The study will be carried out on patients over the age of 18 who were admitted to the
general ward between for at least 24 hours and who had a clinical indication for an IVC
ultrasound. Patients are informed through an informed consent form and are given the
opportunity to opt-out. When there are no objections, the patient's data is collected for
the study. Patients who are using vasopressors at the time of the ultrasound are excluded
from the study. In addition, patients who require invasive or non-invasive ventilation
(optiflow, CPAP, BPAP) are also excluded.
The ultrasounds are performed by trained physicians based on a standard operating
procedure. The longitudinal portion of the IVC is scanned and a cine loop of 10 seconds
is made during a respiratory cycle to determine the diameter of the IVC (dIVC). After the
recording is paused, the dIVC will be measured 2 cm caudal to the junction of the hepatic
vein and IVC to standardize the measurements. Measurements are taken at peak expiration
(dIVCe) and inspiration (dIVCi) by measuring the vein lumen at one respiratory cycle from
one interior wall to the opposite interior wall.
Data is collected at the time of admission and after 48 hours (or prematurely if the
patient is discharged). During the initial assessment, the patient's demographics,
clinical data, physical examination, vitals , laboratory parameters, and the POCUS IVC
(minimal and maximal diameter, percentage collapse) are registered. The Charlson
Comorbidity Index is used to quantify the severity of comorbidities in the patients.
Additionally, the patient's overall health status is measured by the ECOG Performance
Status Scale.
Once the initial measurements are done, a clinical diagnosis of the patient's volume
status will be established. 48 hours later, more data will be gathered for the follow-up.
The data includes vitals and laboratory parameters. It is also noted whether the POCUS
influenced the management of treatment (IV fluid or diuretic therapy) of each patient.
Following this assessment, a clinical diagnosis in retrospect at the time of the
ultrasound at baseline about the volume status is established.
The diagnostic accuracy for hypovolemia and hypervolemia cases are analyzed. The
sensitivity, specificity, positive predictive value, and negative predictive value are
also determined. Furthermore, the area under the curve (AUC) for hypo- and hypervolemia
were computed.
A descriptive analysis of the changes over time will be carried out in the subgroup with
follow-up measurements. The interpretation of the images at the time of the ultrasound
serves as the foundation for the main analysis. A second assessor will verify the images
retrospectively in a subset, recalculating the diameter and evaluating their quality. A
descriptive analysis will be conducted on the quality of measurements. Moreover, an
exploratory analysis will be carried out to ascertain the best location and cutoff points
for identifying volume status.