Localized pneumothorax adjacent to a collapsed lobe: a sign of bronchial obstruction

Pressure-Dependent Pneumothorax and Air Leak: Physiology and Clinical Implications

Pressure-dependent pneumothorax is a common clinical event, often occurring after pleural drainage in patients with visceral pleural restriction, partial lung resection, or lobar atelectasis from bronchoscopic lung volume reduction or an endobronchial obstruction. This type of pneumothorax and air leak is clinically inconsequential. Failure to appreciate the benign nature of such air leaks may result in unnecessary pleural procedures or prolonged hospital stay. This review suggests that identification of pressure-dependent pneumothorax is clinically important because the air leak that results is not related to a lung injury that requires repair but rather to a physiological consequence of a pressure gradient. A pressure-dependent pneumothorax occurs during pleural drainage in patients with lung-thoracic cavity shape/size mismatch. It is caused by an air leak related to a pressure gradient between the subpleural lung parenchyma and the pleural space. Pressure-dependent pneumothorax and air leak do not need any further pleural interventions.

Pneumothorax Ex-vacuo or Trapped Lungs Appearing as Iatrogenic Hydropneumothorax: A Case Report and Review of Non-expandable Lungs (NEL)

Non-expandable lungs are usually diagnosed after a pleural intervention. It can be challenging to differentiate between an iatrogenic pneumothorax and a new diagnosis of non-expandable lungs following a pleural intervention. The correct assessment can save the patient from undergoing the insertion of an unnecessary intercostal chest drain, which often leads to catastrophe. Suspicion and early evaluation remain the keys, particularly in patients with chronic effusion. Often the diagnosis is reached through a combination of history, pleural fluid analysis, and radiological features such as the absence of a straight line in the chest X-ray, which is commonly found in a true hydropneumothorax, along with computed tomographic evidence of chronic effusion with thick pleural rind. Although not routinely performed, pleural manometry can confirm the diagnosis of trapped lungs. We present our case, where a 64-year-old woman with metastatic oesophageal cancer developed a right-sided effusion. The post-procedure chest X-ray following therapeutic aspiration of the pleural fluid gave an impression of iatrogenic hydropneumothorax, which on further careful assessment revealed a rather pneumothorax ex-vacuo along with effusion due to underlying trapped lungs. We present a review of non-expandable lungs.

Pneumothorax ex vacuo: Three cases of an uncommon entity

Pneumothorax is a frequently encountered entity in pulmonary practice and can be primary or secondary. Traumatic and iatrogenic causes also account for a minority of cases presenting to the chest physician. The most common therapeutic intervention done is a tube thoracostomy in all but the mildest of cases. Pneumothorax ex vacuo is a distinctly uncommon entity that differs considerably from the rest of the pneumothorax cases in its pathogenesis, clinical manifestations, radiological findings, and management. Pneumothorax in this entity results from the sucking in of air into the pleural space caused by an exaggerated negative intrapleural pressure, which is most frequently secondary to acute lobar collapse. Symptoms attributable to pneumothorax per se are distinctly mild and the vital aspect of treatment is to relieve the bronchial obstruction. Tube thoracostomy fails to relieve the pneumothorax in such cases and should be avoided. We share three cases of pneumothorax ex vacuo encountered in our institution and alert clinicians of the presentation, radiology, and management of this uncommon condition.

Foreign Body Aspiration Presenting as Pneumothorax in a Child

A typical presentation of a foreign body aspiration (FBA) in a child includes witnessed choking, respiratory distress, cyanosis, coughing, wheezing, diminished breath sounds, and/or altered mental status. Following an extensive literature review, we found pneumothorax occurring secondary to FBA is a rare occurrence and should elicit prompt treatment. This 17-month-old female was admitted for respiratory syncytial virus (RSV) bronchiolitis and developed a subsequent pneumothorax during her hospital stay, consequent to aspiration of a cashew fragment two weeks before presentation. In light of the National Institute of Allergy and Infectious Diseases (NIAID)-sponsored expert panel’s addended guidelines, published and endorsed by the American Academy of Pediatrics (AAP) in 2017, we highlight a potential complication of increasing encouragement of peanut consumption in children as young as four months.

