The effect of local hardware hypothermia on microcirculation in vivo

Abstract

Purpose. Demonstrate microcirculatory changes and justify the effectiveness of controlled hardware hypothermia in an experiment Material and methods. To study microcirculatory changes during local instrumental hypothermia, everted cheek pouches of 20 hamsters were used. Local hardware hypothermia (LHH) was carried out using the ViThermo device in a mode with a target temperature of 18°C for 60 minutes. Optical coherence tomography (OCT) was performed for intravital monitoring of microcirculatory changes. Results. At an interval of up to 5 min. There was an increase in vascular density to a value of 5.31% and a decrease to 4.76%. At the same time, the peak vascular system density (VSD) was reached at 3 minutes of LHH (5.31%). After 5 minutes of LHH application, and subsequently until 60 minutes, VSD decreased in steps from 0.1% to 0.02% per 1 minute per step. The lowest VSD was achieved at 57-60 minutes of VSD. The temperature of the outer surface of the golden hamster’s cheek pouch decreased slowly and gradually in increments of 1°C to 0.1°C in 1-10 minutes. After 60 minutes of LHH, the temperature of the golden hamster’s cheek pouch began to increase: at step 61 minutes, 19.80°C and 62 minutes, 21.40°C. VSD at 61-62 minutes stabilized to values of 3.62% and 4.43%, respectively. Conclusions. The effect of LHH on the microvascular bed of the hamster buccal mucosa revealed a number of characteristic physiological changes. With a gradual decrease in tissue temperature, a slow decrease and then an increase in vascular VSD was detected on OKT scans. This substantiates the hypothesis that the use of “soft” tissue cooling in the form of PAH is more rational in relation to the microcirculation.