• Sinonasal cilia functions similarly to lower airway cilia, therefore testing nasal mucociliary transport is accepted as representative of pulmonary clearance.
• 1 mm saccharin particle placed onto medial surface of inferior turbinate, 1 mm posterior to anterior head
• Patient must hold head flexed to 10 degrees, must not cough, sneeze, sniff, or take PO.
• Patient notifies examiner when saccharin taste is appreciated.
1. Normal: ≤20 minutes
2. Prolonged: 21 to 30 minutes
3. Severely prolonged: 31 to 60 minutes
4. Grossly prolonged: >60 minutes
• Pros: useful screening technique; materials are readily available and inexpensive; non-invasive, easy to perform
• Cons: non-specific; affected by taste threshold of patient (can be combined with colored dye to improve detection); results can be affected by multiple factors
• If positive for prolonged clearance, referral for further testing for primary ciliary dyskinesia, cystic fibrosis, or consideration of secondary ciliary dysfunction necessary
• Technetium-based particles (ie, albumin, resin) placed at inferior turbinate similar to saccharin test and percent of remaining radiation measured after 30 minutes
• Sensitive test for measuring objective changes within setting of paranasal surgery follow-up as well as following efficacy of nasal medications
• Pros: not influenced by sniffing
• Cons: limited by price, availability of materials; lack of human study confirming reproducibility; radiation exposure (although very low); false positives
Nasal Nitric Oxide (nNO) Testing
• Patients with primary ciliary dyskinesia tend to have 10× less nasal nitric oxide than control subjects.
• Screening test for PCD
• Pros: non-invasive and inexpensive
• Subjective nasal patency has traditionally been considered a factor of nasal resistance.
• Although resistance and subjective nasal patency are interrelated, data have also shown increased sensation of nasal patency with mucosal cooling without reduction in nasal resistance.
• The nasal valve (within the first 2 to 4 cm of the nasal cavity) is the area of greatest resistance within the nasal cavity and is commonly thought to be the most clinically relevant anatomic unit in regard to nasal airflow.
• Even though the most important metrics for assessment of nasal airflow are patient symptoms, objective assessments are useful and attempt to identify objective targets for therapeutic and/or surgical intervention.
• Nasal exam +/− endoscopy is essential for clinical correlation.
• Objective tests typically correlate better with patient symptoms (a) when a patient is symptomatic (ie, suffers from nasal airway obstruction) and (b) the larger the measured differences measured between a patient’s two nasal cavities (ie, correlation with subjective scores improves when one nasal cavity is severely obstructed and the other is widely patent versus two similarly obstructed nasal cavities).
1. Correlations have been observed between nasal resistance and patient symptoms before and after surgical intervention; however, this does not necessarily imply causation.
• Inspiratory or expiratory flow
1. Inspiratory better correlates with nasal resistance.
• Pros: fast, simple, minimal equipment, readily available/portable; of all techniques, most reproducible results during repeated measurements of a single patient (ie, following patient response to medication)
• Cons: relies on patient cooperation and effort; conflicting evidence regarding sensitivity compared to rhinomanometry for detecting changes in nasal patency following pharmaceutical (ie, histamine) challenge
• Measures transnasal pressure and airflow simultaneously
• Anterior (most common), posterior, and postnasal techniques described
• Resistance recorded at maximum flow and pressure during normal respiration was found to correlate best with patient symptoms.
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