I can offer only a personal experience on this one but I believe it to be
valid.  I called Ruth Lawrence's breastfeeding resource line (for
professionals) at the University of Rochester (NY) for the information.  I
was faced with surgery requiring a general anesthetic when my breastfeeding
son was 4 months old.

I was advisd to find out what sort of general would be used.  The flourane
(flouride ?) based gases apparently take a bit longer to work out of your
system.  But I was told that as soon as I felt alert that I could breastfeed.

She did warn me to find out what sort of pre-op meds I would be given, what
if any post-operative meds and antibiotics would also be known.  And also to
make everyone aware that I was breastfeeding.

One thing I do remember clearly about this experience was the reluctance on
the anesthesiologist's part to tell me exactly what drugs and anesthesia I
would be given.  He favored answers like, "Somehting to make you sleepy" or
"Something from the barbiturate family".  Finally he came clean with all the
information--propbably because I was so insistant and explained to him about
my commitment to breastfeeding.

I woke up (actually I was in that pre-groggy, can't quite open your eyes
state) to a tech and a nurse trying to figure out how to put together the
breastpump should I require it before I was truly alert.  It was quite
comical.  They had never had to deal with this before and this was a BIG
hospital!

Pat Predmore, RN, BSN, ICCE
Birth Matters