In one study, surgical risk was 9.7 times higher in men with very limited preoperative activity levels than in those with normal activity levels. Whether preoperative use of nutritional supplements can improve surgical outcome is controversial. However, in severely malnourished patients who received TPN, infection rates did not increase and fewer complications occurred. Most experts agree that surgery should not be delayed to provide TPN preoperatively, except possibly for severely malnourished patients. However, even in these patients, evidence supporting preoperative use of TPN is inconclusive.
Postoperative complications are also more common in demented patients.
The best predictor of postoperative cardiac complications is the presence of ischemic heart disease. However, a significant number of cardiac complications occur in patients with a low score, demonstrating that the predictive power of this cardiac index and others is poor in low-risk patients. The exercise tolerance of patients with heart disease should be assessed by asking them what their usual daily activities are and how easily they tire. The risk of postoperative cardiac complications is increased if any rhythm other than sinus rhythm is present or if premature atrial contractions, often considered a benign finding, are present. An occasional solitary premature ventricular contraction does not require preoperative treatment.