Effect of chronic hyperinflation on diaphragm length and surface area

CT-Based Evaluation of the Shape of the Diaphragm Using 3D Slicer

The diaphragm is the main inspiratory muscle and separates the thorax and the abdomen. In COPD, the evaluation of the diaphragm shape is clinically important, especially in the case of hyperinflation. However, delineating the diaphragm remains a challenge as it cannot be seen entirely on CT scans. Therefore, the lungs, ribs, sternum, and lumbar vertebrae are used as surrogate landmarks to delineate the diaphragm. We herein describe a CT-based method for evaluating the shape of the diaphragm using 3D Slicer-a free software that allows delineation of the diaphragm landmarks-in ten COPD patients. Using the segmentation performed with 3D Slicer, the diaphragm shape was reconstructed with open-source Free Pascal Compiler. From this graduated model, the length of the muscle fibers, the radius of curvature, and the area of the diaphragm-the main determinants of its function-can be measured. Inter- and intra-user variabilities were evaluated with Bland and Altman plots and linear mixed models. Except for the coronal length (p = 0.049), there were not statistically significant inter- or intra-user differences (p values ranging from 0.326 to 0.910) suggesting that this method is reproducible and repeatable. In conclusion, 3D Slicer can be applied to CT scans for determining the shape of the diaphragm in COPD patients.

Automated evaluation of diaphragm configuration based on chest CT in COPD patients

BACKGROUND

Severe chronic obstructive pulmonary disease (COPD) often results in hyperinflation and flattening of the diaphragm. An automated computed tomography (CT)-based tool for quantifying diaphragm configuration, a biomarker for COPD, was developed in-house and tested in a large cohort of COPD patients.

METHODS

We used the LungQ platform to extract the lung-diaphragm intersection, as direct diaphragm segmentation is challenging. The tool computed the diaphragm index (surface area/projected surface area) as a measure of diaphragm configuration on inspiratory scans in a COPDGene subcohort. Visual inspection of 250 randomly selected segmentations served as a quality check. Associations between the diaphragm index, Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages, forced expiratory volume in 1 s (FEV1) % predicted, and CT-derived emphysema scores were explored using analysis of variance and Pearson correlation.

RESULTS

The tool yielded incomplete segmentation in 9.2% (2.4% major defect, 6.8% minor defect) of 250 randomly selected cases. In 8431 COPDGene subjects (4240 healthy; 4191 COPD), the diaphragm index was increasingly lower with higher GOLD stages (never-smoked 1.83 ± 0.16; GOLD-0 1.79 ± 0.18; GOLD-1 1.71 ± 0.15; GOLD-2: 1.67 ± 0.16; GOLD-3 1.58 ± 0.14; GOLD-4 1.54 ± 0.11) (p < 0.001). Associations were found between the diaphragm index and both FEV1% predicted (r = 0.44, p < 0.001) and emphysema score (r = -0.36, p < 0.001).

CONCLUSION

We developed an automated tool to quantify the diaphragm configuration in chest CT. The diaphragm index was associated with COPD severity, FEV1%predicted, and emphysema score.

RELEVANCE STATEMENT

Due to the hypothesized relationship between diaphragm dysfunction and diaphragm configuration in COPD patients, automatic quantification of diaphragm configuration may prove useful in evaluating treatment efficacy in terms of lung volume reduction.

KEY POINTS

Severe COPD changes diaphragm configuration to a flattened state, impeding function. An automated tool quantified diaphragm configuration on chest-CT providing a diaphragm index. The diaphragm index was correlated to COPD severity and may aid treatment assessment.

Improvements of the shape and strength of the diaphragm after endoscopic lung volume reduction

RATIONALE

Endoscopic lung volume reduction improves lung function, quality of life and exercise capacity in severe emphysema patients. However, its effect on the diaphragm function is not well understood. We hypothesised that endoscopic lung volume reduction increases its strength by modifying its shape.

OBJECTIVES

To investigate changes in both diaphragm shape and strength induced by the insertion of endobronchial valves.

METHODS

In 19 patients, both the diaphragm shape and strength were investigated respectively by 3D Slicer software applied on CT scans acquired at functional residual capacity and by transdiaphragmatic pressure measurements by bilateral magnetic stimulation of the phrenic nerves before and 3 months after unilateral valves insertion.

MEASUREMENTS AND MAIN RESULTS

After lung volume reduction (median (IQR), 434 mL (-597 to -156], p<0.0001), diaphragm strength increased (transdiaphragmatic pressure: 3 cmH2O (2.3 to 4.2), p<0.0001). On the treated side, this increase was associated with an increase in the coronal (16 mm (13 to 24), p<0.0001) and sagittal (26 mm (21 to 30), p<0.0001) lengths as well as in the area of the zone of apposition (62 cm2 (3 to 100), p<0.0001) with a decrease in the coronal (8 mm (-12 to -4), p<0.0001) and sagittal (9 mm (-18 to -2), p=0.0029) radii of curvature.

CONCLUSIONS

Endoscopic lung volume reduction modifies the diaphragm shape by increasing its length and its zone of apposition and by decreasing its radius of curvature on the treated side, resulting in an increase in its strength.

TRIAL REGISTRATION NUMBER

NCT05799352.

Inspiratory Muscle Dysfunction Mediates and Predicts a Disease Continuum of Hypercapnic Failure in Chronic Obstructive Pulmonary Disease

INTRODUCTION

Advanced chronic obstructive pulmonary disease (COPD) is associated with chronic hypercapnic failure. The present work aimed to comprehensively investigate inspiratory muscle function as a potential key determinant of hypercapnic respiratory failure in patients with COPD.

METHODS

Prospective patient recruitment encompassed 61 stable subjects with COPD across different stages of respiratory failure, ranging from normocapnia to isolated nighttime hypercapnia and daytime hypercapnia. Arterialized blood gas analyses and overnight transcutaneous capnometry were used for patient stratification. Assessment of respiratory muscle function encompassed body plethysmography, maximum inspiratory pressure (MIP), diaphragm ultrasound, and transdiaphragmatic pressure recordings following cervical magnetic stimulation of the phrenic nerves (twPdi) and a maximum sniff manoeuvre (Sniff Pdi).

RESULTS

Twenty patients showed no hypercapnia, 10 had isolated nocturnal hypercapnia, and 31 had daytime hypercapnia. Body plethysmography clearly distinguished patients with and without hypercapnia but did not discriminate patients with isolated nocturnal hypercapnia from those with daytime hypercapnia. In contrast to ultrasound parameters and transdiaphragmatic pressures, only MIP reflected the extent of hypercapnia across all three stages. MIP values below -48 cmH2O predicted nocturnal hypercapnia (area under the curve = 0.733, p = 0.052).

CONCLUSION

In COPD, inspiratory muscle dysfunction contributes to progressive hypercapnic failure. In contrast to invasive tests of diaphragm strength only MIP fully reflects the pathophysiological continuum of hypercapnic failure and predicts isolated nocturnal hypercapnia.

Change in diaphragmatic morphology in single-lung transplant recipients: a computed tomographic study

Introduction: The influence of lung disease on the diaphragm has been poorly studied. The study aimed to evaluate the diaphragm morphology (height and thickness) in single-lung transplantation (SLTx), using computed tomography (CT), by assessing the evolution of the hemidiaphragm of the transplanted and the native side. Methods: Patients who underwent single lung transplantation in our center (Marseille, France) between January 2009 and January 2022 were retrospectively included. Thoracic or abdominal CT scans performed before and the closest to and at least 3 months after the surgery were used to measure the diaphragm crus thickness and the diaphragm dome height. Results: 31 patients mainly transplanted for emphysema or pulmonary fibrosis were included. We demonstrated a significant increase in diaphragm crus thickness on the side of the transplanted lung, with an estimated difference of + 1.25 mm, p = <0.001, at the level of the celiac artery, and + 0.90 mm, p < 0.001, at the level of the L1 vertebra while no significant difference was observed on the side of the native lung. We showed a significant reduction in the diaphragm height after SLTx on the transplanted side (-1.20 cm, p = 0.05), while no change on the native side (+0.02 cm, p = 0.88). Conclusion: After a SLTx, diaphragmatic morphology significantly changed on the transplanted lung, while remaining altered on the native lung. These results highlights that an impaired lung may have a negative impact on its diaphragm. Replacement with a healthy lung can promote the recovery of the diaphragm to its anatomical morphology, reinforcing the close relationship between these two organs.

