BACKGROUND:This study was undertaken to observe the characteristics of blood pressure variability (BPV) and sepsis and to investigate changes in blood pressure and its value on the severity of illness in patients with sepsis. METHODS:Blood parameters, APACHE Ⅱ score, and 24-hour ambulatory BP were analyzed in 89 patients with sepsis. RESULTS:In patients with APACHE Ⅱ score>19, the values of systolic blood pressure (SBPV), diasystolic blood pressure (DBPV), non-dipper percentage, cortisol (COR), lactate (LAC), platelet count (PLT) and glucose (GLU) were significantly higher than in those with APACHE Ⅱ score ≤19 (P<0.05 ), whereas the values of procalcitonin (PCT), white blood cell (WBC), creatinine (Cr), PaO2, C-reactive protein (CRP), adrenocorticotropic hormone (ACTH) and tumor necrosis factor α(TNF-α) were not statistically significant (P>0.05). Correlation analysis showed that APACHE Ⅱ scores correlated significantly with SBPV and DBPV (P<0.01, r=0.732 and P<0.01, r=0.762). SBPV and DBPV were correlated with COR (P=0.018 and r=0.318; P=0.008 and r=0.353 respectively). However, SBPV and DBPV were not correlated with TNF-α, IL-10, and PCT (P>0.05). Logistic regression analysis of SBPV, DBPV, APACHE Ⅱ score, and LAC was used to predict prognosis in terms of survival and non-survival rates. Receiver operating characteristics curve (ROC) showed that DBPV was a better predictor of survival rate with an AUC value of 0.890. However, AUC of SBPV, APACHE Ⅱ score, and LAC was 0.746, 0.831 and 0.915, respectively. CONCLUSIONS:The values of SBPV, DBPV and non-dipper percentage are higher in patients with sepsis. DBPV and SBPV can be used to predict the survival rate of patients with sepsis.