Prognostic value of difference between peripheral venous and arterial partial pressure of carbon dioxide in patients with septic shock: a pilot study / 南方医科大学学报

OBJECTIVE@#To evaluate the prognostic value of the difference between peripheral venous and arterial partial pressure of carbon dioxide in patients with septic shock following early resuscitation.@*METHODS@#This prospective study was conducted among the patients with septic shock treated in our department during the period from May, 2017 to May, 2018. Peripheral venous, peripheral arterial and central venous blood samples were collected simultaneously and analyzed immediately at bedside after 6-h bundle treatment. Arterial blood lactate concentration (Lac) and the arterial (PaCO), peripheral venous (PpvCO) and central venous partial pressure of carbon dioxide (PcvCO) were recorded. The differences between PpvCO and PaCO (Ppv-aCO) and between PcvCO and PaCO (Pcv-aCO) were calculated. Pearson correlation analysis was used to test the agreement between Pcv-aCO and Ppv-aCO. Multivariable logistic regression analysis was performed to analyze the possible risk factors for 28-day mortality, and the receiver-operating characteristic curve (ROC) was plotted to assess the prognostic values of these factors for 28-day mortality.@*RESULTS@#A total of 62 patients were enrolled in this study, among who 35 survived and 27 died during the 28-day period. Compared with the survivor group, the patients died within 28 days showed significantly higher Acute Physiology and Chronic Health Evaluation Ⅱ (APACHE Ⅱ) score (24.2±6.0 20.5±4.9, =0.011), sequential organ failure assessment (SOFA) score (14.9±4.7 12.2±4.5, =0.027), PcvaCO (5.5±1.6 7.1±1.7, < 0.001), PpvaCO (7.1±1.8 10.0±2.7, < 0.001), and arterial lactate level (3.3±1.2 4.2±1.3, =0.003) after 6-h bundle treatment. Pearson correlation analysis showed that Ppv-aCO was significantly correlated with Pcv-aCO (=0.897, R= 0.805, < 0.001). Multiple logistic regression analysis identified Ppv-aCO (β=0.625, =0.001, OR=1.869, 95% CI: 1.311-2.664) and lactate level (β=0.584, =0.041, OR=1.794, 95%CI: 1.024-3.415) as the independent risk factors for 28-day mortality. The maximum area under the ROC (AUC) of Ppv-aCO was 0.814 (95%CI: 0.696- 0.931, < 0.001), and at the best cut- off value of 9.05 mmHg, Ppv-aCO had a sensitivity of 70.4% and a specificity of 88.6% for predicting 28-day mortality. The AUC of lactate level was 0.732 (95%CI: 0.607-0.858, =0.002), and its sensitivity for predicting 28-day mortality was 70.4% and the specificity was 74.3% at the best cut-off value of 3.45 mmol/L; The AUC of Pcv-aCO was 0.766 (95%CI: 0.642-0.891, < 0.001), and its sensitivity was 66.7% and the specificity was 80.0% at the best cut-off value of 7.05 mmHg.@*CONCLUSIONS@#A high Ppv-aCO after early resuscitation of septic shock is associated with poor outcomes. Ppv-aCO is well correlated with Pcv-aCO and can be used as an independent indicator for predicting 28-day mortality in patients with septic shock.

Prognostic value of differences between peripheral arterial and venous blood gas analysis in patients with septic shock / 中华危重病急救医学

Objective To investigate the value of the difference between peripheral arterial and venous blood gas analysis for the prognosis of patients with septic shock after resuscitation.Methods Patients with septic shock aged 18 to 80 years admitted to intensive care unit (ICU) of Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine from May 2016 to December 2017 were enrolled. The peripheral arterial blood and peripheral venous blood gas analysis were measured simultaneously after the early 6 hours resuscitation, including pH, partial pressure of oxygen (PO2), partial pressure of carbon dioxide (PCO2), base excess (BE), bicarbonate (HCO3-) and lactate (Lac) level, and the difference values between peripheral arterial and venous blood were calculated. According to the 28-day survival, the patients were divided into survival group and death group. Multiple Logistic regression analysis was used to analyze the risk factors of death, and the receiver operating characteristic curve (ROC) was used to analyze the prognostic value of blood gas analysis parameters for prognosis.Results A total of 65 patients with septic shock resuscitation were enrolled in the study, 35 survived while 30 died during the 28-day period. ① There was no significant difference in gender, age, and mean arterial pressure (MAP), central venous pressure (CVP), central venous oxygen saturation (ScvO2) and norepinephrine (NE) dose between the two groups.② The arterial and venous Lac, the difference of Lac (ΔLac) and PCO2 (ΔPCO2) between arterial and venous blood in death group were significantly higher than those in survival group [arterial Lac (mmol/L): 7.40±3.10 vs. 4.82±2.91, venous Lac (mmol/L): 9.17±3.27 vs. 5.81±3.29, ΔLac (mmol/L): 1.77±0.54 vs. 0.99±0.60, ΔPCO2 (mmHg, 1 mmHg =0.133 kPa): 9.64±5.08 vs. 6.70±3.71, allP < 0.01], and there was no significant difference in the other arterial and venous blood gas analysis index and its corresponding differential difference between two groups. ③ Multiple Logistic regression analysis showed that ΔPCO2 [β = 0.247, odd ratio (OR) = 1.280, 95％ confidential interval (95％CI) = 1.057-1.550,P = 0.011], and ΔLac (β = 2.696,OR = 14.820, 95％CI = 2.916-75.324,P = 0.001) were the independent risk factors for the prognosis of septic shock. ④ It was shown by ROC curve analysis that arterial blood Lac, ΔLac andΔPCO2 had predictive value on prognosis of septic shock, the area under ROC curve (AUC) was 0.792, 0.857, 0.680, respectively (allP < 0.05). When the best cut-off value of arterial Lac was 4.00 mmol/L, the sensitivity was 100％, and the specificity was 62.86％ for predictor of death in 28-day; when the best cut-off value of ΔLac was 1.25 mmol/L, the sensitivity was 93.33％, and the specificity was 68.57％ for predictor of death in 28-day; when the best cut-off value of ΔPCO2 was 4.35 mmHg, the sensitivity was 83.33％, and the specificity was 37.14％ for predictor of death in 28-day.Conclusions Compared to other parameters, the difference between peripheral arterial and venous blood gas analysis, ΔPCO2 and ΔLac had the best correlation with the prognosis of septic shock. The ΔPCO2 and ΔLac are the independent prognostic predictors for 28-day survival.