BACKGROUND: In advanced chronic obstructive pulmonary disease (COPD), hypercapnia may occur due to severe bronchial obstruction with lung hyperinflation. Non-invasive ventilation (NIV) provides the standard of care intended to achieve physiological PCO2 levels, thereby reducing overall mortality. The present study aimed to evaluate pulmonary function parameters derived from spirometry (forced vital capacity [FVC], forced expiratory volume in 1 s [FEV1]), body plethysmography (residual volume [RV], total lung capacity [TLC]), and lung diffusion capacity for carbon monoxide (single-breath method [DCO-SB], alveolar-volume corrected values [DCO-VA]) as predictors of chronic hypercapnia in patients with advanced COPD.
METHODS: This monocentric, retrospective observational study included 423 COPD patients. Receiver operating characteristic (ROC) curve analysis and cross-validation were used to assess lung function parameters\' diagnostic accuracy for predicting chronic hypercapnia, with the resulting performance expressed as area under the ROC curve (AUROC). We performed univariable and multivariable binary logistic regression analysis to determine if these parameters were independently associated with chronic hypercapnia, with probabilities reported as odds ratios [OR] with 95% confidence intervals [95%CI].
RESULTS: FVC% (AUROC 0.77 [95%CI 0.72-0.81], P < 0.01) and FEV1% (AURIC 0.75 [95%CI 0.70-0.79], P < 0.01) exhibited reasonable accuracy in the prediction of chronic hypercapnia, whereas lung diffusion capacity performed poorly (AUROC 0.64 [95%CI 0.58-0.71] for DCO-SB%, P < 0.01). FVC% (OR 0.95 [95%CI 0.93-0.97], P < 0.01) and FEV1% (OR 0.97 [95%CI 0.94-0.99], P = 0.029) were the only parameters associated independently with chronic hypercapnia in logistic regression analysis. FVC and FEV1 thresholds that best separated hypercapnic from normocapnic subjects reached 56% and 33% of predicted values.
CONCLUSIONS: Routinely collected pulmonary function parameters, particularly FVC% and FEV1%, may predict chronic hypercapnia during COPD progression.

UNASSIGNED: The aim of this study was to estimate the effects of a pulmonary rehabilitation programme (PR) on the functional capacity and respiratory muscle strength of patients with post-COVID syndrome.
UNASSIGNED: A cross-sectional study was conducted using hospital data on patients who participated in a pulmonary rehabilitation programme at the Clinic for Lung Diseases, University Hospital Centre Zagreb, Croatia, between January 2021 and December 2022. Data on the spirometry, respiratory muscle strength, and functional exercise capacity of patients were collected at baseline and three weeks after the start of rehabilitation. The study included 80 patients (43 females, 37 males) with a mean age of 51±10 years.
UNASSIGNED: A significant increase in respiratory muscle strength (P<0.001) was observed after pulmonary rehabilitation, with effect sizes ranging from small to large (Cohen\'s d from 0.39 to 1.07), whereas the effect for PImax expressed as a percentage was large (Cohen\'s d=0.99). In addition, the pulmonary rehabilitation programme significantly improved the parameters of the six-minute walk test in patients, and the parameters of lung function, FVC, FEV1, and DLCO also improved significantly after PR (P<0.05).
UNASSIGNED: The results showed that the pulmonary rehabilitation programme has clinically significant effects on functional capacity and respiratory muscle strength in patients with post-COVID syndrome.
UNASSIGNED: Cilj te študije je bil oceniti učinek programa pljučne rehabilitacije na funkcionalno sposobnost in moč dihalnih mišic pri bolnikih z dolgim covidom.
UNASSIGNED: Opravili smo presečno študijo na podlagi bolnišničnih podatkov o bolnikih, ki so med januarjem 2021 in decembrom 2022 sodelovali v programu pljučne rehabilitacije v Kliniki za pljučne bolezni v Univerzitetnem bolnišničnem centru v Zagrebu. Podatke o spirometriji, moči dihalnih mišic in funkcionalni zmogljivosti za telesno aktivnost bolnikov smo zbrali ob izhodišču in tri tedne po začetku rehabilitacije. Študija je vključevala 80 bolnikov (43 žensk, 37 moških) povprečne starosti 51±10 let.
UNASSIGNED: Ugotovili smo bistveno povečanje moči dihalnih mišic (P < 0,001) po pljučni rehabilitaciji, pri čemer so bile velikosti učinka od majhnih do velikih (Cohen d od 0,39 do 1,07), učinek za PImax, izražen v odstotku, pa je bil velik (Cohen d = 0,99). Poleg tega je program pljučne rehabilitacije precej izboljšal parametre 6-minutnega sprehoda pri bolnikih, parametri pljučne funkcije FVC, FEV1 in DLCO pa so se po pljučni rehabilitaciji prav tako znatno izboljšali (P < 0,05).
UNASSIGNED: Rezultati so pokazali, da ima program pljučne rehabilitacije pri bolnikih z dolgim covidom klinično pomemben učinek na funkcionalno sposobnost in moč dihalnih mišic.