Computed tomography reveals hypertrophic remodelling of the diaphragm in cystic fibrosis but not in COPD

Background

Computed tomography (CT) is increasingly used for assessing skeletal muscle characteristics. In cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD), reduced limb muscle mass predicts poor clinical outcomes. However, the degree to which quantity or quality of respiratory and nonrespiratory muscles is affected by these diseases remains controversial.

Methods

Thoracic CT images of 29 CF, 21 COPD and 20 normal spirometry control subjects were analysed to measure indices of muscle quantity (volume or cross-sectional area) and quality (radiodensity) in respiratory (diaphragm, abdominal) and nonrespiratory (pectoralis, lumbar paraspinal) muscles. Multivariable linear regression assessed relationships of CT measurements with body mass index (BMI), forced expiratory volume in 1 s (FEV1) % pred, inflammation and infection biomarkers, nutritional status and CF genotype.

Results

Diaphragm volume in CF was significantly higher than in COPD (by 154%) or controls (by 140%). Abdominal muscle area in CF was also greater than in COPD (by 130%). Nonrespiratory muscles in COPD had more low radiodensity muscle (marker of lipid content) compared to CF and controls. In CF but not COPD, higher BMI and FEV1 % pred were independently associated with higher diaphragm and/or abdominal muscle quantity indices. Serum creatinine also predicted respiratory and nonrespiratory muscle quantity in CF, whereas other biomarkers including genotype correlated poorly with muscle CT parameters.

Conclusions

Our data suggest that the CF diaphragm undergoes hypertrophic remodelling, whereas in COPD the nonrespiratory muscles show altered muscle quality consistent with greater lipid content. Thoracic CT can thus identify distinctive respiratory and nonrespiratory muscle remodelling signatures associated with different chronic lung diseases.

Is manual therapy of the diaphragm effective for people with Obstructive Lung Diseases? A Systematic Review

BACKGROUND

Diaphragm dysfunction is common among people with obstructive lung disease (OLD). The effectiveness of manual therapy (MT) techniques specifically targeting this region remains unclear. The scope of this systematic review is to investigate the effectiveness of MT on the zone of apposition (ΖΟΑ) of the diaphragm in lung function, diaphragm excursion (DE), chest expansion, exercise capacity (EC), maximal inspiratory pressure (PImax) and dyspnea in people suffering from OLD.

METHODS

Key databases were systematically searched. Two independent reviewers screened the papers for inclusion. Methodological quality and the quality of evidence were assessed using the PEDro scale and the GRADE approach, respectively.

RESULTS

Two studies were included. One showed that diaphragmatic stretching and the manual diaphragm release technique (MDRT) improved DE and CE (p<0.001, p<0.05, respectively). The other showed that MDRT improved DE and EC (p<0.05, p<0.05, respectively).

CONCLUSION

This systematic review provides preliminary evidence on the effectiveness of MT on the ZOA of the diaphragm in people with COPD. Further research is needed in order for definitive conclusions to be drawn.

REGISTRATION NUMBER IN PROSPERO

CRD42022308595.

Inspiratory and expiratory CT analyses of the diaphragmatic crus in chronic obstructive pulmonary disease

PURPOSE

This study aimed to investigate the association between the results of pulmonary function tests (PFTs) in patients with chronic obstructive pulmonary disease (COPD) and the size of their diaphragmatic crus (DC) using inspiratory and expiratory CT.

MATERIALS AND METHODS

Thirty-three patients who underwent inspiratory and expiratory CT and PFTs between July and December 2019 were studied retrospectively. The short axis, long axis, and cross-sectional area (CSA) of the bilateral DC were measured, and the percentage change of the DC after expiration (% change of DC) in the size was calculated. The correlation between the results of the PFTs (forced expiratory volume in 1 s [FEV₁], FEV₁/forced vital capacity [FVC], and percent predicted FEV₁ [%FEV₁]) and the size and % change of DC was statistically analyzed.

RESULTS

Significant correlations were observed between the short axis of the right and left DC at expiration and PFTs (FEV₁, r = -0.35, -0.48, p = 0.04, .007; FEV₁/FVC, r = -0.52, -0.65, p = 0.002, < .001; %FEV₁, r = -0.56, -0.60, p < 0.001, < 0.001; respectively), between the CSA of the right DC at expiration and PFTs (FEV₁/FVC, r = -0.42, p = 0.01; %FEV₁, r = -0.41, p = 0.017; respectively), and between the % change of the short axis of the left DC and the CSA of the left DC and PFTs (FEV₁, r = 0.64, 0.56, p < 0.001, .001; %FEV₁, r = 0.52, 0.51, p = 0.004, 0.004; respectively). The smaller the short axis of the DC and CSA at expiration and the larger the % change in DC of the CSA, the lower the airflow limitation.

CONCLUSION

There were significant correlations between airflow limitation and the short axis of the bilateral DC at expiration, and the % change in the DC of the CSA. Certain CT measurements of the DC may reflect airflow limitation in patients with COPD.

Does mobilisation of the thoracic spine using mechanical massage affect diaphragmatic excursion in individuals with thoracic hyperkyphosis?

BACKGROUND

Thoracic mobilisation improves thoracic hyperkyphosis and respiratory function. Diaphragmatic excursion is associated with respiratory function; however, limited studies have assessed the effect of thoracic mobilisation on diaphragmatic excursion.

OBJECTIVE

This study aimed to investigate the effects of thoracic mobilisation on diaphragmatic excursion and respiratory function in individuals with thoracic hyperkyphosis.

METHODS

Participants were recruited through Internet advertising and participated voluntarily. Nineteen healthy participants (age: 33.37 ± 6.56 years; height: 170.32 ± 7.92 cm; weight: 69.77 ± 14.70 kg) with thoracic hyperkyphosis underwent thoracic mobilisation for 8 weeks. Diaphragmatic excursion, thoracic kyphosis, and respiratory function were measured. Thoracic mobilisation was provided using a mechanical massage device.

RESULTS

Thoracic mobilisation for 8 weeks significantly improved diaphragmatic excursion during deep breathing (p= 0.015), forced vital capacity (p< 0.01), and thoracic hyperkyphosis (p< 0.01).

CONCLUSIONS

Thoracic mobilisation can be recommended in respiratory rehabilitation programs to increase diaphragmatic excursion and respiratory function for the management and prevention of respiratory dysfunction in individuals with thoracic hyperkyphosis.

Dynamic Quantitative Magnetic Resonance Imaging Assessment of Areas of the Lung During Free-Breathing of Patients with Chronic Obstructive Pulmonary Disease

RATIONALE AND OBJECTIVES

Changes in the geometry of the chest wall due to lung hyperinflation occur in COPD. However, the quantitative assessment of impaired lung motions and its association with the clinical characteristics of COPD patients are unclear. This study aimed to investigate the respiratory kinetics of COPD patients by dynamic MRI.

