Detection of impaired gas exchange using the 1-minute sit-to-stand test in patients with interstitial lung disease

BACKGROUND

Although pulmonary function tests (PFTs) are important in patients with interstitial lung disease (ILD), they cannot be easily performed in a primary healthcare setting. This study aimed to examine the usefulness of the difference between pulse oxygen saturation (SpO2) at rest and the lowest SpO2 during the 1-min sit-to-stand test (delta SpO2-1STST) for predicting pulmonary function impairment.

METHODS

We retrospectively reviewed 116 patients with ILD who underwent 1STST and PFTs.

RESULTS

The delta SpO2-1STST and diffusing capacity for carbon monoxide (DLco) strongly correlated (ρ = 0.70). The delta SpO2-1STST was effective in predicting impaired gas exchange (cut-off value, -4%; AUC, 0.86; sensitivity, 74%; specificity, 87%).

CONCLUSIONS

The Delta SpO2-1STST may be a reasonable tool for predicting abnormalities in PFTs.

Risk assessment and dose-effect of co-exposure to benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS) on pulmonary function: A cross-sectional study

Inhalation is the most frequent route and the lung is the primary damaged organ for human exposure to benzene, toluene, ethylbenzene, xylene, and styrene (BTEXS). However, there is limited information on the risk and dose-effect of the BTEXS mixture on pulmonary function, particularly the overall effect. We conducted a cross-sectional study in a petrochemical plant in southern China. Spirometry and cumulative exposure dose (CED) of BTEXS were used to measure lung function and exposure levels for 635 workers in 2020, respectively. Forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁) were tested and interpreted as percentages to predicted values [FVC or FEV₁% predicted], and FEV₁ to FVC ratio [FEV₁/FVC (%)]. We found the reduction in FVC% predicted and the risk of lung ventilation dysfunction (LVD) and its two subtypes (mixed and restrictive ventilation dysfunction, MVD, and MVD) were significantly associated with BTEXS individuals. In addition, pulmonary function damage associated with BTEXS was modified by the smoking status and age. Generalized weighted quantile sum (gWQS) regressions were used to estimate the overall dose-effect on lung function damage induced by the BTEXS mixture. Our results show wqs, an index of weighted quartiles for BTEXS, was potentially associated with the reduction in FVC and FEV₁% predicted with the coefficients [95% confidence intervals (CI)] between -1.136 (-2.202, -0.070) and -1.230 (-2.265, -0.195). Odds ratios (ORs) and 95% CIs for the wqs index of LVD, MVD, and RVD were 1.362 (1.129, 1.594), 1.323 (1.084, 1.562), and 1.394 (1.096, 1.692), respectively. Furthermore, xylene, benzene, and toluene in the BTEXS mixture potentially contribute to the development of lung function impairment. Our novel findings demonstrated the dose-response relationships between pulmonary function impairment and the BTEXS mixture and disclosed the potential key pollutants in the BTEXS mixture.

Pulmonary function impairment of asymptomatic and persistently symptomatic patients 4 months after COVID-19 according to disease severity

Objective

Evaluation of pulmonary function impairment after COVID-19 in persistently symptomatic and asymptomatic patients of all disease severities and characterisation of risk factors.

Methods

Patients with confirmed SARS-CoV-2 infection underwent prospective follow-up with pulmonary function testing and blood gas analysis during steady-state cycle exercise 4 months after acute illness. Pulmonary function impairment (PFI) was defined as reduction below 80% predicted of DLCOcSB, TLC, FVC, or FEV1. Clinical data were analyzed to identify risk factors for impaired pulmonary function.

Results

76 patients were included, hereof 35 outpatients with mild disease and 41 patients hospitalized due to COVID-19. Sixteen patients had critical disease requiring mechanical ventilation, 25 patients had moderate–severe disease. After 4 months, 44 patients reported persisting respiratory symptoms. Significant PFI was prevalent in 40 patients (52.6%) occurring among all disease severities. The most common cause for PFI was reduced DLCOcSB (n = 39, 51.3%), followed by reduced TLC and FVC. The severity of PFI was significantly associated with mechanical ventilation (p < 0.001). Further risk factors for DLCO impairment were COPD (p < 0.001), SARS-CoV-2 antibody-Titer (p = 0.014) and in hospitalized patients CT score. A decrease of paO2 > 3 mmHg during cycle exercise occurred in 1/5 of patients after mild disease course.

Conclusion

We characterized pulmonary function impairment in asymptomatic and persistently symptomatic patients of different severity groups of COVID-19 and identified further risk factors associated with persistently decreased pulmonary function. Remarkably, gas exchange abnormalities were revealed upon cycle exercise in some patients with mild disease courses and no preexisting pulmonary condition.

Supplementary Information

The online version contains supplementary material available at 10.1007/s15010-021-01669-8.