Abstract
目的
脓毒症相关性脑病(sepsis associated encephalopathy，SAE)是脓毒症的一种常见神经并发症，谵妄是SAE的一种常见表现形式。SAE的病理生理学机制尚不明确，现有研究发现线粒体和内皮细胞功能障碍、神经递质异常、钙失调、脑微循环障碍和脑低灌注等可能参与其中。近红外光谱法(near-infrared spectroscopy，NIRS)是一种无创监测区域脑氧饱和度(regional cerebral oxygen saturation，rSO2)的方法，也是近年来研究的前沿热点。研究显示重症患者NIRS监测rSO2异常与谵妄相关，且基于NIRS监测的治疗有助于改善患者的器官灌注和预后。本研究旨在通过NIRS监测脓毒症休克患者rSO2的动态变化，并分析其与预后之间的关系。
方法
收集2017年8月到2018年5月中南大学湘雅医院重症医学科收治的48例脓毒症休克患者资料，诊断依据欧美危重病医学会指定国际专家制订的脓毒症3.0标准。患者入重症监护室(intensive care unit，ICU)后在双侧前额放置NIRS监测探头对rSO2进行连续动态监测至少6 h，记录rSO2最高值(rSO2max)和最低值(rSO2min)，计算rSO2平均值和rSO2变异度。收集患者的一般资料、入ICU 24 h内的实验室检查结果(血常规、肝肾功能、血气分析、感染指标、凝血功能)、评分结果[格拉斯哥昏迷量表(Glasgow Coma Scale，GCS)评分、急性生理学与慢性健康状况评价II(Acute Physiology and Chronic Health Evaluation II，APACHE II)评分、序贯器官衰竭评价(Sequential Organ Failure Assessment，SOFA)评分等]。谵妄的评估采用ICU意识模糊评估法(Confusion Assessment Method for ICU，CAM-ICU)量表。记录患者机械通气(mechanical ventilation，MV)时间、ICU时间、住院时间和28 d病死率。首要结局指标为28 d病死率，次要结局指标为谵妄发生率、ICU时间和住院时间。分析存活与死亡患者、有谵妄与无谵妄患者之间实验室和临床指标的差异，评估谵妄的危险因素，评价rSO2相关指标(rSO2max、rSO2min、rSO2平均值和rSO2变异度)用于预测28 d病死率和谵妄的能力及其界值。
结果
脓毒症休克患者总的28 d病死率为47.92%(23/48)，谵妄发生率为18.75%(9/48)。死亡患者的rSO2min显著低于存活患者(P=0.042)。谵妄患者的rSO2变异度显著高于无谵妄患者(P=0.006)。谵妄的独立危险因素是rSO2max、直接胆红素(direct bilirubin，DBIL)水平和6 h集束化治疗是否达标。采用rSO2相关指标预测脓毒症休克患者28 d是否死亡，rSO2max、rSO2min、rSO2平均值和rSO2变异度的受试者工作特征曲线下面积(area under the receiver operating characteristic curve，AUROC)分别为0.616、0.606、0.623和0.504；预测脓毒症休克患者是否发生谵妄，rSO2max、rSO2min、rSO2平均值和rSO2变异度的AUROC分别为0.682、0.617、0.580和0.501。rSO2max预测谵妄的最佳界值是77.5%(敏感度为0.444，特异度为0.897)，rSO2min预测谵妄的最佳界值是65.5%(敏感度为0.556，特异度为0.744)。
结论
rSO2过低、过高或波动过大均与脓毒症休克不良预后和谵妄发生相关，需要引起临床重视。动态监测脓毒症休克患者的rSO2并维持其平稳，可能对该类患者具有重要临床意义。
Keywords: 区域脑氧饱和度, 近红外光谱法, 脓毒症休克, 谵妄, 病死率
Abstract
Objective
Sepsis associated encephalopathy (SAE) is a common neurological complication of sepsis. Delirium is a common symtom of SAE. The pathophysiology of SAE is still unclear, but several likely mechanisms have been proposed, such as mitochondrial and endothelial dysfunction, neurotransmission disturbances, derangements of calcium homeostasis, cerebral microcirculation dysfunction, and brain hypoperfusion. Near-infrared spectroscopy (NIRS) is a non-invasive measure for regional cerebral oxygen saturation (rSO2), which has attracted more attention these years. Previous studies have reported that abnormal NIRS values were associated with delirium in critically ill patients. Blood pressure management according to NIRS monitoring improved the organ perfusion and prognosis of patients. This study aimed to observe the dynamic changes of rSO2 using NIRS in septic shock patients, and analyze the relationship between them.
