Infrared Thermometer: an accurate tool for temperature measurement during renal surgery

Abstract

To evaluate infrared thermometer (IRT) accuracy compared to standard digital thermometer in measuring kidney temperature during arterial clamping with and without renal cooling. 20 pigs weighting 20Kg underwent selective right renal arterial clamping, 10 with (Group 1 - Cold Ischemia with ice slush) and 10 without renal cooling (Group 2 - Warm Ischemia). Arterial clamping was performed without venous clamping. Renal temperature was serially measured following clamping of the main renal artery with the IRT and a digital contact thermometer (DT): immediate after clamping (T0), after 2 (T2), 5 (T5) and 10 minutes (T10). Temperature values were expressed in mean, standard deviation and range for each thermometer. We used the T student test to compare means and considered p < 0.05 to be statistically significant. In Group 1, mean DT surface temperature decrease was 12.6 ± 4.1°C (5-19°C) while deep DT temperature decrease was 15.8 ± 1.5 °C (15-18 °C). For the IRT, mean temperature decrease was 9.1 ± 3.8 °C (3-14°C). There was no statistically significant difference between thermometers. In Group 2, surface temperature decrease for DT was 2.7 ± 1.8°C (0-4°C) and mean deep temperature decrease was 0.5 ± 1.0 °C (0-3 °C). For IRT, mean temperature decrease was 3.1 ± 1.9°C (0-6°C). No statistically significant difference between thermometers was found at any time point. IRT proved to be an accurate non-invasive precise device for renal temperature monitoring during kidney surgery. External ice slush cooling confirmed to be fast and effective at cooling the pig model.