Interventional bronchoscopy for chronic obstructive pulmonary disease: more than a pipe dream.

Endoscopic lung volume reduction (ELVR) is recognised in both national and international expert guidelines as one of the few additive treatments to benefit patients with advanced chronic obstructive pulmonary disease (COPD) who are otherwise receiving optimal medical and supportive care. Despite these recommendations and a growing evidence base, these procedures are not widely offered across Australia and New Zealand, and general practitioner and physician awareness of this therapy can be improved. ELVR aims to mitigate the impact of hyperinflation and gas trapping on dyspnoea and exercise intolerance in COPD. Effective ELVR is of proven benefit in improving symptoms, quality of life, lung function and survival. Several endoscopic techniques to achieve ELVR have been developed, with endobronchial valve placement to collapse a single lobe being the most widely studied and commonly practised. This review describes the physiological rationale underpinning lung volume reduction, highlights the challenges of patient selection, and provides an overview of the evidence for current and investigational endoscopic interventions for COPD.

Lung Volume Reduction in Pulmonary Emphysema.

Severe emphysema with hyperinflation presents a therapeutic challenge. Inhaled medication has limited efficacy in individuals with mechanical constraints to the respiratory pump and impaired gas exchange. Lung volume reduction surgery (LVRS) reestablishes some semblance of normal physiology, resecting grossly expanded severely diseased tissue to restore the function of compromised relatively healthy lung, and has been shown to significantly improve exercise capacity, quality of life, and survival, especially in individuals with upper-lobe predominant emphysema and low-baseline exercise capacity, albeit with higher early morbidity and mortality. Bronchoscopic lung volume reduction achieved by deflating nonfunctioning parts of the lung is promoted as a less invasive and safer approach. Endobronchial valve implantation has demonstrated comparable outcomes to LVRS in selected individuals and has recently received approvals by the National Institute of Clinical Excellence in the United Kingdom and the Food and Drug Administration in the United States of America. Endobronchial coils are proving a viable treatment option in severe hyperinflation in the presence of collateral ventilation in selected cases of homogeneous disease. Modalities including vapor and sealant are delivered using a segmental strategy preserving healthier tissue within the same target lobe-efficacy and safety-data are, however, limited. This article will review the data supporting these novel technologies.

Cardio-Pulmonary Changes After Bronchoscopic Lung Volume Reduction with Endobronchial One-Way Valves.

INTRODUCTION: To evaluate the cardio-pulmonary hemodynamics changes before and after valve treatment, and their correlation with lobe volume reduction. METHODS: This retrospective multicentre study included consecutive patients undergoing bronchoscopic valve treatment for heterogeneous emphysema. In addition to standard functional evaluation, patients underwent cardiac evaluation by Doppler trans-thoracic echocardiography. The difference in respiratory and cardio-pulmonary hemodynamics indexes before and 3-month after the procedure, and their relationship with changes in lobar volume were evaluated. RESULTS: Seventy-seven patients were included in the study; of these 13 (17%) presented pulmonary hypertension. Only patients with target lobar volume reduction ≥ 563 mL (n = 50) presented a significant improvement of forced expiratory volume in one second, residual volume, 6 min-walk test, and St. George's Respiratory Questionnaire score; a significant reduction of pulmonary artery pressure, and an improvement of left and right ventricle end-systolic volume; of left and right ventricle end-diastolic volume, and of left and right ventricle stroke volume. The change in residual volume was significantly correlated with changes in forced expiratory volume in one second (r = 0.68; p < 0.001); in 6 min-walk test (r = 0.71; p < 0.001); in St. George's Respiratory Questionnaire (r = 0.54; p < 0.001); in pulmonary artery pressure (r = 0.39; p = 0.001), in left (r = 0.28; p = 0.01) and right (r = 0.33; p = 0.002) ventricle end-systolic volume, in left (r = - 0.29; p = 0.008) and right (r = - 0.34; p = 0.007) end-diastolic volume, and in left (r = - 0.76; p = 0.009) and right (r = - 0.718; p = 0.001) ventricle stroke volume. CONCLUSION: Bronchoscopic valve treatment seemed to have positive effects on cardio-pulmonary hemodynamics, and these changes were correlated with reductions of lobar volume.

Endobronchial coils for emphysema: Dual mechanism of action on lobar residual volume reduction.

