The use of pupillometry as monitoring of intraoperative analgesia in the consumption of analgesics during the first 12 hours after surgery.

INTRODUCTION: Intraoperative evaluation of analgesia remains today often based on heart rate and arterial pressure fluctuations. None of these parameters is specific. Incorrect handling during this process may increase surgical morbi-mortality of the patients and their acute postoperative pain. The aim of this study was to evaluate the impact of intraoperative analgesia controlled by pupillometry on postoperative analgesic consumption and the pain intensity in the first 12h in the hospital room, after major gynecological surgery. PATIENTS AND METHODS: A prospective, cohort study with allocation of groups of sequentially according to programming of operating room was designed. ASA I-III patients scheduled for elective surgery of abdominal hysterectomy by laparotomy or laparoscopy through intravenous general anesthesia were included. Patients were divided into 2 groups: pupillometry group (P-1), in which intraoperative analgesia was guided by pupillometry, and hemodynamic group (H-2) according to values of blood pressure and heart rate. In the hospitalization room the values of visual analogue scale (VAS) were routinely registered with 3 courts for the study: 3, 8 and 12h of the postoperative period. Postoperative analgesia was standardized as follows: NSAIDs was administered if VAS was ≥ 3 or if the patient expressly requested an analgesic. After this, the efficacy of treatment was assessed. If the patient had pain, the next scheduled drug was given up to an VAS<3. Data for total analgesic consumption administered in the hospital room, VAS and adverse effects were collected within 12h postoperatively. RESULTS: A total of 59 patients, 30 group P-1 and 29 group H-2, were included. Group P-1 experienced less pain than group H-2, with statistical significance in each phase (VAS 3h, VAS 8h and VAS 12h). These data are consistent with the consumption of analgesics for patients. There was a statistically significant reduction (p<0.001) in the group P-1 (1.80 [DE 0.99]; medium 2, 95% confidence interval 1.43-2.17) compared with group H-2 (5.66 [1.58]; medium 6, 95% confidence interval 5.05-6.26). CONCLUSIONS: Monitoring of the intraoperative analgesia by pupillometry was able to reduce the intensity of the acute postoperative pain and analgesic consumption in the first 12h in the hospital room after major gynecological surgery.