Sonographic Measurement Of Inferior Vena Cava Diameter A Noninvasive Tool To Detect Acute Blood Loss

Detection and monitoring of blood loss in trauma patients can often be challenging. Change in the inferior vena cava diameter (IVCd) occurs due to alteration in circulating blood volume (CBV) and blood loss. Ultrasonographic measurement of IVCd provides a noninvasive real-time information of the CBV. The present study was designed to determine whether acute blood loss could be detected by sonographic measurement of the IVCd. A total of 50 volunteer blood donors aged 18 to 57 years were studied in the Department of Radiology and Imaging of Dhaka Medical College Hospital (DMCH) from July 2004 to June 2005. The inferior vena cava diameters, both during inspiration and expiration were measured by ultrasound examination immediately before and after donation of a single unit (450ml) of blood. During examination, the transducer was applied to the epigastrium parallel to the median line about 2 cm to the right of it for sagittal sections, and at a right angle to the median line about 3 cm below the xiphoid process for transverse sections. In sagittal sections, the inferior vena cava behind the liver were imaged during inspiration and expiration. The mean diameter of IVC during expiration before and after the blood donation was 17.5mm (±1.56mm) and 11.93mm (±1.48mm) respectively. Likewise, the mean diameter of IVC during inspiration before and after the blood donation was 12.96mm (±1.61mm) and 7.58mm (±1.29mm) respectively. The decrease in INV diameter following blood loss was significant (p< 0.01). Thus, the acute depletion of CBV could be detected by measuring the change of IVCd by sonography. Further study may be undertaken to determine the relationship of unit change of IVCd due to acute blood loss in case of trauma or other conditions. DOI: http://dx.doi.org/10.3329/imcj.v5i2.10099 IMCJ 2011; 5(2): 51-53