ALB and chronic obstructive pulmonary disease: Millan et al5 reported that the risk factors for POI after colorectal surgery (including open and laparoscopic surgery) were male sex, an American Society of Anesthesiologists physical status of >3, current smoking, a serum albumin concentration of <3.5 g/dL, cardiac disorders, COPD, rectal tumors, performance of ileostomy or colostomy, and blood loss of >500 mL.