For serious medical emergencies when
a patient can't walk or be carried out, a helicopter
rescue can be arranged through the Royal Nepalese
Army or by a private company. The service is expensive
and must be paid for by the rescue. Your embassy or
trekking agency may vouch for you but they won't pick
up the tab a good reason to arrange for comprehensive
trip insurance beforehand.
The helicopter company's must receive
assurance of payment before it dispatches a flight.
This will be provided by your trekking agency if you're
with a group; embassies usually provide this for their
citizens, but they may need to contact the family
in advance. Registering at your embassy be fore a
trek greatly expedites this process. Once the helicopter
takes off, you're liable for the costs even if it
doesn't find you.