MATERIALS AND METHODS

This study enrolled 22 COPD patients and 10 normal participants who underwent dynamic MRI and pulmonary function testing (PFT). Changes in the areas of the lung and mediastinum during respiration were compared between the COPD patients and the normal controls. Relationships between MRI, CT parameters, and clinical measures that included PFT results also were evaluated.

RESULTS

Asynchronous movements and decreased diaphragmatic motion were found in COPD patients. COPD patients had a larger ratio of MRI-measured lung areas at expiration to inspiration, a smaller magnitude of the peak area change ratio, and a smaller mediastinal-thoracic area ratio than the normal participants. The lung area ratio was associated with FEV₁/FVC, predicted RV%, and CT lung volume/predicted total lung capacity (pTLC). The lung area ratio of the right lower and left lower lungs was significantly correlated with emphysema of each lower lobe. The expiratory mediastinal-thoracic area ratio was associated with FEV₁% predicted and RV/TLC.

CONCLUSION

Changes in the lung areas of COPD patients as shown on MRI reflected the severity of airflow limitation, hyperinflation, and the extent of emphysema. Dynamic MRI provides essential information about respiratory kinetics in COPD.

Maximal Voluntary Breath-Holding Tele-Inspiratory Test in Patients with Chronic Obstructive Pulmonary Disease

Maximal voluntary inspiratory breath-holding time (MVIBHT) has proved to be of clinical utility in some obstructive ventilatory defects. This study aims to correlate the breath-holding time with pulmonary function tests in patients with chronic obstructive pulmonary disease (COPD) and to determine the feasibility of using a breath-holding test in assessing the severity of COPD.

A cross-sectional study including male patients with stable COPD were conducted. Patients with respiratory comorbidities and severe or unstable cardiac diseases were excluded. Patients were interviewed and examined. Six-minute walk test (6MWT) and plethysmography were performed.For MVIBHT collection, the subject was asked to inspire deeply and to hold the breath as long as possible at the maximum inspiratory level. This maneuver was repeated three times. The best value was used for further analysis.

A total of 79 patients (mean age: 64.2 ± 8) were included in this study. The mean value of MVIBHT was 24.2 ± 8.5 s. We identified a positive and significant correlations between MVIBHT and forced vital capacity (r = .630; p < .001) as well as MVIBHT and forced expiratory volume in 1 s (FEV1%) (r = .671; p < .001). A significant inverse correlation with total lung capacity (r = −.328; p = .019) and residual volume to total lung capacity ratio (r = −.607; p < .001) was noted. MVIBHT was significantly correlated to the distance in the 6MWT (r = .494; p < .001). The mean MVIBHT was significantly different within spirometric grades (p < .001) and GOLD groups (p = .002). At 20.5 s, MVIBHT had a sensitivity of 72% and specificity of 96% in determining COPD patients with FEV1 <50%.

Our results provide additional evidence of the usefulness of MVIBHT in COPD patients as a pulmonary function parameter.

[Inspiratory muscle training during pulmonary rehabilitation]

INTRODUCTION

Inspiratory muscle training (IMT) is part of the management of patients with pulmonary diseases during rehabilitation. Since the last recommendations of the Société de pneumologie de langue française, several studies have focused on the role of inspiratory muscle training during pulmonary rehabilitation.

BACKGROUND

IMT, in comparison to standard care or sham-IMT, improves the strength and endurance of the inspiratory muscles, decreases dyspnoea during the activities of daily living, improves walking distance and quality of life. However, the different studies did not show an additional effect of IMT during a pulmonary rehabilitation program compared to a rehabilitation program without IMT, with regard to improvement of exercise capacity and quality of life.

OUTLOOK

One study showed an improvement in dyspnoea of effort, but these results are yet to be confirmed. Finally, it seems appropriate to associate IMT with an exercise-training program before chest or abdominal surgery, even if further studies are necessary.

CONCLUSION

During a pulmonary rehabilitation program, IMT does not provide additional benefits. However, when patients cannot perform a global exercise training, IMT has shown benefit. IMT provides additional benefits in pre-operative programs.

Ultrasound and non-ultrasound imaging techniques in the assessment of diaphragmatic dysfunction

Diaphragm muscle dysfunction is increasingly recognized as an important element of several diseases including neuromuscular disease, chronic obstructive pulmonary disease and diaphragm dysfunction in critically ill patients. Functional evaluation of the diaphragm is challenging. Use of volitional maneuvers to test the diaphragm can be limited by patient effort. Non-volitional tests such as those using neuromuscular stimulation are technically complex, since the muscle itself is relatively inaccessible. As such, there is a growing interest in using imaging techniques to characterize diaphragm muscle dysfunction. Selecting the appropriate imaging technique for a given clinical scenario is a critical step in the evaluation of patients suspected of having diaphragm dysfunction. In this review, we aim to present a detailed analysis of evidence for the use of ultrasound and non-ultrasound imaging techniques in the assessment of diaphragm dysfunction. We highlight the utility of the qualitative information gathered by ultrasound imaging as a means to assess integrity, excursion, thickness, and thickening of the diaphragm. In contrast, quantitative ultrasound analysis of the diaphragm is marred by inherent limitations of this technique, and we provide a detailed examination of these limitations. We evaluate non-ultrasound imaging modalities that apply static techniques (chest radiograph, computerized tomography and magnetic resonance imaging), used to assess muscle position, shape and dimension. We also evaluate non-ultrasound imaging modalities that apply dynamic imaging (fluoroscopy and dynamic magnetic resonance imaging) to assess diaphragm motion. Finally, we critically review the application of each of these techniques in the clinical setting when diaphragm dysfunction is suspected.

Quantitative Videofluoroscopic Analysis of Swallowing Physiology and Function in Individuals With Chronic Obstructive Pulmonary Disease

Purpose Dysphagia is a serious extra pulmonary manifestation of chronic obstructive pulmonary disease (COPD). However, the nature of abnormalities in swallowing physiology in COPD has yet to be clearly established. We explored the frequency of swallowing measures outside the healthy reference range in adults with COPD. Method Participants were 28 adults aged 41-79 years (18 men, 20 women) with stable COPD. Disease severity was classified as GOLD (Global Initiative For Chronic Obstructive Lung Disease) Stages 1 (4%), 2 (25%), 3 (53%), and 4 (18%). Participants underwent a videofluoroscopy and swallowed 20% w/v thin barium in, followed by 20% w/v mildly, moderately, and extremely thick barium prepared with a xanthan gum thickener. Blinded duplicate ratings of swallowing safety, efficiency, kinematics, and timing were performed according to the ASPEKT method (Analysis of Swallowing Physiology: Events, Kinematics and Timing). Comparison data for healthy adults aged < 60 years were extracted from an existing data set. Chi-square and Fisher's exact tests compared the frequencies of measures falling < 1 SD/ > 1 SD from mean reference values (or < the first or > the third quartile for skewed parameters). Results Participants with COPD did not display greater frequencies of penetration-aspiration, but they were significantly more likely (p < .05) to display incomplete laryngeal vestibule closure (LVC), longer time-to-LVC, and shorter LVC duration. They also displayed significantly higher frequencies of short upper esophageal sphincter opening, reduced pharyngeal constriction, and pharyngeal residue. Conclusion This analysis reveals differences in swallowing physiology in patients with stable COPD characterized by impaired safety related to the mechanism, timing, and duration of LVC and by impaired swallowing efficiency with increased pharyngeal residue related to poor pharyngeal constriction.

