ABSTRACT
This is based on the diameter of the IVC (subcostal view) and response to sniffing (Table 6.1). Estimating RA pressure<sup> <xref ref-type="bibr" rid="ref6_2">2</xref> </sup> <xref ref-type="fn" rid="fnt6_1"> <sup>*</sup> </xref>
Normal 0–5 mmHg (mean 3 mmHg)
Intermediate 5–10 mmHg (mean 8 mmHg)
High 10–20 mmHg (mean 15 mmHg)
IVC diameter
≤2.1 cm
≤2.1 cm
>2.1 cm
>2.1 cm
Collapse with sniff
>50%
<50%
>50%
<50%
Either a range or a mean value may be used depending on local preference
The diameter should be measured at end expiration close to the junction with the hepatic veins situated 0.5–3.0 cm from the ostium of the right atrium (RA).
During sniffing, avoid the IVC moving out of the imaging plane as this can exaggerate the reduction in diameter
In acutely ill patients in whom the subcostal view is suboptimal, a right anterior oblique midaxillary view can be used instead. 1
