Hacettepe Universitesi Tip Fakultesi, Ankara, Turkey.
Hacettepe Universitesi Tip Fakultesi, Ankara, Turkey.
Pulmonology. 2020 Jul-Aug;26(4):192-197. doi: 10.1016/j.pulmoe.2019.11.008. Epub 2020 Feb 14.
Several studies have reported that computed tomography pulmonary angiography is the best method for diagnosing pulmonary embolism (PE). This study, however, aimed to predict or exclude PE using the end-tidal carbon dioxide (ETCO) value and alveolar dead space fraction (AVDSf) together.
One-hundred patients were included in the present study. Patients with suspected PE were evaluated using clinical prediction rules proposed by the Wells and the Modified Geneva scoring systems. PE was ruled out in patients with normal d-dimer concentrations (< 0.55 mg/dl). Patient ETCO values were recorded using time versus waveform capnography before performing imaging studies. Capnography was performed for 2 min; however, the average ETCO values measured over the final 1 min were recorded in "full continuous" mode. Arterial puncture was performed simultaneously for arterial blood gas analysis. Additionally, AVDSf was calculated according to the Bohr equation.
PE was detected in 36 % of patients. Patients were classified into high-, moderate, and low-risk groups according to the Wells and Modified Geneva scores. PE was excluded in 95 % and 100 % of patients with low Wells and Modified Geneva system scores, respectively, when ETCO was > 28.5 mmHg. The diagnosis of PE was excluded in 100 % of patients with low Wells and Modified Geneva scoring system scores with AVDSf < 0.128. High wells and Modified Geneva system scores were helpful in diagnosing of PE (100 %) when AVDSf was > 0.128.
It was possible to exclude/predict PE based on ETCO and AVDSf values calculated using capnography when evaluated with clinical prediction rules and d-dimer test using an algorithm.
多项研究表明，计算机断层肺动脉造影（CTPA）是诊断肺栓塞（PE）的最佳方法。然而，本研究旨在通过呼气末二氧化碳（ETCO）值和肺泡死腔分数（AVDSf）联合预测或排除 PE。
本研究共纳入 100 例患者。采用 Wells 和改良 Geneva 评分系统的临床预测规则评估疑似 PE 患者。在正常 D-二聚体浓度（<0.55mg/dl）患者中排除 PE。在进行影像学检查前，使用时间-波形二氧化碳图记录患者的 ETCO 值。进行 2 分钟的二氧化碳图检查，但以“全连续”模式记录最后 1 分钟的平均 ETCO 值。同时进行动脉穿刺行血气分析。根据 Bohr 方程计算 AVDSf。
36%的患者被诊断为 PE。根据 Wells 和改良 Geneva 评分，患者被分为高、中、低危组。当 ETCO > 28.5mmHg 时，低 Wells 和改良 Geneva 评分系统评分患者中 95%和 100%可排除 PE。低 Wells 和改良 Geneva 评分系统评分患者中，当 AVDSf < 0.128 时，可排除 100%的 PE 诊断。高 Wells 和改良 Geneva 评分系统评分有助于在 AVDSf > 0.128 时诊断 PE（100%）。
通过使用算法结合临床预测规则和 D-二聚体检测，使用二氧化碳图计算 ETCO 和 AVDSf 值，可排除/预测 PE。
