Microcirculation

This study aims to investigate how sepsis and critical illness can impair the cardiovascular system and microcirculation in intensive care unit (ICU) patients, which can lead to long-lasting muscle weakness/dysfunction or ICU-Acquired Weakness (ICU-AW) and exercise limitations.

Assessment of capillary refill time (CRT) is a cornerstone of tissue perfusion monitoring in critically ill patients. CRT measurement is performed by applying brief and gentle pressure (for a few seconds) to a small area of skin until blanching occurs. CRT is defined as the time, in seconds, required for the skin surface to return to its initial color after release of pressure. Although CRT is a monitoring tool used on a daily basis in emergency departments and critical care units, its practical measurement modalities remain poorly standardized and time-consuming. Consequently, there is no consensus regarding the most reproducible bedside method for CRT assessment. Moreover, repeated CRT measurements during patient management are resource-intensive in terms of medical time and may raise issues related to healthcare staff availability. The perfusion index (PI) is a marker of tissue perfusion derived from a pulse oximetry sensor. This monitoring device is routinely used in all critically ill patients. It is placed on the finger and worn continuously, including during patient transport. Because PI measurement is automatic and continuous, establishing its correlation with CRT could allow for more precise tissue perfusion monitoring while reducing the time burden associated with bedside assessments in critically ill patients.

The hypothesis is that fluid-responsive patients who show signs of venous congestion experience a worsening of microcirculatory status after fluid administration compared to patients without signs of venous congestion

Despite early treatment, the deterioration and mortality of sepsis patients remains high. A possible explanation could be persistent tissue hypoperfusion, or undetected in the early phase despite the normalization of macro-hemodynamic parameters. This interventional study evaluates the impact of measuring microcirculation parameters by nurses on patient prognosis through early initiation of vascular filling.

Intraoperative fluid therapy (IFT) is an integral part of anesthesia care during surgery. Its main indication is the optimization of oxygen supply to the tissues. For elective surgery that is not associated with higher blood loss and a long period of preoperative fasting, including fluids IFT is dosed to cover the basal daily need for fluids. However, it is not clear whether this fluid dose is optimal. Surgery is a stress factor that leads, among other things, to damage of the endothelial glycocalyx (EG). EG binds a significant amount of plasma, which is released during EG destruction and causes relative hemodilution. Isovolumic hemodilution is an established intraoperative procedure that serves to better control bleeding in procedures where bleeding is expected. However, partial hemodilution occurs even with standard IFT, and even when fluids are hardly given at all. Flow parameters in microcirculation have not yet been described depending on IFT conduction. The parameters of the microcirculation reflect its functioning, which will consequently affect the postoperative phase of the patient's moaning and clinical outcome.

We will perform this single-center pilot trial to determine if the intraoperative urethral perfusion index is higher in patients assigned to maintaining postinduction baseline urethral perfusion index than in patients assigned to routine care (with blinded urethral perfusion index monitoring). As pre-planned substudies, we will also assess the agreement between a) urethral perfusion index-derived pulse rate and heart rate measured with an electrocardiogram and b) between the urethral perfusion index and the peripheral perfusion index.

Sepsis is a common and life-threatening condition caused by a dysregulated host immune response to infection. Given the prominent role of endothelial breakdown and dysfunction in sepsis, therefore, there is an urgent need to establish strategies to protect the endothelium and preserve microcirculatory function. This study is a randomised clinical study investigating intravenous fluid therapy and oral imatinib therapy in healthy human volunteers exposed to intravenous lipopolysaccharide (LPS). The objective of the study is to investigate the biological effects of fluid and imatinib therapy on LPS-induced microcirculatory dysfunction.