Tyagi Diksha, Govindagoudar Manjunath B, Jakka Sushmitha, Chandra Sateesh, Chaudhry Dhruva
Department of Pulmonary and Critical Care Medicine, PGIMS, Rohtak, Haryana, India.
Indian J Crit Care Med. 2021 Mar;25(3):305-309. doi: 10.5005/jp-journals-10071-23762.
Chronic obstructive pulmonary disease (COPD) patients in hypercapnic respiratory failure require multiple arterial blood gas (ABG) analysis for monitoring. It is a painful, invasive, and expensive investigation. This study was aimed at finding an agreement between end-tidal carbon dioxide (ETCO, a noninvasive modality) and arterial carbon dioxide (PaCO) in COPD patients with acute exacerbation on mechanical ventilation. A prospective observational study was conducted in COPD patients who required mechanical ventilation. ETCO was recorded by mainstream capnography along with ABG analysis. An agreement between PaCO and ETCO was assessed. The effect of various factors on correlation was also studied. A total of 100 patients with COPD in hypercapnic respiratory failure were included. Seventy-three percentage of patients were managed on invasive mechanical ventilation (IMV). The mean ETCO and PaCO were 48.66 ± 15.57 mm Hg and 75.52 ± 21.9 mm Hg, respectively. There was a significant correlation between PaCO and ETCO values ( = 0.82, 95% confidence interval of = 0.78-0.86, <0.0001). The Bland-Altman analysis shows the mean bias as -19.4 (95% limits of agreement = -40.0-1.1). Pearson's correlation coefficient was 0.84 in intubated patients and 0.58 in patients on noninvasive ventilation (NIV). Pearson's correlation coefficient between PaCO and ETCO in subjects with consolidation, cardiomegaly, hypotension, and raised pulmonary artery pressures was 0.78, 0.86, 0.85, and 0.86, respectively. Mainstream ETCO measurement accurately predicts the PaCO in COPD patients on IMV. However, for patients on NIV, ETCO is insufficient in monitoring PaCO levels due to weak correlation. ETCO can be used as a noninvasive modality in intensive care unit for monitoring the PaCO in COPD patients on IMV. This can reduce the requirement of arterial blood sampling to a minimum number, in turn, reducing the cost of the treatment and discomfort to the patients. Tyagi D, Govindagoudar MB, Jakka S, Chandra S, Chaudhry D. Correlation of PaCO and ETCO in COPD Patients with Exacerbation on Mechanical Ventilation. Indian J Crit Care Med 2021;25(3):305-309.
慢性阻塞性肺疾病（COPD）合并高碳酸血症呼吸衰竭的患者需要多次进行动脉血气（ABG）分析以进行监测。这是一项痛苦、有创且昂贵的检查。本研究旨在探讨在机械通气的急性加重期COPD患者中，呼气末二氧化碳（ETCO₂，一种无创方式）与动脉血二氧化碳（PaCO₂）之间的一致性。对需要机械通气的COPD患者进行了一项前瞻性观察性研究。通过主流二氧化碳监测仪记录ETCO₂，并同时进行ABG分析。评估PaCO₂与ETCO₂之间的一致性。还研究了各种因素对相关性的影响。共纳入100例COPD合并高碳酸血症呼吸衰竭的患者。73%的患者接受有创机械通气（IMV）治疗。ETCO₂和PaCO₂的平均值分别为48.66±15.57 mmHg和75.52±21.9 mmHg。PaCO₂与ETCO₂值之间存在显著相关性（r = 0.82，95%置信区间r = 0.78 - 0.86，P<0.0001）。Bland-Altman分析显示平均偏差为-19.4（95%一致性界限=-40.0 - 1.1）。插管患者的Pearson相关系数为0.84，无创通气（NIV）患者为0.58。合并实变、心脏扩大、低血压和肺动脉压升高的受试者中，PaCO₂与ETCO₂之间的Pearson相关系数分别为0.78、0.86、0.85和0.86。主流ETCO₂测量可准确预测接受IMV治疗的COPD患者的PaCO₂。然而，对于接受NIV治疗的患者，由于相关性较弱，ETCO₂在监测PaCO₂水平方面不足。ETCO₂可作为重症监护病房中监测接受IMV治疗的COPD患者PaCO₂的无创方式。这可以将动脉采血的需求降至最低，进而降低治疗成本并减轻患者的不适。Tyagi D, Govindagoudar MB, Jakka S, Chandra S, Chaudhry D. 机械通气急性加重期COPD患者PaCO₂与ETCO₂的相关性。《印度危重症医学杂志》2021年；25(3):305 - 309。