BACKGROUND AND OBJECTIVE: The RENEW trial demonstrated that bronchoscopic lung volume reduction using endobronchial coils improves quality of life, pulmonary function and exercise performance. In this post hoc analysis of RENEW, we examine the mechanism of action of endobronchial coils that drives improvement in clinical outcomes. METHODS: A total of 78 patients from the RENEW coil-treated group who were treated in one or both lobes that were deemed as the most destroyed were included in this retrospective analysis. Expiratory and inspiratory HRCT scans were used to assess lobar volume change from baseline to 12 months post coil treatment in treated and untreated lobes. RESULTS: Reduction in lobar RV in treated lobes was significantly associated with favourable clinical improvement. Independent predictor of the change in RV and FEV1 was the change in lobar RV reduction in the treated lobes and for change in 6MWD the absence of cardiac disease and the change in SGRQ, while the independent predictor of change in SGRQ was the change in 6MWD. CONCLUSION: Our results suggest that residual lobar volume reduction in treated lobes measured by QCT is the driving mechanism of action of endobronchial coils leading to positive clinical outcomes. However, the improvement in exercise capacity and quality of life seems to be affected by the presence of cardiac disease.

Diaphragm thickening assessed by ultrasonography is lower than healthy adults in patients with chronic obstructive pulmonary disease.

BACKGROUND: Ultrasound imaging has been widely used for imaging of the diaphragm thickness (Tdi) and thickening. Few studies assessed the Tdi using ultrasonography in patients with chronic obstructive pulmonary disease (COPD). We measured the Tdi and thickening in patients with COPD compared with healthy younger and healthy older adults to reveal the influence of ageing and/or COPD. METHODS: Thirty-eight male patients with COPD (age 72 ± 8 years), 15 healthy younger (age 22 ± 1 years) and 15 healthy older (age 72 ± 5 years) male volunteers were recruited. We measured Tdi at total lung capacity (TdiTLC ), functional residual capacity (TdiFRC ) and residual volume (TdiRV ) using B-mode ultrasonography. We calculated the change ratio of TdiTLC and TdiRV (ΔTdi%). We used a one-way analysis of variance and multiple comparison test for the comparison analysis. RESULTS: The TdiTLC and the ΔTdi% were significantly lower in patients with COPD compared to the healthy adults. There was no significant difference in these values with age. There was no between group difference in the TdiFRC or TdiRV . CONCLUSIONS: Our results indicate significant differences in TdiTLC and ΔTdi% between patients with COPD and healthy adults. Therefore, diaphragm ultrasonography can assess diaphragm dysfunction associated with COPD. We suggest that it is better to use TdiTLC and ΔTdi% (not only Tdi at rest) to assess diaphragm function.

Valoración funcional respiratoria previa a la reducción de volumen pulmonar en pacientes con enfisema / Functional respiratory assessment before lung volume reduction in patients with emphysema

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Static hyperinflation is associated with ventilatory limitation and exercise tolerance in adult cystic fibrosis.

INTRODUCTION: Lung hyperinflation is a potential mechanism limiting exercise tolerance. However, available data on the impact of static hyperinflation on exercise performance in adult cystic fibrosis are lacking. Furthermore, the relative contribution of both static and dynamic hyperinflation to exercise performance is unknown. OBJECTIVES: The aim of this study was to determine the impact of static hyperinflation on exercise tolerance and lung dynamics in adult cystic fibrosis. METHODS: Clinical data of 107 adult patients with cystic fibrosis, including pulmonary function, lung volumes and cardiopulmonary exercise from the Toronto Cystic Fibrosis database, were collected and analyzed. Patients were classified as having static hyperinflation with a residual volume to total lung capacity (RV/TLC) ratio of 30% or greater. RESULTS: Patients with static hyperinflation demonstrated a significant reduction in exercise performance [peak oxygen uptake (% predicted) 70 ± 17 vs 80 ± 17; P = .006] and were more likely to experience ventilatory limitation when exercising (Fisher's exact test P < .001). Correlation analysis showed significant relationships between measures of static hyperinflation [RV/TLC ratio (%)] and exercise performance [peak oxygen uptake (% predicted); r = -.38, P < .001] and dynamic hyperinflation (r = -.35, P < .001). Multiple linear regression showed that the contribution of static hyperinflation to exercise performance [peak oxygen uptake (% predicted)] was greater than that of airway obstruction (forced expiratory volume in 1 second). CONCLUSION: Clinicians working with this patient group in a pulmonary rehabilitation or health care setting may wish to consider using measures of static hyperinflation as end points to determine program or treatment efficacy.

