gas vs. battery powered automatics

[McDoc]

To those who do use, or have used, automatic resuscitation devices, are gas powered “only” systems (i.e. no batteries required) preferred over systems that require both an oxygen gas source as well as rechargeable batteries? The advantages of electronic control circuits are numerous, but we would like to know if having to keep batteries charged would pose any field problems. Our aim is to design superior EMS products that meet all the needs of both the patients and the users.

Thanks for your input.