Dear Marion,

This URL
http://www.nejm.org/doi/full/10.1056/NEJMc1105847?query=TOC
from the current issue of the New England Journal of Medicine
suggests that pulse oximetry values less that 70% have not been
calibrated and cannot be interpreted, i.e., are meaningless.

Tomorrow morning, I will review the Internet descriptions of
available pulse oximetry equipment and report to you.

As I've said so often before: I don't know what's going on in
your lungs; I'm persuaded the doctors don't know either.

My (worm's eye) view is that you should should not be stampeded
into lung biopsy or steroid treatment as long as you feel
relatively well.

Margaret and I are always happy - and eager - to have you with
us in Belmont, and would change our plans to suit your convenience.
To visit Massachusetts, of course, you wouldn't need to fly.
You could come by car or by train. Am I naughty when I admit
that I would worry about your flying to France?

If you think it might help, feel free to telephone at your
convenience, any time (617-484-8109). I'll write you
more about pulse oximetry meters tomorrow. Good night.

Jochen