Fig. 1. A and B Model structure. (A ) A decision tree. The short-term model starts with the decision between alternative fluid strategies (rectangle ) followed by arrows  that represent transitions toward selected postoperative complications. (B ) The Markov structure. The long-term model: upon entering the model, hypothetical individuals have quality of life that is associated with postoperative outcome. The individuals make transitions along the arrows  among health states or stay in the same state during 1 yr, that is, one cycle. During this cycle, survival decreases and survivors' quality of life declines by decrements. One cycle is repeated five times, representing 5 postoperative years.