SMACC: The Dark Art of IVC Ultrasound
Thanks to plenty of people for their input, but especially Kylie Baker and Adrian Goudie When I was first taught about sonographic assessment of the Inferior Vena Cava (IVC), the following table was unveiled with great solemnity: IVC diameter (cm) IVCCI Estimated RA pressure (mm Hg) <1.7 >50% 0-5 >1.7 >50% 6-10 >1.7 <50% 11-15 ‘dilated’ none >15 We were told to learn these measurements, take them to the bedside and use them on our critically ill patients to guide resuscitation. We were commanded to use M-mode assessment in the subxiphoid ling axis, and ideally a sniff test. IVC ultrasound was, and still is, touted as The Next Big Thing in assessment of fluid status and fluid responsiveness. Sound familiar? It should. Every time a flash new test comes along (D-dimer, proBNP, procalcitonin) we are told by its starry-eyed devotees that this time it’s the real thing. But is it? This is the current state of ‘knowledge’: IVC is not a great test for intravascular volume status, fluid responsiveness or even fluid tolerance. Then again, it might be. The problem is that no-one really knows. A lot of big statements have come out of a lot of teeny studies that don’t really back them up. It’s probably better for ventilated patients than spontaneously breathing patients (you can remove much of the breath-to-breath variation that confounds so many of these assessment tools). It’s also probably OK at extremes (flat versus full) and s...
Source: Life in the Fast Lane - Category: Emergency Medicine Doctors Authors: Justin Bowra Tags: Emergency Medicine Featured Intensive Care SMACC inferior vena cava ivc justin bowra Ultrasound Source Type: blogs
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