Severe Air Trapping Research Articles

Granulomatosis with polyangiitis and associated pulmonary emphysema: Breathtaking vasculitis.

Pulmonary emphysema occasionally occurs in the absence of smoking or noxious exposures. Other than through a known association with alpha-1 antitryspin deficiency, to our knowledge, no reports implicate granulomatosis with polyangiitis (GPA) in causing airflow obstruction with small airway involvement and severe air trapping. To extend available experience, we report a 51-year-old male with biopsy-proven cytoplasmic–antineutrophilic cytoplasmic antibody proteinase 3 (ANCA PR3)-positive GPA who developed centrilobular emphysema and airflow obstruction during a phase of active vasculitis. He was a lifelong non-smoker and had a normal alpha-1 antitrypsin level and a PI*MM phenotype. Treatment with corticosteroids and cyclophosphamide caused clinical remission of his vasculitis which was associated with improvement in his respiratory symptoms. However, to date, structural changes of emphysema have persisted for over 9 years of follow-up. Clinicians should remain vigilant to the possibility of emphysema in patients with pulmonary vasculitis.

B-Mode Ultrasound Assessment of Diaphragm Structure and Function in Patients With COPD

Electromyographic evaluation of diaphragmatic neuromuscular disease in patients with COPD is technically difficult and potentially high risk. Defining standard values for diaphragm thickness and thickening ratio using B-mode ultrasound may provide a simpler, safer means of evaluating these patients. Fifty patients with a diagnosis of COPD and FEV₁ < 70% underwent B-mode ultrasound. Three images were captured both at end expiration (Tmin) and at maximal inspiration (Tmax). The thickening ratio was calculated as (Tmax/Tmin), and each set of values was averaged. Findings were compared with a database of 150 healthy control subjects. There was no significant difference in diaphragm thickness or thickening ratio between sides within groups (control subjects or patients with COPD) or between groups, with the exception of the subgroup with severe air trapping (residual volume > 200%), in which the only difference was that the thickening ratio was higher on the left (P = .0045). In patients with COPD presenting for evaluation of coexisting neuromuscular respiratory weakness, the same values established for healthy control subjects serve as the baseline for comparison. This knowledge expands the role of ultrasound in evaluating neuromuscular disease in patients with COPD.

Expiratory air trapping on thoracic computed tomography. A diagnostic subclassification.

Multiple causes for air trapping as identified by expiratory computed tomography (CT) have been reported, but a unified evaluation schema has never been proposed. It was our purpose to identify imaging features that would help distinguish etiologies of mosaic air trapping. Cases with the term "air trapping" in the radiology report in 2010 were identified by searching the Radiology Information System of an academic tertiary care center and associated community hospital. Medical records and CT examinations were reviewed for the causes of air trapping. Causes for moderate to severe air trapping could be identified in 201 of 230 (87.4%) cases and could be subdivided into those associated with bronchiectasis (76 of 201, 38%), those associated with interstitial lung disease (62 of 201, 31%), those associated with tree-in-bud opacities (5 of 201, 2%), and those with air trapping alone (58 of 201, 29%). When found with bronchiectasis, nontuberculous mycobacteria, cystic fibrosis, idiopathic bronchiectasis, and transplant-related bronchiolitis obliterans were the most common causes of air trapping. When found with interstitial lung disease, sarcoidosis, hypersensitivity pneumonitis, or unspecified interstitial lung disease were the most common cause of air trapping. When found in isolation, chronic bronchitis, asthma, bronchiolitis obliterans, and unspecified small airways disease were the most common causes of air trapping. Unusual conditions causing isolated air trapping included vasculitis and diffuse idiopathic neuroendocrine cell hyperplasia. A variety of conditions can cause air trapping. Associated imaging findings can narrow the differential diagnosis.

Acute Neurological Symptoms During Hypobaric Exposure: Consider Cerebral Air Embolism

Cerebral arterial gas embolism (CAGE) is well known as a complication of invasive medical procedures and as a risk in diving and submarine escape. In the underwater environment, CAGE is caused by trapped air, which expands and leads to lung vessel rupture when ambient pressure decreases during ascent. Pressure decrease also occurs during hypobaric activities such as flying and, therefore, CAGE may theoretically be a risk in hypobaric exposure. We reviewed the available literature on this subject. Identified were 12 cases of CAGE due to hypobaric exposure. Based on these cases, we discuss pathophysiology, diagnosis, and treatment of CAGE due to hypobaric exposure. The low and slow pressure decrease during most hypobaric activities (as opposed to diving) account for the low incidence of CAGE during these exposures and suggest that severe air trapping must be present to cause barotrauma. This is also suggested by the large prevalence of air filled cysts in the case reports reviewed. We recommend considering CAGE in all patients presenting with acute central neurological injury during or shortly after pressure decrease such as flying. A CT scan of head and chest should be performed in these patients. Treatment with hyperbaric oxygen therapy should be initiated as soon as possible in cases of proven or probable CAGE.

