Preoperative psychologic and demographic predictors of pain perception and tramadol consumption using intravenous patient-controlled analgesia

OBJECTIVES: Postoperative pain is characterized by a wide variability of patients' pain perception and analgesic requirement. The study investigated the extent to which demographic and psychologic variables may influence postoperative pain intensity and tramadol consumption using patient-controlled analgesia (PCA) after cholecystectomy. METHODS: Eighty patients, aged 18 to 70 years, with an American Society of Anesthesiologists physical status I or II and a body mass index between 18.5 and 24.9, undergoing laparoscopic cholecystectomy were enrolled. Self-rating anxiety scale (SAS) and self-rating questionnaire for depression (SRQ-D) were used--1 day before surgery--to assess patients' psychologic status. General anesthesia was standardized. PCA pump with intravenous tramadol was used for a 24-hour postoperative analgesia. Visual analog scale at rest (VASr) and after coughing (VASi) and tramadol consumption were registered. Pearson's and point biserial correlations, analysis of variance, and step-wise regression were used for statistical analysis. RESULTS: Pearson r showed positive correlations between anxiety, depression, and pain indicators (P<0.05). Moreover, female patients had higher pain indicators (P<0.05). Analysis of variance showed that anxious (P<0.05) and depressed (P<0.001) patients had higher pain indicators, which significantly decreased during the postoperative 24 hours (P<0.00001). Regression analysis revealed that tramadol consumption was predicted by preoperative depression (P<0.001). VASr was predicted by sex and SRQ-D (P<0.05). VASi was predicted by sex and SAS (P<0.05). DISCUSSION: Pain perception intensity was primarily predicted by sex with an additional role of depression and anxiety in determining VASr and VASi, respectively. Patients with high depression levels required a larger amount of tramadol