principal Investigators: Noelle Husen, MD; Edward M. Weaver, MD, MPH
Co-Investigators: Vishesh Kapur, MD, MPH; Nicole Maronian, MD; Nathaniel F. Watson, MD

Poor tolerance and inadequate use are the greatest limitations to CPAP therapy for sleep apnea. This retrospective cohort study evaluated 306 patients who were prescribed CPAP therapy for sleep apnea at the University of Washington’s Sleep Disorders Center during the period January 2000 thru August 2002. Nasal exam findings, polysomnography and CPAP data were extracted from medical charts.

Abnormal nasal findings (e.g. turbinate hypertrophy, septal deviation) were dichotomized as abnormality yes or no. The variable for CPAP tolerance was dichotomized as tolerated well (and using as recommended) vs. not tolerating well (using less than recommended).

Results - 108 (35%) of patients studied had an abnormal nasal exam and of the 200 patients with follow up CPAP data available 145 (73%) were using CPAP, and 68 (34%) were tolerating CPAP well. On multivariate analysis, the adjusted odds ratio for CPAP tolerance was 0.42 (95%CI 0.20, 0.90; p=0.03) for those with an abnormal exam relative to those without abnormal exam. The adjusted odds ratio for CPAP use was 0.32 (95%CI 0.15, 0.66; p=0.003) for those with an abnormal exam relative to those without an abnormal exam, adjusting for body mass index, apnea-hypopnea index, and titration method.

Conclusions - Patients with an abnormal nasal exam, but not nasal symptoms, were found to have decreased CPAP use and tolerance (Figure 1). This fact should be confirmed with a prospective cohort study. These data suggest that treatment of nasal conditions should be considered before prescribing CPAP as this may improve CPAP tolerance and use.

Abstract: Abnormalities on Nasal Exam Associated with Decreased CPAP Tolerance and Use


Radiofrequency Treatment of Turbinate Hypertrophy in Subject Using Continuous Positive Airway Pressure: A Randomized, Double-Blind, Placebo-Controlled Clinical Pilot Trial

Principal Investigator: Nelson B. Powell, MD
Co-Investigators: Adriane I. Zonato, MD; Edward M. Weaver, MD, MPH; Kasey Li, DDS, MD; Robert Troell, MD; Robert W. Riley, DDS, MD; Christian Guilleminault, MD

Laryngoscope 111(10):1783-90, October 2001

Patients using nasal continuous positive airway pressure (CPAP) devices for sleep disordered breathing and have nasal complaints, may benefit from treatment of the shrinkable turbinate tissues in the nose. This prospective, randomized, double-blind, placebo-controlled trial was conducted at Stanford Sleep Disorders and Research Center and included twenty-two CPAP treated patients randomized to turbinate treatment (n=17) or placebo control (n=5).

The primary outcome in this trial was assessed changes in blinded examiner’s findings of nasal obstruction on a visual analogue scale. Secondary outcomes included blinded patients’ and unblinded examiner assessments of nasal obstruction, nightly CPAP use, adherence, and tolerance, along with sleepiness and general health status scales. Findings in the treatment group were subtracted from the changes in the placebo group to yield treatment effect.

Results: The primary outcome treatment effect by visual analog scale was -0.9 cm (95% CI -2.4, 0.7) and beyond the placebo effect of -1.5cm (95%CI -3.4, 0.3). The secondary treatment effect of the unblinded examiner was -3.0cm (95%CI -4.9, -1.1). A beneficial treatment effect was also seen on every other secondary outcome (except general health status) but only self-reported CPAP adherence was statistically significant (p=0.03).

Conclusions: Temperature controlled turbinate treatment appears to benefit nasal obstruction and CPAP treatment for sleep disordered breathing. A future trial should be done to establish statistical significance of these findings.

