外周静脉-动脉血二氧化碳分压差可预测感染性休克患者预后：62例前瞻性研究

目的探讨早期复苏后外周静脉-动脉血二氧化碳分压差对感染性休克患者预后的预测价值。方法采用前瞻性研究方法，选择2017年5月~2018年5月南京中医药大学附属中西医结合医院重症医学科收治的感染性休克患者，测定患者早期复苏6 h后中心静脉、动脉及外周静脉血血气分析，记录患者中心静脉、动脉及外周静脉血二氧化碳分压（PCO2），计算患者外周静脉-动脉血二氧化碳分压差（Ppv-aCO2）及中心静脉-动脉血二氧化碳分压差（Pcv-aCO2），根据患者28 d预后将患者分为存活组及死亡组，采用Pearson相关性分析法分析Ppv-aCO2与Pcv-aCO2相关性，采用多因素Logistic分析筛选患者死亡的危险因素，并通过受试者工作特征曲线（ROC）评价各项指标预测患者预后的价值。结果共入选62例感染性休克患者，28 d存活35例，死亡27例。与存活组比较，死亡组患者急性生理与慢性健康评分Ⅱ（APACHEⅡ）（24.2±6.0 vs 20.5±4.9，P=0.011）及序贯器官衰竭的评分（SOFA）（14.9±4.7 vs 12.2±4.5，P=0.027）明显升高。6 h复苏后死亡组患者Pcv-aCO2（5.5±1.6 vs 7.1±1.7，P<0.001），Ppv-aCO2（7.1±1.8 vs 10.0±2.7，P<0.001），及动脉乳酸（Lac）（3.3±1.2 vs 4.2±1.3，P=0.003）明显高于存活组。Pearson相关性分析显示PpvaCO2与Pcv-aCO2明显相关，r=0.897，R2=0.805，P<0.001。多因素Logistic回归分析显示Ppv-aCO2和Lac是感染性休克患者28 d生存率的独立预后因素[（Ppv-aCO2：β=0.625，P=0.001，相对危险度（OR）=1.869，95%CI：1.311~2.664；Lac：β=0.584，P=0.041，OR=1.794，95%CI：1.024~3.415）]。ROC曲线分析显示，Ppv-aCO2、Pcv-aCO2和Lac对感染性休克患者预后均有预测价值，其中Ppv-aCO2的ROC曲线下面积（AUC）最大，为0.814（95%CI：0.696~0.931，P<0.001），最佳临界值为9.05 mmHg时，预测患者28 d死亡的敏感度为70.4%，特异度为88.6%；Lac的AUC=0.732（95%CI：0.607~0.858，P=0.002），最佳临界值为3.45 mmol/L 时，敏感度为70.4%，特异度为74.3%；Pcv-aCO2的AUC=0.766（95%CI：0.642~0.891，P<0.001），最佳临界值为7.05 mmHg时，敏感度为66.7%，特异度为80.0%。结论Ppv-aCO2与Pcv-aCO2相关，与感染性休克患者预后相关，可作为评估感染性休克患者28 d生存率的独立预后指标。

Prognostic value of difference between peripheral venous and arterial partial pressure ofcarbon dioxide in patients with septic shock: a pilot study

Objective To evaluate the prognostic value of the difference between peripheral venous and arterial partial pressureof carbon dioxide in patients with septic shock following early resuscitation. Methods This prospective study was conductedamong the patients with septic shock treated in our department during the period from May, 2017 to May, 2018. Peripheralvenous, peripheral arterial and central venous blood samples were collected simultaneously and analyzed immediately atbedside after 6-h bundle treatment. Arterial blood lactate concentration (Lac) and the arterial (PaCO2), peripheral venous(PpvCO2) and central venous partial pressure of carbon dioxide (PcvCO2) were recorded. The differences between PpvCO2 andPaCO2 (Ppv-aCO2) and between PcvCO2 and PaCO2 (Pcv-aCO2) were calculated. Pearson correlation analysis was used to testthe agreement between Pcv-aCO2 and Ppv-aCO2. Multivariable logistic regression analysis was performed to analyze thepossible risk factors for 28-day mortality, and the receiver-operating characteristic curve (ROC) was plotted to assess theprognostic values of these factors for 28-day mortality. Results A total of 62 patients were enrolled in this study, among who 35survived and 27 died during the 28-day period. Compared with the survivor group, the patients died within 28 days showedsignificantly higher Acute Physiology and Chronic Health Evaluation II (APACHE II) score (24.2 ± 6.0 vs 20.5 ± 4.9, P=0.011),sequential organ failure assessment (SOFA) score (14.9±4.7 vs 12.2±4.5, P=0.027), Pcv-aCO2 (5.5±1.6 vs 7.1±1.7, P<0.001), PpvaCO2(7.1±1.8 vs 10.0±2.7, P<0.001), and arterial lactate level (3.3±1.2 vs 4.2±1.3, P=0.003) after 6-h bundle treatment. Pearsoncorrelation analysis showed that Ppv-aCO2 wassignificantly correlated with Pcv-aCO2 (r=0.897, R2=0.805, P<0.001). Multiple logistic regression analysisidentified Ppv-aCO2 (β=0.625, P=0.001, OR=1.869, 95%CI: 1.311-2.664) and lactate level (β =0.584, P=0.041,OR=1.794, 95%CI: 1.024-3.415) as the independent riskfactors for 28-day mortality. The maximum area underthe ROC (AUC) of Ppv-aCO2 was 0.814 (95%CI: 0.696-0.931, P<0.001), and at the best cut- off value of 9.05was 0.732 (95%CI: 0.607-0.858, P=0.002), and its sensitivity for predicting 28-day mortality was 70.4% and the specificity was74.3% at the best cut-off value of 3.45 mmol/L; The AUC of Pcv-aCO2 was 0.766 (95%CI: 0.642-0.891, P<0.001), and its sensitivitywas 66.7% and the specificity was 80.0% at the best cut- off value of 7.05 mmHg. Conclusions A high Ppv-aCO2 after earlyresuscitation of septic shock is associated with poor outcomes. Ppv-aCO2 is well correlated with Pcv-aCO2 and can be used asan independent indicator for predicting 28-day mortality in patients with septic shock.