Relationship Between the Subcostal and Right Lateral Ultrasound Views of Inferior Vena Cava Collapse

cIVCRC and cIVCSS measures are discordant, where cIVCRC underestimates cIVCSS. The degree of discordance is directly proportional to the value of F-IVC. Therefore, we recommend that cIVCRC ≥ 42% be used to rule in, but not to rule out, fluid responsivity. Wherever possible, F-IVC should be assessed to understand the clinical relevance of cIVCRC.