Reasons to Use APAP
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In a forum discussion thread, CPAPtalkers wished for a list of APAP features that they could share with their doctors. This article lists features that CPAPtalkers have discussed. It's part of a longer article, CPAP Machines, which discusses CPAP, APAP, BiPAP, selection criteria and other features. Read that article for a broader perspective.
1. An APAP machine offers a “two-fer.” It can be set to a straight CPAP mode, giving the advantages of a constant pressure plus the other advantages of APAP (such as home titration and a range of pressures), without the disadvantages of CPAP (such as a wrong pressure setting that isn't machine reported or lack of range of pressures to meet various sleep conditions). CPAP therapy needs may differ at various stages of treatment, such as start-up or after other health changes. Some people do better on straight CPAP. Some people do better on APAP. Some people, working with their doctor, use APAP and software to confirm or find their ideal straight CPAP pressure setting.
2. In the APAP mode, the machine automatically adjusts pressure to meet changing pressure needs when you change positions from side to back, are in various sleep stages, are extra tired, have a blocked nose due to a cold or allergy, or have taken alcohol or sedatives. A fixed CPAP setting to handle some of these situations might be too high for comfortable continued use.
3. Without changing the comfort of the baseline lower pressure, the upper range of the APAP pressure setting will respond to the upper range of apnea/hypopnea events (requiring higher pressure), potentially making APAP therapy more effective. A titrated fixed pressure that is too low may miss a sizable number of events on straight CPAP, labeling them as non-responsive, leading to poorer therapy results.
4. APAP automatically adjusts pressure if your pressure need change when you change masks, develop a mask leak, or experiment nightly with various mask fitting adjustments. Theoretically, pressure settings should remain the same with any mask. With APAP and software, the patient can detect and assess the volume of mask leak and test his/her mask adjustments under various pressures. The same holds for the patient’s new mask trials.
5. Some CPAPers trying APAP machines have experienced that they need a lower overall pressure on APAP than their original titrated pressure. A lower pressure may be more comfortable for the patient.
6. Studies have shown that there is better compliance with APAP than with CPAP. Possible reasons may be more comfortable treatment from a lower pressure setting or range, and (with machine display or software) immediate feedback on treatment leading to higher levels of satisfaction and improved treatment.
7. Self-titration. If the patient has a smart card and optional software (or ready access to a DME for printouts) and the requisite skills, willingness, and ability (or a helper), he/she can monitor his/her pressure settings and results and find the optimal pressure setting for straight CPAP, or narrow range of settings for APAP, in consultation with the physician. Research:
American Journal of Respiratory and Critical Care Medicine, Can Patients with Obstructive Sleep Apnea Titrate Their Own Continuous Positive Airway Pressure? http://ajrccm.atsjournals.org/cgi/content/full/167/5/716 Quote: Home self-titration of CPAP is as effective as in-laboratory manual titration in the management of patients with OSA.
Nonattended home automated continuous positive airway pressure titration: Comparison with polysomnography http://www.sleepsolutions.com/clinical_library/Unattended_auto-CPAP.pdf Quote: Nasal APAP titration in this study correctly identified residual apnea equivalent to the use of PSG. This correct identification allows the physician to accurately access the efficacy of treatment.
8. Once optimal pressure settings are found, with software the patient can monitor his/her progress. Software reports provide specific data for the doctor’s analysis.
9. Use of an APAP may reduce the need for sleep doctor visits (and probably DME visits), if the patient is responsibly managing their own therapy and therapy is assisted by APAP capabilities and software.
10. Use of an APAP reduces the need for subsequent expensive sleep tests since the patient is auto-titrating. Working with a doctor and periodically using a pulse oximeter (borrowed, rented, or purchased), the patient can test for oxygen levels at home with the report interpreted by the doctor.
11. Lower APAP pressure settings may do a better job of reducing or eliminating aerophagia (swallowing air) than higher CPAP pressure settings. Others find that aerophagia is reduced by using CPAP rather than APAP, or by using BiPAP.
12. Some of the Respironics CPAP and APAP machines have exhalation relief, called C-Flex, for patient comfort; if more comfortable, it may result in better compliance. (The current ResMed machine does not have EPR exhalation relief in the APAP mode.) CFlex provides some degree of exhalation relief at a much lower cost than a BiPAP machine, although a BiPAP provides a greater degree of relief for those who require it.
APAP versus CPAP Research
Google APAP vs. CPAP studies. A few research articles: