Use of American Society of Anesthesiologists physical status classification to assess perioperative risk in patients undergoing radical nephrectomy for renal cell carcinoma.

Objectives: To perform a retrospective analysis to determine the operative morbidity in patients with substantial comorbidities requiring renal surgery. Increasing numbers of patients requiring renal surgery are presenting with substantial comorbidities, such as diabetes mellitus, chronic obstructive pulmonary disease, and cardiovascular disease.
Methods: The American Society of Anesthesiologists (ASA) physical status classification was used to define perioperative risk. Of 1087 patients who underwent nephrectomy between 1989 and 2001, 237 patients were classified as ASA classification 1 or 2 (low risk), 297 were ASA classification 3 (intermediate risk), and 17 were ASA classification 4 (high risk).
Results: No statistically significant differences were found among the low-risk, intermediate-risk, or high-risk patients with regard to 1997 T stage distribution, mean tumor size, vascular and/or inferior vena cava involvement, percentage of partial nephrectomy, adjacent organ resection, or preoperative hemoglobin. Intermediate-risk patients did have a greater estimated blood loss (946 versus 739 mL, P = 0.05), leading to greater transfusion rates (42% versus 28%, P = 0.001). However, no increase occurred in intraoperative or postoperative morbidity. High-risk patients also had greater transfusion rates, as well as a greater rate of complications occurring more than 24 hours after surgery.
Conclusions: Partial or radical nephrectomy can be offered to patients with comorbid conditions. ASA classification 3 patients are more likely to require transfusion. This may have been a result of a lower threshold to transfuse patients with preoperative morbidities. However, the perioperative and postoperative complication rates were similar to those of low-risk patients. Not surprisingly, high-risk patients had greater rates of transfusions and complications.