Pneumothorax ex-vacuo or "trapped lung" in the setting of hepatic hydrothorax

Background

Hepatic hydrothorax is a major pulmonary complication of liver disease occurring in up to 5-10% of patients with cirrhosis.

Case presentation

We report four observations of the development of pneumothorax ex-vacuo or trapped lung in the setting of hepatic hydrothorax. The diagnosis of trapped lung was made based on the presence of a hydropneumothorax after evacuation of a longstanding hepatic hydrothorax with failure of the lung to re-expand after chest tube placement in three of the four cases. Two patients underwent surgical decortication with one subsequent death from post-operative bleeding. The other two patients remarkably had spontaneous improvement of their “trapped lung” without surgical intervention.

Conclusions

While pneumothorax ex-vacuo is a known phenomenon in malignant effusions, to our knowledge, it has never been described in association with hepatic hydrothoraces. The pathophysiology of this phenomenon remains unclear but could be related to chronic inflammation with development of a fibrous layer along the visceral pleura.

Experimental lung collapse following deployment of a self-expandable bronchial occluder in a rabbit model

OBJECTIVES

Closure of a bronchopleural fistula is required to prevent fatal empyema or aspiration pneumonia. The purpose of this study was to determine the feasibility and efficacy of bronchial occlusion with a self-expandable occluder to induce experimental lung collapse in a rabbit model.

METHODS

10 bronchial occluders (wine glass appearance; 8 mm in diameter and 15 mm in length) were implanted in the native left main bronchi of 10 rabbits via an endotracheal route. We analysed the following: (1) diameters and morphological changes of the bronchial occluders during follow-up; (2) percentage volume of the collapsed lung during follow-up; and (3) complications and gross pathology. 1-day and 2-week follow-up CT scans were routinely obtained. Rabbits were sacrificed 4 weeks after the experiment.

RESULTS

In all 10 rabbits, the bronchial occluders were successfully implanted and were completely expanded within 2 weeks. Complete collapse of the left lung occurred in three rabbits on day 1 and in an additional two rabbits 2 weeks following implantation. Two other rabbits maintained the percentage volume of the collapsed lung between 51% and 99% during follow-up; the other three rabbits had <50% during follow-up. Pneumothoraces occurred in nine rabbits, but completely resolved at the 2-week follow-up. Right lung herniation across the midline progressed 2 weeks after occluder implantation.

CONCLUSION

Placement of self-expandable occluders in a rabbit bronchus model was feasible and showed a potential to induce artificial lung collapse. While pneumothoraces were common, they resolved during follow-up.

Pneumomediastinum caused by foreign body aspiration in children

In a retrospective review of 155 children with tracheobronchial foreign body aspiration (FBA), there were ten patients who had pneumomediastinum (PM) on an initial chest radiograph. Nine of ten presented with PM and one patient had PM noted after bronchoscopy. In a child less than two years of age with no history of trauma, the radiographic finding of PM should prompt further investigation for FBA.

Lobar atelectasis: diagnostic pitfalls on chest radiography

This pictorial review looks at the pitfalls in the diagnosis of lobar atelectasis on chest radiographs. Lobar atelectasis with marked volume loss is hard to recognize and may be easily missed. Lobar atelectasis presenting as a mass-like opacity may be misdiagnosed as mediastinal or lung tumour. Lobar atelectasis in an unusual location may also be misdiagnosed as other entities. Familiarity with such manifestations and consideration of anatomical alterations as the signs of lobar atelectasis are important in making the correct diagnosis.

Benign pleural diseases

The pleural space is a potential space under normal physiologic circumstances. It envelops the lung, the mediastinum, the diaphragm and the chest wall. A thin film of pleural fluid provides lubrication for the two pleural layers; only 2-10 ml of pleural fluid is present in healthy people. For the purposes of this review, pleural abnormalities will be divided into pleural effusion, pneumothorax, and pleural calcification.

Endotracheal suctioning causes right upper lobe collapse in intubated children

OBJECTIVE

Right upper lobe collapse is a common radiographic finding in intubated children. We hypothesized that deep suctioning and uncontrolled negative pressures during endotracheal tube suctioning were significant contributory factors.

METHODS

The incidence of right upper lobe (RUL) collapse in intubated, ventilated children on a paediatric cardiac intensive care unit was determined over a 3-month period (n = 102). Graduated suction catheters and suction vacuums of < 165 cm H2O were then introduced. Another prospective audit was carried out 3 months later (n = 60).