Pediatric fiberoptic bronchoscopy as adjunctive therapy in acute asthma with respiratory failure

Status asthmaticus respiratory failure is associated with thickened mucus secretions necessitating aggressive pulmonary clearance. The role of bronchoscopy in pediatric mechanically ventilated asthmatic patients has not been published. A chart review was performed on all pediatric intensive care unit (PICU) asthmatics with respiratory failure over 13 years. Forty-four patients were identified. Patients were managed per standardized guidelines for status asthmaticus with mechanical ventilation. Ventilator management prioritized spontaneous breathing with pressure support. Extubation criteria included spontaneous tidal volumes of 5-7 cm(3) /kg on low-pressure support. Standard endotracheal tube pulmonary toilet were implemented. Twenty-nine patients underwent bronchoscopy as an adjunctive therapy. Indications for bronchoscopy included: Pathogen identification via bronchoalveolar ravage, atelectasis, mucus obstruction resulting in severe air trapping, suspected aspiration, and poor response to standard therapy. Clinical outcomes of this intervention were compared to the fifteen patient cohort who did not undergo bronchoscopy. Bronchoscopies revealed thick mucus plugs, secretions, and bronchial casts. The large airways were lavaged for clearance of obstructive secretions with normal saline. All patients tolerated the procedure without any complications. Demonstrable improvement in pulmonary compliance was noted. The median time of intubation for the bronchoscopy group was 10 hr compared to 20.5 hr for the control group (P < 0.0005). The mean intensive care unit length of stay was 3.06 days for the bronchoscopy group versus 3.4 days for the non-bronchoscopy group (P < 0.05). Flexible bronchoscopy with bronchial lavage is a safe adjunctive therapy in pediatric asthmatics with respiratory failure resulting in reduced mechanical ventilation and intensive care length of stay. Restoring lung volume in certain asthmatics during respiratory failure may be deemed beneficial. Further validated studies are necessary to recommend bronchoscopy to the present, accepted treatment regimen in pediatric asthmatic respiratory failure.

High Resolution Computed Tomography in Asthma

High-resolution computed tomography (HRCT) can detect the structural abnormalities in asthma. This study attempts to correlate these abnormalities with clinical and pulmonary function test (PFT) data. Consecutive stable asthma patients attending Mubarak Al Kabeer Hospital, Kuwait, were subjected to HRCT during a six month period from July 2004 to December 2004, after initial evaluation and PFT. Of the 28 cases, sixteen (57.1%) had moderate, 6 (21.4%) had mild and 6 (21.4%) had severe persistent asthma. Thirteen (46.4%) patients had asthma for 1 to 5 years and 12 (42.9%) were having asthma for >10 years. Bronchial wall thickening (57.1%), bronchiectasis (28.6%), mucoid impaction (17.9%), mosaic attenuation (10.7%), air trapping (78.6%) and plate like atelectasis (21.4%) were noted. Bronchial wall thickening (p=0.044) and bronchiectasis (p=0.063) were most prevalent in males. Ten (35.7%) patients exhibited mild, 9 (32.1%) had moderate and 3 (10.7%) had severe air trapping. The difference in Hounsfield units between expiratory and inspiratory slices (air trapping) when correlated with percent-predicted FEV1 in right upper (r=0.25; p=0.30), left upper (r=0.20; p=0.41), right mid (r=0.15; p=0.53), left mid (r=-0.04; p=0.60), right lower (r=0.04; p=0.86) and left lower zones (r=-0.13; p=0.58) showed no relation. The same when correlated as above with the percent predicted FEF 25-75 did not show any significant association. The presence of air trapping was compared with sex (p=0.640), nationality (p=1.000), disease duration (p=1.000) and severity of symptoms (p=0.581). Abnormal HRCT findings are common in asthma; however, air trapping when present was not related to the duration or severity of the illness or to the FEV1.