Article: Radiofrequency Treatment of Turbinate Hypertrophy in Subjects Using Continuous Positive Airway Pressure: A Randomized, Double-Blind, Placebo-Controlled Clinical Pilot Trial


Nasal Obstruction and CPAP Outcomes Cohort Study

Principal Investigator: Edward M. Weaver, MD, MPH
Co-Investigators: Richard Deyo, MD, MPH; Vishesh Kapur, MD, MPH; Michael Vitiello, PhD; Allan I. Pack, MB, ChB, PhD; Derek Lam, MD

Introduction:
Obstructive sleep apnea syndrome is defined as symptomatic repetitive obstruction of the upper airway during sleep (1) and occurs in 2 – 4% of adults (2). Nasal CPAP is the first line treatment for sleep apnea due to its safety and efficacy. Wearing the device usually normalizes physiologic sleep parameters and may reduce the risk of medical complications associated with sleep apnea(3-5). CPAP users have improved symptoms, function, and quality of life(6, 7).

Inadequate use is the major limitation to CPAP therapy(8, 9). Emerging data indicate 6 hours per night is required for adequate effect(8), yet objective measures suggest < 35% of CPAP patients meet this threshold (10, 11). We hypothesize that nasal obstruction is associated with decreased CPAP use and ultimately reduced CPAP treatment effect.

This prospective cohort study is currently underway at the University of Washington’s Sleep Disorders Center in Seattle, WA. The Seattle Sleep Cohort is comprised of patients recruited at the time of initial polysomnography in the Sleep Lab and are being followed for six months. The current rate of enrollment is approximately three hundred per year. Participants are asked to complete a questionnaire and undergo non-invasive nasal measurements at baseline as well as complete a follow-up questionnaire at six months.

This observational cohort study will be useful for prognosticating outcomes in new CPAP patients. This information will help identify patients who may require extra attention with CPAP and may ultimately benefit from nasal surgery. It may also help define the level of nasal obstruction that impacts CPAP usage and quality of life outcomes.

Research Questions

Specific Aim - To determine whether nasal obstruction influences CPAP treatment outcomes above and beyond other behavioral and biomedical factors.

Primary Hypothesis - Among patients prescribed CPAP for sleep apnea, those with nasal obstruction experience less improvement in sleep apnea quality of life than those without nasal obstruction.

Secondary Hypothesis - Among patients prescribed CPAP for sleep apnea:
•  those with nasal obstruction use CPAP less than those without nasal obstruction
•  those with nasal obstruction require higher CPAP pressure than those without nasal obstruction, controlling for sleep apnea severity.
•  there are "dose-response" relationships between the severity of baseline nasal obstruction and CPAP pressure level, CPAP usage, and degree of improvement in sleep apnea quality of life.

Measures:
In this study, the nasal airway is measured objectively and subjectively. The primary objective measure is obtained via acoustic rhinometry. Acoustic rhinometry is objective, validated, reliable, clinically useful, quick and easy to perform, noninvasive, inexpensive, and widely used for measuring the nasal airway (12,13). It uses acoustic reflectance to produce a profile of the cross-sectional area across the full length of the nasal cavity.


Selected Bibliography
  1. Sleep-related breathing disorders in adults: Recommendations for syndrome definition and measurement techniques in clinical research. The report of an american academy of sleep medicine task force. Sleep 1999; 22:667-89.

  2. Young T, Palta M, Dempsey J, Skatrud J, Weber S, Badr S. The occurrence of sleep-disordered breathing among middle-aged adults. N Engl J Med 1993; 328:1230-5.

  3. Peker Y, Hedner J, Norum J, Kraiczi H, Carlson J. Increased incidence of cardiovascular disease in middle-aged men with obstructive sleep apnea: A 7-year follow-up. Am. J. Respir. Crit. Care Med. 2002; 166:159-65.

  4. Cassel W, Ploch T, Becker C, Dugnus D, Peter JH, von Wichert P. Risk of traffic accidents in patients with sleep-disordered breathing: Reduction with nasal cpap. European Respiratory Journal 1996; 9:2606-11.

  5. He J, Kryger MH, Zorick FJ, Conway W, Roth T. Mortality and apnea index in obstructive sleep apnea. Experience in 385 male patients. Chest 1988; 94:9-14.

  6. Jenkinson C, Davies RJ, Mullins R, Stradling JR. Comparison of therapeutic and subtherapeutic nasal continuous positive airway pressure for obstructive sleep apnoea: A randomised prospective parallel trial. Lancet 1999; 353:2100-5.

