Inferior vena cava diameter as a marker of early hemorrhagic shock: a comparative study.

BACKGROUND: We determined the value of the inferior vena cava (IVC) diameter for predicting acute blood loss in control and blunt trauma patients and compared this with other parameters of hemorrhagic shock.

METHODS: Fifty volunteers and 28 consecutive hemorrhagic shock patients were recruited prospectively to participate in the study. Vital signs, blood lactate, and serum bicarbonate were measured, and shock index and base excess were calculated. Anteroposterior (AP) and mediolateral (ML) IVC diameters during inspiration and expiration were measured in the right subcostal region. IVC diameters in hemorrhagic shock patients were compared with those of controls and were also compared with other hemorrhagic shock parameters.

RESULTS: A significant relationship was determined between mean IVC AP and ML diameters during expiration and inspiration on admission in the study group and in the control group (p=0.000, p=0.000, p=0.000, p=0.000). Serum lactate levels correlated significantly with all IVC diameters (r=55), especially the IVC ML diameter during expiration.

CONCLUSION: IVC diameter, as measured by transabdominal ultrasound, was more accurate than the shock index and other commonly used non-invasive predictors of acute blood loss (blood pressure, heart rate per minute, serum lactate level, base deficit).