OBJECTIVE: To determine the diagnostic utility of spirometry in distinguishing children with Induced Laryngeal Obstruction (ILO) or chronic non-specific cough (a.k.a. tic cough) from those with mild or moderate to severe asthma.
METHODS: Retrospective cross sectional design. Children diagnosed with ILO (N = 70), chronic non-specific cough (N = 70), mild asthma (N = 60), or moderate to severe asthma (N = 60) were identified from the electronic medical record of a large children\'s hospital. Spirometry was completed before ILO, non-specific cough, or asthma diagnoses were made by pediatric laryngologists or pulmonologists. Spirometry was performed following American Thoracic Society guidelines and was interpreted by a pediatric pulmonologist. Forced Vital Capacity (FVC), Forced Expiratory Volume in 1 Second (FEV1), FEV1/FVC Ratio (FEV1/FVC), Forced Mid-Expiratory Flow 25--75 % (FEF25-75%), pulmonologist interpretation of flow volume loops, and overall exam findings were extracted from the medical record.
RESULTS: Ninety seven percent of children with ILO or chronic non-specific cough presented with spirometry values within normative range. Patients with ILO, non-specific cough, and mild asthma presented with FVC, FEV1, FEV1/FVC, and FEF25-75% values in statistically similar range. Children with moderate to severe asthma presented with significantly reduced FVC (p < .001), FEV1 (p < .001), FEV1/FVC (p < .001), and FEF25-75% (p < .001) values when compared with patients in the other groups. Flow volume loops were predominantly normal for children with ILO and non-specific cough.
CONCLUSIONS: Findings indicate that ILO and chronic non-specific cough can neither be diagnosed nor differentiated from mild asthma using spirometry alone. Spirometry should therefore be used judiciously with this population, bearing in mind the limitations of the procedure. Future research should determine the most effective and efficient ways of delineating ILO and non-specific cough from other respiratory conditions in children.

BACKGROUND: Professional cycling puts significant demands on the respiratory system. Exercise-induced bronchoconstriction (EIB) is a common problem in professional athletes. Small airways may be affected in isolation or in combination with a reduction in forced expiratory volume at the first second (FEV1). This study aimed to investigate isolated exercise-induced small airway dysfunction (SAD) in professional cyclists and assess the impact of this phenomenon on exercise capacity in this population.
METHODS: This research was conducted on professional cyclists with no history of asthma or atopy. Anthropometric characteristics were recorded, the training age was determined, and spirometry and specific markers, such as fractional exhaled nitric oxide (FeNO) and immunoglobulin E (IgE), were measured for all participants. All of the cyclists underwent cardiopulmonary exercise testing (CPET) followed by spirometry.
RESULTS: Compared with the controls, 1-FEV3/FVC (the fraction of the FVC that was not expired during the first 3 s of the FVC) was greater in athletes with EIB, but also in those with isolated exercise-induced SAD. The exercise capacity was lower in cyclists with isolated exercise-induced SAD than in the controls, but was similar to that in cyclists with EIB. This phenomenon appeared to be associated with a worse ventilatory reserve (VE/MVV%).
CONCLUSIONS: According to our data, it appears that professional cyclists may experience no beneficial impacts on their respiratory system. Strenuous endurance exercise can induce airway injury, which is followed by a restorative process. The repeated cycle of injury and repair can trigger the release of pro-inflammatory mediators, the disruption of the airway epithelial barrier, and plasma exudation, which gradually give rise to airway hyper-responsiveness, exercise-induced bronchoconstriction, intrabronchial inflammation, peribronchial fibrosis, and respiratory symptoms. The small airways may be affected in isolation or in combination with a reduction in FEV1. Cyclists with isolated exercise-induced SAD had lower exercise capacity than those in the control group.