P7 Occupational eosinophilic constrictive bronchiolitis with asthma in a foam cutter caused by Soya bean products

Introduction and backgroundSoya bean dust is a recognised cause of asthma. More recently Soya bean has bean used in the manufacture of foam. The main market for this ‘environmentally friendly...

A 41-Year-Old Woman With Severe Dyspnea and Painful Oral Mucosal Ulcerations

A 41-year-old woman with a 19 pack-year smoking history presented to her physician with a 2-month history of progressively worsening dyspnea. Pulmonary function testing revealed a severe obstructive ventilatory defect and air trapping with an FEV1 of 0.53 L (18% of predicted) and a residual volume of 4.09 L (254% of predicted). CT chest scan showed diffuse bilateral bronchiectasis and air trapping (Fig 1). She initially received a diagnosis of severe asthma and was started on high-dose oral steroids.

Dornase Alfa Reduces Air Trapping in Children With Mild Cystic Fibrosis Lung Disease: A Quantitative Analysis

To evaluate quantitative air trapping measurements in children with mild cystic fibrosis (CF) lung disease during a 1-year, double-blind, placebo-controlled, recombinant human deoxyribonuclease (rhDNase) [dornase alfa] intervention trial and compare results from quantitative air trapping with those from spirometry or visually scored high-resolution CT (HRCT) scans of the chest.Twenty-five children with CF randomized to either daily rhDNase or placebo aerosol were evaluated at baseline, and at 3 months and 12 months by spirometer-triggered HRCT and spirometry. Outcome variables were percentage of predicted FVC, FEV1, and forced expiratory flow, midexpiratory phase (FEF(25-75%)); total and subcomponent visual HRCT scores; and quantitative air trapping measurements derived from chest HRCT images.At baseline, there were no statistical differences between groups in any of the variables used as an outcome. After 3 months of treatment, both groups had improvements in percentage of predicted FEV1 and FEF(25-75%), and total HRCT visual scores. In contrast, the rhDNase group had a 13% decrease in quantitative air trapping from baseline (severe air trapping [A3]), compared to an increase of 48% in the placebo group (p = 0.023). After 12 months, both groups had declines in percentage of predicted FVC and FEV1, but the rhDNase group retained improvements in percentage of predicted FEF(25-75%) and quantitative air trapping. The mucus plugging and total HRCT visual scores were also improved in the rhDNase group after 12 months of treatment, with and without significant differences between groups (p = 0.026 and p = 0.676). Quantitative air trapping (A3) remained improved in the rhDNase group (- 15.4%) and worsened in the placebo group (+61.3%) with nearly significant differences noted between groups (p = 0.053) after 12 months of treatment.Quantitative air trapping is a more consistent sensitive outcome measure than either spirometry or total HRCT scores, and can discriminate differences in treatment effects in children with minimal CF lung disease.

Endobronchial Blocker Dislodgement Leading to Pulseless Electrical Activity

This is a report of a case in which an endobronchial blocker was dislodged, leading to severe air trapping and a brief episode of pulseless electrical activity. Bronchial blockade for lung deflation was successfully instituted during emergency repair of a ruptured descending aortic aneurysm. During a period not involving manipulation of aortic cross-clamps, end-tidal CO2 decreased precipitously to zero and airway pressures increased markedly, followed by equalization of intracardiac pressures. Prompt deflation of the endobronchial blocker balloon reversed the problem. We hypothesize that when surgical manipulation dislodged the bronchial blocker into the tracheal position, leading to profound air trapping as successive, stacked tidal volumes were forced distal to the blocker.

Relationship between resting hypercapnia and physiologic parameters before and after lung volume reduction surgery in severe chronic obstructive pulmonary disease.

