摘要目的:探讨动脉血氨水平对脓毒症患者病情评估和预后的判断价值。方法:采用前瞻性观察性研究方法，选择2018年1月至2019年6月济宁医学院附属济宁市第一人民医院重症医学科收治的169例成人脓毒症患者作为研究对象；选择同期35例健康体检者作为对照组。记录受试者的一般情况、急性生理学与慢性健康状况评分Ⅱ（APACHEⅡ）。于确诊脓毒症6～8 h或体检时取动脉血检测血氨水平和血常规。观察和比较不同病情严重程度（脓毒症和脓毒性休克）及28 d临床结局（存活和死亡）患者临床资料的差异。各指标间相关性采用非参数Spearman等级相关分析；绘制受试者工作特征曲线（ROC），分析各指标对28 d死亡的预测价值；采用Kaplan-Meier生存曲线比较不同血氨水平患者的28 d累积生存率。结果:169例脓毒症患者中，排除年龄<18岁、妊娠、慢性疾病终末期、诊断脓毒症至入住ICU超过6 h和失访患者12例，最终157例患者纳入分析，其中脓毒症组71例，脓毒性休克组86例；随访28 d存活115例，死亡42例。不同病情严重程度和临床预后组间患者性别和年龄比较差异均无统计学意义；但脓毒症组血氨、白细胞计数（WBC）和中性粒细胞比例（Neut%）均显著高于健康对照组〔血氨（μmol/L）：42.28±28.64比12.05±5.44，WBC（×10 9/L）：17.51±5.13比6.57±2.20，Neut%：0.87（0.82，0.90）比0.62（0.59，0.67），均 P<0.05〕，且脓毒性休克组患者APACHEⅡ评分、血氨、WBC、Neut%和28 d病死率均明显高于脓毒症组〔APACHEⅡ评分（分）：24.49±6.22比14.31±3.32，血氨（μmol/L）：52.93±34.11比29.38±10.37，WBC（×10 9/L）：20.21±3.77比14.02±4.23，Neut%：0.89（0.86，0.92）比0.82（0.79，0.89），28 d病死率：43.0%（37/86）比7.0%（5/71），均 P<0.05〕；死亡组患者APACHEⅡ评分、血氨、WBC和Neut%均显著高于存活组〔APACHEⅡ评分（分）：26.86±7.91比17.34±4.90，血氨（μmol/L）：69.98±41.14比32.17±11.31，WBC（×10 9/L）：20.20±4.78比16.53±4.91，Neut%：0.89（0.87，0.95）比0.87（0.82，0.90），均 P<0.05〕。Spearman相关分析显示，脓毒症患者血氨水平与APACHEⅡ评分呈显著正相关（ r＝0.592， P<0.01），与WBC水平存在中度正相关（ r＝0.343， P<0.01）。ROC曲线分析显示，APACHEⅡ评分及血氨水平预测28 d死亡的ROC曲线下面积（AUC）分别为0.846和0.901，两者比较差异无统计学意义（ P＝0.187）；APACHEⅡ评分联合血氨时的AUC显著高于单用APACHEⅡ评分（0.913比0.846， P＝0.002），但与单用血氨差异无统计学意义（0.913比0.901， P＝0.647）。血氨临界值为36.50 μmol/L时，预测28 d死亡的敏感度、特异度分别为92.9%和73.9%，阳性似然比、阴性似然比分别为3.56和0.10。Kaplan-Meier生存曲线分析显示，血氨>36.50 μmol/L脓毒症患者28 d累积生存率较血氨≤36.50 μmol/L者显著降低（Log-Rank检验： χ2＝9.620， P＝0.002）。 结论:监测动脉血氨对脓毒症患者病情严重程度的判断及预后的评价具有较好的临床实用价值，为脓毒症血氨水平干预治疗提供了依据。

abstractsObjective:To investigate the value of arterial blood ammonia on predicting the severity and prognosis of patients with sepsis.Methods:A prospective observation study was conducted. A total of 169 patients with sepsis admitted to intensive care unit (ICU) of Jining First People's Hospital Affiliated to Jining Medical University from January 2018 to June 2019 were enrolled. Thirty-five healthy volunteers were served as controls. Demographics, acute physiology and chronic health evaluation Ⅱ (APACHEⅡ) score were recorded. At 6-8 hours after the diagnosis of sepsis, the serum levels of arteria blood ammonia and whole blood cell count were run. The septic patients were divided into the sepsis group and septic shock group according to the disease severity, and the septic patients were divided into survival group and death group according to the outcomes during 28-day hospitalization. The clinical data were compared. Spearman rank correlation was applied to determine the correlation between those variables. The predictive value of the parameters on 28-day mortality was evaluated with receiver operating characteristic (ROC) curve. Kaplan-Meier survival curve analysis was used to compare different blood ammonia levels of patients with 28-day cumulative survival rate.Results:Among