Evolution of Muscle Function, Breathlessness and Quality of Life Following Intra or Extra-Abdominal Sepsis in ICU Patients

Sepsis is organ dysfunction secondary to an inappropriate host response to infection. In the most severe cases, circulatory failure necessitating the introduction of vasopressor therapy is called septic shock. Sepsis and septic shock are life-threatening systemic organ dysfunctions requiring hospitalization in a critical care unit. According to several studies, sepsis accounts for around 30% of patients in these units. In this patient population, mortality in the critical care unit or in hospital is 25.8% and 35.3% respectively. Among the organ dysfunctions associated with sepsis, striated skeletal muscle damage is frequent and possibly severe. The literature refers to this as sepsis-induced myopathy, and describes three main mechanisms: mitochondrial dysfunction, exacerbated proteolysis and altered muscle membrane excitability. Of all the striated skeletal muscles that can be affected, the diaphragm and the muscles of the thoracic and abdominal wall play a major role in breathing. The diaphragm remains the main muscle involved in breathing. Its physiology is twofold. Firstly, through its contraction, the diaphragm is responsible for the lateral movement of the lower ribs, thus increasing the transverse diameter of the thorax. This first action is commonly referred to as "insertional". At the same time, lowering the phrenic center of the diaphragm increases abdominal pressure. Its distinctive upwardly convex domed appearance means that it is intimately in contact with both the chest wall and the abdominal cavity. This particular area of contact is called the apposition zone. It is on this zone, under the action of the abdominal compartment, that positive pressure also generates an outward thrust from the medial face of the lower ribs, a second action commonly referred to as "appositional". A number of studies, including that carried out by our team (US\_DIAMONDS, NCT 02474797), have identified a high prevalence of diaphragmatic damage in patients with sepsis or s