Long-COVID is a multisystem disease that can lead to significant impairments in health-related quality of life (HRQoL). Following COVID-19 infection, abnormalities on pulmonary function tests (PFT) are common. The primary aim of this study is to evaluate for any correlation between PFT abnormalities and impairment in HRQoL scores following COVID-19 infection.
This is an analysis of a prospective cohort of patients in Louisville, KY who were infected with COVID-19. Data collected included demographics, past medical history, laboratory tests, PFTs, and several HRQoL questionnaires such as the EuroQol 5 Dimension HRQoL questionnaire (EQ-5D-5 L), Generalized Anxiety Disorder 7 (GAD-7), Patient Health Questionnaire (PHQ-9), and Posttraumatic stress disorder checklist for DSM-5 (PCL-5). Descriptive statistics were performed, comparing PFTs (normal vs abnormal) and time since COVID-19 infection (3- vs 6- vs ≥ 12 months).
There were no significant differences in FEV1, FVC, or the percentage of patients with abnormal PFTs over time after COVID-19 infection. Following COVID-19, patients with normal PFTs had worse impairment in mobility HRQoL scores and change in GAD-7 scores over time. There were no differences over time in any of the HRQoL scores among patients with abnormal PFTs.
Among patients with an abnormal PFT, there was no temporal association with HRQoL scores as measured by EQ-5D-5 L, GAD-7, PHQ-9, and PCL-5. Among patients with a normal PFT, mobility impairment and anxiety may be associated with COVID-19 infection. Following COVID-19 infection, impairment in HRQoL scores is not completely explained by the presence of abnormalities on spirometry.

This review comprehensively examines the intricate relationship between carbon monoxide (CO) diffusion capacity and chronic obstructive pulmonary disease (COPD). COPD, comprising chronic bronchitis and emphysema, presents a substantial global health burden, necessitating a nuanced understanding of pulmonary function parameters for effective diagnosis and management. The review delves into the physiological underpinnings, measurement techniques, and factors influencing CO diffusion capacity, emphasizing its pivotal role in assessing alveolar gas exchange efficiency. Key findings elucidate correlations between altered diffusion capacity and the severity of COPD, providing clinicians with valuable insights into disease progression. Considerations of age, gender, and ethnic disparities in normal CO diffusion capacity values highlight the importance of personalized interpretations. The clinical implications extend beyond diagnosis, influencing COPD management and prognostication, with potential applications in predicting treatment response. The review outlines avenues for future research, including advancements in measurement technologies and the exploration of novel imaging modalities and biomarkers. Ultimately, this review serves as a foundation for refining diagnostic approaches and treatment strategies and enhancing patient care in the dynamic landscape of COPD.

Respiratory failure assessment is among the most debatable research topics in amyotrophic lateral sclerosis (ALS) clinical research due to the wide heterogeneity of its presentation. Among the different pulmonary function tests (PFTs), maximal voluntary ventilation (MVV) has shown potential utility as a diagnostic and monitoring marker, able to capture early respiratory modification in neuromuscular disorders. In the present study, we explored calculated MVV (cMVV) as a prognostic biomarker in a center-based, retrospective ALS population belonging to the Piemonte and Valle d\'Aosta registry for ALS (PARALS). A Spearman\'s correlation analysis with clinical data and PFTs showed a good correlation of cMVV with forced vital capacity (FVC) and a moderate correlation with some other features such as bulbar involvement, ALSFRS-R total score, blood oxygen (pO2), carbonate (HCO3-), and base excess (BE), measured with arterial blood gas analysis. Both the Cox proportional hazard models for survival and the time to non-invasive ventilation (NIV) measurement highlighted that cMVV at diagnosis (considering cMVV(40) ≥ 80) is able to stratify patients across different risk levels for death/tracheostomy and NIV indication, especially considering patients with FVC% ≥ 80. In conclusion, cMVV is a useful marker of early respiratory failure in ALS, and is easily derivable from standard PFTs, especially in asymptomatic ALS patients with normal FVC measures.

