Wiktionary
n. (context rugby English) A temporary substitution for an visibly-bleeding player who must leave the field of play for first-aid treatment.
Wikipedia
In both rugby union and rugby league, a blood replacement (also referred to as a blood substitution or blood bin) is a special kind of substitution which can be used in the case of a player having to leave the field of play temporarily to have a wound attended to. Both rugby union and rugby league are physically demanding games, so musculoskeletal injuries are common, as well as injuries to the head and neck, and fractures. During the IRB 2011 Rugby World Cup, a study was conducted to determine the frequency and nature of the injuries sustained. It confirmed that rugby, like many other contact sports, has a high incidence of injury.
Usage examples of "blood replacement".
All of them, by the time they got back to Gateway, required total blood replacement, and two of them died anyway.
Behind the early interest in transfusion was the quite logical notion that an illness involving blood loss was best treated with blood replacement.