Inferior Vena Cava (IVC) Evaluation Resuscitative ultrasound - focused haemodynamic assessment
Scope and purpose
The IVC is commonly examined with point‑of‑care ultrasound (POCUS) to provide a rapid, non‑invasive estimate of central venous pressure (CVP) and to inform immediate haemodynamic decisions in the emergency department and during peri‑resuscitation.
UK national bodies support inclusion of IVC assessment within competent POCUS practice but emphasise that measurements must be interpreted in context, by trained operators, with appropriate device quality and local governance (RCEM; Resuscitation Council UK; NICE; GOV.UK).
Numeric thresholds cited here are literature‑derived and should not be treated as absolute national standards.
Physiological basis
The IVC is a compliant venous conduit. Its diameter and respiratory variation reflect right atrial pressure and changes in intrathoracic pressure:
- Spontaneous inspiration → negative intrathoracic pressure → increased venous return → IVC collapse.
- Positive‑pressure inspiration → increased intrathoracic pressure → IVC tends to distend and collapse is reduced.
Many factors other than intravascular volume affect IVC behaviour, including:
- Right ventricular function.
- Tricuspid regurgitation.
- Raised intra‑abdominal pressure.
- Pericardial disease.
- Ventilatory mode and applied PEEP.