Methods
A total of 48 septic patients who admitted to the intensive care unit (ICU) of Xiangya Hospital, Central South University from August 2017 to May 2018, were retrospectively study. Septic shock was diagnosed according to the criteria of sepsis 3.0 defined by the American Association of Critical Care Medicine and the European Society of Critical Care Medicine. NIRS monitoring was performed during the first 6 hours admitted to ICU with sensors placed on the bilateral forehead of patients. The maximum (rSO2max), minimum (rSO2min), mean value, and the variation rate during the first 6 hours of monitor were recorded. The following data were collected upon the first 24 h after admission to the ICU: The baseline data of patients, laboratory examination results (routine blood test, liver and renal function, blood gas analysis, indicators of infection, and coagulation function), scoring system results [Glasgow Coma Scale (GCS), Acute Physiology and Chronic Health Evaluation II (APACHE II) and Sequential Organ Failure Assessment (SOFA)]. Delirium was screened with the Confusion Assessment Method for ICU (CAM-ICU). The length of time on mechanical ventilation (MV), length of ICU-stay, length of hospital-stay, and 28-day mortality were also recorded. The primary outcome was 28-day mortality, and the secondary outcomes were the incidence of delirium, length of ICU-stay, and length of hospital-stay. The differences between survivors and non-survivors, and patients with or without delirium were analyzed, and the risk factors for delirium were assessed. The performance of rSO2-related indexes (rSO2max, rSO2min, the mean value, and the variation rate of rSO2) in predicting 28-day mortality and delirium was analyzed and the cutoff values were determined.
Results
The overall 28-day mortality of septic shock patients was 47.92% (23/48), and the incidence of delirium was 18.75% (9/48). The rSO2min was significantly lower in the non-survivors than the survivors (P=0.042). The variation rate of rSO2 was higher in patients with delirium than those without delirium (P=0.006). The independent risk factors for delirium were rSO2max, the level of direct bilirubin (DBIL), and whether achieved the 6-hour bundle. To predict the 28-day mortality of septic shock patients, the area under the receiver operating characteristic curve (AUROC) for rSO2max, rSO2min, the mean value and the variation rate of rSO2 were 0.616, 0.606, 0.623, and 0.504, respectively. To predict the incidence of delirium, AUROC for rSO2max, rSO2min, the mean value and the variation rate of rSO2 were 0.682, 0.617, 0.580, and 0.501, respectively. The best cutoff value for rSO2max in predicting delirium was 77.5% (sensitivity was 0.444, specificity was 0.897). The best cutoff value for rSO2min in predicting delirium was 65.5% (sensitivity was 0.556, specificity was 0.744).
Conclusion
Cerebral anoxia and hyperoxia, as well as the large fluctuation of cerebral oxygen saturation are important factors that affect the outcomes and the incidence of delirium in septic shock patients, which should be paid attention to in clinical practice. Dynamic monitoring of cerebral oxygen saturation and maintain its stability may be of great significance in patients with septic shock.