Clinical Utility of Measuring Inspiratory Neural Drive During Cardiopulmonary Exercise Testing (CPET)

Cardiopulmonary exercise testing (CPET) has traditionally included ventilatory and metabolic measurements alongside electrocardiographic characterization; however, research increasingly acknowledges the utility of also measuring inspiratory neural drive (IND) through its surrogate measure of diaphragmatic electromyography (EMGdi). While true IND also encompasses the activation of non-diaphragmatic respiratory muscles, the current review focuses on diaphragmatic measurements, providing information about additional inspiratory muscle groups for context where appropriate. Evaluation of IND provides mechanistic insight into the origins of dyspnea and exercise limitation across pathologies; yields valuable information reflecting the integration of diverse mechanical, chemical, locomotor, and metabolic afferent signals; and can help assess the efficacy of therapeutic interventions. Further, IND measurement during the physiologic stress of exercise is uniquely poised to reveal the underpinnings of physiologic limitations masked during resting and unloaded breathing, with important information provided not only at peak exercise, but throughout exercise protocols. As our understanding of IND presentation across varying conditions continues to grow and methods for its measurement become more accessible, the translation of these principles into clinical settings is a logical next step in facilitating appropriate and nuanced management tailored to each individual's unique physiology. This review provides an overview of the current state of understanding of IND measurement during CPET: its origins, known patterns of behavior and links with dyspnea in health and major respiratory diseases, and the possibility of expanding this approach to applications beyond exercise.

Assessing the impact of posture on diaphragm morphology and function using an open upright MRI system-A pilot study

PURPOSE

The diaphragm is the most important muscle of respiration. Disorders of the diaphragm can have a deleterious impact on respiratory function. We aimed to evaluate the use of an open-configuration upright low-field MRI system to assess diaphragm morphology and function in patients with bilateral diaphragm weakness (BDW) and chronic obstructive pulmonary disease (COPD) with hyperinflation.

METHOD

The study was approved by the National Research Ethics Committee, and written consent was obtained. We recruited 20 healthy adult volunteers, six subjects with BDW, and five subjects with COPD with hyperinflation. We measured their vital capacity in the upright and supine position, after which they were scanned on the 0.5 T MRI system during 10-s breath-holds at end-expiration and end-inspiration in both positions. We developed and applied image analysis methods to measure the volume under the dome, maximum excursion of hemidiaphragms, and anterior-posterior and left-right extension of the diaphragm.

RESULTS

All participants were able to complete the scanning protocol. The patients found scanning in the upright position more comfortable than the supine position. All differences in the supine inspiratory-expiratory parameters, excluding left-right extension, were significantly smaller in the BDW and COPD groups compared with healthy volunteers. No significant correlation was found between the postural change in diaphragm morphology and vital capacity in either group.

CONCLUSION

Our combined upright-supine MR imaging approach facilitates the assessment of the impact of posture on diaphragm morphology and function in patients with BDW and those with COPD with hyperinflation.

Abnormal Activity of Neck Inspiratory Muscles during Sleep as a Prognostic Indicator in Chronic Obstructive Pulmonary Disease

Rationale: In patients with chronic obstructive pulmonary disease (COPD), increased activity of neck inspiratory muscles has been reported as a compensatory response to hyperinflation-related diaphragmatic dysfunction. The persistence of this activity during sleep could attenuate sleep-related hypoventilation and also negatively impact sleep and clinical outcomes.Objectives: To assess the persistence of neck-muscle activity during sleep in patients with COPD recovering from severe exacerbations (i.e., requiring hospitalization) and its impact on sleep quality and recurrence of exacerbations.Methods: Video polysomnography with neck-muscle EMG was performed in patients with COPD who were recovering from a severe exacerbation. The follow-up period lasted 6 months to record the next severe exacerbation.Measurements and Main Results: Twenty-nine patients were included in the study (median [25th-75th percentile] age, 71 [64-72] yr; 55% male; body mass index, 24 [21-29]; FEV₁% predicted, 37 [29-45]; and BODE [body mass index, airflow obstruction, dyspnea, and exercise] index, 6 [5-7]). Twenty-six of these patients exhibited sleep-related neck-muscle activity, which was intermittent (limited to stage 3 sleep) in 17 and permanent throughout sleep in 9. α-Delta EEG activity during stage 3 sleep was observed in 87% of the patients. Compared with patients with no or intermittent neck-muscle activity, those with permanent neck-muscle activity showed more disrupted sleep, had experienced more exacerbations in the previous year, and suffered their next severe exacerbation earlier.Conclusions: Sleep-related neck-muscle activity occurs frequently in patients with COPD who are recovering from a severe exacerbation and seems to negatively affect sleep quality and prognosis; therefore, identification of this activity might improve COPD management after a severe exacerbation.

Diaphragmatic motor cortex hyperexcitability in patients with chronic obstructive pulmonary disease

Background and objectives

Respiratory muscles dysfunction has been reported in COPD. Transcranial magnetic stimulation (TMS) has been used for assessing the respiratory corticospinal pathways particularly of diaphragm. We aimed to study the cortico-diaphragmatic motor system changes in COPD using TMS and to correlate the findings with the pulmonary function.

Methods

A case control study recruited 30 stable COPD from the out-patient respiratory clinic of Main Alexandria University hospital- Egypt and 17 healthy control subjects who were subjected to spirometry. Cortical conduction of the diaphragm was performed by TMS to all participants followed by cervical magnetic stimulation of the phrenic nerve roots. Diaphragmatic resting motor threshold (DRMT), cortical motor evoked potential latency (CMEPL), CMEP amplitude (CMEPA), peripheral motor evoked potential latency (PMEPL), PMEP amplitude (PMEPA) and central motor conduction time (CMCT) were measured.

Results

66.7% of COPD patients had severe and very severe COPD with median age of 59 (55–63) years. There was statistically significant bilateral decrease in DRMT, CMEPA and PMEPA in COPD group versus healthy subjects and significant increase in CMEPL and PMEPL (p <0.01). Left CMCT was significantly prolonged in COPD group versus healthy subjects (p <0.0001) but not right CMCT. Further, there was significant increase in CMEPL and CMCT of left versus right diaphragm in COPD group (p = 0.003 and 0.001 respectively) that inversely correlated with FEV₁% and FVC% predicted. Right and left DRMT were insignificantly different in COPD group (p >0.05) but positively correlated with FEV₁/FVC, FEV₁% and FVC% predicted.

Conclusion

Central cortico-diaphragmatic motor system is affected in COPD patients with heterogeneity of both sides that is correlated with pulmonary function.

Significance

Coticospinal pathway affection could be a factor for development of diaphragmatic dysfunction in COPD patients accordingly its evaluation could help in personalization of COPD management especially pulmonary rehabilitation programs.

PATHOLOGIC PHYSIOLOGY OF EXACERBATIONS OF CHRONIC OBSTRUCTIVE PULMONARY DISEASE

The lecture describes the mechanisms of deterioration of respiratory exchange during exacerbation of chronic obstructive pulmonary disease (COPD). It has been demonstrated that the rapid diagnosis and treatment of exacerbations is an important part of COPD management. The restriction of expiratory airflow followed by the increased dynamic pulmonary hyperinflation seems to be the most important pathophysiological mechanism in COPD exacerbation, which has catastrophic consequences for the respiratory system with respect to respiratory mechanics and gas exchange. In some patients, associated disorders of cardiopulmonary interactions also undoubtedly play an important role.