the 169 sepsis patients, after excluding 12 patients who did not meet the inclusion criteria and loss to follow-up, there were finally 157 patients enrolled in the analysis. Among the 157 septic patients, 71 of them were in the sepsis group, and 86 in the septic shock group. After 28-day follow-up, 115 patients survived and 42 died. No significant differences were found in age and gender among groups with different severity and clinical prognosis. Compared with the control group, the blood ammonia, counts of white blood cell (WBC) and neutrophils ratio (Neut%) in serum of sepsis patients were significantly higher [blood ammonia (μmol/L): 42.28±28.64 vs. 12.05±5.44, WBC (×10 9/L): 17.51±5.13 vs. 6.57±2.20, Neut%: 0.87 (0.82, 0.90) vs. 0.62 (0.59, 0.67), all P < 0.05]. Compared with the sepsis group, the APACHE Ⅱ score, blood ammonia, WBC, Neut% and 28-day mortality in the septic shock group were significantly higher [APACHE Ⅱ score: 24.49±6.22 vs. 14.31±3.32, blood ammonia (μmol/L): 52.93±34.11 vs. 29.38±10.37, WBC (×10 9/L): 20.21±3.77 vs. 14.02±4.23, Neut%: 0.89 (0.86, 0.92) vs. 0.82 (0.79, 0.89), 28-day mortality: 43.0% (37/86) vs 7.0% (5/71), all P < 0.05]. APACHE Ⅱ score, blood ammonia, WBC and Neut% in the death group were significantly higher than those in the survival group [APACHE Ⅱ score: 26.89±7.91 vs. 17.34±4.90, blood ammonia (μmol/L): 69.98±41.14 vs. 32.17±11.31, WBC (×10 9/L): 20.20±4.78 vs. 16.53±4.91, Neut%: 0.89 (0.87, 0.95) vs. 0.87 (0.82, 0.90), all P < 0.05]. Spearman rank correlation analysis showed that blood ammonia in patients with sepsis was correlated well with APACHE Ⅱ score ( r = 0.592, P < 0.01), and there was moderately positive correlation between blood ammonia and the counts of WBC ( r = 0.343, P < 0.01). ROC curve analysis showed that the areas under ROC curve (AUC) of APACHE Ⅱ score and blood ammonia for predicting 28-day mortality were 0.846 and 0.901, respectively, and there was no statistical significance ( P = 0.187). The AUC of APACHE Ⅱ score combined with blood ammonia was significantly higher than that of APACHE Ⅱ score alone (0.913 vs. 0.846, P = 0.002), but was not higher than that of blood ammonia alone (0.913 vs. 0.901, P = 0.647). Using a blood ammonia cut-off value of > 36.50 μmol/L for predicting 28-day mortality, the sensitivity and specificity was 92.9% and 73.9%, respectively, and the positive and negative likelihood ratios were 3.56 and 0.10, respectively. Kaplan-Meier survival curve analysis indicated that the patients whose blood ammonia was higher than 36.50 μmol/L, had lower 28-day cumulative survival rate when compared with those patients with blood ammonia ≤ 36.50 μmol/L (Log-Rank test: χ 2 = 9.620, P = 0.002). Conclusion:The level of arterial blood ammonia could somehow indicate the severity and prognosis of sepsis, which could provide evidence for the treatment.