I think one day our scientists will solve this problem.
Until that day comes, people will need blood to survive. Accident & surgical victims are not given whole blood as much today. They are given a blood derivitave, washed red blood cells. Washed red blood cells have been separated from whole blood and washed so as to remove the outer layer recepters that can cause some people to have reactions. They also have much reduced risk of carrying diseases as they are separated from blood & washed.
The Watchtower Society does not allow followers to have washed red blood cells. But, the Watchtower Society permits people to have hemoglobin. The washed red blood cell and hemoglobin are not much different. Hemoglobin is what is inside a washed red blood cell. The difference between the two is the cell's skin. What makes the whole red blood cell (i.e. hemoglobin with the skin) "unholy", I'll never know. To give an analogy, it's like saying "a glass of wine is unholy", but you can drink the wine inside it. 
The Society's flawed logic on blood is what causes the more "savvy" witnesses to reject the blood ban.
Watchtower Society hemoglobin is not available for general distribution in the United States. Your doctor has to contact the companies, explaining the patient's case. The companies then contact the FDA for approval of dispensing hemoglobin to that particular patient.
Watchtower Society hemoglobin also has problems. Hemoglobin does not last long in the body. It's my understanding that the cells will only live a day or two. It's used more when the patient can take blood, but blood is temporarily unavailable. Hemoglobin research started with the US army. The Army wanted a single oxygen delivery that could be used on the battlefield to immediately treat battle victims in order to keep them alive while they were being transported back to the MASH units. Hemoglobin has the added benefit of being universally able to be used (no blood type mismatch) and can keep without refridgeration for over a year.
Again, the "best" blood alternative I see on the market today is "washed red blood cells". So, ask for it at a hospital near you.