Sorry I don't know--my husband has a CPAP machine-----he is in a study for heart patients with sleep apnoea.He has found it hard to adjust to.
Lorraine

Hi. I have severe respiratory muscle involvement and in my experience I just find it very difficult to breathe against a constant positive pressure that you get with CPAP. My expiratory muscles aren't strong enough to breathe out against a positive pressure and the moderate constant pressures also don't provide me with sufficient support on inspiration. Cpap is commonly used in obstructive sleep apnoea because the constant positive pressure splints the airways and stops them from closing down and obstructing airflow. It can also be used to hold the airsacs or alveoli open and improve gaseous exchange. The BIPAP machine allows you to set a higher inspiratory pressure to give greater support, whilst setting a lower expiratory pressure which is easier to breathe out with. The difference between the insp and expir pressures then becomes the amount of added pressure support with which the machine is assisting you. Most of the BIPAPs also can be set to breathe for you should you have an apnoea unlike the CPAPs. So the main difference really is that the BIPAP assists deeper breathing with a pressure support whlst the CPAP merely splints the airways and prevents obstruction. The machines are difficult to get used to because the masks usually need to form a tight seal with the face to stop airleakage. It's also not a normal thing to breathe with a machine but they really can help once you get used to them. Mask comfort and proper pressure settings are the key to compliance.

To sum up I would say that people with muscle wakness would be better off on BIPAP than CPAP in general even when there is obstructive apnoea with the weakness because the expiratory pressure can be set to stop obstruction as well. The BIPAP is also alot more expensive than the CPAP though so it depends what component is worst.

I sleep on a BIPAP machine every night and it has helped to give my muscles a good rest. During crisis I have been in ICU and saved from intubation with increased pressure support on my BIPAP. There are times when the support is not enough and then I have needed intubation but it has minimised those times for me thankfully!

Hope this helps.
Hugs
Ange

I have used cpap since January--before being diagnosed with MG 4 months later; maybe the sleep apnea was an early sign of the MG and muscle problems along with the tiredness that led me to the sleep study and finally the eye problems that got to the MG diagnosis.
With MG I have had to boost the pressure some to adjust for the breathing weakness overnight. The simplest test of if it is working is the overnight take-home finger-clip oximeter that measures the amount of oxygen in the blood. I think every MG person with breathing problems should have this kind of test--much much less expensive than a full blown overnight sleep study and will indicate if you should have an overnight apnea study.
A basic discussion of bipap/cpap can be found at http://bipapvscpap.net/ I find the cpap helpful when I am feeling breathing fatigue--it helps and seems to be comforting too that I have it and that I know it will ease my problems when needed. You can buy a used one on Craig's list for about $300--and of course insurances and medicare cover them if you are diagnosed with sleep apnea.

My MG doctor had mentioned the last year switching me from CPAP to BiPAP. I has just had a repeat sleep study, so it was difficult to justify to the insurance the need for another sleep study.

During my recent MG crisis my doctor did not want to discharge me home without a BiPAP. She was able to use my pulmonary distress and different pulmonary tests to justify the switch.

Nothing to add to Ange's explanation on the difference...good job Ange. I do find a difference between the CPAP and BiPAP. Plus I also feel better having the BiPAP available during the day if I need it.

Bruce

I have a BiPap and had to go through an adjustment phase with it. After my hosp when I was on a resp I hated it because it would blow air all over my face. While I was home before a readmit for resp issues I read more about them and how much more appropriate they are for mg than Cpaps because they help with breathing out. The hosp was able to justify it to Medicare and my secondary because it could prevent rehosp. The woman from the company that distributes them came to the hosp a d cited me with a mask. The mask was medium not large like the one in the hospital. It didn't big me blowing air into my eyeball like the other one. I also use it when I tire during the day.