Is the Slow Vital Capacity Clinically Useful to Uncover Airflow Limitation in Subjects With Preserved FEV1/FVC Ratio?

Pulmonary Function Test of Forced Vital Capacity and Slow Vital Capacity Using Spirometry in Young Adults With Respect to Body Mass Index: A Normative Study

“…Similar study done by [33] reported increased BMI did not impair pulmonary function in the higher age group. These changes seen in the pulmonary function between age groups is supported by findings of [34], where differences seen between the age groups are probably a consequence of the physiological effect of aging and also is related to the smaller airways in younger age group. Elderly subjects generating less positive intrapleural pressures on expiration, thereby failing to compress the small airways in the forced maneuver to the same extent as younger subjects.…”

Difference between slow vital capacity and forced vital capacity in the diagnosis of airflow limitation

“…A ∆SVC−FVC > 0.20 L was significantly associated with a body mass index > 30 kg/m². Likewise, Saint-Pierre et al 3 observed lower values for the FEV 1 /SVC ratio versus the FEV 1 /FVC ratio in obese individuals. Reference values do not generally include obese individuals, and, therefore, ∆SVC−FVC data in obese individuals without cardiopulmonary disease are not available for large samples.…”

“…The value of 0.20 L was suggested in the Brazilian Thoracic Association 2002 Guidelines for Pulmonary Function Testing. 2 In 2019, Saint-Pierre et al 3 evaluated functional test results of 13,893 individuals and reported that a preserved FEV 1 /FVC ratio with a reduced FEV 1 /VC ratio was observed in 20.4% of cases. The low predicted value used in that study to characterize the lower limit for the FEV 1 /FVC ratio greatly decreases the sensitivity of this parameter for detecting AFL.…”

“…Kubota et al 5 evaluated pulmonary function in 20,341 normal individuals in Japan and found that, due to the expected loss of elastic recoil, the ∆SVC−FVC increases with age, although a greater difference was also found in certain younger individuals. It is not surprising that Saint-Pierre et al 3 acknowledge that, in the elderly, in whom the prevalence of COPD is higher, the FEV 1 /SVC ratio should not be considered.…”

Obesity: how pulmonary function tests may let us down

“…FVC may underestimate slow VC because FVC is precociously “amputated” by early small airway closure in the forced maneuver, i.e., the FEV 1 /FVC ratio tends to increase. 3 Although functional residual capacity decreases in comparison with that in the earlier stages of obesity, 4 volume “extremities”-RV and TLC-are only mildly affected (unless obesity is massive). It follows that expiratory reserve volume decreases and inspiratory capacity increases in tandem with BMI.…”