There are often questions on here about ascent rates for treks, particularly Everest BC and other popular ones. The following coroner's report, after the death of a young British trekker, makes sobering reading for a number of reasons:
http://www.expeditionmedicine.co.uk/blog/wp-content/uploads/2014/02/2014022...
Not only was the ascent too fast, the symptoms were not diagnosed nor the treatment appropriate, a tragedy made worse by having suitable help nearby. There are several issues mentioned in the report that all prospective trekkers and expedition members should consider when using a guiding company, or when coming across these situations in the mountains.
I originally came to this report via an article on doctors accepting places on expeditions for discounts or free, and how unwise this is:
http://www.expeditionmedicine.co.uk/blog/2014/02/should-you-accept-a-free-o... 
