Division of Pneumology, Department of Medicine, Geneva University Hospitals, Geneva, Switzerland.
Faculty of Medicine, University of Geneva, Geneva, Switzerland.
Am J Physiol Lung Cell Mol Physiol. 2023 Dec 1;325(6):L756-L764. doi: 10.1152/ajplung.00142.2023. Epub 2023 Oct 24.
Inefficient ventilatory response during cardiopulmonary exercise testing (CPET) has been suggested as a cause of post-COVID-19 dyspnea. It has been described in hospitalized patients (HOSP) with lung parenchymal sequelae but also after mild infection in ambulatory patients (AMBU). We hypothesize that AMBU and HOSP have different ventilatory responses to exercise, due to different etiologies. We analyzed CPET realized between July 2020 and May 2022 of patients with persisting respiratory symptoms 3 mo after COVID-19. Chest computed tomography (CT) scan, pulmonary function tests, quality of life, and respiratory questionnaires were collected. CPET data were specifically explored as a function of ventilation (V̇e) and time. Seventy-nine consecutive patients were included (42 AMBU and 37 HOSP, median: 54 [44-60] yr old, 57% female). Patients were hospitalized for a median of 20 [8-34] days, with pneumonia (41%) or acute respiratory distress syndrome (ARDS; 30%). Among HOSP, 12(32%) patients had abnormal values for spirometry and 18(51%) for carbon monoxide diffusing capacity ( < 0.001). CPET showed no differences between AMBU and HOSP in peak absolute O uptake (V̇o) (1.59 [1.22-2.11] mL·min; = 0.65). Tidal volume (VT) as a function of V̇e, was lower in AMBU than in HOSP ( < 0.01) toward the end of exercise. The slope of the V̇e-CO production was higher than normal in both groups (30.9 [26.1-34.3]; = 0.96). In conclusion, the severity of COVID-19 did not influence the exercise capacity, but AMBU demonstrated a less efficient ventilatory response to exercise as compared with HOSP. CPET with exploration of data as a function of V̇e and throughout the exercise better unveil ventilatory inefficiency. We evaluated the exercise ventilatory response in patients with persisting dyspnea after severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection. We found that despite similar peak power and peak absolute O uptake, tidal volume as a function of ventilation was lower in ambulatory than in hospitalized patients toward the end of exercise, reflecting ventilatory inefficiency. We call for evaluation of minute ventilation with the exploration of data throughout the exercise and not only peak data to better unveil ventilatory inefficiency.
心肺运动试验（CPET）期间通气效率低下被认为是 COVID-19 后呼吸困难的原因。它已在患有肺实质后遗症的住院患者（HOSP）中得到描述，但也在门诊患者（AMBU）轻度感染后出现。我们假设 AMBU 和 HOSP 由于不同的病因，对运动的通气反应不同。我们分析了 2020 年 7 月至 2022 年 5 月间 COVID-19 后 3 个月持续存在呼吸症状的患者的 CPET。收集了胸部计算机断层扫描（CT）扫描、肺功能检查、生活质量和呼吸问卷。特别探讨了 CPET 数据作为通气（V̇e）和时间的函数。共纳入 79 例连续患者（42 例 AMBU 和 37 例 HOSP，中位年龄：54[44-60]岁，57%为女性）。患者住院中位时间为 20[8-34]天，其中肺炎（41%）或急性呼吸窘迫综合征（ARDS；30%）。在 HOSP 中，12（32%）例患者的肺活量测定值异常，18（51%）例一氧化碳弥散量异常（<0.001）。CPET 显示 AMBU 和 HOSP 之间的峰值绝对 O 摄取量（V̇o）（1.59[1.22-2.11]mL·min； = 0.65）无差异。在运动结束时，AMBU 的潮气量（VT）作为 V̇e 的函数低于 HOSP（<0.01）。V̇e-CO 产生的斜率在两组中均高于正常（30.9[26.1-34.3]； = 0.96）。总之，COVID-19 的严重程度并未影响运动能力，但 AMBU 与 HOSP 相比，对运动的通气反应效率较低。通过探索作为 V̇e 和整个运动函数的数据的 CPET 更好地揭示通气效率低下。我们评估了严重急性呼吸综合征冠状病毒-2（SARS-CoV-2）感染后持续呼吸困难患者的运动通气反应。我们发现，尽管峰值功率和峰值绝对 O 摄取量相似，但在运动结束时，AMBU 的潮气量作为通气的函数低于 HOSP，反映了通气效率低下。我们呼吁通过在整个运动过程中而不仅仅是峰值数据来评估分钟通气量，以更好地揭示通气效率低下。
