Tissue Oxygen Homeostasis and LifenLight Score (LLS) of Patients in Critical Care Medicine

Abstract

Patients admitted to the emergency room or intensive care units (ICUs) need real time monitoring of body oxygen balance. As of today the availability of monitoring devices that provide real time data on tissue level of oxygen homeostasis is very limited. The involvement of mitochondrial dysfunction in many pathological states such as stroke, sepsis or heart failure is calling for real time evaluation of this intracellular organelle. In order to avoid the deterioration of the most vital organs in the body (brain and heart) we are proposing to monitor a less vital organ, such as the urethral wall, that serves as an early warning signal for the deterioration of body oxygen balance. This review describes the use of a multiparametric monitoring device (CritiView) connected to the patient’s urethral wall via a 3-way Foley catheter that measures in real time 4 parameters representing tissue oxygen balance. Mitochondrial NADH is measured by surface fluorometry/reflectometry. In addition, tissue microcirculatory blood flow, tissue reflectance and hemoglobin oxygenation are measured as well. The measured 4 parameters could be integrated together with systemic hemodynamic parameters to provide in real time a new Tissue Metabolic Score (TMS). The device was tested both in vitro and in vivo in a small animal models (rats and gerbils) exposed to changes in local or systemic oxygen balance. Also preliminary clinical trials in patients undergoing vascular or open heart surgery were performed. In patients, the monitoring started immediately after the insertion of a 3-way Foley catheter (urine collection) to the patient and was stopped when the patient was discharged from the operation room. The results show that monitoring the Urethral wall oxygen balance provides real time information correlated to the state of the surgical procedure performed. We found that the TMS of the urethral wall could serve as an early warning signal for the possible damage that may develop in the most vital organs in the body.