Abstract: OBJECTIVE To observe the application of PICCO detector in elderly patients with severe septic shock and analyze the clinical value of central venous pressure (CVP) and general end-diastolic volume index (GEDVI) in monitoring of circulating blood volume so as to improve the clinical effect of early fluid resuscitation of the elderly patients with severe septic shock. METHODS A total of 24 ICU patients with septic shock who were treated in the hospital from Jan 2013 to Jun 2015 were enrolled in the study, the APACHEⅡ score of all the patients was more than 15 points, all the patients received the PICCO surveillance and were treated with subclavian vein catheterization and inserted the femoral artery thermal dilution catheter via the femoral artery; the time of monitoring of PICCO was T0, the thermal dilution was measured once an hour for 6 hours of consecutive measurement.The PICCO fluid management was conducted based on the cardiac index (CI), GEDVI, and extravascular lung water index (EVLWI). RESULTS As the GEDVI was used as the criterion of the circulating blood volume, the sensitivity of CVP on the hypovolemia was 5.0%, the specificity 100.00%, the positive predictive value 100.0%, the negative predictive value 67.0%; the sensitivity of CVP on the high blood volume was 19.0%, the specificity 58.0%, the positive predictive value 23.0%, the negative predictive value 51.0%.The CVP was not associated with CT, GEDVI, or EVLWI, however, the GEDVI was associated with CI and EVLWI; the changes of CI and GEDVI were consistent, however, the CI changed inversely with the CVP. CONCLUSION Among the elderly patients with severe septic shock undergoing PICCO surveillance, the specificity of CVP on the hypovolemia is high, while the sensitivity is low.The GEDVI can effectively reflect the pre-load of the heart, the sensitivity on the hypovolemia is high, and it has even higher value in the early fluid resuscitation of the patients with severe septic shock.The monitoring of PICCO may effectively reduce the insufficient fluid resuscitation which is caused by the low sensitivity of the CVP on hypovolemia.