A portable hyperbaric chamber (Gamow bag)
Classic stretcher technique
Improvised rucksack stretcher technique

Want to know more?

This is one of the organisations Lucy mentions: British Exploring

And this is the Global Health MSc

The Wilderness Society Guidelines are available here.

This is the link to the Wilderness Medical Society.

Consensus statement from the UAIA

Li Y, Zhang Y, Zhang Y. Research advances in pathogenesis and prophylactic measures of acute high altitude illness. Respiratory Medicine. 2018; 145: 145-152.