Effect of Abdominal Binding on Diaphragmatic Neuromuscular Efficiency, Exertional Breathlessness, and Exercise Endurance in Chronic Obstructive Pulmonary Disease

We tested the hypothesis that abdominal binding (AB) would reduce breathlessness and improve exercise tolerance by enhancing neuromuscular efficiency of the diaphragm during exercise in adults with chronic obstructive pulmonary disease (COPD). In a randomized, controlled, crossover trial, 20 adults with COPD (mean ± SD FEV₁, 60 ± 16% predicted) completed a symptom-limited constant-load cycle endurance exercise test at 75% of their peak incremental power output with concomitant measures of the diaphragm electromyogram (EMGdi) and respiratory pressures without (CTRL) vs. with AB sufficient to increase end-expiratory gastric pressure (Pga,ee) by 6.7 ± 0.3 cmH₂O at rest. Compared to CTRL, AB enhanced diaphragmatic neuromuscular efficiency during exercise (p < 0.05), as evidenced by a 25% increase in the quotient of EMGdi to tidal transdiaphragmatic pressure swing. By contrast, AB had no demonstrable effect on exertional breathlessness and exercise tolerance; spirometry and plethysmography-derived pulmonary function test parameters at rest; and cardiac, metabolic, breathing pattern, inspiratory reserve volume and EMGdi responses during exercise (all p > 0.05 vs. CTRL). In conclusion, enhanced neuromuscular efficiency of the diaphragm during exercise with AB was not associated with relief of exertional breathlessness and improved exercise tolerance in adults with COPD. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT01852006.

Effect of Lung Volume Reduction Surgery on Respiratory Muscle Strength in Advanced Emphysema

Background: Long-term effects of lung volume reduction surgery (LVRS) on respiratory muscle strength and effects of age, sex, and emphysema pattern on these changes are unknown. Therefore, we aimed to determine the long-term effect of LVRS on respiratory muscle strength changes in severe emphysema. Methods: The National Emphysema Treatment Trial was a prospective controlled multicentered trial, comparing LVRS to optimal medical treatment on survival and maximal exercise capacity. We examined percentage change in maximum inspiratory pressure (MIP) from baseline to 36 months follow-up to determine impact of LVRS as well as age, sex, emphysema pattern and exercise capacity on changes in MIP compared to medical treatment. Results: LVRS individuals had significantly greater increases in MIP from baseline compared to medical individuals at all follow-ups (LVRS 19.8 ± 42.3%, medical 3.2 ± 29.3%, p<0.0001, 12 months). The LVRS group had significant decreases in total lung capacity (TLC), residual volume (RV), functional residual capacity (FRC) and RV/TLC compared to the medical arm at all follow-up periods. Males and individuals 65-70 years of age had significantly greater increases in MIP following LVRS compared to the medical arm at all follow-ups; this same relationship was seen at up to 24 months for low exercise capacity, upper lobe predominant emphysema. Conclusions: LVRS significantly increases inspiratory muscle strength up to 3 years post-operatively, with male sex, age 65-70 years and low exercise capacity, upper lobe predominant emphysema especially associated with increased MIP. Inspiratory muscle strength increases were associated with decreases in non-invasive markers of dynamic hyperinflation, suggesting that LVRS allows inspiratory muscles to return to their optimal length-tension relationship.

The Link between Reduced Inspiratory Capacity and Exercise Intolerance in Chronic Obstructive Pulmonary Disease

Low inspiratory capacity (IC), chronic dyspnea, and reduced exercise capacity are inextricably linked and are independent predictors of increased mortality in chronic obstructive pulmonary disease. It is no surprise, therefore, that a major goal of management is to improve IC by reducing lung hyperinflation to improve respiratory symptoms and health-related quality of life. The negative effects of lung hyperinflation on respiratory muscle and cardiocirculatory function during exercise are now well established. Moreover, there is growing appreciation that a key mechanism of exertional dyspnea in chronic obstructive pulmonary disease is critical mechanical constraints on tidal volume expansion during exercise when resting IC is reduced. Further evidence for the importance of lung hyperinflation comes from multiple studies, which have reported the clinical benefits of therapeutic interventions that reduce lung hyperinflation and increase IC. A reduced IC in obstructive pulmonary disease is further eroded by exercise and contributes to ventilatory limitation and dyspnea. It is an important outcome for both clinical and research studies.

Randomized controlled study of intraincisional infiltration versus intraperitoneal instillation of standardized dose of ropivacaine 0.2% in post-laparoscopic cholecystectomy pain: Do we really need high doses of local anesthetics-time to rethink!

BACKGROUND

Earlier studies done to compare the efficacy of use of local anesthetics at intraperitoneal location versus intraincisional use had utilized equal amount of drugs at the two locations, usually 10-20 ml. Using this large amount of drug in the small space of intraincisional location as compared to similar amount of drug in large intraperitoneal space created an inadvertent bias in favor of patients receiving the drug intraincisionally so these patients naturally experienced less pain.

AIMS AND OBJECTIVES

To conduct a randomized, triple-blind, placebo-controlled study by standardizing dose of local anesthetic, to compare the effectiveness of intraperitoneal against intraincisional use of ropivacaine 0.2% for post-laparoscopic cholecystectomy pain relief.

MATERIALS AND METHODS

294 patients underwent elective 4-port laparoscopic cholecystectomy. Patients were triple blindly randomized. All patients received ~ 23 ml of solution, of which 20 ml was given intraperitoneally (1 ml/cm; 16 ml along right hemi-dome and 4 ml in gall bladder fossa) and ~ 3 ml intraincisionally (1 ml/cm of length of incision). Solution was either normal saline or drug (0.2% ropivacaine) depending on the group [controls (n = 86), intraperitoneal group (n = 100), and intraincisional group (n = 108)]. 5 different pain scales were used for assessment of overall pain. Pain scores were assessed at 5 points of time.

RESULTS

Patients in intraincisional group showed significantly less overall pain and rescue analgesia requirement (p < 0.05). Intraincisional group showed significantly less overall pain (p < 0.05) as compared to intraperitoneal group; however, use of rescue analgesia was comparable in the two groups (p > 0.05); and shoulder pain was significantly less in intraperitoneal group (p < 0.05).

CONCLUSION

The intraincisional use of injection ropivacaine at its minimum concentration of 0.2% in minimal doses of 1 ml/cm at the end of procedure provides significantly more post-operative analgesia as compared to intraperitoneal group and controls. However, for controlling shoulder pain, the use of intraperitoneal ropivacaine is desirable.

A New Method for Diaphragmatic Maximum Relaxation Rate Ultrasonographic Measurement in the Assessment of Patients With Diaphragmatic Dysfunction

Measurements of ultrasound diaphragmatic motion, amplitude, force, and velocity of contraction may provide important and essential information about diaphragmatic fatigue, weakness, or paralysis. In this paper, we propose and evaluate a semi-automated analysis system for measuring the diaphragmatic motion and estimating the maximum relaxation rate (MRR_SAUS) from ultrasound M-mode images of the diaphragmatic muscle. The system was evaluated on 27 M-mode ultrasound images of the diaphragmatic muscle [20 with no resistance (NRES) and 7 with resistance (RES)]. We computed semi-automated ultrasound MRR measurements on all NRES/RES images, using the proposed system (MRR_SAUS = 3.94 ± 0.91/4.98 ± 1.98 [1/s]), and compared them with the manual measurements made by a clinical expert (MRR_MUS = 2.36 ± 1.19/5.8 ± 2.1 [1/s],) and those made by a reference manual method (MRR_MB = 3.93 ± 0.89/3.73 ± 0.52 [1/sec], performed manually with the Biopac system. MRR_SAUS and MRR_MB measurements were not statistically significantly different for NRES and RES subjects but were significantly different with the MRR-MUS measurements made by the clinical expert. It is anticipated that the proposed system might be used in the future in the clinical practice in the assessment and follow up of patients with diaphragmatic weakness or paralysis. It may thus potentially help to understand post-operative pulmonary dysfunction or weaning failure from mechanical ventilation. Further validation and additional experimentation in a larger sample of images and different patient groups is required for further validating the proposed system.

