Background. Identification of patients who may become hypercapnic, or develop acidotic hypercapnic respiratory failure (AHRF), is important in chronic obstructive pulmonary disease (COPD) to avoid hospital admission and select patients for use of home NIV. This study aimed to identify factors associated with presence and development of hypercapnia. Methods. 1224 patients, 637 with COPD and 587 with alpha 1 antitrypsin deficiency (AATD), from 4 previously established patient cohorts, were included in cross-sectional analyses of hypercapnia (PaCO₂ ≥ 6.5 kPa or 48.8 mmHg), focusing on phenotypic features of COPD and mortality. Longitudinal associations of rising PaCO₂ were also assessed. A second cohort of 160 COPD patients underwent sleep studies and 1-year follow-up, analysing in a similar way, incorporating additional information from their sleep studies if appropriate. Results. Hypercapnia was 15 times more common in usual COPD than AATD () after adjustment for baseline differences by regression. Independent predictors of hypercapnia in COPD included FEV₁ and current use of oxygen; these variables, together with lack of emphysema, explained 11% of variance in CO₂. Increasing PaCO₂ also associated with higher risk of death (). 44/160 patients exhibited sleep disordered breathing. The sleep study cohort also showed an association of low FEV₁ with hypercapnia. Prior hospital admission for AHRF was also clinically significant, being a feature of almost double the number of hypercapnic patients in both test and sleep study COPD cohorts. Conclusion. Lower FEV₁ and prior AHRF are the main associations of hypercapnia in COPD, which carries a poor prognosis, particularly worsening over time.

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COPD 高碳酸血症的发生及相关性

背景。识别可能出现高碳酸血症或出现酸中毒高碳酸血症呼吸衰竭 (AHRF) 的患者，对于慢性阻塞性肺疾病 (COPD) 而言非常重要，可以避免入院并选择使用家庭 NIV 的患者。本研究旨在确定与高碳酸血症的存在和发展相关的因素。方法。1224 名患者，其中 637 名患有 COPD，587 名患有 α1 抗胰蛋白酶缺乏症 (AATD)，来自 4 个先前建立的患者队列，被纳入高碳酸血症（PaCO ₂  ≥ 6.5 kPa 或 48.8 mmHg）的横断面分析，重点是 COPD 的表型特征和死亡率。PaCO ₂上升的纵向关联也被评估了。第二组 160 名 COPD 患者接受了睡眠研究和 1 年的随访，以类似的方式进行分析，并在适当的情况下纳入睡眠研究的其他信息。结果。高碳酸血症在普通 COPD 患者中的发生率是 AATD 患者的 15 倍（)通过回归调整基线差异后。COPD 高碳酸血症的独立预测因素包括 FEV ₁和当前的氧气使用量；这些变量，加上没有肺气肿，解释了 CO ₂变化的 11%。增加 PaCO ₂也与更高的死亡风险相关（）。44/160 患者表现出睡眠呼吸障碍。睡眠研究队列还显示低 FEV ₁与高碳酸血症有关。AHRF 之前入院也具有临床意义，在测试和睡眠研究 COPD 队列中，高碳酸血症患者的数量几乎翻了一番。结论。较低的 FEV ₁和既往 AHRF 是 COPD 高碳酸血症的主要关联因素，其预后较差，尤其是随着时间的推移而恶化。