Thermal camera as a pain monitor

Today, many subjective methods are used to measure pain. Wong Baker and Hicks Facial Pain Scale is one of the most commonly used method. Clinicians grade pain according to the facial mimetic reaction of the patient. Unfortunately, there is no objective measure for monitoring pain. By using the same principle of the Wong Baker and Hicks Facial Pain Scale, in this study, we aimed to objectively measure pain by using a thermal camera to detect instant facial temperature changes.

Thirty volunteers who attended blood collection unit were subjected to facial thermal monitoring and measurements were obtained 5 minutes before needle puncture (BNP), during needle puncture (DNP), and after needle puncture (ANP). Data were processed with TestoIRSoft 3.8 software program and mean temperatures of the whole face (FFM) and highest temperature points (HP), horizontal line (HOR) between two pupils and first glabellar wrinkle, and bilateral lines starting from the nasolabial sulcus to oral commissure (NLS-1 at right, NLS-2 at left) were evaluated. All data were statistically analyzed with paired sample t-test.

Statistically, temperature measurements of HOR, NLS-1, NLS-2, HP, and FFM were significantly higher between BNP and DNP, significantly lower between ANP and DNP, and significantly higher between BNP and ANP (p<0.05). The most interesting result in our analysis was that the HP point was between the two eyebrows in 26 of the 30 volunteers.

Our results suggest that a thermal camera can be used to objectively monitor pain and in follow-up. However, further studies involving non-healthy volunteers (especially high-fever patients, children, immunosuppressive patients, and cancer and intensive care patients) should be performed.