Residual volume/total lung capacity ratio confers limited additive significance to lung clearance index for assessment of adults with bronchiectasis.

BACKGROUND: Mosaicism and hyperinflation are common pathophysiologic features of bronchiectasis. The magnitude of ventilation heterogeneity might have been affected by the degree of hyperinflation. Some studies have evaluated the discriminative performance of lung clearance index (LCI) in bronchiectasis patients, but the additive diagnostic value of hyperinflation metrics to LCI is unknown. OBJECTIVE: To compare LCI and the ratio of residual volume to total lung capacity (RV/TLC), along with the LCI normalized with RV/TLC, in terms of discriminative performance, correlation and concordance with clinical variables in adults with bronchiectasis. METHODS: Measurement items included chest high-resolution computed tomography, multiple-breath nitrogen washout test, spirometry, and sputum culture. We analyzed bronchodilator responses by stratifying LCI and RV/TLC according to their median levels (LCIHigh/RV/TLCHigh, LCILow/RV/TLCHigh, LCIHigh/RV/TLCLow, and LCILow/RV/TLCLow). RESULTS: Data from 127 adults with clinically stable bronchiectasis were analyzed. LCI had greater diagnostic value than RV/TLC in discriminating moderate-to-severe from mild bronchiectasis, had greater concordance in reflecting clinical characteristics (including the number of bronchiectatic lobes, radiological severity score, and the presence of cystic bronchiectasis). Normalization of LCI with RV/TLC did not contribute to greater discriminative performance or concordance with clinical variables. The LCI, before and after normalization with RV/TLC, correlated statistically with age, sex, HRCT score, Pseudomonas aeruginosa colonization, cystic bronchiectasis, and ventilation heterogeneity (all P<0.05). Different bronchodilator responses were not significant among the four subgroups of bronchiectasis patients, including those with discordant LCI and RV/TLC levels. CONCLUSION: LCI is superior to RV/TLC for bronchiectasis assessment. Normalization with RV/TLC is not required. Stratification of LCI and RV/TLC is not associated with significantly different bronchodilator responses.

Spirometry, Static Lung Volumes, and Diffusing Capacity.

BACKGROUND: Spirometric Z-scores from the Global Lung Initiative (GLI) rigorously account for age-related changes in lung function and are thus age-appropriate when establishing spirometric impairments, including a restrictive pattern and air-flow obstruction. However, GLI-defined spirometric impairments have not yet been evaluated regarding associations with static lung volumes (total lung capacity [TLC], functional residual capacity [FRC], and residual volume [RV]) and gas exchange (diffusing capacity). METHODS: We performed a retrospective review of pulmonary function tests in subjects ≥40 y old (mean age 64.6 y), including pre-bronchodilator measures for: spirometry (n = 2,586), static lung volumes by helium dilution with inspiratory capacity maneuver (n = 2,586), and hemoglobin-adjusted single-breath diffusing capacity (n = 2,508). Using multivariable linear regression, adjusted least-squares means (adjLSMeans) were calculated for TLC, FRC, RV, and hemoglobin-adjusted single-breath diffusing capacity. The adjLSMeans were expressed with and without height-cubed standardization and stratified by GLI-defined spirometry, including normal (n = 1,251), restrictive pattern (n = 663), and air-flow obstruction (mild, [n = 128]; moderate, [n = 150]; and severe, [n = 394]). RESULTS: Relative to normal spirometry, restrictive-pattern had lower adjLSMeans for TLC, FRC, RV, and hemoglobin-adjusted single-breath diffusing capacity (P ≤ .001). Conversely, relative to normal spirometry, mild, moderate, and severe air-flow obstruction had higher adjLSMeans for FRC and RV (P < .001). However, only mild and moderate air-flow obstruction had higher adjLSMeans for TLC (P < .001), while only moderate and severe air-flow obstruction had higher adjLSMeans for RV/TLC (P < .001) and lower adjLSMeans for hemoglobin-adjusted single-breath diffusing capacity (P < .001). Notably, TLC (calculated as FRC + inspiratory capacity) was not increased in severe air-flow obstruction (P ≥ .11) because inspiratory capacity decreased with increasing air-flow obstruction (P < .001), thus opposing the increased FRC (P < .001). Finally, P values were similar whether adjLSMeans were height-cubed standardized. CONCLUSIONS: A GLI-defined spirometric restrictive pattern is strongly associated with a restrictive ventilatory defect (decreased TLC, FRC, and RV), while GLI-defined spirometric air-flow obstruction is strongly associated with hyperinflation (increased FRC) and air trapping (increased RV and RV/TLC). Both spirometric impairments were strongly associated with impaired gas exchange (decreased hemoglobin-adjusted single-breath diffusing capacity).

