The effect of chronic heart failure on the rick of intraoperative hypoxia

Abstract

Any surgical intervention is a surgical trauma, which severity depends on the type and degree of surgical intervention. Several changes occur in the patient's body in response to surgical trauma, which degree depends on the functional state of systems and organs in the preoperative period. In our study, we investigated how chronic heart failure (CHF) affects the development of such a factor of surgical trauma as hypoxia. The aim of our study is to determine whether CHF is a risk factor for the development of intraoperative hypoxia in animals during surgical interventions lasting up to 60 minutes. Lactate level was chosen as a marker of hypoxia. The study was conducted at the facilities of St. Petersburg State University of Veterinary Medicine and VEGA veterinary clinic chain in the city of St. Petersburg, Russia. The study was carried out on 20 dogs with myxomatous mitral valve disease (MMVD). The animals were allocated into three groups depending on the stage of the disease: seven dogs with MMVD in stage B1 — in group 1, eight dogs with MMVD in stage B2 — in group 2, five dogs with MMVD in stage C — in group 3. The lactate level in whole venous blood was measured in all animals before the operation (at rest and under load), during the operation and two hours after the operation. The mean lactate increase under load in group 2 dogs was 0.08 mmol/L, and in group 3 dogs — 0.20 mmol/L. According to the results of statistical analysis, the increase in lactate under load in dogs with MMVD in stage C statistically significantly exceeds the increase in the level of lactate under load in animals with MMVD in stage B2. Thus, MMVD in stage C can be considered a risk factor for the development of intraoperative hypoxia.