Keywords: regional cerebral oxygen saturation, near-infrared spectroscopy, septic shock, delirium, mortality
脓毒症相关性脑病(sepsis-associated encephalo-pathy，SAE)是脓毒症的一种常见神经并发症，主要表现为感染后出现的弥漫性脑功能障碍，除外颅内感染或明确的中枢神经系统疾病[1]。研究[1-3]显示：在脓毒症患者中，SAE的发病率最高可达70%，且SAE患者28 d和180 d病死率显著高于无SAE的脓毒症患者。SAE临床可表现为神志模糊至深昏迷。谵妄是SAE的一种常见临床表现，既往研究[4-5]显示脓毒症患者的谵妄发生率高达42.29%~78.00%。SAE的病理生理学机制尚不明确，线粒体和内皮细胞功能障碍、神经递质异常、钙失调、脑微循环障碍和脑低灌注等均可能参与其中[6-11]。近红外光谱法(near-infrared spectroscopy，NIRS)是一种利用比尔-朗博定律无创监测区域脑氧饱和度(regional cerebral oxygen saturation，rSO2)的方法，也是近年来研究的前沿热点。既往研究[12-13]显示重症患者NIRS监测rSO2异常与谵妄相关。在心脏手术中采用NIRS监测rSO2对改善器官灌注，降低手术相关病死率有重要意义[14]。本研究旨在利用NIRS监测评价rSO2与休克患者谵妄发生率和预后之间关系，为实现脑灌注导向的休克治疗提供理论基础。
1. 对象与方法
1.1. 对象
本研究通过中南大学湘雅医院医学伦理委员会批准(审批号：201706834)。回顾性分析2017年8月至2018年5月收入中南大学湘雅医院重症医学科治疗的48名脓毒症休克患者。按照由欧美危重病医学会指定国际专家制订的脓毒症3.0标准[11]诊断脓毒症休克，参照《拯救脓毒症运动：脓毒症与脓毒性休克处理国际指南(2016)》[15]进行治疗。6 h集束化治疗达标定义为：平均动脉压(mean artery pressure，MAP)≥65 mmHg(1 mmHg=0.133 kPa)，中心静脉压(central venous pressure，CVP) 8~12 mmHg，中心静脉血氧饱和度(central venous oxygen saturation，ScvO2)≥70%，尿量≥0.5 mL/(kg·h)[15]。
纳入标准：1)年龄>18岁的患者；2)诊断为脓毒症休克，并在重症监护室(intensive care unit，ICU)进行休克复苏的患者；3)在休克复苏的最初6 h内进行了连续NIRS监测的患者。排除标准：既往存在认知功能障碍的患者。
1.2. 一般资料的收集
收集患者的性别、年龄、基础疾病、诊断结果、感染部位、病原学结果、衰竭器官的个数、6 h集束化治疗是否达标等一般资料。
1.3. rSO2 相关指标的收集
患者入ICU后，在其双侧前额放置NIRS监测探头(FORE-SIGHT，CAS Medical Systems，美国)，至少连续动态监测rSO2 6 h，每2 s仪器自动记录rSO2值并生成记录表，6 h后从记录表中提取rSO2最低值(rSO2min)和rSO2最高值(rSO2max)，计算rSO2平均值和rSO2变异度[(rSO2max-rSO2min)/rSO2max]。rSO2min<60%定义为存在rSO2的下降。
1.4. 实验室检查结果的收集
收集患者入ICU 24 h内的血常规[WBC数、中性粒细胞百分数、血小板计数(platelet count，PC)]、肝功能指标[TBIL、直接胆红素(direct bilirubin，DBIL)]、肾功能指标(SCr、BUN)、血气分析指标[氧合指数、乳酸(lactic acid，Lac)]、感染指标降钙素原(procalcitonin，PCT)、凝血功能指标[凝血酶原时间(prothrombin time，PT)、活化部分凝血活酶时间(activated partial thromboplastin time，APTT)、D-二聚体(D-dimer)]等结果。
