The aim is to establish ultrasound measurement of the diameter of the inferior vena cava as a predictor of shock in polytraumatized patients. A prospective, observational, analytical and cross-sectional study was conducted to determine the ultrasound measurement of the inferior vena cava in 40 patients at the UPT of the Hospital General del Este ¿Dr. Domingo Luciani¿ located in El Llanito, Sucre Municipality, Miranda State, Caracas-Venezuela in the period between January and April 2018. Two groups were selected; group 1: patients in shock defined as those with a systolic blood pressure below 90 mmHg on admission, and group 2: control patients who will maintain normal blood pressure figures. The imaging study of the inferior vena cava was performed with the ALOKA prosound SSD-¿5 ultrasound machine and the MicroMaxx SonoSite handheld ultrasound, in which the collapsibility index was measured. The findings were recorded on the data collection sheet. The proposed statistical analysis for the comparison of means was done with the student t-test for independent samples and the diagnostic cut-off assessment will be done with the ROC test.