Impact of cavity and infiltration on pulmonary function and health-related quality of life in pulmonary Mycobacterium avium complex disease: A 3-dimensional computed tomographic analysis.

BACKGROUND AND OBJECTIVES: Pulmonary Mycobacterium avium complex (pMAC) disease manifests as various types of lesions, such as infiltrates, nodules, cavities, and bronchiectasis. However, the important determinants for clinical parameters in lung involvement are poorly understood. The objective of this study was to obtain quantitative parameters by 3-dimensional CT, and investigate the relationship between these parameters and the pulmonary function tests (PFTs) and health-related quality of life. MATERIAL AND METHODS: Quantitative analysis using CT was performed in 67 pMAC patients. The relationship between new quantitative parameters for evaluating lung involvement using 3-dimensional CT and PFTs or St George's Respiratory Questionnaire (SGRQ) was evaluated. RESULTS: The ratio of infiltration to total lung volume showed significant correlation with the PFT results, especially the percent-predicted forced vital capacity (%FVC; ρ = -0.52), residual volume (ρ = -0.51), and total lung capacity (ρ = -0.59). The cavity volume was strongly correlated with the %FVC (ρ = -0.78) in the cavity group, while the ratio of infiltration to total lung volume was strongly correlated with the %FVC (ρ = -0.53) in the non-cavity group. The ratio of infiltration to total lung volume was significantly correlated with all SGRQ parameters (ρ = 0.41-0.52) in the non-cavity group. CONCLUSIONS: Infiltration was an important parameter for the PFTs and SGRQ in pMAC patients according to the 3-dimensional CT analysis. Moreover, cavity volume was an important parameter of the PFTs in the cavity group. Therefore, infiltration and cavity volume are key features for the management of pMAC disease.

Clinical and Functional Lung Parameters Associated With Frequent Exacerbator Phenotype in Subjects With Severe COPD.

BACKGROUND: COPD is currently recognized as a syndrome associated with a high prevalence of comorbidities and various phenotypes. Exacerbations are very important events in the clinical history of COPD because they drive the decline in lung function. In the present study, we aim to identify whether there are any clinical and functional specific features of frequent exacerbators in a population of patients with severe COPD. METHODS: We conducted a cross-sectional, case control study. All subjects had Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage 3 or 4 COPD (FEV1 < 50% predicted). Frequent exacerbators (n = 183) reported ≥2 exacerbations or ≥1 determining hospitalization during the previous 12 months, and infrequent exacerbators (n = 162) reported <2 exacerbations over the last 12 months without hospitalization. Multivariate logistic regression was performed to determine the clinical and functional factors significantly associated with frequent exacerbator status. RESULTS: Frequent exacerbators had a significantly lower inspiratory capacity percentage predicted. The Motley index (residual volume/total lung capacity percentage) was significantly increased in frequent exacerbators. Infrequent exacerbators had lower Modified Medical Research Council dyspnea scale and BODE index than frequent exacerbators. In the multivariate model, a reduced inspiratory capacity percentage predicted and an increase of residual volume/total lung capacity percentage, BODE index and Modified Medical Research Council dyspnea scale were associated with the frequent exacerbation phenotype. CONCLUSIONS: Static hyperinflation and respiratory disability, measured by Motley index and Modified Medical Research Council dyspnea scale, respectively, in the same way as the multidimensional BODE index staging system, were independently associated with frequent exacerbation status in subjects with severe COPD.

Longer duration of asthma is significantly associated with increased RV/TLC ratio.