1.5. 量表评分的收集
收集患者入ICU 24 h内的格拉斯哥昏迷量表(Glasgow Coma Scale，GCS)评分、急性生理学与慢性健康状况评价II(Acute Physiology and Chronic Health Evaluation II，APACHE II)评分、序贯器官衰竭评价(Sequential Organ Failure Assessment，SOFA)评分等。
采用ICU意识模糊评估(Confusion Assessment Method for ICU，CAM-ICU)量表[17]评估患者是否存在谵妄，每日评估3次，3次中出现1次阳性即为谵妄阳性。将患者分为谵妄(谵妄阳性)组和无谵妄(谵妄阴性)组，对2组患者的各项指标进行比较。
1.6. 结局指标的收集
记录患者机械通气(mechanical ventilation，MV)时间、ICU时间、住院时间和28 d死亡人数，根据28 d内是否死亡将患者分为死亡组和存活组，对2组患者的各项指标进行比较。首要结局指标为28 d病死率，次要结局指标为谵妄发生率、ICU时间和住院时间。
1.7. 统计学处理
采用SPSS 19.0统计软件建立数据库并进行统计分析。服从正态分布的计量资料表示为均数±标准差( ±s)，组间比较采用t检验(Student's t test)或单因素方差分析(one-way ANOVA)；偏态分布的计量资料表示为中位数(第1四分位数，第3四分位数)[M(P 25,P 75)]，组间比较采用Mann-Whitney U或Kruskal-Wallis H检验。计数资料采用率/构成比表示，组间比较采用卡方检验。P<0.05认为差异有统计学意义。
谵妄和28 d死亡的危险因素分析首先采用单因素回归分析，将P<0.20的变量纳入多因素回归分析，并对混杂因素进行校正。Logistic回归分析结果用比值比(odds ratio，OR)和95%置信区间(confidence interval，CI)表示。rSO2相关参数预测谵妄和28 d病死率的能力通过受试者工作特征曲线下面积(area under the receiver operating characteristic curve，AUROC)来评价。
2. 结 果
2.1. 一般资料
共纳入48名脓毒症休克患者，包括28名男性和20名女性，年龄18~87(54.21±16.01)岁。最常见的基础疾病为高血压(14.6%)、糖尿病(14.6%)、冠心病(14.6%)、慢性肾病(6.3%)和脑血管病(4.2%)。最常见的感染为腹腔感染(52.1%)、肺部感染(39.6%)、血行感染(22.9%)和尿路感染(20.8%)。病原学培养阳性率为66.7%(32/48)。48名脓毒症休克患者的APACHE II评分、SOFA评分和GCS评分分别为20.60±7.00、12.81±14.93和12.02±3.88。ICU时间、住院时间和MV时间分别为(9.92±8.08)、(17.27±11.60)和(5.58±6.49) d。其中37.5%(18/48)存在rSO2下降。
48名患者中28 d内死亡23例(死亡组)，存活25例(存活组)，病死率为47.92%(23/48)；谵妄阳性患者9例(谵妄组)，阴性患者39例(无谵妄组)，谵妄发生率为18.75%(9/48)。
2.2. 存活组和死亡组比较
死亡组的rSO2min显著低于存活组(P=0.042)，但2组间rSO2max、rSO2平均值和rSO2变异度差异均无统计学意义(均P>0.05)。存活组的WBC数、TBIL、DBIL、SCr、BUN、Lac均显著低于死亡组(均P<0.05)。死亡组的MV时间显著长于存活组(P=0.001)，而ICU时间和住院时间2组间差异无统计学意义(均 P>0.05，表1)。
表1.
