Bear in mind, however, that physicians are not generally inclined to take unsolicited medical advice from a religious publishing corporation to begin with, particularly when there is no double blind study to confirm it is a best practice.
As per my experience, JW HLC members do not provide any medical advice to the physicians. The medical documents that they provide to the physicians contains options and alternative medical treatment that is available in the city/country which can be used as an alternative to blood transfusion.
And these documents possessed by the HLC are not just watchtower or awake articles, but actual medical documents written by medical experts. A sample of this can be seen on https://www.jw.org/en/medical-library/
In India, around 5 years ago, a family friend of ours was admitted with a severe heart disease that required immediate blood transfusion. The local surgeon flatly refused the option for bloodless surgery and mentioned that there is no option yet available for such a treatment in the country. It was then that the HLC explained the surgeon about the treatment options and immediately shifted her to another hospital with a surgeon who agreed for the bloodless treatment. The treatment was successful and the story went on to become national headlines:
Another case that happened with the intervention of the local HLC:
http://www.moolchandfertility.com/media-centre/press-releases/india-s-first-bloodless
My brother in law, who is a member of the HLC, mentioned that every month, meetings are organized with the leading surgeons of the country and quarterly conferences are arranged by the HIS department by the local branch where physicians and surgeons are invited to address and update the community with the latest drugs and options available for JW's.