Hemorrhagic Shock in Polytrauma Patients: Early Detection with Renal Doppler Resistive Index Measurements

Purpose: To investigate whether renal Doppler resistive index (RI) changes occur early during posttraumatic bleeding and may be predictive of occult hypoperfusion-and thus hemorrhagic shock-in patients with polytrauma. Materials and Methods: This study was approved by the institutional ethics committee, and informed consent was obtained from all patients. The renal Doppler RI was measured in 52 hemodynamically stable adult patients admitted to the emergency department (ED) because of polytrauma. Renal Doppler RI, hemoglobin, standard base excess, lactate, systolic blood pressure, pH, heart rate, and inferior vena cava diameter values were recorded at admittance and correlated with outcome (progression or nonprogression to hemorrhagic shock). Logistic regression analysis was performed to assess the risk factors for progression to hemorrhagic shock. Results: Twenty-nine patients developed hemorrhagic shock, and 23 did not. At univariable analysis, the hemorrhagic shock group, as compared with the nonhemorrhagic shock group, had higher renal Doppler RI (mean, 0.80 +/- 0.10 [standard deviation] vs 0.63 +/- 0.03; P < .01), injury severity score (mean, 36 +/- 11 vs 26 +/- 5; P < .01), and standard base excess (mean, -4.0 mEq/L +/- 4 vs 1 mEq/L +/- 3; P = .04) values. At logistic regression analysis, a renal Doppler RI greater than 0.7 (vs less than or equal to 0.7) was the only independent risk factor for progression to hemorrhagic shock (odds ratio, 57.8; 95% confidence interval: 10.5, 317.0) (P < .001). Conclusion: In polytrauma patients who are hemodynamically stable at admittance to the ED, renal cortical blood flow redistribution occurs very early in response to occult bleeding and might be noninvasively detected by using the renal Doppler RI. A renal Doppler RI greater than 0.7 is predictive of progression to hemorrhagic shock in polytrauma patients. (C) RSNA, 2011