Mechanisms of gas transfer impairment utilizing nitric oxide following severe COVID ‐19 pneumonitis

作者：Leigh M. Seccombe, David Heath, Claude S. Farah, James Di Michiel, Elizabeth Veitch, Matthew Peters · 发表于：Physiological Reports · 年份：2023 · DOI：10.14814/phy2.15660 · 被引用次数：8 · 研究领域：Long-Term Effects of COVID-19、Chronic Obstructive Pulmonary Disease (COPD) Research、Respiratory Support and Mechanisms

Abstract Reduced carbon monoxide diffusing capacity (DL CO ) is common after recovery from severe COVID‐19 pneumonitis. The extent to which this relates to alveolar membrane dysfunction as opposed to vascular injury is uncertain. Simultaneous measurement of nitric oxide diffusing capacity (DL NO ) and DL CO can partition gas diffusion into its two components: alveolar–capillary membrane conductance (D mCO ) and capillary blood volume (V C ). We sought to evaluate D mCO and V C in the early and later recovery periods after severe COVID‐19. Patients attended for post‐COVID‐19 clinical review and lung function testing including DL NO /DL CO . Repeat testing occurred when indicated and comparisons made using t ‐tests. Forty‐nine (eight female) subjects (mean ± SD age: 58 ± 13, BMI: 34 ± 8) who had severe COVID‐19 pneumonitis, WHO severity classification of 6 ± 1, and prolonged (21 ± 22 days) hospital stay, were assessed 2 months (61 ± 35 days) post discharge. DL CO adj ( z ‐score −1.70 ± 1.49, 25/49 < lower limit of normal [LLN]) and total lung capacity ( z ‐score −1.71 ± 1.30) were both reduced. D mCO and V C and were reduced to a similar extent ( z ‐score −1.19 ± 1.05 and −1.41 ± 1.20, p = 0.4). Seventeen (one female) patients returned for repeat testing 4 months (122 ± 61 days) post discharge. In this subgroup with more impaired lung function, DL CO adj improved but remained below LLN ( z ‐score −3.15 ± 0.83 vs. −2.39 ± 0.86, p = 0.01), 5/17 improved to >LNN. D mCO impro...