AeroFlow Inc. Blog

Home Sleep Testing Clarified

With the emergence of home sleep testing, there has been some confusion regarding the indications for home sleep testing. This letter is an attempt to provide clarity on the use of home sleep testing. Patients should be prescreened for sleep apnea before using any home sleep testing program.

It is important to use a validated screening tool. The Berlin questionnaire is
the most validated screening tool, but unfortunately it is not easy to use or score.

http://www.swclab.com/images/PDFS/Berlin-Questionnaire.pdf

However, the Stop-Bang questionnaire is extremely simple!

http://www.newent.com/FCKeditor/UserFiles/file/Forms/STOP%20BANG.pdf

 If the patient answers yes to any 3 of the questions – they are at high risk for sleep apnea. Home sleep testing should only be used in patients who are at high risk for sleep apnea. Anyone who screens positive to the Stop-Bang questionnaire is high risk.

The Watermark Ares home testing device performs level 2 sleep studies. Level 2
studies measure indices of both sleep and breathing. These studies have proven to be
equivalent to laboratory testing for the assessment of sleep apnea.

Most home testing equipment performs level 3 sleep studies which only record indices of breathing. Level 3 studies are also appropriate for testing for sleep apnea. A positive level 3 study is sufficient for the diagnosis of sleep apnea.

However a negative level 3 study in a high risk patient does not rule out sleep apnea and necessitates a laboratory study.  Home sleep testing is not appropriate for patients who are not at high risk for obstructive sleep apnea. It is also contraindicated in circumstances in which the accuracy of the testing equipment may be altered.

The most common scenario that will decrease the accuracy of a home sleep testing device is the use of nasal oxygen. This is because nasal airflow is usually measured by monitoring nasal pressure changes at the nose. The slightly positive pressure of nasal oxygen can alter the signal.

Continuous positive airway pressure (CPAP) is the preferred therapy for sleep apnea.
There are 2 big categories of CPAP: traditional fixed pressure CPAP machines and autotitrating CPAP machines. These have been shown to be equivalent in the treatment of obstructive sleep apnea in multiple clinical trials.

They are both recognized as an acceptable treatment for sleep apnea by the American Academy of Sleep Medicine.

http://www.aasmnet.org/

 Fixed pressure CPAP machines require a study to determine the best pressure for treatment. Auto-titrating CPAP machines are equipped with a microprocessor that constantly monitors the patient’s breathing. 

If an increase in airway resistance is noted, CPAP pressure is slowly increased. Therapy with an auto-titrating CPAP machine can be initiated in the home. Cost and convenience are the two areas that differ greatly between laboratory and home based testing and treatment. Home sleep testing is roughly one-seventh the cost of laboratory testing!

In summary, it is no longer necessary to send your routine sleep apnea patients to a sleep laboratory. The use of an auto-titrating CPAP machine can eliminate the need for a second sleep study.  High quality, more cost effective care can be provided in the comfort and convenience of the home.

Please contact Aeroflow Healthcare at 888-345-1780 if we can be of assistance in managing your patients.

Additional Links,

Validation of a Self-Applied Unattended Monitor for Sleep Disordered Breathing

Clinical Guidelines for the Use of Unattended Portable Monitors

Practice Parameters for the Use of Autotitrating CPAP

Outcomes of Home-Based Diagnosis and Treatment of Obstructive Sleep Apnea

Aeroflow Healthcare offers an overnight pulse oximetry to measure the oxygen saturation in the blood and pulse rate at night.  It is a simple test that has a finger probe that uses an infra-red light to measure the saturation levels. 

The test allows your doctor to have a picture of your breathing and pulse rate while you are asleep.  The oxygen levels help determine whether or not you are dropping below the normal level of 90% SpO2 or if you have periodic drops in oxygen levels throughout the night.  If the oxygen is dropping below the normal level of 90% SpO2, then it might be that your doctor will prescribe supplemental oxygen therapy.  Based on the periodic drops in oxygen levels could be indicative of an underlying sleep disorder.  Typically the next step is to have an additional sleep study to get a more detail picture with additional recordings of breathing patterns at night.  An overnight pulse oximetry can also be used to ensure if your doctor has prescribed the proper liter flow of supplemental oxygen at night by using the pulse oximetry at night while also using the supplemental oxygen.  If the levels saturation levels are remaining below the 90% SpO2, then the liter flow may need to be increased.  Another use is to the pulse oximetry with CPAP/BiPAP therapy.  This gives a snapshot of to see if the therapy is eliminating the periodic drops in saturation levels.  If the periodic drops are present, then your doctor may prescribe an auto titrating CPAP/BiPAP to reevaluate the pressure settings needed to overcome the apnea or hypopnea that’s still occurring.

Unlike most sleep programs that require you to check into a traditional hospital or Sleep Laboratory overnight for a full polysomnography Study (PSG). This program can help the patient get accurately tested with a small portable device while sleeping in your natural sleeping location. This preferred logistic approach saves time and money, getting the patient tested, treated, and back on the job, or just the relief of the symptoms in less time. Among those who have experienced both methods, portable testing is the clear choice.
PSG testing is still offered for all patients who present with potentially complex sleep issues. However, portable testing is rapidly growing in use and stature as an equally accurate method of diagnosing sleep apnea for groups who have been pre-screened and are known to be at risk for sleep apnea. If you were having car trouble, why would you spend the time and money to replace the engine? Especially if you could do a quick, inexpensive diagnostic test that will probably tell you that you just need a tune up?