Oğuz Merve Sinem, Bingöl Züleyha, Pıhtılı Aylin, Karaca Özer Pelin, Sarıtaş Arslan Melike, Kılıçaslan Zeki, Bilge Ahmet Kaya, Kıyan Esen, Okumuş Gülfer
Department of Pulmonary Diseases, Istanbul Medical Faculty, Istanbul University, Capa-Fatih, Istanbul, Turkey.
Department of Cardiology, Istanbul Medical Faculty, Istanbul University, Capa-Fatih, Istanbul, Turkey.
BMC Pulm Med. 2024 Jul 31;24(1):373. doi: 10.1186/s12890-024-03188-2.
The six-minute walk test (6MWT) is widely used to assess functional capacity and prognosis in patients with idiopathic pulmonary fibrosis (IPF). However, studies on oxygen saturation recovery after the 6MWT in patients with IPF are rare. In our study, we investigated the relationship between oxygen saturation recovery time and dyspnea, fatigue, quality of life, prognostic markers and pulmonary hypertension (PH).
In this cross-sectional study, IPF patients diagnosed according to current guidelines and followed up in our Interstitial Lung Disease Outpatient Clinic between 2021 and 2022 were included. Demographics, data from spirometry, diffusion capacity measurement, arterial blood gas analysis, transthoracic echocardiography and the 6MWT were recorded. The oxygen saturation recovery time, distance saturation product (DSP), gender-age-physiology (GAP) index and composite physiological index (CPI) scores were calculated. Dyspnea severity was assessed by the modified Medical Research Council (mMRC) and Dyspnoea-12 (D-12) scales, fatigue severity by the Multidimensional Fatigue Inventory (MFI-20) and quality of life by the St George's Respiratory Questionnaire (SGRQ).
Fifty IPF patients (34 men, 16 women, age: 66.8 ± 7.3 years) were included in the study. The mean FVC was 77.8 ± 19.3%, the DLCO was 52.9 ± 17.1%, the 6-minute walk distance (6MWD) was 385.7 ± 90.6 m, the GAP index was 3.5 ± 1.5, and the CPI was 43.7 ± 14.1. Oxygen saturation after the 6MWT reached pretest values at an average of 135.6 ± 73.5 s. The oxygen saturation recovery time was longer in patients with higher GAP index scores (Rs = 0.870, p < 0.001), CPI scores (Rs = 0.906, p < 0.001), desaturation (Rs = 0.801, p < 0.001), FVC%/DLCO% (Rs = 0.432, p = 0.002), sPAP (Rs = 0.492, p = 0.001), TRV (Rs = 0.504, p = 0.001), mMRC (Rs = 0.913, p < 0.001), MFI-20 (Rs = 0.944, p < 0.001), D-12 scale (Rs = 0.915, p < 0.001) and SGRQ scores (Rs = 0.927, p < 0.001); lower FVC (%) (Rs=-0.627, p < 0.001), DLCO (%) (Rs=-0.892, p < 0.001), PaO (Rs=-0.779, p < 0.001), DSP (Rs=-0.835, p < 0.001), and 6MWD (Rs=-0.763, p < 0.001). A total of twenty patients (40%) exhibited an increased risk of PH. According to our multiple regression analysis, oxygen saturation recovery time was independently associated with the GAP index (p = 0.036), the lowest oxygen saturation occurring during the 6MWT (p = 0.011) and the SGRQ score (p < 0.001).
Our results showed that oxygen saturation recovery time is associated with dyspnea, fatigue, quality of life, increased risk of PH and prognostic markers in IPF. Therefore, we recommend continuous measurement of oxygen saturation after 6MWT until pretest values are reached.
六分钟步行试验（6MWT）广泛用于评估特发性肺纤维化（IPF）患者的功能能力和预后。然而，关于IPF患者6MWT后氧饱和度恢复情况的研究较少。在我们的研究中，我们调查了氧饱和度恢复时间与呼吸困难、疲劳、生活质量、预后标志物和肺动脉高压（PH）之间的关系。
在这项横断面研究中，纳入了根据现行指南诊断并于2021年至2022年在我们的间质性肺病门诊随访的IPF患者。记录人口统计学资料、肺量计数据、弥散功能测量、动脉血气分析、经胸超声心动图和6MWT的数据。计算氧饱和度恢复时间、距离饱和度乘积（DSP）、性别-年龄-生理学（GAP）指数和综合生理指数（CPI）评分。呼吸困难严重程度通过改良医学研究委员会（mMRC）和呼吸困难-12（D-12）量表评估，疲劳严重程度通过多维疲劳量表（MFI-20）评估，生活质量通过圣乔治呼吸问卷（SGRQ）评估。
本研究纳入了50例IPF患者（34例男性，16例女性，年龄：66.8±7.3岁）。平均用力肺活量（FVC）为77.8±19.3%，一氧化碳弥散量（DLCO）为52.9±17.1%，六分钟步行距离（6MWD）为385.7±90.6米，GAP指数为3.5±1.5，CPI为43.7±14.1。6MWT后氧饱和度平均在135.6±73.5秒达到测试前值。GAP指数评分较高（Rs = 0.870，p < 0.001）、CPI评分较高（Rs = 0.906，p < 0.001）、去饱和（Rs = 0.801，p < 0.001）、FVC%/DLCO%（Rs = 0.432，p = 0.002）、收缩期肺动脉压（sPAP）（Rs = 0.492，p = 0.001）、三尖瓣反流速度（TRV）（Rs = 0.504，p = 0.001）、mMRC（Rs = 0.913，p < 0.001）、MFI-20（Rs = 0.944，p < 0.001）、D-12量表（Rs = 0.915，p < 0.001）和SGRQ评分（Rs = 0.927，p < 0.001）的患者氧饱和度恢复时间较长；FVC（%）较低（Rs = -0.627，p < 0.0
