Comparison of Forced Oscillation Technique, Lung Volumes by Body Plethysmography, and Spirometry in Moderate Persistent Adult Asthma.

BACKGROUND: Spirometry is used extensively, but airway oscillometry is gaining acceptance for evaluating obstructive airway disorders. Moderate persistent asthma requires daily treatment with inhaled corticosteroids (ICS). MATERIALS AND METHODS: We aimed to examine the relationship between airway oscillometry and lung volumes, which are the markers of lung physiology in obstructive airway disease and spirometry in the real-world clinical setting. A total of 72 adults with moderate persistent asthma followed up in our outpatient department from November 2021 to August 2022, and their clinical details and tests of spirometry, forced oscillation technique (FOT), and lung volumes by body plethysmography (BP) performed before and after bronchodilator administration were analyzed. RESULTS: The mean age of the study population was 40 years, and the majority (57%) were females. FOT detected airflow limitation in 12 of the 31 patients with normal spirometry. BP detected abnormalities in more patients than both spirometry and FOT (91.6 vs 73.6%, p < 0.001). Respiratory resistance 5 (R5) had a negative correlation with functional residual capacity (FRC) and total lung capacity (TLC). Reactance 5 (X5) correlated positively with inspiratory capacity (IC) and TLC and negatively with reserve volume (RV)/TLC ratio. A positive correlation was found between IC/TLC% and postbronchodilator X5 and between R5 and 19 and RV/TLC. R5 had a negative and X5 had a positive correlation with forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC, and maximal mid expiratory flow rates (MMEF). ∇X5 had a negative correlation with FEV1, MMEF, and FEV1/FVC. Spirometry detected postbronchodilator responsiveness in more patients than FOT when only the R5 criterion was used and in a comparable number when the X5 criterion was added. ∇X5 and R5-R19/R5 declined significantly after bronchodilators. CONCLUSION: We concluded that there is a moderate correlation between FOT and spirometry and lung volumes by BP. FOT and spirometry should be used together to identify airflow obstruction and postbronchodilator responsiveness in asthma. Lung volumes by BP identify more abnormalities in adults with asthma than both spirometry and FOT. Thresholds to define postbronchodilator responsiveness (PBDR) for ∇X5 and R5-R19 need to be defined.

Impact of Using Global Lung Initiative Race-neutral Equations for Chronic Respiratory Disease in Western India.

The Global Lung Initiative (GLI) race-neutral equations are considered to be race agnostic, using inverse probability weight, and have lower limits of normality (LLN) different from the GLI mixed equations. In this observational study, we analyzed the impact of using GLI equations to interpret spirometry of 1,169 patients with chronic respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), COPD suspects, small airway obstruction, posttubercular lung disease, and preserved ratio with impaired spirometry (PRISm) (46% females, average age 46 years). Predicted normal and the LLN using GLI equations were significantly higher than those using Indian equations. The GLI race-neutral equations changed the category in 35.17% of males and 42.64% of females compared to Indian equations. The GLI mixed equations categorized a greater percentage of patients to have a mixed ventilatory pattern compared to the GLI race-neutral equations. There was a significant change in the grading of the severity of COPD using Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages based on the percentage of predicted values of FEV1. Although GLI race-neutral equations have greater concordance with Indian equations than GLI Mixed equations, these substantially overdiagnose abnormal ventilatory patterns on spirometry in adult Indians in western India with chronic respiratory disease. A substantial number of patients with normal or obstructive patterns on spirometry are recategorized to have mixed or restrictive patterns. The use of GLI race-neutral equations increases the severity of airflow limitation in COPD patients. GLI race-neutral predictions for FEV1 result in substantially fewer patients demonstrating postbronchodilator responsiveness (PBDR).

Platypnea-orthodeoxia Syndrome (POS) in Moderate COVID-19: An Uncommonly Common Bedside Sign?

Platypnoea-Orthodeoxia syndrome (POS) is the presence of postural hypoxaemia along with breathlessness in recumbent position. It is an uncommon syndrome with elusive pathophysiologic mechanisms. We observed POS in patients of moderate COVID-19 who required hospital admission to our indoor facility and oxygen supplementation when saturation was documented in sitting and supine positions for evaluation of platypnea. MATERIALS AND METHODS: We conducted an observational, cross sectional, retrospective analysis of pulse oximetry readings of patients with stage 2 COVID-19 admitted in ward during the period from 15th May 2020 to 30th May 2020. The difference in the peripheral oxygen saturation in sitting and supine positions, documented as a routine standard of care, especially in patients with platypnea, was calculated and demographic details and co-morbidities were noted from indoor record forms. RESULTS: Of the 53 patients of stage 2 COVID-19 who were included in the study, 15 (28%) had platypnoea-orthodeoxia syndrome at the time of presentation and 18(33.9%) patients with platypnoea had ≥ 3% desaturation in sitting position as compared to supine position. Rest of the 20 (37.7%) patients had neither platypnoea nor orthodeoxia. All the patients presenting with platypnoea-orthodeoxia required oxygen therapy during the course of treatment. Amongst the 33 patients who were hypoxic and required oxygen supplementation, 15 patients (45.4%) had oxygen saturation of ≥94% in the supine position at presentation. CONCLUSION: Platypnoea-orthodeoxia syndrome is common in patients with stage 2 COVID 19 infection who require oxygen therapy. POS can be easily documented by using pulse oximeter without the need of any specialised equipment. Hence, we propose that documentation of POS at the time of admission in primary health care or resource depleted settings would help in successful triage of the patients needing oxygen therapy. We also propose that oxygen saturation in sitting position be documented as far as possible. Further clinical studies are necessary to validate this observation.

Hemoptysis after COVID: Pulmonary artery pseudoaneurysm treated with endovascular coiling.

Pulmonary artery pseudoaneurysms are a rare but life-threatening cause of hemoptysis. These are saccular dilatations of the pulmonary artery which do not involve all the three layers of the vessel and are prone to rupture. PAPAs are most commonly associated with infections but may also be caused by vasculitis, lung fibrosis, pulmonary hypertension and a multitude of other causes. CT pulmonary angiography is the diagnostic modality of choice allowing delineation of the PAPA, underlying cause and allowing planning of further management. Although treating the underlying cause is an important part of management, endovascular intervention is required in cases with hemoptysis. Long COVID is an entity that is still under evaluation. It has multisystem involvement. We describe the case of a 30-year-old teacher with hemoptysis after COVID who was diagnosed with a PAPA of segmental branch of left upper lobar pulmonary artery and treated with endovascular embolization with coils and glue. His hemoptysis has stopped since then. He also had pulmonary fibrosis and growth of multidrug resistant Klebsiella pneumoniae in sputum. These were treated medically and he has resumed his work as a teacher.