BACKGROUND: Coronary artery bypass grafting(CABG) is a surgical treatment for coronary artery disease aiming at improving symptoms and life expectancy. Despite this, there are pulmonary and functional complications that may arise during the postoperative period due to invasive mechanical ventilation(IMV), cardiopulmonary bypass and immobility, leading to longer hospital stays.
OBJECTIVE: To evaluate the clinical and functional outcomes related to pulmonary complications in the postoperative period of CABG.
METHODS: Prospective cohort. During the ICU stay the patients were divided into: Non Complicated Group(NCG) who did not present complications and Complicated Group(CG) who presented complication. Functional variables were applied as the six-minute walk test(6MWT), gait speed, sit up and stand up test, Timed Up and Go, peripheral muscle strength, ventilatory, pulmonary function and Functional Independence Measure. These tests were applied preoperatively, at ICU discharge, hospital discharge and six months after surgery.
RESULTS: The study evaluated 90 patients, 59 in the NCG and 31 CG. In the 6MWT there was a 2%(p = 0.43) decrease in the NCG, while the decrease was 13%(p < 0.01) in the CG. In the MRC the drop was 2%(p = < 0.01) in the CNG, while in the CG the drop was 14%(p = < 0.01). In MIP the NCG had a 6%(p = 0.67) decrease, while the CG had a 16%(p = < 0.01) decrease.
CONCLUSIONS: Patients with postoperative complications of CABG may have reduced functional performance, muscle strength, and pulmonary function at hospital discharge and after six months.

Stroke is a significant cause of mortality and chronic morbidity caused by cardiovascular disease. Respiratory muscles can be affected in stroke survivors, leading to stroke complications, such as respiratory infections. Respiratory function can be assessed using pulmonary function tests (PFTs). Data regarding PFTs in stroke survivors are limited. We reviewed the correlation between PFTs and stroke severity or degree of disability. Furthermore, we reviewed the PFT change in stroke patients undergoing a respiratory muscle training program. We searched PubMed until September 2023 using inclusion and exclusion criteria in order to identify studies reporting PFTs post-stroke and their change after a respiratory muscle training program. Outcomes included lung function parameters (FEV1, FVC, PEF, MIP and MEP) were measured in acute or chronic stroke survivors. We identified 22 studies of stroke patients, who had undergone PFTs and 24 randomised controlled trials in stroke patients having PFTs after respiratory muscle training. The number of patients included was limited and studies were characterised by great heterogeneity regarding the studied population and the applied intervention. In general, PFTs were significantly reduced compared to healthy controls and predicted normal values and associated with stroke severity. Furthermore, we found that respiratory muscle training was associated with significant improvement in various PFT parameters and functional stroke parameters. PFTs are associated with stroke severity and are improved after respiratory muscle training.

BACKGROUND: The COVID-19 pandemic has constrained access to spirometry, and the inherent risk of infectious transmission during aerosol-generating procedures has necessitated the rapid development of Remotely Supervised Spirometry (RSS). This innovative approach enables patients to perform spirometry tests at home, using a mobile connected spirometer, all under the real-time supervision of a technician through an online audio or video call.
METHODS: In this retrospective study, we examined the quality of RSS in comparison to conventional Laboratory-based Spirometry (LS), using the same device and technician. Our sample included 242 patients, with 129 undergoing RSS and 113 participating in LS. The RSS group comprised 51 females (39.5%) with a median age of 37 years (range: 13-76 years). The LS group included 63 females (55.8%) with a median age of 36 years (range: 12-80 years).
RESULTS: When comparing the RSS group to the LS group, the percentage of accurate Forced Expiratory Volume in one second (FEV1) measurements was 78% (n = 101) vs. 86% (n = 97), p = 0.177; for Forced Vital Capacity (FVC) it was 77% (n = 99) vs. 82% (n = 93), p = 0.365; and for both FEV1 and FVC, it was 75% (n = 97) vs. 81% (n = 92), p = 0.312, respectively.
CONCLUSIONS: Our findings demonstrate no significant difference in the quality of spirometry testing between RSS and LS, a result that held true across all age groups, including patients aged over 65 years. The principal advantages of remote spirometry include improved access to pulmonary function tests, reduced infectious risk to curtail disease spread, and enhanced convenience for patients.