Circulatory Shock

Circulatory shock is characterized by tissue hypoxia. Although fluid resuscitation is an essential treatment in many forms of circulatory shock, its benefits are variable, and its administration carries a risk of potentially harmful fluid overload. Assessment of fluid responsiveness generally relies on changes in cardiac output. However, the actual therapeutic objective is rather to improve tissue oxygen utilization, as reflected by oxygen consumption. Despite its physiological relevance, direct measurement of oxygen consumption remains complex and difficult to perform in routine clinical practice. Capillary refill time is a simple, rapid, non-invasive, and readily available marker of peripheral perfusion. It is associated with outcomes in patients with circulatory shock, and a capillary refill time-guided therapeutic strategy may improve outcomes in patients with septic shock. This study hypothesizes that changes in capillary refill time following fluid resuscitation may predict changes in oxygen consumption induced by fluid administration. If confirmed, capillary refill time and its changes could be incorporated into the criteria used to assess the indication for fluid resuscitation in patients with shock. They would also provide additional physiological information regarding the relationship between peripheral perfusion and oxygen consumption.

This prospective multicenter observational study aims to investigate the relationship between palpable peripheral pulses and simultaneously measured arterial blood pressure in adult patients with circulatory shock or impending circulatory failure. Peripheral pulse palpation is routinely used in emergency medicine, trauma care, critical care, and cardiopulmonary resuscitation as a rapid clinical assessment of circulation. However, the association between palpable pulses and actual arterial blood pressure remains poorly validated. Patients treated in emergency departments, intensive care units, operating rooms, and other acute care settings will undergo routine pulse palpation at predefined anatomical locations including carotid, femoral, and radial arteries. Simultaneously measured non-invasive and/or invasive arterial blood pressure values will be recorded from routine clinical monitoring systems. Additional clinical variables relevant to circulatory status will also be collected. The study seeks to define blood pressure thresholds associated with pulse palpability and evaluate the agreement between invasive and non-invasive blood pressure measurements in patients with circulatory shock.