BACKGROUND During cardiopulmonary exercise testing (CPET), Idiopathic Pulmonary Fibrosis (IPF) patients do not reach their direct maximum voluntary ventilation (MVV) and have deranged gas exchange. Their exercise limitation is therefore attributed to a pulmonary vascular mechanism. METHODS We studied two cohorts (derivation and validation) of IPF patients with lung function testing and CPET. Maximal ventilation at exercise (VEpeak) was compared to direct MVV by Bland-Altman analysis. RESULTS In the derivation cohort (n = 101), direct MVV over-estimated VEpeak by a factor of 1.51, driven by respiratory rate during MVV that was 1.99 times higher at rest as compared to VEpeak at exercise. The formula (FEV1 × 20.1) + 15.4 was shown to predict VEpeak (r2 = 0.56) in the derivation cohort. In the validation cohort of 78 patients, VEpeak was within a factor of 1.27 (6.8 l/min) of predicted according to the novel formula. According to the novel prediction formula the majority of patients (58%) in the entire cohort have VEpeak within 85% of their predicted MVV, which would indicate a mechanical respiratory limitation to exercise. CONCLUSION Estimation of direct MVV performed at rest leads to significant over-estimation of the breathing reserve in IPF patients. This may lead to over-diagnosis of pulmonary vascular limitation in these patients. Expected maximal ventilation at exercise may be accurately predicted indirectly by an IPF-specific formula.

中文翻译：

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IPF患者受到机械而非肺血管因素的限制-衍生验证队列研究的结果。

背景技术在心肺运动测试（CPET）期间，特发性肺纤维化（IPF）患者未达到直接最大自愿通气（MVV）且气体交换异常。因此，他们的运动受限归因于肺血管机制。方法我们通过肺功能测试和CPET研究了IPF患者的两个队列（推导和验证）。通过Bland-Altman分析将运动时的最大通气量（VEpeak）与直接MVV进行了比较。结果在派生队列（n = 101）中，直接MVV高估了VEpeak的系数为1.51，这是由MVV期间的呼吸频率所驱动，比运动时的VEpeak高出1.99倍。公式（FEV1×20.1）+ 15.4显示出可以预测派生队列中的VEpeak（r2 = 0.56）。在78名患者的验证队列中，VEpeak处于根据新公式预测的1.27（6.8 l / min）的范围内。根据新的预测公式，整个队列中的大多数患者（58％）的VEpeak在其预测的MVV的85％以内，这表明运动存在机械性呼吸限制。结论静息时进行的直接MVV估计会导致IPF患者的呼吸储备明显过高。这可能导致这些患者的肺血管局限性过度诊断。可以通过IPF特定公式间接准确地预测运动时预期的最大通气量。这表示运动受到机械性呼吸限制。结论静息时进行的直接MVV估计会导致IPF患者的呼吸储备明显过高。这可能导致这些患者的肺血管局限性过度诊断。可以通过IPF特定公式间接准确地预测运动时预期的最大通气量。这表示运动受到机械性呼吸限制。结论静息时进行的直接MVV估计会导致IPF患者的呼吸储备明显过高。这可能导致这些患者的肺血管局限性过度诊断。可以通过IPF特定公式间接准确地预测运动时预期的最大通气量。