抽象
使用简单的床头旁脉冲血氧血管血管血管血红蛋白去饱和度曲线可用于COVID-19的三环患者。脑内旋转与Covid-19中更糟糕的结果有关,分流程度似乎预测结果
介绍
Hypoxaemia是Covid-19附近入院的关键指标[1,2]。争议围绕过血氧血症的病理生理学,用血管内分流,通风到灌注中的不匹配(V.A/ q)比率,内皮损伤,微血管凝固和宿主炎症反应假设发挥作用[3–6]。It has recently been proposed that COVID-19 pneumonia may exist as two phenotypes dependent on the preservation of lung mechanics and the relative contribution of VA/ q不匹配和血糖血症血氧血症[7]。我们假设Covid-19肺炎中的V / Q不匹配和血管内旋转,旨在评估其对结果的影响。使用数学模型构建氧气 - 血红蛋白解离曲线(ODC)[8]确定分流的程度和vA/ q在严重的Covid-19患者队列中不匹配。确定了有助于分流和死亡率的因素。
Methods
All patients presenting to our hospital in March 2020 with a diagnosis of COVID-19 through real-time PCR were included [1]。
Epidemiological, clinical, laboratory, and radiological characteristics were collected in addition to level of oxygen therapy required and outcome. Unless anticoagulated prior to admission, all patients received venous thromboembolism prophylaxis. The NEWS2 score was used for all patients, a validated aggregate scoring system of patient physiological observations [9]。
我们回顾性地收集了由护理人员和急诊部门的指尖脉冲血氧数据数据。在进入的不同FiO2值下进行两种饱和度,除以少于六小时,用于构建ODC。在十名患者中,该模型无法导出计算VA / Q的曲线。这可能是因为它们在入场时迅速恶化,歪曲数据。然而,使用单个数据点,该模型仍然能够计算这些患者的脑室分流器。
其他地方详细描述了ODC的构建(fig. 1a)[7,8]。The method uses a two-compartment model [10.]并校正血红蛋白浓度。旋转通过动脉氧饱和度降低动脉氧饱和,通过增加FIO不能纠正2。The shunt can therefore be calculated from depression of the ODC [10.]。V.A/ q减少降低后肺泡血氧含量,转向ODC向右移动[10.]。This is reversible by increasing FiO2。通过与参考曲线比较来量化这些参数。
![FIGURE 1](http://www.qdcxjkg.com/content/erj/early/2020/11/26/13993003.03841-2020/F1.medium.gif)
a)对死亡和幸存者群体中的灌注率通气。b)死亡和幸存者群中的肺肺分流(%)。c)肺内分流水平增加(%)的死亡率。
Spearman等级相关共同效率用于检查分流器和临床参数之间的关系。
结果
In March 2020, 108 patients were admitted with confirmed COVID-19 [1]。排除了十四个不需要氧气,没有足够的数据可用。剩下的87个包括在内。平均年龄为68·3±1·8年,41%(n = 36)是女性。平均bmi是28·3±0·1 kg·m−2。65名患者(75%)是英国白人;whi 8 (9%)te other; 8 (9%) black, Asian, or minority ethnic (BAME); and 6 (7%) unknown ethnicity. 46% of patients were ex or current smokers. Cardiovascular diseases (hypertension [46%], stroke [16%], ischaemic heart disease [13%]), diabetes (25%) and respiratory diseases (asthma [15%], COPD [15%]) were the most common comorbidities. 24% of patients had previous or current cancer.
Baseline blood tests showed an activated inflammatory response (median CRP 82, IQR 49–156; lactate dehydrogenase 628, 528–807; ferritin 926, 357–1620) and coagulation cascade (median D-dimer 1100, 663–1550). One patient had a possible pulmonary embolus on CTPA in addition to severe COVID-19 changes. Thirty one patients (36%) died.
The median shunt was 14% (IQR 4–21) and VA/ q为0·58(IQR 0·50-0·68)(fig. 1a)。Shunt was 45% higher (p=0.03) in patients that died (16%, IQR 6–23) than survived (11%, IQR 1–17) (fig. 1b)。中位数V之间没有区别(p = 0.69)A/ q死亡患者的q(0.59,0.49-0.70)的患者比存活(0.50 IQR 0.56-0.68)(图2)。死亡率增加了分流严重程度(fig. 1c)。All five patients with a shunt greater than 30% died.
