An additional determinant of peripheral oxygen delivery is cardiac output. Mild hypercapnia increases cardiac output: for example, augmenting arterial carbon dioxide tension (PaCO2) just 10-12 mmHg increases the cardiac index 15%. Our preliminary studies confirm that mild hypercapnia increases cardiac output and additionally indicate the hypercapnia markedly improves tissue oxygenation. For example, tissue oxygen tension increased 16 mmHg, from 58 to 74 mmHg over a 20 mmHg range of PaCO2 in anesthetized volunteers. We have also shown that increasing PaCO2 by just 15 mmHg increased tissue oxygen tension 16 mmHg in surgical patients. Similar results were observed in morbidly obese patients. Previous work indicates that similar increases in PsqO2 reduces the risk of surgical wound infection by about 30%. We thus propose to test the hypothesis that mild hypercapnia significantly reduces the incidence of surgical wound infection in normothermic patients undergoing colon resection. Secondary outcomes will include the duration of hospitalization, cost of care, the incidence of nosocomial pneumonia, the incidence of postoperative nausea and vomiting (PONV) and return to function.