Obesity modulates diaphragm curvature in subjects with and without COPD

Obesity is a common comorbidity of chronic obstructive pulmonary disease (COPD) and has been associated with worse outcomes. However, it is unknown whether the interaction between obesity and COPD modulates diaphragm shape and consequently its function. The body mass index (BMI) has been used as a correlate of obesity. We tested the hypothesis that the shape of the diaphragm muscle and size of the ring of its insertion in non-COPD and COPD subjects are modulated by BMI. We recruited 48 COPD patients with postbronchiodilator forced expiratory volume in 1 s (FEV1)-to-forced vital capacity (FVC) < 0.7 and 29 age-matched smoker/exsmoker control (non-COPD) subjects, who underwent chest computed tomography (CT) at lung volumes ranging from functional residual capacity (FRC) to total lung capacity (TLC). We then computed maximum principal diaphragm curvature in the midcostal region of the left hemidiaphragm at the end of inspiration during quiet breathing (EI) and at TLC. The radius of maximum curvature of diaphragm muscle increased with BMI in both COPD and non-COPD subjects. The size of diaphragm ring of insertion on the chest wall also increased significantly with increasing BMI. Surprisingly, COPD severity did not appear to cause significant alteration in diaphragm shape except in normal-weight subjects at TLC. Our data uncovered important factors such as BMI, the size of the diaphragm ring of insertion, and disease severity that modulate the structure of the ventilatory pump in non-COPD and COPD subjects.

Relação entre a mobilidade diafragmática e as curvaturas da coluna vertebral em pacientes com doença pulmonar obstrutiva crônica

RESUMO Na doença pulmonar obstrutiva crônica (DPOC), os pacientes podem apresentar redução da mobilidade diafragmática e uma série de compensações na coluna torácica, nas cinturas escapular e pélvica. No entanto, não está clara a relação da mobilidade diafragmática com alterações posturais na coluna vertebral e na pelve desses indivíduos. Objetivou-se verificar se existe relação entre a mobilidade diafragmática com as curvaturas da coluna vertebral de pacientes com DPOC e em indivíduos aparentemente saudáveis. Foram avaliados 22 pacientes com DPOC e 22 indivíduos aparentemente saudáveis. As avaliações foram: antropometria, espirometria, mobilidade diafragmática e avaliação postural. Foram analisadas quatro alterações posturais: lordose cervical, cifose torácica, lordose lombar, posição pélvica. Não houve diferença estatisticamente significativa entre os grupos, em relação às variáveis idade, massa corporal, estatura e IMC, confirmando que os grupos foram pareados. Não houve diferença estatisticamente significante em nenhuma das variáveis referentes às curvaturas da coluna vertebral e à posição da pelve entre os grupos estudados. No grupo DPOC houve correlação da mobilidade diafragmática com a cifose torácica (r=-0,543; p=0,009). Já em relação ao grupo de indivíduos aparentemente saudáveis, não houve correlação da mobilidade quanto os indivíduos aparentemente saudáveis apresentaram os mesmos ângulos de curvatura da coluna vertebral e a mesma posição da pelve. Contudo, os pacientes com DPOC apresentaram relação entre a mobilidade diafragmática e o ângulo da curvatura torácica.

Relationship between costovertebral joint kinematics and lung volume in supine humans

This study investigates the relationship between the motion of the first ten costovertebral joints (CVJ) and lung volume over the inspiratory capacity (IC) using detailed kinematic analysis in a sample of 12 asymptomatic subjects. Retrospective codified spiral-CT data obtained at total lung capacity (TLC), middle of inspiratory capacity (MIC) and at functional residual capacity (FRC) were analysed. CVJ 3D kinematics were processed using previously-published methods. We tested the influence of the side, CVJ level and lung volume on CVJ kinematics. In addition, the correlations between anthropologic/pulmonary variables and CVJ kinematics were analysed. No linear correlation was found between lung volumes and CVJ kinematics. Major findings concerning 3D kinematics can be summarized as follows: 1) Ranges-of-motion decrease gradually with increasing CVJ level; 2) rib displacements are significantly reduced at lung volumes above the MIC and do not differ between CVJ levels; 3) the axes of rotation of the ribs are similarly oriented for all CVJ levels.

Airflow limitation is accompanied by diaphragm dysfunction

Chronic airflow limitation, caused by chronic obstructive pulmonary disease (COPD) or by asthma, is believed to change the shape and the position of the diaphragm due to an increase in lung volume. We have made a comparison of magnetic resonance imaging (MRI) of diaphragm in supine position with pulmonary functions, respiratory muscle function and exercise tolerance. We have studied the differences between patients with COPD, patients with asthma, and healthy subjects. Most interestingly we found the lung hyperinflation leads to the changes in diaphragmatic excursions during the breathing cycle, seen in the differences between the maximal expiratory diaphragm position (DPex) in patients with COPD and control group (p=0.0016). The magnitude of the diaphragmatic dysfunction was significantly related to the airflow limitation expressed by the ratio of forced expiratory volume in 1 s to slow vital capacity (FEV(1)/SVC), (%, p=0.0007); to the lung hyperinflation expressed as the ratio of the residual volume to total lung capacity (RV/TLC), (%, p=0.0018) and the extent of tidal volume constrain expressed as maximal tidal volume (V(Tmax)), ([l], p=0.0002); and the ratio of tidal volume to slow vital capacity (V(T)/SVC), (p=0.0038) during submaximal exercise. These results suggest that diaphragmatic movement fails to contribute sufficiently to the change in lung volume in emphysema. Tests of respiratory muscle function were related to the position of the diaphragm in deep expiration, e.g. neuromuscular coupling (P(0.1)/V(T)) (p=0.0232). The results have shown that the lung volumes determine the position of the diaphragm and function of the respiratory muscles. Chronic airflow limitation seems to change the position of the diaphragm, which thereafter influences inspiratory muscle function and exercise tolerance. There is an apparent relationship between the position of the diaphragm and the pulmonary functions and exercise tolerance.

3D lung motion assessments on inspiratory/expiratory thin-section CT: Capability for pulmonary functional loss of smoking-related COPD in comparison with lung destruction and air trapping

PURPOSE

To evaluate the utility of three-dimensional (3D) lung motion on inspiratory and expiratory CT for pulmonary functional loss in smoking-related COPD in comparison with lung destruction and air trapping assessments.

METHOD AND MATERIALS

Forty-four consecutive smokers and COPD patients prospectively underwent inspiratory and expiratory CT. A 3D motion vector map was generated from these CTs, and regional motion magnitudes were measured at the horizontal axis (X-axis), the ventrodorsal axis (Y-axis), and the craniocaudal axis (Z-axis). All mean magnitudes within the entire lung (MMLX, MMLY, and MMLZ) were normalized by expiratory CT lung volume. Moreover, CT-based functional lung volume (FLV) on inspiratory CT and air trapping lung volume (ATLV) on expiratory CT were assessed quantitatively. To evaluate the capability for pulmonary function loss assessment, all MMLs were correlated with pulmonary function tests. Then, discrimination analysis was performed to determine the concordance capability for clinical stage, and correct classification capabilities were compared by means of McNemar's test.

RESULTS

Multiple regression analysis showed MMLY (β=0.657, p<0.001) and FLV (β=0.375, p=0.019) were correlated with percentage of predicted forced expiratory volume in 1 second. Correct classification capabilities using patient characteristics and MMLs (68.2 (30/44)%) were significantly higher than those obtained by patient characteristics, FLV, and ATLV (54.5 (24/44)%), p=0.031).

CONCLUSION

3D lung motion parameter assessment is useful for smoking-related COPD assessment as well as lung parenchymal destruction and/or air trapping evaluations.

Effect of total lung capacity and gender on CT densitometry indexes

OBJECTIVE

Testing the hypothesis that CT densitometry indexes could be influenced by total lung capacity (TLC), gender and height in normal individuals.