RESULTS

We found that 24% developed RUL collapse and 4 developed an apical pneumothorax. Following the introduction of graduated catheters and controlled vacuums pressures; a significant reduction in the incidence of RUL collapse, to 7%, was observed (p < 0.05).

CONCLUSIONS

We conclude that high negative pressure and deep-suctioning causes RUL collapse in children. Any lobar collapse not only prolongs the child's stay in intensive care, but can be associated with further morbidity which may have a serious implication. By improving suctioning technique this morbidity can be significantly reduced.

Pneumothorax ex vacuo

Pneumothorax ex vacuo is a little-known complication of lobar collapse. In this condition, acute bronchial obstruction from mucous plugs, aspirated foreign bodies, or malpositioned endotracheal tubes causes acute lobar collapse and a marked increase in negative intrapleural pressure around the collapsed lobe. As a result, gas is drawn into the pleural space around the collapsed lobe while the seal between the visceral and parietal pleura of the adjacent lobe or lobes remains intact. The pneumothorax spontaneously resolves when the bronchial obstruction is relieved and the lobe reexpands. Recognition of pneumothorax ex vacuo is crucial in directing treatment to relieve the bronchial obstruction rather than inserting a chest tube into the pleural space.

Localized pneumothorax with lobar collapse and diffuse obstructive airway disease

Localized pneumothorax adjacent to a collapsed lobe has been reported in children with bronchial obstruction. We present our findings in seven children with a similar phenomenon occurring in association with diffuse obstructive airway disease. The children, aged from 3 weeks to 17 years, were admitted for diffuse obstructive airway disease and, subsequently, developed lobar collapse with adjacent localized pneumothorax. In five of the seven patients there was a paradoxical shift of the mediastinum toward the side of the pneumothorax. In six cases, the pneumothorax resolved spontaneously with lobar reexpansion. A conservative treatment approach to patients with this constellation of radiographic findings appears justified.

Pneumothorax secondary to foreign body inhalation in a 20 month old child

A 20 month old child presented with acute onset of respiratory embarrassment as a result of a left-sided tension pneumothorax. This proved to be caused by inhalation of an unusual foreign body: the hair from a rag doll.

Acute bronchial obstruction: an experimental rabbit model study

An animal model of bronchial obstruction was developed to radiologically follow up the development of postobstructive pulmonary changes. The study material consisted of 21 healthy rabbits (New Zealand White) of which 5 animals served as controls. A piece of Surgicel (Ethicon) shaped as a 3 x 3 x 10 mm cylinder was placed endobronchially through a 3-mm bronchoscope. The animals were followed up radiologically and endoscopically during the first 30 min after which the bronchoscope was extracted. Sixteen animals were followed up for at least 4 h and, in 4 animals, the foreign body (FB) was removed after 24 h. During follow-up, total collapse of the lung was observed after 1-4 h in all but 2 animals with obstruction of the main brochus. After extraction of the FB, atelectasis of the respective lung had resolved within 24 h. The animal model developed in the present study seems to be rather physiological resembling the development of pulmonary atelectasis in pediatric patients.

How accurate is chest radiography in the diagnosis of tracheobronchial foreign bodies in children?

The radiographic and endoscopic findings of 83 consecutive patients with suspected foreign body (FB) inhalation into the tracheobronchial tree were compared and the accuracy of chest radiography was estimated. Typical radiologic signs of FB aspiration, such as localized air trapping, atelectasis and infection occurred on radiographs of patients with and without FB. Twenty-four percent of patients with endoscopically verified FB had no abnormalities on chest radiography. In an analysis of radiographs of 83 consecutive patients, in which the prevalence of FB aspiration was 41%, the diagnostic accuracy was 67%, sensitivity 68% and specificity 67%. Plain film radiology alone is not a sufficiently sensitive nor specific method for the diagnosis of FB aspiration.

The opaque chest: when to suspect a bronchial foreign body

A bronchial foreign body should be strongly suspected in a child with an opaque chest without a previous history of airways disease when there is: any sign of volume loss or atelectasis in the lung density and bronchiectasis within the lung density. Ultrasound may be helpful to rule out the presence of pleural fluid and may even demonstrate the bronchiectasis when the bronchi are fluid-filled.