Evaluation of parameters used in echocardiography and ultrasound protocol for the diagnosis of shock etiology in emergency setting

BACKGROUND: Early recognition and appropriate treatment has shown to decrease morbidity and mortality in patients with undifferentiated shock. There are many ultrasound protocols in shock; each protocol combines core ultrasound elements such as IVC and cardiac assessment which includes detection of cardiac tamponade, left ventricular function and right ventricular strain.Valvular assessment is absent in majority of ultasound protocols, while lung ultrasound is included in some of them. OBJECTIVE: In this study we investigated which parameters used in Echo – US protocol help differentiate shock types. METHODS: This cross sectional study was conducted on 150 patients with shock (140 patients were included while, 10 patients were excluded).Sensitivity and specificity of different parameters used in the Echo-US protocol were analyzed to detect which parameters can diffentiate shock types. RESULTS: Velocity time integral of Aorta and IVC maximum diameter were good discriminators for distributive shock, with area under the ROC curve (AUC) = 0.8885 (95% CI 0.8144 to 0.9406) and 0.7728 (95% CI 0.6832 to 0.8473) (Z = 10.256 p < 0.0001) and (Z = 5.079 p < 0.0001) respectively. Left ventricular systolic function, presence of pneumonia, pneumothorax or valve vegetations were of great value in differentiating shock types, while CUST, FAST, TAPSE and RV diameter were not useful in differentiating shock types. CONCLUSION: Ultrasound and echocardiography are powerful tools that can be used to identify shock etiology when the clinical picture overlaps.