BACKGROUND: Although FEV1/FVC ratio has been shown to be negatively associated with longer duration of asthma; an association between RV/TLC ratio and longer duration of asthma has not been explored. MATERIAL AND METHODS: Patients with established asthma for more than a year and met inclusion and exclusion criteria were recruited. Data obtained by questionnaire after informed consent was obtained, Pulmonary function tests and laboratory results were collected through chart review. Correlation and multiple linear regressions were used to analyze the data. RESULTS: Among the 93 subjects, 61 were women. The mean age of patients was 58 ± 15 years, and the mean duration of asthma was 21 ± 18 years. The ethnic composition included: Caucasians 64%, Hispanics 28% and other groups 8%. The FEV1/FVC ratio was not significantly associated with duration of asthma (R2 = 0.15, p = 0.05). However, the RV/TLC ratio was significantly associated with duration of asthma (R2 = 0.46, p < 0.001). CONCLUSION: RV/TLC ratio may be a better indicator than FEV1/FVC ratio to detect airway obstruction related to longer duration of asthma. Lung volume measurements should be done in addition to spirometry to detect changes related to airway obstruction in patients with longer duration of asthma.

Evaluation of bronchoscopic lung volume reduction coil treatment results in patients with severe emphysema.

INTRODUCTION: Bronchoscopic lung volume reduction coil (BLVR-C) implantation is an alternative therapeutic approach that can be applied together with medical treatment for patients with severe emphysema. BLVR-C is both easier and safer in terms of complications than volume reduction surgery. This study aimed to evaluate medium-term outcomes following BLVR-C treatment. METHODS: Forty patients who underwent BLVR-C between September 2013 and March 2014 were reviewed retrospectively. We compared changes between the baseline and 6-month post-procedural results with respect to pulmonary function tests, a 6-min walk test (6MWT), chronic obstructive pulmonary disease (COPD) assessment test (CAT), St. George's Respiratory Questionnaire (SGRQ), and pulmonary artery pressure (PAP) and arterial blood gas analyses. Secondary outcomes included procedure-related and follow-up complications. RESULTS: An average of 9.5 (range: 5-11) coils were placed per lung in an average procedural duration of 20.8 ± 7.0 min (range: 9-45) min. Six months after BLVR-C treatment, significant improvements were observed in patients' pulmonary function tests and quality of life. Changes were observed in the forced exhalation volume in 1 s (+150 mL), residual volume (-14.5%), 6MWT (+48 m), SGRQ (-10.5) and CAT Score (-7.5). Changes in the PAP and partial pressure of carbon dioxide values were not significant, and pneumothorax did not occur. In a 6-month follow-up, 11 cases of COPD exacerbation (41.4%), 7 cases of pneumonia (16.9%) and 1 death (2%) occurred. Treatment in 1 case was postponed because of hypotension and bradycardia during the process. CONCLUSION: BLVR-C treatment appears to be effective over the medium-term and safe for patients with severe emphysema.

Predictors of outcome for urethral injection of botulinum toxin to treat detrusor sphincter dyssynergia in men with spinal cord injury.

STUDY DESIGN: This is a retrospective study. OBJECTIVES: The objective of this study was to determine outcome predictors for urethral injection of botulinum toxin to treat detrusor sphincter dyssynergia (DSD) in patients with spinal cord injury. METHODS: Botulinum toxin type A (100 Units Botox, Allergan) was injected into the external urethral sphincter using a transperineal approach under EMG guidance. Treatment was indicated if DSD was found on urodynamic testing with a post-void residual volume (PVR) above 100 ml. Urodynamic tests and cystourethrograms were performed at baseline. Dysuria (scale of 1-5) and PVR (48- h bladder diary) were evaluated at baseline and 1 month. The outcome was deemed excellent when PVR was equal to or <100 ml and 20%, and dysuria rated <3. RESULTS: Seventy-two men with tetraplegia and 27 with paraplegia were included. There were significant reductions in PVR (from 227 to 97 ml and 63% to 27%) and dysuria (from 4.3 to 2.3). Excellent outcomes were found in 48 patients (48%), and the duration of effectiveness was 6.5 months. The need for catheterisation was decreased or eliminated in 18 patients. Vesicoureteral reflux disappeared in some patients. Poor outcome was significantly related to the presence of bladder neck dyssynergia and the absence of detrusor contraction in standard cystometry. Outcome was also related to the severity of DSD, with a strong correlation between PVR before and after injection (r=0.58). Injections were repeated in 36 patients and yielded similar outcomes in most cases (89%). CONCLUSIONS: Detrusor contractions (odds ratio=8.6) and normal bladder neck activity (odds ratio=7.1) are strong predictors of excellent outcome.

The Prognostic Value of Residual Volume/Total Lung Capacity in Patients with Chronic Obstructive Pulmonary Disease.

