In vivo Doppler sonographic examination of temperature-related reactions of the facial artery.

This study was performed to investigate the reactions of the facial artery to changes in facial temperature. Healthy volunteers (10 female, 10 male) underwent three 30-min applications of facial cooling at 18 °C (Hilotherm HomeCare) and warming at 42 °C (preheated gel packs) in separate sessions. Colour Doppler ultrasound measurements of artery diameter, blood flow velocity, and blood flow volume were made every 30 min. The measured values were compared with two-sided t-test. After warming, the participants showed an increase in mean artery diameter: males, 0.183-0.217 cm; females, 0.162-0.190 cm. There were increases in mean velocity (4.818-5.011 cm/s in males; 4.580-5.052 cm/s in females) and mean blood flow volume (0.132-0.188 cm³/s in males; 0.099-0.145 cm³/s in females). Cooling reduced the mean diameter: 0.201-0.153 cm in males; 0.190-0.138 cm in females. Mean velocity changed slightly (males, 4.531-4.578 cm/s; females, 4.036-4.390 cm/s), blood flow volume dropped from 0.143 cm³/s to 0.090 cm³/s in males and from 0.111 cm³/s to 0.067 cm³/s in females. Approximately two-fold difference between the blood flow volume at 18 °C and 42 °C was observed, highlighting the significance of the facial artery in microvascular surgery and supportive therapies.