Pain Evaluation During Colonoscopy by the Erythema Index of the Facial Image

Endoscopy of the digestive tract is useful but is associated with significant pain to the patient. Its safety and tolerability could be improved by an immediate and objective method to evaluate the pain level and give feedback to the examiner. However, under the current circumstances, it is difficult to measure and assess the pain level objectively.

We previously developed a discomfort assessment device that measures the changes in brain activity caused by changes in the pain level by extracting the changes in the erythema index from facial color data. In this study, to evaluate the usefulness of this discomfort assessment device, the association between the changes in the erythema index of facial images during colonoscopy and the subjective pain level during the examination were evaluated. For the recording of the subjective pain level during the examination, a subjective pain level recording device that we developed to measure grip strength over time was used. The subjective pain level, facial image, and percutaneous venous oxygen saturation during the examination were recorded in 30 patients who underwent colonoscopy at our hospital.

The duration of colonoscopy was divided into the insertion section and the removal section. The subjective pain level was found to be significantly greater during the insertion section than during the removal section, and the changes in the erythema index of the facial images were significantly different between the two groups.

These findings indicate that the erythema index changes on facial images determined by the discomfort assessment device may facilitate objective evaluation of the pain level during colonoscopy.