Figure 9.

Thermal response associated with acute pain in dogs undergoing surgery. (A) Before surgery. A 1-year-old bitch of the Chihuahua breed was subjected to ovariohysterectomy under analgesic management with meloxicam (0.1 mg/kg IV). The maximum temperature of the lacrimal caruncle (El1) had values of 36.6 °C (red triangle), while the minimum was 35.1 °C (blue triangle). (B) 1 h after surgery. A decrease in the temperature of the lacrimal caruncle is observed, with maximum (red triangle) and minimum (blue triangle) values of 35.3 °C and 32.6 °C, respectively. This represents a decrease of 1.3 °C and 2.5 °C, respectively. This could represent a sympathetic response to the effect of pain despite the use of analgesics. (C) 2 h after surgery. After administering tramadol as rescue analgesia, the maximum and minimum temperatures of the lacrimal caruncle (El1) (37.0 °C and 34.0 °C) were recorded above the basal values, due to the effect of the drug that reduces sympathetic tone. (D) 3 h post-surgery. Although it is observed that the maximum temperature of the lacrimal caruncle (El1) decreased by 0.6 °C (red triangle), the minimum increased by 0.3 °C (blue triangle), which could be associated with post-surgical stability. The thermal images were taken by the authors of the present review. Radiometric images were obtained using a T1020 FLIR thermal camera. Image resolution 1024 × 768; up to 3.1 MP with UltraMax. FLIR Systems, Inc. Wilsonville, OR, USA.