Emergency laparotomy, particularly in cases of intra-abdominal sepsis such as perforated peritonitis, carries a high risk of morbidity and mortality despite advances in surgical and critical care management. Accurate early predictors of patient outcomes are essential to guide clinical decision-making and optimize resource allocation in these critically ill patients.

One of the key pathophysiological drivers of poor outcomes in sepsis and systemic inflammatory conditions is endothelial dysfunction, which contributes to hemodynamic instability, impaired tissue perfusion, and eventual multi-organ failure. Recognizing this, recent interest has turned toward non-invasive vascular markers that reflect endothelial health. Adult patients with suspected infection can be rapidly identified as being more likely to have poor outcomes typical of sepsis if they have at least 2 of the following clinical criteria that together constitute a new bedside clinical score termed quick SOFA (qSOFA): respiratory rate of 22/min or greater, altered mentation, or systolic blood pressure of 100 mm Hg or less.

Brachial artery reactivity (BAR)—measured through ultrasound-based assessments like Flow Mediated Dilation (FMD) and Hyperaemic Velocity (HV)—has emerged as a surrogate marker of systemic endothelial function. FMD evaluates the dilation capacity of the brachial artery following ischemia, while HV reflects the speed of blood flow recovery and is influenced by microvascular function.

While FMD has traditionally been used in cardiovascular research, its prognostic value in sepsis remains inconsistent. Conversely, recent studies have demonstrated that reduced HV is associated with increased mortality in critically ill patients with sepsis, suggesting it may be a more sensitive indicator of adverse outcomes. 

In the context of emergency laparotomy for perforation peritonitis, where rapid risk 1stratification is crucial, assessing brachial artery reactivity could serve as a valuable, bedside tool to predict mortality. This study explores the predictive utility of BAR parameters— especially HV and FMD—as potential early biomarkers for in-hospital mortality in this high risk surgical population.