Four Studies Evaluate the Effectiveness of Optical Rhinometry
Otorhinolaryngologists at The University of Texas Health Science Center at Houston (UTHealth) Medical School are engaged in research efforts that move medicine forward into the future. They presented the results of a capsaicin challenge study using optical rhinometry in non-allergic irritant rhinitis – the fourth in a series of studies evaluating the use of optical rhinometry in the assessment of rhinitis – at the 2012 American Academy of Otolaryngic Allergy (AAOA) Annual Meeting in Washington, D.C.
In a 2010 study published in Otolaryngology Head and Neck Surgery , researchers The University of Texas Health Science Center at Houston (UTHealth) Medical School evaluated the effectiveness of optical rhinometry in assessing nasal congestion using nasal provocation testing in allergic and nonallergic subjects. A relatively new method of assessing nasal airway patency, the optical rhinometer uses a wavelength light emitter and an optical sensor placed across the bridge of the nose to detect changes in blood flow into the nasal mucosa. The study was the first to demonstrate a correlation between subjective symptoms of nasal patency and objective measures with the optical rhinometer during challenges with histamine and oxymetazoline in both healthy controls and patients with allergic rhinitis.
Since that time, the UTHealth research team published a follow-up study that was the first to show, during nasal provocation testing with Dermatophagoides farinae, a correlation between optical rhinometry and acoustic rhinometry, the gold standard for measuring nasal congestion. The results suggested that optical rhinometry is effective in assessing nasal reactions to challenges with a common allergen – dust mites .
“In nasal provocation testing, we introduce the antigen into the nasal cavity and then monitor the response,” says Amber U. Luong, MD, PhD, an assistant professor and director of research in the Department of Otorhinolaryngology-Head and Neck Surgery at McGovern Medical School. “If the nasal mucosa swells from an influx of blood and the nasal airway is reduced, we can detect these changes with the optical rhinometer by a change in optical density. The principle of the device is very similar to a pulse oximeter used to measure oxygen in the blood.”
Dr. Luong was also the senior investigator of a follow-up study using nasal provocation testing to identify patients with sensitivity to molds . “Because it worked well with dust mite antigen, we moved on to test other allergens and chose mold because it is a major allergen in the Houston area.”
Twenty-two patients – 11 healthy controls and 11 with allergic rhinitis – were enrolled in the study, which was funded by the American Academy of Otolaryngic Allergy (AAOA) and presented by resident Garima Agarwal, MD, at the AAOA 2011 Annual Meeting in San Francisco. Both acoustic and optical rhinometry had a poor association with the presence of a positive skin test to mold. “When we nasally challenged patients who had hypersensitivity to molds based on skin testing, their symptoms worsened, but we didn’t see a consistent objective increase in nasal blood flow or decrease in nasal area, either with optical or acoustic rhinometry,” says Dr. Luong, a physician scientist who holds joint appointments in the Department of Otorhinolaryngology-Head and Neck Surgery and in the Institute of Molecular Medicine within the Center for Immunology and Autoimmune Diseases at McGovern Medical School. “Our overall conclusion, unlike the dust mite study, was that the presence of positive skin testing by molds does not correlate with increased nasal congestion in response to a nasal challenge with that mold. As allergens, molds are a unique family and may be more complicated than other allergens, like ragweed, that are associated with allergies.”
The results of a fourth optical rhinometry study, also funded by the AAOA, were presented by resident Elton Lambert, MD, at the 2012 annual meeting held in Washington, D.C. Six healthy controls and six patients with non-allergic irritant rhinitis (NAIR) were challenged intranasally with saline solution followed by increasing concentrations of capsaicin at 15-minute intervals. The researchers recorded maximum optical density (OD) and visual analog scale (VAS) scores for nasal irritation, nasal congestion and rhinorrhea at various concentrations of capsaicin between the two groups.
Based on the correlation between OD and VAS scores, the investigators concluded that optical rhinometry with intranasal capsaicin challenge could prove to be a viable option in the diagnosis of non-allergic irritant rhinitis. Future studies will investigate its use to monitor a patient’s response to pharmacologic therapy and provide more information about the underlying mechanisms of NAIR.
1. Luong A, Cheung EJ, Citardi MJ, Batra PS. Evaluation of optical rhinometry for nasal provocation testing in allergic and nonallergic subjects. Otolaryngology Head and Neck Surgery, 2010, Aug;143(2):284-9.
2. Cheung EJ, Citardi MJ, Fakhri S, Cain J, Batra PS, Luong A. Comparison of optical rhinometry to acoustic rhinometry using nasal provocation testing with Dermatophagoides farinae. Otolaryngology Head and Neck Surgery, 2010 Aug;143(2):290-3. Epub 2010 Jun 8.
3. Agarwal G, Hernandez D, Citardi MJ, Fakhri S, Luong A. Poor correlation of nasal provocation testing in fungi-sensitive patients with either acoustic or optical rhinometry. Presented at the 2011 American Academy of Otolaryngic Allergy Fall Meeting in San Francisco.
4. Lambert EM, Patel C, Fakhri S, Citardi MJ, Luong A. Optical rhinometry in non-allergic irritant rhinitis (NAIR): A capsaicin challenge study. Presented at the 2012 American Academy of Otolaryngic Allergy Fall Meeting in Washington, D.C.