存活者和死亡者临床与实验室指标的比较
| 组别 | n | 年龄/岁 | APACHE II评分 | SOFA评分 | GCS评分 | WBC/(×109·L-1) | 中性粒细胞百分数/% |
|---|---|---|---|---|---|---|---|
| P | 0.073 | 0.058 | 0.109 | 0.053 | 0.044 | 0.481 | |
| 存活组 | 25 | 53.84±16.01 | 17.24±6.11 | 9.36±2.50 | 13.20±3.38 | 14.68±15.68 | 78.89±27.51 |
| 死亡组 | 23 | 54.60±16.35 | 24.26±6.09 | 16.57±21.00 | 10.74±4.06 | 15.27±16.29 | 80.73±21.65 |
| 组别 | PLT/(×109·L-1) | PT/s | APTT/s | TBIL/(μmol·L-1) | DBIL/(μmol·L-1) | SCr/(μmol·L-1) | BUN/(mmol·L-1) |
|---|---|---|---|---|---|---|---|
| 存活组 | 153.08±173.60 | 20.23±20.92 | 56.08±41.03 | 28.03±29.11 | 14.26±15.44 | 121.90±44.33 | 9.66±6.07 |
| 死亡组 | 101.95±74.07 | 18.10±6.98 | 54.04±40.91 | 72.90±96.01 | 40.48±49.54 | 194.19±150.55 | 14.71±8.71 |
| P | 0.237 | 0.221 | 0.739 | <0.001 | <0.001 | <0.001 | 0.001 |
| 组别 | PCT/(ng·mL-1) | 氧合指数 | Lac/(mmol·L-1) | rSO2min | rSO2max | rSO2平均值 | rSO2变异度/% |
|---|---|---|---|---|---|---|---|
| 存活组 | 52.10±67.73 | 304.00±128.84 | 2.02±1.04 | 62.72±6.64 | 72.04±7.63 | 66.47±6.72 | 14.02±7.43 |
| 死亡组 | 44.41±57.89 | 243.48±113.50 | 4.67±3.55 | 58.09±10.78 | 68.70±7.92 | 62.91±7.92 | 17.90±21.27 |
| P | 0.247 | 0.233 | <0.001 | 0.042 | 0.919 | 0.341 | 0.113 |
| 组别 | 器官衰竭个数 | 培养阳性率/% | 谵妄发生率/% | 6 h集束化治疗达标率/% | ICU时间/d | 住院时间/d | MV时间/d |
|---|---|---|---|---|---|---|---|
| 存活组 | 2.68±0.75 | 64.0 | 12.0 | 76.0 | 10.44±8.44 | 20.88±12.04 | 2.88±3.67 |
| 死亡组 | 3.65±0.94 | 69.6 | 26.1 | 60.1 | 9.35±7.81 | 13.35±9.92 | 8.52±7.61 |
| P | 0.123 | 0.683 | 0.212 | 0.259 | 0.976 | 0.370 | 0.001 |
APACHE II：急性生理学与慢性健康状况评价II；SOFA：序贯器官衰竭评价；GCS：格拉斯哥昏迷量表；WBC：白细胞分类计数；PLT：血小板计数；PT：凝血酶原时间；APTT：活化部分凝血活酶时间；TBIL：总胆红素；DBIL：直接胆红素；SCr：血肌酐；BUN：血尿素氮；PCT：降钙素原；Lac：乳酸；rSO2：区域脑氧饱和度；MV：机械通气。
Figure 1 Comparison of clinical characteristics and biochemical indicators between the group of survivors and the group of non-survivors
2.3. 谵妄组和无谵妄组比较
谵妄组rSO2min、rSO2变异度均显著高于无谵妄组(P=0.048、P=0.006)，但rSO2max和rSO2平均值2组间差异无统计学意义(均P>0.05)。
谵妄组的PT、TBIL和DBIL均显著高于无谵妄组(均P<0.05)。因无谵妄组包含了昏迷患者，故谵妄组的GCS显著高于无谵妄组(P<0.001)。谵妄组的6 h集束化治疗达标率更低(P=0.015)。
谵妄组的MV时间显著长于无谵妄组(P=0.035)，而ICU时间和住院时间2组间差异无统计学意义(均 P>0.05，表2)。
表2.
