Tube size…

[robsmuir]

During the lengthy recall process with Philips, I had cause to reach out to Kaiser Permanente to contact them for a new and updated CPAP prescription. They were very helpful and as an interim step, they arranged to send me bacterial filters and new hoses for my older System One.

Lo and behold, they sent another box of stuff even though I have already received my two replacement DreamStation 2s.

I note that the DreamStations are provided with 12mm hoses, while the older units use larger diameter 15mm hoses.

Is there a functional reason to use larger hoses? I've been getting good performance with the DreamStation 2, getting a nightly average of less than 1.0 AHI. I could set the machines for a larger diameter hose if I had a compelling reason to do so.

And, with the new machines, is there any reason to use the spherical, inline bacterial filters?

[srlevine1]

I would use the device manufacturer's recommended hose selection as that was the one the device probably was calibrated for during testing. If you are unsure or simply seek peace of mind, I suggest you talk with your sleep doctor or DME respiratory technician. I am sure fellow forum members will have additional suggestions.

As for bacterial filters, it depends on your environment and if it is a warm moist area conducive to bacteria growth. Unless you are immunocompromised or sensitive to airborne allergens, additional protection is often unnecessary. If you do use an AB filter, check if there is a machine setting to compensate for the additional airflow resistance. There is such a setting on the ResMed devices, but I am unsure of the new DreamStations.

I noticed your settings indicate 4-20 pressure range, so be aware that the use of Inline Bacterial Viral Filters may adversely affect auto-sensing on Auto-CPAP systems, especially at pressures below 7 CM H2O -- so you want to check the impact of the filter before use.

However, according to Phillips, "Humidification can increase the resistance of the bacteria filter, and the operator must monitor the bacteria filter frequently for increased resistance and blockage to ensure the delivery of the therapeutic pressure."

[robsmuir]

Thank you, good information. However, I am now using a fixed CPAP setting with a max of 16 and getting much better therapy.

The DreamStations clearly have a setting to adjust for tube diameter, so I'm not entirely certain that the supplied 12mm is 'recommended.' I could adjust the machine to accommodate different types of tubes including heated ones. 

I still wonder what the functional difference in tube sizes might be. Larger amounts of air volume? Differences in machine noise? Better, or worse, performance?