Contribution of peripheral airway function to changes in FEV1/FVC and RV/TLC with aging

Association between age, gender, body mass index, and pulmonary function in preoperative patients with lung cancer

INTRODUCTION

Many confounding factors such as sex, age, and body mass index (BMI) affect pulmonary function parameters, but there are limited data about the direct and/or indirect effects of small airway function on lung function for differences in confounding factors.

OBJECTIVES

This study aimed to use structural equation model (SEM) to explain the influence of the confounding factors (age, sex, and BMI) on the relationship between small airway function and lung function in patients with lung cancer.

METHODS

A cross-sectional observational study was conducted in a single medical center. Subjects were assessed; small airway function was specified by MEF25% and MEF50%; lung function by FVC; pulmonary obstruction by FEV1, FEV1%, and FEV1/FVC; and PEF and PEF% reflected the strength of abdominal muscles. The measurement model was analyzed by confirmatory factor analysis. The SEM was conducted to analyze the structural models of the effects of the confounding factors.

RESULTS

In the measurement model, variables were fit to their domains, the path linking age and sex to pulmonary obstruction was positive and statistically significant, and the path linking sex to muscle strength was also positive and statistically significant. Muscle strength positively and significantly mediates the path between sex and FVC. As a moderator, BMI increased the effects of small airway function on FVC.

CONCLUSION

Age and sex were directed to pulmonary obstruction, and muscle strength as a mediator between sex and lung function was novel, and BMI adjusted the effects of small airway function on FVC.

Pulmonary function, exercise capacity and dyspnea in patients 7 ​years after Nuss surgery

PURPOSE

Pectus excavatum is a frequent thoracic malformation increasingly treated with minimally invasive methods (MIRPE), which are performed for cardio-respiratory problems and in some centers also for esthetic considerations. Theoretically, MIRPE may increase thoracic elastic recoil, work of breathing and cause emphysema. The aim of the present study was to determine whether teenagers who underwent MIRPE may expect normal thoracic cage development, cardio-respiratory function, exercise capacity and asymptomatic functioning.

MATERIAL AND METHODS

Fifty five patients (21.1 ​± ​3.0 years) who underwent MIRPE between 2000 and 2010 were assessed 6.8 (±2.4) years after surgery. Controls were matched for sex, age and height to the intervention participants. Spirometry, body plethysmography, diffusion capacity and the 6 ​min walking test (6MWT) were performed. Anteroposterior (AP) and transverse chest diameters were measured.

RESULTS

Participants who underwent MIRPE had normal pulmonary function, and exercise capacity. After adjustment for potential confounders, the intervention group had lower mean BMI [-1.88 ​± ​0.56 (kg/m²); p ​= ​0.001] and chest AP diameter [-2.79 ​± ​0.57 (cm); p ​< ​0.001], but higher residual volume (RV%) [12.98 ​± ​5.31 (%); p ​= ​0.001], RV% total lung capacity (TLC) [5.56 ​± ​0.92 (%); p ​< ​0.001], forced expiratory volume in 1 ​s/forced vital capacity (FEV₁/FVC) [2.64 ​± ​1.28 (%); p ​= ​0.039] and 6MWT distance [29.10 ​± ​13.02 (m); p ​= ​0.025].

CONCLUSIONS

Young adults who undergo MIRPE may expect normal pulmonary function and exercise capacity. Observed differences in air trapping require further assessment in terms of emphysema development risk.

Lung clearance index in healthy volunteers, measured using a novel portable system with a closed circuit wash-in

Introduction

Lung clearance index (LCI) is a sensitive measure of early lung disease, but adoption into clinical practice has been slow. Challenges include the time taken to perform each test. We recently described a closed-circuit inert gas wash-in method that reduces overall testing time by decreasing the time to equilibration. The aim of this study was to define a normative range of LCI in healthy adults and children derived using this method. We were also interested in the feasibility of using this system to measure LCI in a community setting.

Methods

LCI was assessed in healthy volunteers at three hospital sites and in two local primary schools. Volunteers completed three washout repeats at a single visit using the closed circuit wash-in method (0.2% SF₆ wash-in tracer gas to equilibrium, room air washout).

Results

160 adult and paediatric subjects successfully completed LCI assessment (95%) (100 in hospital, 60 in primary schools). Median coefficient of variation was 3.4% for LCI repeats and 4.3% for FRC. Mean (SD) LCI for the analysis cohort (n = 53, age 5–39 years) was 6.10 (0.42), making the upper limit of normal LCI 6.8. There was no relationship between LCI and multiple demographic variables. Median (interquartile range) total test time was 18.7 (16.0–22.5) minutes.

Conclusion

The closed circuit method of LCI measurement can be successfully and reproducibly measured in healthy volunteers, including in out-of-hospital settings. Normal range appears stable up to 39 years. With few subjects older than 40 years, further work is required to define the normal limits above this age.

Dismantling airway disease with the use of new pulmonary function indices

We are currently limited in our abilities to diagnose, monitor disease status and manage chronic airway disease like asthma and chronic obstructive pulmonary disease (COPD). Conventional lung function measures often poorly reflect patient symptoms or are insensitive to changes, particularly in the small airways where disease may originate or manifest. Novel pulmonary function tests are becoming available which help us better characterise and understand chronic airway disease, and their translation and adoption from the research arena would potentially enable individualised patient care.

In this article, we aim to describe two emerging lung function tests yielding novel pulmonary function indices, the forced oscillation technique (FOT) and multiple breath nitrogen washout (MBNW). With a particular focus on asthma and COPD, this article demonstrates how chronic airway disease mechanisms have been dismantled with the use of the FOT and MBNW. We describe their ability to assess detailed pulmonary mechanics for diagnostic and management purposes including response to bronchodilation and other treatments, relationship with symptoms, evaluation of acute exacerbations and recovery, and telemonitoring. The current limitations of both tests, as well as open questions/directions for further research, are also discussed.

Spirometry is used to diagnose and manage airway disease such as asthma and COPD, but relates poorly to symptoms, lacks sensitivity and is effort dependent. FOT and MBNW are emerging clinical lung function tests that help us dismantle disease mechanisms.http://ow.ly/nM0G30nS6Ct