Screening Tools & Measurement Guides

Proprietary Algorithms & Screening Tool

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Davidson Nasal Function Screening Tool©
Association Between NAR Breathing Disorders and AHI

Measurement Guides

Nasal Flow & Disease Progression

Scale Log 10R (VR, REFF) Flow (ccm/s) Obstruction, Resistance (NR6) Disease Progression Scale
1 < = 0.75 >500 Very Low Normal Breathing
2 0.75 - 1.00 300 - 500 Low Snoring May Occur
3 1.00 - 1.25 180 - 300 Moderate Chronic to Heavy Snoring RDI-RERAS-UARS
4 1.00 - 1.50 60 - 180 High Mild to Moderate OSA
5 >1.50 <60 Very High Hypoventilation (AHI)-Severe OSA

Nasal Volume Normal Values & Ranges

G: Girls | B: Boys

Age (Years) MCA (cm² L+R/2) Distance 0-3 cm³ Decongested Distance 0-5 cm³ Decongested Distance 2-5 cm³ Decongested (most sensitive for patency) Measurement Considerations
Neonates 0.33 0.44 1.19 NA No second notch or MCA2 noted
1 0.43 0.63 1.05 NA No second notch or MCA2 noted
2 0.27 0.75 2.14 NA
3 0.31 0.76 2.59 NA
4 0.30 0.77 2.86 2.43
5 0.32 0.88 2.89 2.49
6 0.35 0.90-1.43 2.92 2.52
7 0.38 0.90-1.43 2.95 2.55
8 0.39 G | 0.37 B 0.90-1.43 3.00 2.56-2.59
9 0.43 G | 0345 B 0.89-1.40 3.36-4.89 2.62 Decongestion will increase NV by 16%
10 0.46 G | 0.41 B 0.89-1.40 3.36-4.89 2.66
11 0.39 G | 0.42 B 1.01-1.52 3.36-4.89 2.70 Natural decrease in volume occurs
12 0.48 G | 0.50 B 1.01-1.52 3.49- 2.73 MCA changes significant for girls 11-13
13 0.53 G | 0.52 B 1.11-1.58 Varies with growth 2.76 Age will vary with growth, but the average increase is 0.32cm³
14 0.52 G | 0.55 B 1.11-1.58 Varies with growth 3.58-3.84 The MCA (CSA) becomes larger in boys
15 0.50 G | 0.54 B 1.14-1.80 Varies with growth 3.58-3.84 MCA changes significant for boys 15-17
16 0.53 G | 0.61 B 1.14-1.80 Varies with growth 3.58-3.84
17 0.58 G | 0.70 B 1.19-1.88 Varies with growth 4.16 May not reach full adult volume size in males at 17 years old.
>18 0.73 1.24-1.91 6.01-8.14 4.48

Adults

Age (Years) MCA (cm² L+R/2) Distance 0-3 cm³ Congested Distance 0-3 cm³ Decongested Distance 2-5 cm³ Congested Distance 2-5 cm³ Deongested Distance 0-5 cm³ Congested Distance 0-5 cm³ Decongested Measurement Considerations
19+ 0.73 1.80-3.34 M | 1.96-3.10 F 2.41-3.97 M | 2.47-3.73 F 2.95-6.47 M | 3.09-5.77 4.06-8.76 M | 4.72-8.40 F 6.01-6.43 7.62-8.14 Congested MCA 0.41-0.67
~20% increase in nasal volume ~25% increase in nasal volume Decongestion at MCA2 opens up with decongestion up to 35%

Disclaimer: This website is not a sole source in determining patient healthcare outcomes and should not be exclusive without a physical exam, patient questionnaire, patient interview of symptoms, or additional diagnostics completed by a licensed healthcare provider. The website is for information and educational purposes to show how nasal airway measurements allow the HCP to objectively quantify the patency of the nasal away and its part in airflow limitations.  It is not medical advice, but based on evidenced based medicine, nasal aerodynamic studies, and validated research over 20+ years using the noninvasive technology methods. The noninvasive, objective nasal measurement processes do not diagnosis a breathing disorder, but allow the HCP to screen and understand how the treatment options are helping for better results towards nasal breathing.  Additional questions and educational assistance on the methods, processes for results, and the theory of nasal aerodynamics may be sent through our website query.

Citations provided by request only.

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