Defining trajectories of acute pain in surgical patients short title: Acute pain follow-up

Abstract

INTRODUCTION: Assessment of acute postoperative pain is mandatory for effective treatments. Pain trajectories may help professionals improve treatments. It has been suggested that uncontrolled pain in the immediate postoperative period generates higher pain intensities on the following days of hospital stay. OBJECTIVE: To determine the relationship between pain during the first postoperative hour and the first 24 postoperative hours. METHODS: Setting: a general university hospital. Study design: a prospective observational, analytical study of patients undergoing surgical procedures under general anesthesia and hospitalized for at least 24 hours. Five assessments of pain were carried out during the first hour in the recovery room followed by three assessments during the first 24 hours. The slopes of pain trajectories were calculated, and the relationship between them was analyzed. RESULTS: 234 patients were recruited, 31.3% had uncontrolled pain on arrival at the recovery room; at the end of the first 24 hours after surgery, 5.5% of the patients had uncontrolled pain. The first pain intensity score in the recovery room correlated negatively with the slope for the first hour (P1): rS = -0.657 (p = 0.000). Similarly, the first pain intensity score had a negative association with the pain trajectory slope during the hospital stay (P2): rS = -0.141 (p = 0.032). When comparing the two slopes, a nonsignificant negative correlation was found: rS = -0.126. CONCLUSIONS: the trajectory of pain during the first hour does not predict the behavior of the trajectory during the first day after surgery.