谵妄患者和无谵妄患者临床与实验室指标的比较
| 组别 | n | 年龄/岁 | APACHE II评分 | SOFA评分 | GCS评分 | WBC/(×109·L-1) | 中性粒细胞百分数/% |
|---|---|---|---|---|---|---|---|
| P | 0.061 | 0.404 | 0.464 | <0.001 | 0.645 | 0.489 | |
| 谵妄组 | 9 | 52.33±21.27 | 22.78±6.91 | 12.22±2.54 | 13.56±1.13 | 17.74±18.80 | 80.81±20.94 |
| 无谵妄组 | 39 | 54.64±14.96 | 20.10±7.01 | 12.95±16.56 | 11.67±4.21 | 14.32±15.25 | 79.53±23.42 |
| 组别 | PLT/(×109·L-1) | PT/s | APTT/s | TBIL/(μmol·L-1) | DBIL/(μmol·L-1) | SCr/(μmol·L-1) | BUN/(mmol·L-1) |
|---|---|---|---|---|---|---|---|
| 谵妄组 | 122.10±63.35 | 32.41±33.87 | 63.62±46.42 | 93.99±126.10 | 48.00±62.98 | 208.10±127.76 | 12.68±8.19 |
| 无谵妄组 | 130.08±150.39 | 16.16±3.68 | 53.13±39.48 | 39.27±50.82 | 21.93±28.67 | 144.64±108.63 | 11.94±7.81 |
| P | 0.278 | <0.001 | 0.524 | <0.001 | <0.001 | 0.363 | 0.966 |
| 组别 | PCT/(ng·mL-1) | 氧合指数 | Lac/(mmol·L-1) | rSO2min | rSO2max | rSO2平均值 | rSO2变异度/% |
|---|---|---|---|---|---|---|---|
| 谵妄组 | 79.33±55.91 | 207.22±80.01 | 4.66±3.35 | 61.00±15.12 | 74.22±9.74 | 66.08±9.94 | 22.28±32.24 |
| 无谵妄组 | 40.99±62.43 | 290.64±128.10 | 2.98±2.70 | 60.38±7.37 | 69.56±7.12 | 64.46±6.89 | 14.40±8.41 |
| P | 0.656 | 0.131 | 0.201 | 0.048* | 0.363 | 0.198 | 0.006* |
| 组别 | 器官衰竭个数 | 培养阳性率/% | 28 d病死率/% | 6 h集束化治疗达标率/% | ICU时间/d | 住院时间/d | MV时间/d |
|---|---|---|---|---|---|---|---|
| 谵妄组 | 3.67±0.71 | 66.7 | 66.7 | 22.2 | 8.67±7.11 | 14.44±9.93 | 6.44±7.09 |
| 无谵妄组 | 3.03±0.99 | 66.7 | 43.6 | 66.7 | 10.21±8.34 | 17.92±11.97 | 5.38±6.42 |
| P | 0.062 | 1.000 | 0.212 | 0.015 | 0.682 | 0.319 | 0.035 |
APACHE II：急性生理学与慢性健康状况评价II；SOFA：序贯器官衰竭评价；GCS：格拉斯哥昏迷量表；WBC：白细胞分类计数；PLT：血小板计数；PT：凝血酶原时间；APTT：活化部分凝血活酶时间；TBIL：总胆红素；DBIL：直接胆红素；SCr：血肌酐；BUN：血尿素氮；PCT：降钙素原；Lac：乳酸；rSO2：区域脑氧饱和度；MV：机械通气。
Figure 2 Comparison of clinical characteristics and biochemical indicators between the groups of patients with and without delirium
2.4. 谵妄的危险因素
谵妄的独立危险因素为rSO2max(OR=1.248，P=0.018，95% CI：1.039~1.500)、(OR=1.027，P=0.037，95% CI：1.002~1.053)、6 h集束化治疗是否达标(OR=0.040，P=0.015，95% CI：0.003~0.541；表3)。
表3.