The prognostic role of resting pulmonary hyperinflation as measured by residual volume (RV)/total lung capacity (TLC) in chronic obstructive pulmonary disease (COPD) remains poorly understood. Therefore, this study aimed to identify the factors related to resting pulmonary hyperinflation in COPD and to determine whether resting pulmonary hyperinflation is a prognostic factor in COPD. In total, 353 patients with COPD in the Korean Obstructive Lung Disease cohort recruited from 16 hospitals were enrolled. Resting pulmonary hyperinflation was defined as RV/TLC ≥ 40%. Multivariate logistic regression analysis demonstrated that older age (P = 0.001), lower forced expiratory volume in 1 second (FEV1) (P < 0.001), higher St. George Respiratory Questionnaire (SGRQ) score (P = 0.019), and higher emphysema index (P = 0.010) were associated independently with resting hyperinflation. Multivariate Cox regression model that included age, gender, dyspnea scale, SGRQ, RV/TLC, and 6-min walking distance revealed that an older age (HR = 1.07, P = 0.027), a higher RV/TLC (HR = 1.04, P = 0.025), and a shorter 6-min walking distance (HR = 0.99, P < 0.001) were independent predictors of all-cause mortality. Our data showed that older age, higher emphysema index, higher SGRQ score, and lower FEV1 were associated independently with resting pulmonary hyperinflation in COPD. RV/TLC is an independent risk factor for all-cause mortality in COPD.

Obesity and Pulmonary Function in African Americans.

BACKGROUND: Obesity prevalence in United States (US) adults exceeds 30% with highest prevalence being among blacks. Obesity is known to have significant effects on respiratory function and obese patients commonly report respiratory complaints requiring pulmonary function tests (PFTs). However, there is no large study showing the relationship between body mass index (BMI) and PFTs in healthy African Americans (AA). OBJECTIVE: To determine the effect of BMI on PFTs in AA patients who did not have evidence of underlying diseases of the respiratory system. METHODS: We reviewed PFTs of 339 individuals sent for lung function testing who had normal spirometry and lung diffusion capacity for carbon monoxide (DLCO) with wide range of BMI. RESULTS: Functional residual capacity (FRC) and expiratory reserve volume (ERV) decreased exponentially with increasing BMI, such that morbid obesity resulted in patients breathing near their residual volume (RV). However, the effects on the extremes of lung volumes, at total lung capacity (TLC) and residual volume (RV) were modest. There was a significant linear inverse relationship between BMI and DLCO, but the group means values remained within the normal ranges even for morbidly obese patients. CONCLUSIONS: We showed that BMI has significant effects on lung function in AA adults and the greatest effects were on FRC and ERV, which occurred at BMI values < 30 kg/m2. These physiological effects of weight gain should be considered when interpreting PFTs and their effects on respiratory symptoms even in the absence of disease and may also exaggerate existing lung diseases.

Pletismografía corporal (I): estandarización y criterios de calidad / Body plethysmography (I): Standardisation and quality criteria

La pletismografía corporal completa permite la medición de volúmenes, capacidades y resistencias pulmonares. Es una técnica bien estandarizada y ampliamente utilizada en neumología pediátrica, aunque requiere equipo específico, personal especializado y cierta colaboración por parte del paciente. La pletismografía utiliza la ley de Boyle para determinar el volumen de gas intratorácico o capacidad residual funcional, y una vez determinada esta, se extrapolan el volumen residual y la capacidad pulmonar total. La medición de la capacidad pulmonar total es necesaria para el diagnóstico de patología restrictiva. La resistencia de la vía aérea es una medida de obstrucción, pudiéndose determinar la resistencia total, que incluye la resistencia de la pared torácica, tejido pulmonar y vía aérea, y la resistencia específica, que es un parámetro más estable que corresponde al producto de la resistencia de la vía aérea por la capacidad residual funcional. La complejidad de esta técnica, las ecuaciones de referencia, las diferencias en el equipamiento, la variabilidad de la misma y las condiciones en las que se realiza han hecho necesaria su estandarización. Se analizan a lo largo del artículo los aspectos prácticos de esta técnica, especificando las recomendaciones para su realización, sistemática de calibración y los cálculos que se deben llevar a cabo, así como la interpretación de los resultados obtenidos. El objetivo de esta publicación es favorecer una mejor comprensión de los principios de la pletismografía completa con el fin de optimizar la interpretación de los resultados favoreciendo un mejor manejo del paciente y un consenso en la especialidad (AU)