METHODS

In this ethics committee-approved prospective study, 100 healthy non-smoking volunteers who provided written informed consent were included. From a helical scan of the chest, the relative area (RA) of the lung with attenuation coefficients lower than -960 HU and the 1st and 15th percentiles of the distribution of attenuation coefficients were calculated. Regression lines were drawn between each CT index and volunteers' height and total TLC at CT.

RESULTS

In males, there was no statistically significant correlation between any CT index and height. In females, there was a statistically significant correlation between the RA of the lung with attenuation coefficients lower than -960 HU and the 1st percentile and height but not with the 15th percentile. For both genders, there were significant correlations between all CT indexes and TLC. The relationships between CT indexes and TLC were different in males and females.

CONCLUSION

CT indexes are correlated with TLC and height but more closely with TLC than with height, and differently in males and females.

ADVANCES IN KNOWLEDGE

CT indexes are influenced by TLC, gender and height in normal individuals and are more closely correlated with TLC than with height. The relationships between CT indexes and TLC or height are different in males and females. CT indexes used to quantify emphysema should thus be adjusted according to TLC and gender.

Analysis of diaphragmatic movement before and after pulmonary rehabilitation using fluoroscopy imaging in patients with COPD

Background

The diaphragm is the principal inspiratory muscle. The purpose of this study was to assess improvements in diaphragmatic movement before and after pulmonary rehabilitation in patients with chronic obstructive pulmonary disease (COPD), using a fluoroscopy-guided chest X-ray.

Patients and methods

Among 117 patients with COPD receiving pulmonary rehabilitation who underwent the initial fluoroscopy-guided chest X-ray and pulmonary function test, 37 of those patients who underwent both initial and follow-up fluoroscopy and pulmonary function tests were enrolled in this study. After hospital education, participants received pulmonary rehabilitation through regular home-based training for at least 3 months by the same physiatrist. We assessed the changes in diaphragm area with fluoroscopy-guided posteroanterior chest X-rays between pre- and postpulmonary rehabilitation. To minimize radiation hazards for subjects, the exposure time for fluoroscopy to take chest X-rays was limited to less than 5 seconds.

Results

There were significant improvements (2,022.8±1,548.3 mm² to 3,010.7±1,495.6 mm² and 2,382.4±1,475.9 mm² to 3,315.9±1,883.5 mm²; right side P=0.001 and left side P=0.019, respectively) in diaphragmatic motion area during full inspiration and expiration in both lungs after pulmonary rehabilitation. Pulmonary function tests showed no statistically significant difference between pre- and postpulmonary rehabilitation.

Conclusion

The study suggests that the strategy to assess diaphragm movement using fluoroscopy is a relatively effective tool for the evaluation of pulmonary rehabilitation in COPD patients in terms of cost and time savings compared with computed tomography or magnetic resonance imaging.

Effect of anatomical landmark perturbation on mean helical axis parameters of in vivo upper costovertebral joints

The literature concerning quantification of costovertebral joint (CVJ) motion under in vivo conditions is scarce. Most papers concerning this topic are related to ex vivo loading conditions. In vivo protocols are available from the literature to determine rib and vertebra kinematics but new developments are needed to improve data processing concerning CVJ behaviour obtained from discrete breathing positions showing limiting ranges-of-motion and sensitive to noise. Data from previous work were used to implement a method analyzing mean helical axis (MHA) and pivot point parameters of the CVJ complexes. Several levels of noises were estimated within Monte-Carlo simulations to optimize MHA results. MHA parameters were then used to transform and define a CVJ-specific local coordinate system. This study proposes an improvement for CVJ kinematics processing and description from in vivo data obtained from computed tomography. This methodology emphasizes the possibility to work with variability of MHA parameters using Monte-Carlo procedures on anatomical landmark coordinates and to define a local coordinate system from this particular joint behaviour. Results from the CVJ joint model are closer to a hinge joint (secondary motions inferior to 3°) when anatomical frames are expressed from MHA orientation. MHA orientation and position data obtained from the proposed method are relevant according to angular dispersion obtained (from 7.5° to 13.9°) and therefore relevant to define behaviour of CVJ.

In vivo thorax 3D modelling from costovertebral joint complex kinematics

BACKGROUND

The costovertebral joint complex is mechanically involved in both respiratory function and thoracic spine stability. The thorax has been studied for a long time to understand its involvement in the physiological mechanism leading to specific gas exchange. Few studies have focused on costovertebral joint complex kinematics, and most of them focused on experimental in vitro analysis related to loading tests or global thorax and/or lung volume change analysis. There is however a clinical need for new methods allowing to process in vivo clinical data. This paper presents results from in vivo analysis of the costovertebral joint complex kinematics from clinically-available retrospective data.

METHODS

In this study, in vivo spiral computed tomography imaging data were obtained from 8 asymptomatic subjects at three different lung volumes (from total lung capacity to functional residual capacity) calibrated using a classical spirometer. Fusion methods including 3D modelling and kinematic analysis were used to provide 3D costovertebral joint complex visualization for the true ribs (i.e., first seven pairs of ribs).

FINDINGS

The 3D models of the first seven pairs of costovertebral joint complexes were obtained. A continuous kinematics simulation was interpolated from the three discrete computerized tomography positions. Helical axis representation was also achieved.

INTERPRETATION

Preliminary results show that the method leads to meaningful and relevant results for clinical and pedagogical applications. Research in progress compares data from a sample of healthy volunteers with data collected from patients with cystic fibrosis to obtain new insights about the costovertebral joint complex range of motion and helical axis assessment in different pathological conditions.

Influence of Hamstring and Abdominal Muscle Activation on a Positive Ober's Test in People with Lumbopelvic Pain

PURPOSE

To assess the immediate effect of hamstring and abdominal activation on pain levels as measured by the Numeric Pain Scale (NPS) and hip range of motion as measured by Ober's Test in people with lumbopelvic pain.

METHODS

Thirteen participants with lumbopelvic pain and positive Ober's Tests completed an exercise developed by the Postural Restoration Institute™ to recruit hamstrings and abdominal muscles.

RESULTS

There was a significant increase in passive hip-adduction angles (p<0.01) and decrease in pain (p<0.01) immediately after the intervention.

CONCLUSION

Specific exercises that activate hamstrings and abdominal muscles appear to immediately improve Ober's Test measurements and reduce pain as measured by the NPS in people with lumbo-pelvic pain. Hamstring/abdominal activation, rather than iliotibial band stretching, may be an effective intervention for addressing lumbopelvic pain and a positive Ober's Test.

Ventilatory failure, ventilator support, and ventilator weaning

The development of acute ventilatory failure represents an inability of the respiratory control system to maintain a level of respiratory motor output to cope with the metabolic demands of the body. The level of respiratory motor output is also the main determinant of the degree of respiratory distress experienced by such patients. As ventilatory failure progresses and patient distress increases, mechanical ventilation is instituted to help the respiratory muscles cope with the heightened workload. While a patient is connected to a ventilator, a physician's ability to align the rhythm of the machine with the rhythm of the patient's respiratory centers becomes the primary determinant of the level of rest accorded to the respiratory muscles. Problems of alignment are manifested as failure to trigger, double triggering, an inflationary gas-flow that fails to match inspiratory demands, and an inflation phase that persists after a patient's respiratory centers have switched to expiration. With recovery from disorders that precipitated the initial bout of acute ventilatory failure, attempts are made to discontinue the ventilator (weaning). About 20% of weaning attempts fail, ultimately, because the respiratory controller is unable to sustain ventilation and this failure is signaled by development of rapid shallow breathing. Substantial advances in the medical management of acute ventilatory failure that requires ventilator assistance are most likely to result from research yielding novel insights into the operation of the respiratory control system.