谵妄的危险因素
| 影响因素 | b | SE | Wald χ2 | P | OR | 95% CI |
|---|---|---|---|---|---|---|
| rSO2max | 0.222 | 0.094 | 5.598 | 0.018 | 1.248 | 1.039~1.500 |
| DBIL | 0.027 | 0.013 | 4.334 | 0.037 | 1.027 | 1.002~1.053 |
| 6 h集束化治疗是否达标 | -3.222 | 1.330 | 5.868 | 0.015 | 0.040 | 0.003~0.541 |
rSO2：区域脑氧饱和度；DBIL：直接胆红素。
Figure 3 Risk factors for delirium
2.5. rSO2 相关指标预测脓毒症休克患者28 d病死率 和谵妄的能力
rSO2max、rSO2min、rSO2平均值和rSO2变异度预测脓毒症休克患者28 d是否死亡的AUROC分别为0.616、0.606、0.623和0.504，预测脓毒症休克患者是否发生谵妄的AUROC分别为0.682、0.617、0.580和0.501。rSO2max预测谵妄的最佳界值为77.5%(敏感度为0.444，特异度为0.897)，rSO2min预测谵妄的最佳界值为65.5%(敏感度为0.556，特异度为0.744)。
3. 讨 论
在本研究中，脓毒症休克患者的谵妄发生率高达27.3%，病死率高达47.92%。既往研究显示：脑微循环障碍和脑灌注不足是SAE的重要发病机制[10-11]，脓毒症晚期患者出现脑血流自动调节功能受损[18]，且脑血流自动调节功能受损与谵妄的发生密切相关[12]。因此，对于脓毒症休克患者，采用脑灌注导向的休克治疗可能有助于改善患者的预后。NIRS是近年来逐步推广的一种无创rSO2监测方法，具有操作简便、实时动态的优点。通过动态监测rSO2评价脑组织氧供与氧耗的平衡情况，有助于在脓毒症休克患者中实现脑灌注导向的休克治疗。既往研究[19]显示：与非脓毒症患者相比，脓毒症患者rSO2值显著下降。本研究显示37.5%的脓毒症休克患者存在rSO2的下降，需要引起临床重视；存活组rSO2min明显高于死亡组，这说明脓毒症休克患者脑缺血、缺氧可能是导致死亡的一个重要因素。此外，谵妄患者的rSO2变异度明显高于无谵妄患者，这提示rSO2波动过大与谵妄的发生相关，临床中应尽可能保持rSO2的稳定。rSO2max是谵妄的独立危险因素，提示高脑氧饱和度与谵妄密切相关，临床中应适当控制脑氧饱和度范围，不能一味追求高脑氧饱和度。
本研究还评价了rSO2max、rSO2min、rSO2平均值和rSO2变异度预测28 d病死率和谵妄的能力，结果显示：以上rSO2相关指标预测28 d病死率和谵妄的能力相对较弱，其中rSO2max和rSO2min预测谵妄发生的AUROC相对较高，rSO2max大于77.5%，rSO2min小于65.5%可预测谵妄。既往研究[19-21]报道低rSO2与患者预后不良相关，也有研究[22-23]显示心脏手术中低rSO2与术后谵妄相关。rSO2过低和过高均可预测谵妄，说明脑缺氧和高氧均可对患者神经功能造成损伤。在脓毒症休克患者的治疗中，应注意避免低氧和高氧，同时尽可能减少rSO2的波动以改善患者预后。
本研究存在一定局限性。首先，本研究为单中心回顾性研究，样本量偏少，可能会影响结果；其次，受到NIRS电极片稳定记录时长的影响，本研究只记录了脓毒症休克最初6 h的rSO2值，没有进行长期监测；最后，NIRS监测值可能会受到电极放置部位，患者的体位、局部组织水肿、动静脉分布比例的差异等因素的影响。
综上，脓毒症休克患者复苏最初6 h出现rSO2下降的比例很高。死亡组的rSO2min显著低于存活组，谵妄组的rSO2变异度显著大于无谵妄组，且rSO2max是谵妄的独立预测因子。rSO2max大于77.5%和rSO2min小于65.5%可预测谵妄发生。rSO2过低、过高或波动过大均与不良预后和谵妄发生相关，对此临床工作者需要重视。动态监测脓毒症休克患者的rSO2并维持其平稳，对该类患者具有重要临床意义。
基金资助
国家自然科学基金(81974285)；湖南省自然科学基金(2020JJ5918)。
This work was supported by the National Natural Science Foundation (81974285) and the Natural Science Foundation of Hunan Province (2020JJ5918), China.
利益冲突声明
作者声称无任何利益冲突。
原文网址
http://xbyxb.csu.edu.cn/xbwk/fileup/PDF/2021111212.pdf
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