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We have developed mathematical formulas to compare the expected mean drops in AHI in CPAP therapy and sleep surgery. We published our theory, formulas,
graphs and results in an article titled: Reliable Calculation of the Efficacy of Non-surgical and Surgical treatment of Obstructive Sleep apnea, in the
Journal Sleep^{3}.

As to make to these formulas more accessible for clinical practice, we developed this website and **the apnea calculator!**

The calculator can help to:

- Calculate the mean AHI over the night
- Calculate the percentage of total sleep time CPAP must be used to reduce the AHI below 5
- Calculate the percentage of total sleep time CPAP must be used to reduce the AHI below 10
- Calculate whether a patient may be suffering from positional OSA (POSA)

The results can be used to calculate the efficacy of the current treatment, measure the minimum amount of sleep time needed to be cured of OSA and to motivate patients to use CPAP. However, if the CPAP is not used sufficiently, other treatment modalities might be preferable.

All you need is

- The baseline AHI
- AHI whilst using CPAP
- Average hours of CPAP use per night
- And the average total sleeping time
- Percentages of various sleep positions, for calculations of POSA

On the site you will find more background information and explanation of the terms, as well as the calculators. We hope you find the site helpful and easy to use!

Nico de Vries & Madeline Ravesloot

^{3}MJL Ravesloot, N. de Vries. Reliable calculation of the efficacy of non-surgical and surgical treatment of obstructive sleep apnea revisited. Sleep 2011 Jan 1;34(1):105-10.