While the subject is not directly mentioned in the Bible, God never intended that man try to solve his self-inflicted ailments through surgery and blood transfusions. The possibility of contracting disease through these medical treatments is very high. Therefore, one who is considering undergoing (or being advised to undergo) a surgical procedure involving the risk of substantial blood loss (and thus the possibility of a transfusion) should carefully and prayerfully weigh the benefits and risks.
Also, while Christians are not “immune” to accidents (Ecc. 9:11), if we are seeking to truly please God, He has promised that He will not allow us to be “tempted above that we are able” (I Cor. 10:13). This means, among other things, that we will not have to make a choice between “bleeding to death” and taking the chance of receiving disease-infected blood through a transfusion. Certain choices being made for a person, due to his incapacity to decide for himself, is an entirely different matter. God would not hold one accountable for such decisions.
We discourage this practice, but the decision ultimately rests on the individual. In the overall “big picture,” wisdom and discretion must always be employed in order to avoid accidents and disease. In other words, we must treat the cause, and not just the effect.