Patients with severe chronic obstructive pulmonary disease (COPD) have varying degrees of hypercapnia. Recent studies have demonstrated inconsistent effects of lung volume reduction surgery (LVRS) on PaCO2; however, most series have excluded patients with moderate to severe hypercapnia. In addition, no study has examined the mechanisms responsible for the reduction in PaCO2 post-LVRS. We obtained spirometry, body plethysmography, diffusion capacity, respiratory muscle strength, 6-min walk test, and incremental symptom-limited maximal exercise data in 33 consecutive patients pre- and 3 to 6 mo post-LVRS, and explored the relationship between changes in PaCO2 and changes in the measured physiologic variables. All patients underwent bilateral LVRS via median sternotomy and stapling resection by the same cardiothoracic surgeon. Patients were 57 +/- 8 yr of age with severe COPD, hyperinflation, and air trapping (FEV1, 0.73 +/- 0.2 L; TLC, 7.3 +/- 1.6 L; residual volume [RV], 4.8 +/- 1.4 L), and moderate resting hypercapnia (PaCO2, 44 +/- 7 mm Hg; range, 32 to 56 mm Hg). Post-LVRS, PaCO2 decreased by 4% (PaCO2 pre 44 +/- 7 mm Hg, PaCO2 post 42 +/- 5 mm Hg; p = 0.003). Patients with higher baseline values of PaCO2 had the greatest reduction in PaCO2 post-LVRS (r = -0.61, p < 0.001). Significant correlations existed between reduction in PaCO2 and changes in FEV1 (r = -0.56; p = 0.0007), maximal inspiratory pressure (PImax) (r = -0.46; p = 0.009), diffusing capacity of the lungs for carbon monoxide (DLCO) (r = -0.47; p = 0.008), and RV/TLC (r = 0.41; p = 0. 02). Correlation existed also between reduction in PaCO2 and breathing pattern at maximal exercise: maximal minute ventilation (V Emax) (r = -0.47; p = 0.009), and tidal volume (VT) (r = -0.40; p = 0.02). The changes in PaCO2 post-LVRS showed marked intersubject variability. We conclude that LVRS, by reducing hyperinflation, air trapping, and improving respiratory muscle function, enables the lung and chest wall to act more effectively as a pump, thereby increasing alveolar ventilation and reducing baseline resting PaCO2. In addition, patients with higher baseline levels of PaCO2 demonstrate the greatest reduction in PaCO2 post-LVRS, and should not be excluded from receiving LVRS.

Focal air trapping in patients with HIV infection: CT evaluation and correlation with pulmonary function test results.

HIV-positive individuals commonly have symptoms of airway disease. We evaluated thin-section CT scans of HIV-infected individuals during inspiration and expiration for evidence of focal air trapping. We also correlated imaging findings with pulmonary function test results. Fifty-nine subjects, 48 of whom were HIV-positive and 11 of whom were HIV-negative, underwent thin-section CT of the thorax during inspiration and expiration. All subjects also underwent pulmonary function tests. Two radiologists, who were unaware of the subjects' HIV status and smoking history and of the results of pulmonary function tests, evaluated the CT scans for the presence and severity of focal air trapping. Expiratory CT revealed focal air trapping in 33 subjects: 30 were HIV-positive and three were HIV-negative (p = .0338). The mean values of forced expiratory volume in 1 sec (FEV1), forced mid expiratory flow, and diffusion capacity (DL(CO)) were significantly lower for subjects with focal air trapping (mean = 88.85, 84.52, and 80.80, respectively) than for those with normal findings on CT (mean = 100.84, 99.24, and 95.82, respectively; p = .001, p = .021, and p = .003, respectively). We found no significant differences in smoking history between HIV-positive and HIV-negative subjects. Severe air trapping on expiratory CT scans was seen in three subjects: All three had HIV infection, low CD4 counts, and abnormally decreased FEV1 and DL(CO) values. Focal air trapping was a common finding on thoracic CT scans obtained during expiration in HIV-positive subjects. In addition, focal air trapping was associated with significantly lower FEV1, forced mid expiratory flow, and DL(CO) values than those found for subjects in whom CT revealed no focal air trapping. These results suggest that small airways disease may accompany a decline in pulmonary function in HIV-positive individuals.

Pulmonary Intravascular Lymphomatosis: Presentation with Dyspnea and Air Trapping

Intravascular lymphomatosis (IVL) is a rare lymphoid neoplasm that is typically of B-cell lineage and characterized by proliferation of malignant cells within small arterioles, capillaries, and venules. We report a patient with pulmonary IVL who presented clinically with progressive dyspnea, fever, and a dry cough. Pulmonary function tests revealed a marked decrease in diffusion capacity with airflow obstruction and severe air trapping. High-resolution CT (HRCT) of the chest with inspiratory and expiratory images revealed mosaic attenuation consistent with air trapping. Transbronchial biopsies revealed the diagnosis of IVL with capillary expansion in the alveolar and peribronchiolar interstitial tissue. IVL should be considered in the differential diagnosis of a patient with an interstitial lung disease, air trapping on pulmonary function tests, and mosaic attenuation on HRCT. Transbronchial biopsies may be the initial diagnostic procedure of choice.

Airway obstruction in asthmatic and healthy individuals: inspiratory and expiratory thin-section CT findings.

