Ultrasonographic assessment of inferior vena cava/abdominal aorta diameter index: a new approach of assessing hypovolemic shock class 1.

BACKGROUND We designed this study to expand the usage of ultrasound to detect early occurrence of hypovolemia. We explore the potential use of inferior vena cava (IVC) and abdominal aorta (AA) diameter index (IVC:AA) measured ultrasonographically to detect class 1 hypovolemic shock with blood loss less than 15%.ᅟ METHODS The aim of this study was to determine the changes in the diameter of inferior vena cava and abdominal aorta in blood donors by using ultrasound, pre and post blood donation. The result of the study would be further explorated to determine the inferior vena cava (IVC) abdominal aorta (Aorta) diameter index (IVC:Aorta). This was a prospective study done in the blood bank of a university hospital. Researcher was trained by a senior radiologist to assess inferior vena cava and abdominal aorta diameter. Fifty-two healthy blood donors were included in the study. Inclusion criteria were same with the blood bank criteria to donate blood. Demographic data and vital signs were taken before the ultrasound measurement done for inferior vena cava and abdominal aorta diameter. Once the volunteers donated their blood of approximately 450 mls; the measurements were repeated using the same methods. RESULTS There were differences in IVC, abdominal aorta and inferior vena cava:aorta diameters index pre and post donation. With mathematical analysis, we suggested the number of IVC:Aorta index as 1.14±2SD with SD 0.18 as a cut off value for class 1 hypovolemic shock. CONCLUSION The IVC:Aorta diameter index can be used as a parameter for detecting early phase (Class 1) of hypovolemic shock.