分流与入场报数2分(Spearman相关系数0.33,P = 0.0002),CRP(0.38,p = 0.001),LDH(0.45,P = 0.002),尿素(0.29,P = 0.007),以及持续时间CPAP(0.40,P = 0.001)和住院时间长度(0.25,P = 0.02)。V.A/ q不匹配与任何测量参数无关。
Discussion
Covid-19中的患病性低氧血症的病理生理学是有争议的[3–5]。该研究鉴定了片内分流作为主要病理生理机制。分流严重程度是预测更糟糕的结果:逗留时间;CPAP持续时间;和死亡率。此外,分流与CRP和LDH相关,但不是D-二聚体相关。V.A/ q不匹配,虽然存在,但没有预后。
Micro and macrovascular thrombosis within the pulmonary architecture [5] have been implicated in the pathogenesis of COVID-19 hypoxaemia. Dual–energy CT-scans identified profound perfusion abnormalities with shunting of blood to areas of lung with impaired gas exchange [6]。Our study confirms that pulmonary vascular shunting may play a significant role in the development of hypoxaemia in COVID-19. From a pathophysiological perspective, the strong correlation of CRP with intrapulmonary shunt and outcomes such as length of CPAP and death implies that a more profound inflammatory response correlates with more severe shunting, which in turn is related to worse clinical outcomes.
It has been hypothesised that COVID-19 pneumonia may exist on a spectrum between two phenotypes [7]。严重的形式(“L”较小的形式(“L”)可能与保存的肺部力学相关,所述缺氧提出是次级化的肺血管炎症损害缺氧肺癌和生理通气灌注匹配。更严重的形式(“h”)可能与更“典型的”急性呼吸窘迫综合征(ARDS)图片相关联:降低肺顺应性,增强的炎症和分流。这种理论模型来自临床医生观察,迄今尚未正式证实。我们的研究提供了通过证实更严重的分流与更严重的结果相关,而vA/Q mismatching does not correlate with severity of disease. The pathophysiology underlying a shunt means hypoxaemia cannot be completely reversed by increasing FiO2。这可能对这些患者的结果较差的原因提供了解释。进一步的研究还可以提供对负责Covid-19中描述的“沉默缺氧”的潜在机制的洞察力,以及血管内旋转的作用。
This study also demonstrates that oxygen saturations at two different FiO2values can be used to construct ODCs useful for predicting outcome. A simple computer-based algorithm was used that can be performed at the bedside on admission and may help prioritise treatment pathways. The strength of this method is that the ODC is a predictable physical property of haemoglobin which even in fluctuating clinical situations allows the objective and accurate measurement of shunting and VA/Q mismatch. It performs well against more complex methods [11.]。
该研究受到小样本大小的限制。然而,在其他临床条件下使用该技术的数量超过了研究[12.]。Furthermore, the retrospective design means that oxygen saturations were taken up to six hours apart. Future prospective studies will be able to collect oxygen saturations at different FiO2 in a shorter time period, reducing the risk of patient deterioration in the interval period.
This study highlights the utility of simple clinical measurements to construct an ODC quantifying shunt and VA/ q Covid-19患者中的不匹配。我们还表明,分流程度似乎预测结果。此外,这些观察结果还为我们对Covid-19中对低氧血症负责的病理生理机制的理解。我们的研究具有显着的临床适用性。我们的未侵入性的早期计算的分流方法可以有助于决定进行三环和风险分层。但是,虽然,我们研究的受试者数量和回顾性质有限,我们的研究的下一阶段将旨在验证这些结果,更大,前瞻性队列。
致谢
We sincerely thank all the doctors, nurses, and health care staff involved in the management of patients with COVID-19 at the Royal Surrey NHS Foundation Trust.
Footnotes
道德和知情同意:The study was approved by the local Patient Safety and Quality Control Committee. The Medical Research Council ethics decision tool indicates that this research does not require review by an NHS Research Ethics Committee in England. As all patient data was anonymised, informed consent was not deemed necessary for this study, in line with local guidance.
贡献者:AK,HK,NM,ERJ和DRJ起草了稿件。AK,TD和HK执行了数据分析。所有作者都有助于研究概念和设计,修订稿件,数据收集和患者入学。DRJ是通讯作者,可以访问研究中的所有数据,并对决定提交出版物进行最终责任。
患者和公众参与:A patient advisory group consisting of four current inpatients not included in the study cohort commented on the findings and contributed to the discussion and dissemination plan.
支持声明:None.
Conflict of interest: Dr. Kotwica has nothing to disclose.
Conflict of interest: Dr. Knights has nothing to disclose.
利益冲突:市长博士无需披露。
Conflict of interest: Professor Russell-Jones has nothing to disclose.
Conflict of interest: Dr. Dassios has nothing to disclose.
利益冲突:罗素·琼斯博士无需披露。
- 收到10月13日,2020年。
- Accepted2020年11月26日。
- 版权所有©ers 2020
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