Investigation of doppler ultrasonography measurement of inferior vena cava blood flow velocity for intravascular (effective) volume assessment in patients presenting to the emergency department with gastrointestinal system bleeding as an acute hemorrhage model

The subset of patients presenting to the emergency department with hemorrhagic shock due to acute gastrointestinal bleeding constitutes a significant portion of critically ill patients. Accurate assessment of intravascular volume status in this patient group guides the fluid resuscitation strategy. Currently used invasive methods, such as inferior vena cava (IVC) diameter and collapsibility index measurement, have limitations in determining intravascular fluid status, leading to controversial points in the literature. Additionally, non-invasive hemodynamic monitoring methods have been described in the literature with validations but are not widely used in emergency departments. Therefore, we hypothesized that measuring flow velocity through the IVC could have a predictive role in evaluating intravascular volume. We enrolled 18 patients presenting with suspected acute gastrointestinal bleeding. Upon arrival, demographic data, vital signs, blood gas values, cardiac measurements, type and amount of fluids administered at arrival; 30 minutes, and 60 minutes post-fluid replacement IVC diameter and collapsibility measurements, CW Doppler IVC peak velocity measurements, and data from a non-invasive hemodynamic monitoring device (used as a reference test) were recorded. Statistical analyses were performed on the collected data. In our study, the IVC peak velocity measurement at arrival showed statistically significant differences when compared with stroke volume variation (SVV) Group (p=0.009). The specificity of IVC peak velocity measurement was 100% and sensitivity was 84%. However, no statistically significant results were found when comparing measurements at 30 minutes, 60 minutes, and post-replacement values. As a result of our study, VCI peak velocity measurement was found to be significant in predicting hypovolemia, but it was not found to be suitable for volume level monitoring. VCI peak velocity measurement is more valuable than VCI diameter and collapsibility measurement in predicting hypovolemia. Keywords: Peak Velocity, CW Doppler, IVC, Stroke Volume Variation, Volume Status