Application of the Analgesia Nociception Index and Visual Analog Scale to Assess Pain During Hysteroscopy Under Local Anesthesia

Background/Objectives: Pain assessment during hysteroscopy facilitates rapid operator intervention (e.g., repeated anesthesia, administration of additional analgesics, or termination of the procedure), thereby improving patient comfort. Traditionally, pain intensity has been evaluated based on the patient’s subjective reporting; however, the introduction of an objective indicator in combination with subjective measures can considerably improve pain assessment. In this context, the present study aimed to evaluate pain intensity in patients undergoing hysteroscopy under local anesthesia (GUBBINI Mini Hystero-Resectoscope; Tontarra Medizintechnik, Tuttlingen, Germany), with simultaneous assessment using the Visual Analog Scale (VAS) and the Analgesia Nociception Index (ANI). Determining the relationship between ANI and VAS could contribute to improving patient comfort during hysteroscopic procedures performed under local anesthesia. Methods: The study included a total of 221 patients between the ages of 22 and 82 years, divided into two groups: 125 patients underwent diagnostic hysteroscopy (HD) and 96 patients underwent operative hysteroscopy (HO). After the procedure, patients were asked to assess pain intensity by using the VAS. The ANI was also monitored during the procedure. Measurements were conducted immediately before the procedure (T0), at the 1st minute (T1), mid-procedure (T1/2), and at the end of the procedure (T2). Results: The mean pain score in the study group was 3 points (3.04 ± 2.29), with a mean post-procedure score of 2.79 ± 2.19 and 3.36 ± 2.38 in the DH and OH groups, respectively. At Tmean, the ANI values ranged from 42 to 97 points, with a mean value of 70 points (70.37 ± 10.99). All correlations between the ANI values and VAS pain scores were statistically nonsignificant (p > 0.05), with correlation coefficients close to zero. This finding indicates that subjective pain assessment (VAS) does not correspond to the ANI values, which reflects the physiological autonomic response. Conclusions: Further research on pain assessment during hysteroscopy is warranted. Future studies should include larger patient populations, conduct continuous ANI monitoring, and correlate ANI with real-time subjective pain assessments (e.g., VAS during the procedure). The determination of psychological factors, such as pre-procedural anxiety, and the use of additional autonomic nervous system measures (e.g., skin conductance and pupillometry) could facilitate the development of a comprehensive model for objective pain assessment in patients undergoing gynecological procedures through hysteroscopy.