Association between early central venous pressure measurement and mortality in patients with sepsis: a data analysis of MIMIC-Ⅲ database / 中华危重病急救医学

ABSTRACT

Objective:To investigate the association between early central venous pressure (CVP) measurement and mortality in patients with sepsis.Methods:The adult patients with sepsis were identified from the health data of Medical Information Mart for Intensive Care-Ⅲ v1.4 (MIMIC-Ⅲ v1.4). Data of all adult patients with sepsis were collected, including gender, age, comorbidities, length of survival, total length of hospital stay and intensive care unit (ICU) stay, sequential organ failure assessment (SOFA) score, vital signs, laboratory test results on the first day, vasoactive agents usage, fluid input, urine output and fluid balance on the first day, need for renal replacement therapy and mechanical ventilation, diagnosis of sepsis, and the time and value of the first CVP measurement in the ICU. Patients were divided into early measurement and control groups based on whether or not they had a CVP measurement within the first 6 hours of ICU stay. According to the time of the first CVP measurement, the patients were subdivided into four subgroups: ≤ 3 hours, 4-6 hours, 7-12 hours and no measurement within 12 hours. The primary endpoint was 28-day mortality. The relationship between initial CVP and mortality was analyzed by Lowess smoothing method. Kaplan-Meier survival analysis and Log-Rank test were performed for univariate analysis. Cox regression analysis was performed for multivariate analysis to estimate the relationship between timeliness of CVP measurement and mortality.Results:A total of 4 733 sepsis patients were enrolled, 1 673 of whom had CVP measured within 6 hours of admission to the ICU, and the other 3 060 patients served as the control group. There were no differences in demographic characteristics and underlying diseases between the two groups, except that the early CVP measurement group had less underlying renal failure compared with control group. The early CVP measurement group had higher lactic acid (Lac) levels and SOFA scores, indicating worse severity of disease as compared with control group. The 28-day mortality in the early CVP measurement group was significantly lower than that in the control group (34.2% vs. 40.7%, P < 0.01). The early CVP measurement group had shorter length of total hospitalization and longer length of ICU stay, higher rate of mechanical ventilation and vasoactive agents dependent, and more fluid input and fluid balanced in the first day of ICU stay compared with control group. Lowess smoothing analysis showed that a "U"-shaped relationship between initial CVP and mortality was identified, suggesting that too high or too low initial CVP was associated with worse survival. Kaplan-Meier survival analysis showed that compared with the patients without early CVP measurement within 12 hours, the cumulative survival rate of patients with CVP measured within 3 hours was significantly higher (66.7% vs. 59.1%; Log-Rank test: χ2 = 15.810, adjusted P < 0.001); while no significant difference was found in patients with CVP measured between 4 hours and 6 hours and between 7 hours and 12 hours compared with the patients without early CVP measurement within 12 hours (64.4%, 60.3% vs. 59.1%; Log-Rank test: χ2 values were 5.630 and 0.100, and adjusted P values were 0.053 and > 0.999, respectively). Cox multivariate analysis showed that the Cox proportional risk model was established by taking patients without CVP measurement within 12 hours as reference, timely CVP measurement after ICU admission was associated with reduced 28-day mortality of patients with sepsis [≤3 hours: hazard ratio ( HR) = 0.65, 95% confidence interval (95% CI) was 0.55-0.77, P < 0.001; 4-6 hours: HR = 0.72, 95% CI was 0.60-0.87, P = 0.001; 7-12 hours: HR = 0.80, 95% CI was 0.66-0.98, P = 0.032] after the confounding variables (gender, age, SOFA score, initial Lac, renal failure, maximal blood glucose and white blood cell count, and minimal platelet count within 24 hours) were adjusted. Conclusions:Early CVP measurement is associated with decreased 28-day mortality in patients with sepsis. CVP should be considered as a valuable and easily accessible safety parameter during early fluid resuscitation.