Whole body plethysmography is used to measure lung volumes, capacities and resistances. It is a well standardised technique, and although it is widely used in paediatric chest diseases units, it requires specific equipment, specialist staff, and some cooperation by the patient. Plethysmography uses Boyle's law in order to measure the intrathoracic gas volume or functional residual capacity, and once this is determined, the residual volume and total lung capacity is extrapolated. The measurement of total lung capacity is necessary for the diagnosis of restrictive diseases. Airway resistance is a measurement of obstruction, with the total resistance being able to be measured, which includes chest wall, lung tissue and airway resistance, as well as the specific airway resistance, which is a more stable parameter that is determined by multiplying the measured values of airway resistance and functional residual capacity. The complexity of this technique, the reference equations, the differences in the equipment and their variability, and the conditions in which it is performed, has led to the need for its standardisation. Throughout this article, the practical aspects of plethysmography are analysed, specifying recommendations for performing it, its systematic calibration and the calculations that must be made, as well as the interpretation of the results obtained. The aim of this article is to provide a better understanding of the principles of whole body plethysmography with the aim of optimising the interpretation of the results, leading to improved management of the patient, as well as a consensus among the speciality (AU)

Lung Volume Reduction in Emphysema Improves Chest Wall Asynchrony.

BACKGROUND: Lung volume reduction (LVR) techniques improve lung function in selected patients with emphysema, but the impact of LVR procedures on the asynchronous movement of different chest wall compartments, which is a feature of emphysema, is not known. METHODS: We used optoelectronic plethysmography to assess the effect of surgical and bronchoscopic LVR on chest wall asynchrony. Twenty-six patients were assessed before and 3 months after LVR (surgical [n = 9] or bronchoscopic [n = 7]) or a sham/unsuccessful bronchoscopic treatment (control subjects, n = 10). Chest wall volumes were divided into six compartments (left and right of each of pulmonary ribcage [Vrc,p], abdominal ribcage [Vrc,a], and abdomen [Vab]) and phase shift angles (θ) calculated for the asynchrony between Vrc,p and Vrc,a (θRC), and between Vrc,a and Vab (θDIA). RESULTS: Participants had an FEV1 of 34.6 ± 18% predicted and a residual volume of 217.8 ± 46.0% predicted with significant chest wall asynchrony during quiet breathing at baseline (θRC, 31.3° ± 38.4°; and θDIA, -38.7° ± 36.3°). Between-group difference in the change in θRC and θDIA during quiet breathing following treatment was 44.3° (95% CI, -78 to -10.6; P = .003) and 34.5° (95% CI, 1.4 to 67.5; P = .007) toward 0° (representing perfect synchrony), respectively, favoring the LVR group. Changes in θRC and θDIA were statistically significant on the treated but not the untreated sides. CONCLUSIONS: Successful LVR significantly reduces chest wall asynchrony in patients with emphysema.

Lung function over the first 3 years of life in children with congenital diaphragmatic hernia.

OBJECTIVES: Infants with congenital diaphragmatic hernia (CDH) have variable degrees of pulmonary hypoplasia at birth. Few reports of lung function over the first years of life exist in this group of children. HYPOTHESIS: Pulmonary function abnormalities correlate with severity of neonatal disease and intensity of neonatal therapies needed. We also hypothesized that longitudinal measurements of lung function over the usual period of rapid lung growth would lend some insight into how the lung remodels in CDH infants. METHODOLOGY: Ninety-eight infants with CDH between 11 days and 44 months of age underwent pulmonary function testing (PFT) on 1-5 occasions using the raised volume rapid thoracic compression technique. Demographic data were also collected. MAIN RESULTS: Forced expiratory flows were below normal. Total lung capacity was normal, but residual volume and functional residual capacity were elevated. Children requiring patch closure, ECMO, or pulmonary vasodilators generally had lower lung functions at follow up. Additionally, longer duration of mechanical ventilation correlated with worse lung function. CONCLUSIONS: Lung functions of survivors of CDH remain abnormal throughout the first 3 years of life. The degree of pulmonary function impairment correlated both with markers of the initial degree of pulmonary hypoplasia and the duration of mechanical ventilation. Understanding the relationship between the phenotypic presentation of CDH and the potential for subsequent lung growth could help refine both pre- and postnatal therapies to optimize lung growth in CDH infants.