This study aims to compare ultrasound-guided inferior vena cava (IVC) assessment with central venous pressure (CVP) monitoring for the detection of hypovolemia in shock patients in the emergency department. The primary objective is to evaluate the diagnostic accuracy and clinical utility of IVC collapsibility index compared to CVP values in both early and post-resuscitation phases. The study will prospectively enroll shock patients, collect demographic and clinical data, and analyze the correlation between IVC and CVP measurements to determine their role in guiding fluid resuscitation and hemodynamic management.

Hypovolemia is a major contributor to morbidity and mortality among patients presenting with shock in the emergency department. Early recognition and accurate assessment of intravascular volume status are essential for effective resuscitation. Central venous pressure (CVP) monitoring has traditionally been used but is invasive and may not always accurately reflect volume status. Ultrasound-guided inferior vena cava (IVC) assessment offers a non-invasive alternative, with the IVC collapsibility index shown to correlate with volume responsiveness. This prospective observational study will enroll patients diagnosed with shock and compare IVC measurements with CVP values during both early presentation and post-resuscitation phases. The findings are expected to provide evidence on the diagnostic agreement between IVC ultrasound and CVP monitoring, potentially supporting the use of IVC ultrasound as a rapid, reliable, and less invasive tool for guiding fluid therapy in emergency settings.

Inclusion Criteria:

1- Adult patients aged ≥18 years. 2.Both male and female patients will be included in the study. 3. Presentation to the Emergency Department with clinical evidence of shock, defined by: Hypotension (systolic blood pressure <90 mmHg or mean arterial pressure <65 mmHg).

Evidence of tissue hypoperfusion (e.g., altered mental status, cold extremities, or oliguria).

Elevated serum lactate (>2 mmol/L). 4. Shock attributed to hypovolemic, septic, or hemorrhagic etiologies. 5. Patients requiring fluid resuscitation and hemodynamic monitoring.

Exclusion Criteria:

1 - Patients younger than 18 years. 2. Pregnancy. 3.Cardiogenic or obstructive shock (e.g., cardiac tamponade, massive pulmonary embolism, or tension pneumothorax).

4.Known inferior vena cava (IVC) anomalies (e.g., congenital absence, thrombosis).

5. Increased intra-abdominal pressure or severe ascites. 6. Morbid obesity (BMI ≥40 kg/m²) or any condition interfering with adequate IVC ultrasound visualization.

7. Prior central venous catheterization performed before Emergency Department arrival.

8. Congestive heart failure (CHF) with left ventricular ejection fraction (LVEF <40%) or pulmonary hypertension.

9. Refusal of the patient or legal guardian to participate in the study.

The study population will include adult patients aged 18-65 years presenting with shock to the emergency department and requiring volume status assessment through both IVC ultrasound and central venous pressure monitoring.

Individual participant data (IPD) will not be shared because the study is conducted as part of an academic thesis project. Data are limited to internal use within the research team and protected by institutional and ethical regulations.