Private hospitals, Hyperbaric medicine, Sick day rules to reduce kidney damage, Warfarin

As more NHS operations are done in the private sector, how much do we know about patient safety in private hospitals? Kits to self-monitor warfarin have been recommended by NICE, so why is the uptake so poor? Hyperbaric medicine - using high doses of oxygen to accelerate healing; And sick day rules - the medicines you should stop taking while you are unwell to reduce kidney damage.