Tag: Volume Assessment

Answer

No, the patient’s IVC is small and collapsing almost 75% with normal respiratory variation. This predicts a fluid-responsive state. The patient was given another liter of lactated ringers, his blood pressure improved to 108/69, and his lactate cleared. You start maintenance IV fluids, call the hospitalist back, and the patient is admitted upstairs and does well.

Learning Points

• • Fluid responsiveness is a controversial topic that continues to plague emergency medicine physicians and intensivists alike
  • In patients whom a fluid bolus is being considered, ultrasound can be a useful tool to assess for cardiac function, lung fluid status (interstitial edema) and whether a patient will improve their cardiac output in response to this fluid challenge
  • A recent study showed that the cIVC (inferior vena cava collapsibility) can be used as a predictor of who will be a fluid responder [1]
    • cIVC = (IVC expiratory diameter - IVC inspiratory diameter)/IVC expiratory diameter
    • Patients with a cIVC > 25% are likely to be fluid responders (LR + 4.56)
    • Patients with a cIVC < 25% are unlikely to be fluid responders (LR - 0.16)
  • The IVC should be examined in the subxiphoid region with the probe in a sagittal plane, and can be found by first identifying the right atrium and following this caudally
    • A back-up approach involves using the liver as an acoustic window , placing the probe in the mid axillary line in a coronal plane,  and fanning anteriorly and posteriorly until the IVC is visualized
    • The IVC should be measured 3 cm caudal to the junction of the right atrium and IVC [2]
  • M-mode can be used to evaluate the cIVC and has the advantage of measuring the exact same spot along the IVC over an extended period of time
  • As with all adjuncts to clinical decision making, fluid responsiveness should not be determined solely on a single ultrasound measurement such as cIVC but should be taken into context with the rest of the clinical picture