  7. Woodson BT, Steward DL, Weaver EM, Javaheri S. A randomized trial of temperature-controlled radiofrequency, continuous positive airway pressure, and placebo for obstructive sleep apnea syndrome. Otolaryngol Head Neck Surg 2003; 128:848-61.

  8. Weaver T, Maislin G, Venditti L, Mahowald M, Kader G, Bloxham T, George C, Greeberg H, Younger J, Dinges D, Pack A. Cpap dose duration for effective outcome response. Am J Respir Crit Care Med 2003; 167:A324.

  9. Grote L, Hedner J, Grunstein R, Kraiczi H. Therapy with ncpap: Incomplete elimination of sleep related breathing disorder. Eur Respir J 2000; 16:921-7.

  10. Kribbs NB, Pack AI, Kline LR, Smith PL, Schwartz AR, Schubert NM, Redline S, Henry JN, Getsy JE, Dinges DF. Objective measurement of patterns of nasal cpap use by patients with obstructive sleep apnea. Am Rev Respir Dis 1993; 147:887-95.

  11. Pepin JL, Krieger J, Rodenstein D, Cornette A, Sforza E, Delguste P, Deschaux C, Grillier V, Levy P. Effective compliance during the first 3 months of continuous positive airway pressure. A european prospective study of 121 patients. Am J Respir Crit Care Med 1999; 160:1124-9.

  12. Hilberg O. Objective measurement of nasal airway dimensions using acoustic rhinometry: Methodological and clinical aspects. Allergy 2002; 57:5-39.

  13. Pallanch JF, McCaffrey TV, Kern EB.Chapter 42. Evaluation of nasal breathing function with objective airway testing. In: CW Cummings, editor, translator and editor Otolaryngology head & neck surgery. 3rd edn. Vol. 2. St. Louis, MO: Mosby--Year Book, Inc.; 1998; p. 799-832.

  14. Min YG, Jang YJ. Measurements of cross-sectional area of the nasal cavity by acoustic rhinometry and ct scanning. Laryngoscope 1995; 105:757-9.

  15. Mamikoglu B, Houser S, Akbar I, Ng B, Corey JP. Acoustic rhinometry and computed tomography scans for the diagnosis of nasal septal deviation, with clinical correlation. Otolaryngol Head Neck Surg 2000; 123:61-8.

  16. Terheyden H, Maune S, Mertens J, Hilberg O. Acoustic rhinometry: Validation by three-dimensionally reconstructed computer tomographic scans. J Appl Physiol 2000; 89:1013-21.

  17. Corey JP, Gungor A, Nelson R, Fredberg J, Lai V. A comparison of the nasal cross-sectional areas and volumes obtained with acoustic rhinometry and magnetic resonance imaging. Otolaryngol Head Neck Surg 1997; 117:349-54.

  18. Corey JP, Nalbone VP, Ng BA. Anatomic correlates of acoustic rhinometry as measured by rigid nasal endoscopy. Otolaryngol Head Neck Surg 1999; 121:572-6.

  19. Grymer LF, Hilberg O, Pedersen OF, Rasmussen TR. Acoustic rhinometry: Values from adults with subjective normal nasal patency. Rhinology 1991; 29:35-47.

  20. Lenders H, Schaefer J, Pirsig W. Turbinate hypertrophy in habitual snorers and patients with obstructive sleep apnea: Findings of acoustic rhinometry. Laryngoscope 1991; 101:614-8.

  21. Grymer LF, Hilberg O, Pedersen OF. Prediction of nasal obstruction based on clinical examination and acoustic rhinometry. Rhinology 1997; 35:53-7.

  22. Corey JP, Kemker BJ, Nelson R, Gungor A. Evaluation of the nasal cavity by acoustic rhinometry in normal and allergic subjects. Otolaryngol Head Neck Surg 1997; 117:22-8.

  23. Roithmann R, Cole P, Chapnik J, Sergio MB, Szalai JP, Zamel N. Acoustic rhinometry, rhinomanometry, and the sensation of nasal patency: A correlative study. J Otolaryngology 1994; 23:454-8.

  24. Rasmussen TR, Andersen A, Pedersen OF. Particle deposition in the nose related to nasal cavity geometry. Rhinology 2000; 38:102-7.

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