To determine differences in computed tomographic (CT) findings in asthmatic and healthy individuals and to correlate the findings with severity of airway obstruction. Thirty-nine asthmatic patients and 14 healthy subjects were prospectively evaluated with thin-section CT. Inspiratory CT scans were subjectively evaluated for presence of bronchial wall thickening, bronchial dilatation, and mosaic lung attenuation; expiratory scans were subjectively evaluated for presence of air trapping. Objective measurement of bronchoarterial-diameter ratio was performed on inspiratory scans. CT findings were compared with pulmonary function test results. Bronchial wall thickening, severe air trapping, and reduced bronchoarterial-diameter ratio were observed more commonly in asthmatic patients than in healthy subjects. Bronchial wall thickening was more prevalent among patients with severe airflow obstruction (10 of 12 readings [83%]) than in patients with normal airflow (15 of 40 readings [38%]) or mild obstruction (nine of 26 readings [35%]). Other subjectively determined CT findings did not correlate with pulmonary function test results. The mean bronchoarterial-diameter ratios +/- 1 standard deviation were 0.65 +/- 0.16 in healthy subjects and 0.60 +/- 0.16, 0.60 +/- 0.18, and 0.48 +/- 0.11 in patients with normal airflow and mild and severe obstruction, respectively. Thin-section CT is of limited value in distinguishing asthmatic patients with normal airflow or mild airflow obstruction from healthy subjects.

Bronchial reactivity in infants in acute respiratory failure with viral bronchiolitis.

Airway reactivity and the effects of bronchodilators in infants are controversial. We studied the response to bronchodilator treatment in 14 mechanically ventilated infants (mean age, 2.74 months; range, 0.6-5.9) in respiratory failure caused by respiratory syncytial virus (RSV)-associated bronchiolitis. Sixteen infants without lung disease, undergoing elective surgery, provided normal values. Maximum expiratory deflation flow-volume (DFV) curves were produced by manual inflation of the lungs with an anesthesia bag to a predetermined static airway pressure followed by rapid deflation with a negative airway pressure before and after administration of bronchodilator. At baseline, the bronchiolitis group had a forced vital capacity (FVC) of 34.5 +/- 3.6 ml/kg compared with 41.8 +/- 1.5 ml/kg in the normal group; maximum expiratory flow rate at 25% of FVC (MEF25) was 10.2 +/- 2.0 ml/kg/s compared with 27.3 +/- 2.0 ml/kg/s in the normal group. The clinical and radiologic impression was severe lower airway obstruction and air trapping. After administration of bronchodilator, FVC did not increase significantly, but MEF25isov increased by over 30% in 13 of 14 infants. Mean MEF25 increased by 148 +/- 43.2% to 21.7 +/- 3.9 ml/kg/s (P less than 0.02). These findings indicate that during the acute phase of severe RSV-positive bronchiolitis most infants have airway reactivity that responds positively to bronchodilator treatment.

Radiological aspects of the pulmonary complications resulting from intermittent positive pressure ventilation (I.P.P.V.).

SummaryThe use of intermittent positive pressure ventilation is associated with a number of pulmonary complications which are of radiological importance. These complications are grouped into three categories.In the first category are cases of asthma which require resuscitation with intermittent positive pressure ventilation. These cases may develop severe air trapping which can progress to pulmonary interstitial emphysema, although the latter complication is known to develop without a respirator being used. The second category includes pulmonary oedema, and there is brief reference to the effects of oedema of the bronchial mucosa. In an appendix to the paper the possible relationship of pulmonary oedema to the body handling of salt and water when intermittent positive pressure ventilation is used is examined. The analysis of accurately recorded fluid balance data did not reveal any statistical association between the retention of sodium, potassium or water, or any combination of these three and the presence of pulmonary oedema. The third category is represented by the serious condition of obliterative pneumonitis (respirator lung syndrome).In all three categories the clinical and radiological findings and, where relevant, the pathological findings, are described.During the year 1967 it was found that of a total of 267 admissions five developed pulmonary interstitial emphysema, four during intermittent positive pressure ventilation therapy. Two died. Sixty‐nine cases (26%) developed pulmonary oedema, and in 15 cases there seemed no adequate explanation for the oedema other than factors associated with the use of a respirator. The number of cases of pulmonary oedema closely related to the use of intermittent positive pressure ventilation is considered to be higher than 15, however. Two adults and two children under 10 years of age developed fatal obliterative pneumonitis confirmed by necropsy.