Factors affecting intravenous analgesic requirements after colectomy

BACKGROUND: The purpose of this study was to determine factors that influence postoperative IV analgesic use after colectomy. STUDY DESIGN: We retrospectively evaluated patients who underwent colectomy between January 1997 and December 2000 at our medical center and calculated the amount of postoperative IV narcotics needed in morphine equivalents. Statistical differences (p < 0.05 considered significant) were measured using the Wilcoxon rank-sum test. Correlations were performed using Spearman correlation coefficients, and linear regression analysis was also performed. RESULTS: Four hundred eighty-one patients (235 men, 246 women) underwent colectomy; patients had a mean age of 60.6 years (range, 17 to 96 years). Procedures performed included total/subtotal colectomy (10%, n = 49), right colectomy (42%, n = 200), transverse colectomy (3%, n = 12), left/sigmoid colectomy (40%, n = 195), and low anterior resection (4%, n = 17). Laparoscopic colectomy was performed in 53 (11%) patients. Mean postoperative morphine equivalent use was 160.2 mg. Narcotic analgesic use was significantly less for women (p = 0.02), diagnosis of cancer (p = 0.02), and laparoscopic colectomy (p = 0.0001). Patients undergoing a right colectomy required less postoperative narcotics than patients having other types of colectomies (p < 0.02). There was a positive correlation between postoperative narcotic use and operative time (r = 0.14, p = 0.007) and a negative correlation with patient age (r = -0.37, p = 0.0001). Linear regression analysis demonstrated that age (p = 0.0001), female gender (p = 0.04), and laparoscopy (p = 0.001) were independent predictors for decreased narcotic use. CONCLUSIONS: Postoperative IV narcotic analgesic use is affected by gender, patient age, indication for colectomy, operative time, type of procedure, and operative technique.