Clinical Research Directory

CHECK-NIRS2D-Study

The study investigates how external, physiological, and behavioral factors influence the measurement of regional tissue oxygenation using two-dimensional near-infrared spectroscopy (NIRS) imaging in healthy volunteers. It aims to improve the standardization and reliability of this non-invasive method for assessing microvascular perfusion and tissue oxygenation. The study also examines the effects of temporary vascular occlusion, ambient temperature, physical activity, caffeine consumption, and nicotine consumption on NIRS-based tissue oxygenation measurements. The findings are intended to establish a standardized measurement protocol for future clinical research and the assessment of microvascular perfusion in critically ill patients.

Correlation Between Capillary Refill Time and Perfusion Index in Critically Ill Patients

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.

Clinical Value of CT Perfusion in Peripheral Artery Disease

Peripheral artery disease (PAD) affects millions worldwide and can lead to serious complications such as leg ulcers, gangrene, and amputation. Current imaging methods mainly evaluate large blood vessels but do not measure microcirculation in the foot. Computed tomography perfusion (CTP) is a new technique that can assess blood flow in small vessels. The purpose of this study is to see whether combining CTP measurements with standard CT angiography images and patient clinical information can help predict which PAD patients are more likely to have poor outcomes after surgery to restore blood flow (revascularization). Poor outcomes include death or major limb problems such as amputation or need for another procedure. This is an observational study. Researchers will collect data from about 200 adult PAD patients who are scheduled to undergo revascularization. Participants will receive routine care including CT scans before and after surgery. No experimental drugs or devices are given. Researchers will follow participants for up to 2 years after surgery through medical records and phone calls to track their recovery and any complications. The results may help doctors identify high-risk patients earlier and improve treatment decisions.

ICU Combined Assessment of Cardio-Respiratory Exercise

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.

Evaluation of the Microcirculatory Response to Fluids in Critically Ill Patients With Venous Congestion: A Prospective Observational Study

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

The Effect of Photobiomodulation on Microvascular Blood Flow: The Role of Wavelength and Skin Temperature

The objective of this study is to assess peripheral microcirculatory hemodynamic responses to photobiomodulation in participants with normal circulation and with functional peripheral vasoconstriction, using noninvasive thermography, photoplethysmography, and laser Doppler flowmetry.

Hemodynamic Evaluation Using Microcirculation for Early Treatment of Septic Patients

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.

The Impact of Intra-operative Fluid Infusion Rate on Microcirculation

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.

Urethral PeRfusion Index-Guided Hemodynamic ManagemenT in Patients Having Major Abdominal Surgery: the UPRIGHT Randomized Feasibility Trial

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.

Investigation of Novel and Established Therapies in a Human Intravenous Lipopolysaccharide Model of Sepsis

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.

The Cerebral Microcirculation Diseases and Coronary Microcirculation Disease Study

Ischaemic heart disease (IHD) and degenerative brain disease are two major sources of death and disability affecting all countries. While the consequences of obstructive disease in major vessels supplying blood to both organs have been widely documented, less attention has been paid to disease processes affecting the microcirculation that may affect cardiac and cerebral function. Yet, over the last decade significant progress has been made in understanding the substrate of microvascular disease in both organs. In the heart, arteriolar thickening and capillary rarefaction that reduce the conductance of the microvasculature and its ability to vasodilate in response to increased myocardial oxygen demands constitute the leading cause of coronary microvascular dysfunction (CMD). In the brain, concentric hyaline thickening of deep penetrating small arteries (arteriolosclerosis) with associated fibrosis of the vessel wall constitutes the most frequent substrate for cerebral small vessel disease (CSVD). Of note, both CMD and CSVD share common risk factors, such as age, hypertension, and diabetes.3 These factors might have a common effect on the microvascular domain of cardiac and cerebral vascular beds. Although a potential link between both conditions has been hypothesized based on the similarities between pathological changes and risk factors, advance in knowledge exploring this has been hampered by lacking objective evidence of CMD and pathological brain changes indicative of CSVD in prior research studies. Thus, the relationship between CMD and CSVD is unknown. The main objective of this study was to analyse the relationship between cerebrovascular disease and CMD in patients with atherosclerotic coronary artery disease (CAD).