The book was created to teach techniques that surgeons adopted, abandoning old habits. For example, they no longer pump saline into a patient with massive trauma to try to get the blood pressure back up to 120. “You do that, you end up with a highly diluted, cold patient with no clotting factors, and the high pressure restarts bleeding,” Dr. Lounsbury said. Instead, they try to bring it up to just 80 or 90 with red cells and extra platelets, which encourage clotting.