Study of the body thermal response during a hyperacute phase of septic shock and its correlation with mortality in rats

• Grant number: 20/16408-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date until: February 01, 2021
• End date until: January 31, 2022
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Ivan Hong Jun Koh
• Grantee: Tatiane Lissa Yamada
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
• Associated research grant: 17/21052-0 - Sepsis: mechanisms, therapeutic targets and epidemiology, AP.TEM

Abstract

The growing understanding of the pathophysiology in sepsis led to a gradual reduction in mortality. The fundamental factors that promoted this reduction in morbidity and mortality are attributed to the early diagnosis, adequate antibiotic therapy, fluid therapy, and improvement in general care. However, it still has unacceptable mortality, being approximately 65% in developing countries like Brazil. The main concern in sepsis is the correction of hemodynamic dysfunction in shock that continues to be guided by the parameters of macro-hemodynamics due to the absence of a non-invasive method of monitoring the microcirculatory dysfunction progression that clearly precedes the events of macrocirculatory dysfunction. This results in the delay in the early diagnosis of organ dysfunction and loss of therapeutic moment in real-time. Besides, there is a complexity of the host's response that overcomes the current knowledge. In this scenario, we propose to assess whether the dysfunction of the physiology of thermal regulation, central and peripheral, occurs in the worsening stages of sepsis since there is a direct relationship between blood flow, inflammation, and local tissue temperature. In addition, it is intended to identify whether there is a correlation between thermal variation and the outcome of mortality. Wistar-EPM rats, 3 months old, 250 to 300g in weight, will be induced to septic shock by inoculation of 2mL E.coli 109 CFU / mL (DL70-80), and monitored in the hyper acute phase: T = 1h, T = 2h, T = 3h, T = 4h, T = 5, T = 6h and T = 24h (n = 5 / period). The animals in the control group (CG) will receive an injection of 2mL of saline and monitored in the same periods (n = 5). The central and peripheral temperature of the entire body will be captured by the FLIR T540 thermographic camera and the images analyzed by the FLIR Resarch IR Max4 computer analysis program. The animals will be monitored to assess changes in the thermographic pattern, during the growing phase of acute inflammation in sepsis and to the evolutionary phases for death or survival. The expected results are that the central and/or peripheral temperature correlates with the state of the acute hemodynamic dysfunction and enables the evolutionary diagnosis of increasing stage-severities in septic shock and in survival.