Severe acute asthma exacerbation in children: a stepwise approach for escalating therapy in a pediatric intensive care unit

OBJECTIVES

An increasing prevalence of pediatric asthma has led to increasing burdens of critical illness in children with severe acute asthma exacerbations, often leading to respiratory distress, progressive hypoxia, and respiratory failure. We review the definitions, epidemiology, pathophysiology, and clinical manifestations of severe acute asthma, with a view to developing an evidence-based, stepwise approach for escalating therapy in these patients.

METHODS

Subject headings related to asthma, status asthmaticus, critical asthma, and drug therapy were used in a MEDLINE search (1980-2012), supplemented by a manual search of personal files, references cited in the reviewed articles, and treatment algorithms developed within Le Bonheur Children's Hospital.

RESULTS

Patients with asthma require continuous monitoring of their cardiorespiratory status via noninvasive or invasive devices, with serial clinical examinations, objective scoring of asthma severity (using an objective pediatric asthma score), and appropriate diagnostic tests. All patients are treated with β-agonists, ipratropium, and steroids (intravenous preferable over oral preparations). Patients with worsening clinical status should be progressively treated with continuous β-agonists, intravenous magnesium, helium-oxygen mixtures, intravenous terbutaline and/or aminophylline, coupled with high-flow oxygen and non-invasive ventilation to limit the work of breathing, hypoxemia, and possibly hypercarbia. Sedation with low-dose ketamine (with or without benzodiazepines) infusions may allow better toleration of non-invasive ventilation and may also prepare the patient for tracheal intubation and mechanical ventilation, if indicated by a worsening clinical status.

CONCLUSIONS

Severe asthma can be a devastating illness in children, but most patients can be managed by using serial objective assessments and the stepwise clinical approach outlined herein. Following multidisciplinary education and training, this approach was successfully implemented in a tertiary-care, metropolitan children's hospital.

Postoperative Respiratory Muscle Dysfunction

Postoperative pulmonary complications are responsible for significant increases in hospital cost as well as patient morbidity and mortality; respiratory muscle dysfunction represents a contributing factor. Upper airway dilator muscles functionally resist the upper airway collapsing forces created by the respiratory pump muscles. Standard perioperative medications (anesthetics, sedatives, opioids, and neuromuscular blocking agents), interventions (patient positioning, mechanical ventilation, and surgical trauma), and diseases (lung hyperinflation, obesity, and obstructive sleep apnea) have differential effects on the respiratory muscle subgroups. These effects on the upper airway dilators and respiratory pump muscles impair their coordination and function and can result in respiratory failure. Perioperative management strategies can help decrease the incidence of postoperative respiratory muscle dysfunction. Such strategies include minimally invasive procedures rather than open surgery, early and optimal mobilizing of respiratory muscles while on mechanical ventilation, judicious use of respiratory depressant anesthetics and neuromuscular blocking agents, and noninvasive ventilation when possible.

No room to breathe: the importance of lung hyperinflation in COPD

Patients with chronic obstructive pulmonary disease (COPD) are progressively limited in their ability to undertake normal everyday activities by a combination of exertional dyspnoea and peripheral muscle weakness. COPD is characterised by expiratory flow limitation, resulting in air trapping and lung hyperinflation. Hyperinflation increases acutely under conditions such as exercise or exacerbations, with an accompanying sharp increase in the intensity of dyspnoea to distressing and intolerable levels. Air trapping, causing increased lung hyperinflation, can be present even in milder COPD during everyday activities. The resulting activity-related dyspnoea leads to a vicious spiral of activity avoidance, physical deconditioning, and reduced quality of life, and has implications for the early development of comorbidities such as cardiovascular disease. Various strategies exist to reduce hyperinflation, notably long-acting bronchodilator treatment (via reduction in flow limitation and improved lung emptying) and an exercise programme (via decreased respiratory rate, reducing ventilatory demand), or their combination. Optimal bronchodilation can reduce exertional dyspnoea and increase a patient's ability to exercise, and improves the chance of successful outcome of a pulmonary rehabilitation programme. There should be a lower threshold for initiating treatments appropriate to the stage of the disease, such as long-acting bronchodilators and an exercise programme for patients with mild-to-moderate disease who experience persistent dyspnoea.

The effect of posture on asynchronous chest wall movement in COPD

Chronic obstructive pulmonary disease (COPD) patients often show asynchronous movement of the lower rib cage during spontaneous quiet breathing and exercise. We speculated that varying body position from seated to supine would influence rib cage asynchrony by changing the configuration of the respiratory muscles. Twenty-three severe COPD patients (forced expiratory volume in 1 s = 32.5 ± 7.0% predicted) and 12 healthy age-matched controls were studied. Measurements of the phase shift between upper and lower rib cage and between upper rib cage and abdomen were performed with opto-electronic plethysmography during quiet breathing in the seated and supine position. Changes in diaphragm zone of apposition were measured by ultrasounds. Control subjects showed no compartmental asynchronous movement, whether seated or supine. In 13 COPD patients, rib cage asynchrony was noticed in the seated posture. This asynchrony disappeared in the supine posture. In COPD, upper rib cage and abdomen were synchronous when seated, but a strong asynchrony was found in supine. The relationships between changes in diaphragm zone of apposition and volume variations of chest wall compartments supported these findings. Rib cage paradox was noticed in approximately one-half of the COPD patients while seated, but was not related to impaired diaphragm motion. In the supine posture, the rib cage paradox disappeared, suggesting that, in this posture, diaphragm mechanics improves. In conclusion, changing body position induces important differences in the chest wall behavior in COPD patients.

[Respiratory pump failure. Clinical symptoms, diagnostics and therapy]

The total anatomical and functional apparatus which allows normal ventilation of the lungs is known as the respiratory pump. An insufficiency of this system, which can be caused by a multitude of reasons, primarily affects the inspiratory musculature and especially the diaphragm. One of the essential clinical characteristics is rapid shallow breathing. Exhaustion of the repiratory musculature due to acute respiratory insufficiency is normally clinically registered but can also be functionally determined in particular by the maximum static inspiratory closed mouth pressure. A further option is invasive measurement of the transdiaphragmal pressure, which however is not suitable as a routine procedure. Mechanical ventilation is used as treatment of respiratory pump insufficiency independent of the cause. This is initially a non-invasive procedure but if unsuccessful intubation and invasive ventilation are indicated. The technical developments in the field of extracorporeal gas exchange systems are very promising. However, in view of the insufficient data, ventilation procedures using masks and tubes still remain the first choice methods.

Efficacy of diaphragmatic breathing in patients with chronic obstructive pulmonary disease

This study investigated the effects of diaphragmatic breathing (DB) on ventilation and breathing pattern, seeking to identify predictors of its efficacy in patients with chronic obstructive pulmonary disease (COPD). Twenty-nine patients with moderate and severe COPD were monitored using respiratory inductance plethysmography and metabolic gas analysis. After 4 minutes of natural breathing, subjects completed 2 minutes of DB followed by 4 minutes of natural breathing. Dyspnea was measured using a visual analogue scale. Diaphragmatic mobility was assessed using chest radiography. DB was associated with a significant increase in tidal volume and reduction in breathing frequency, leading to higher ventilation and oxygen saturation, with a reduction in dead space ventilation and ventilatory equivalent for carbon dioxide. A total of 10 subjects with moderate (5) and severe (5) COPD performed DB with asynchronous thoracoabdominal motion, worsening the dyspnea, and decreasing the gain of tidal volume. Diaphragmatic mobility, inspiratory muscular strength, lower scores for dyspnea and hypoxemia as well as coordinated thoracoabdominal motion are associated with effective DB. In patients with COPD, DB can improve breathing pattern and ventilatory efficiency without causing dyspnea in patients whose respiratory muscular system is preserved.