Shock is a life-threatening clinical syndrome characterized by inadequate tissue perfusion and oxygenation due to circulatory failure. Among its subtypes, hypovolemic and distributive shock are the most frequently encountered forms in emergency settings, both of which can rapidly progress to multiple organ dysfunction if not promptly recognized and appropriately managed. Early assessment of intravascular volume status and prompt initiation of fluid resuscitation are widely recognized as critical interventions to prevent irreversible organ damage and to improve overall patient outcomes in shock management.

Traditionally, invasive hemodynamic monitoring methods such as central venous pressure (CVP) and pulmonary artery catheterization have been used to guide fluid therapy. However, these methods are often impractical in the emergency department due to their invasiveness, time constraints, and potential complications. In recent years, non-invasive bedside tools have gained increasing popularity for dynamic volume assessment, especially in critically ill patients.

This prospective observational study was conducted in the Emergency Department of Gazi University Faculty of Medicine, a tertiary academic hospital, between November 2017 and January 2018. The study was approved by the institutional ethics committee, and written informed consent was obtained from all participants. In this study, adults (≥18 years) presenting to the emergency department with clinical signs of shock (systolic blood pressure <90 mmHg, mean arterial pressure <65 mmHg, or a ≥40 mmHg decrease in systolic blood pressure from baseline) and judged to require intravenous fluid resuscitation due to suspected intravascular volume depletion (e.g., hypovolemic or distributive shock) were eligible for inclusion, provided they gave informed consent. Patients were excluded if they were younger than 18 years, pregnant, refused or were unable to provide informed consent, were intubated prior to or at presentation, presented with cardiopulmonary arrest on arrival, had incomplete or technically inadequate IVC-CI, PI, or PVI measurements at presentation, or exhibited hemodynamic instability requiring immediate vasopressor therapy or advanced airway intervention before initial measurements. All eligible patients underwent initial hemodynamic and bedside ultrasonographic assessment upon presentation. Inferior vena cava (IVC) diameter was measured using a 5 MHz curvilinear abdominal probe (LOGIQ™ S7, GE Healthcare) in the longitudinal subxiphoid view, approximately 2 cm caudal to the junction of the hepatic vein and the IVC. M-mode ultrasonography was employed to obtain respiratory variations in IVC diameter during spontaneous breathing. The IVC Collapsibility Index (IVC-CI) was calculated from inspiratory and expiratory diameters. Simultaneously, perfusion index (PI) and pleth variability index (PVI) values were recorded using the Masimo Root® monitor with a digital pulse oximetry probe. Patients then received a standardized fluid bolus of 500 mL isotonic saline administered over approximately 15–30 minutes, in accordance with the NICE 2016 guidelines for intravenous fluid therapy in adults. All ultrasonographic and perfusion measurements were repeated within 15 minutes following the completion of fluid resuscitation. To ensure consistency, all assessments were performed by a senior emergency medicine resident who had previously completed formal training in point-of-care ultrasound and had extensive hands-on experience in its routine clinical application. This study employed a prospective, self-controlled observational design. Each patient served as their own control, with hemodynamic and ultrasonographic parameters compared specifically between the baseline (pre-resuscitation) and post-fluid administration states.

Gözlemsel Çalışma Dizaynı / Prospective