The tissues in the mediastinum will slowly resorb the air in the cavity so most pneumomediastinums are treated conservatively. Breathing high flow oxygen will increase the absorption of the air.

If the air is under pressure and compressing the heart, a needle may be inserted into the cavity, releasing the air.

Surgery may be needed to repair the hole in the trachea, esophagus or bowel.

If there is lung collapse, it is imperative the affected individual lies on the side of the collapse, although painful, this allows full inflation of the unaffected lung.

It is most commonly caused by:

- Oesophageal rupture, for example in Boerhaave syndrome

- Asthma or other conditions leading to alveolar rupture

- Bowel rupture, where air in the abdominal cavity tracts up into the chest.

It has also been associated with:

- "Mycoplasma pneumoniae" pneumonia

- obesity

It can be induced to assist thoracoscopic surgery. It can be caused by a pulmonary barotrauma resulting when a person moves to or from a higher pressure environment, such as when a SCUBA diver, a free-diver or an airplane passenger ascends or descends.

In rare cases, pneumomediastinum may also arise as a result of blunt chest trauma (e.g. car accidents, fights, over pressure of breathing apparatus), while still evolving in the same fashion as the spontaneous form.

Pneumomediastinum is most commonly seen in otherwise healthy young male patients and may not be prefaced by a relevant medical history of similar ailments.

Air in subcutaneous tissue does not usually pose a lethal threat; small amounts of air are reabsorbed by the body. Once the pneumothorax or pneumomediastinum that causes the subcutaneous emphysema is resolved, with or without medical intervention, the subcutaneous emphysema will usually clear. However, spontaneous subcutaneous emphysema can, in rare cases, progress to a life-threatening condition, and subcutaneous emphysema due to mechanical ventilation may induce ventilatory failure.

Subcutaneous emphysema is usually benign. Most of the time, SCE itself does not need treatment (though the conditions from which it results may); however, if the amount of air is large, it can interfere with breathing and be uncomfortable. It occasionally progresses to a state "Massive Subcutaneous Emphysema" which is quite uncomfortable and requires surgical drainage. When the amount of air pushed out of the airways or lung becomes massive, usually due to positive pressure ventilation, the eyelids swell so much that the patient cannot see. Also the pressure of the air may impede the blood flow to the areolae of the breast and skin of the scrotum or labia. This can lead to necrosis of the skin in these areas. The latter are urgent situations requiring rapid, adequate decompression. Severe cases can compress the trachea and do require treatment.

In severe cases of subcutaneous emphysema, catheters can be placed in the subcutaneous tissue to release the air. Small cuts, or "blow holes", may be made in the skin to release the gas. When subcutaneous emphysema occurs due to pneumothorax, a chest tube is frequently used to control the latter; this eliminates the source of the air entering the subcutaneous space. If the volume of subcutaneous air is increasing, it may be that the chest tube is not removing air rapidly enough, so it may be replaced with a larger one. Suction may also be applied to the tube to remove air faster. The progression of the condition can be monitored by marking the boundaries with a special pencil for marking on skin.

Since treatment usually involves dealing with the underlying condition, cases of spontaneous subcutaneous emphysema may require nothing more than bed rest, medication to control pain, and perhaps supplemental oxygen. Breathing oxygen may help the body to absorb the subcutaneous air more quickly.

Vehicle occupants who wear seat belts have a lower incidence of TBI after a motor vehicle accident. However, if the strap is situated across the front of the neck (instead of the chest), this increases the risk of tracheal injury. Design of medical instruments can be modified to prevent iatrogenic TBI, and medical practitioners can use techniques that reduce the risk of injury with procedures such as tracheotomy.

Pneumopericardium is a medical condition where air enters the pericardial cavity. This condition has been recognized in preterm neonates, in which it is associated with severe lung pathology, after vigorous resuscitation, or in the presence of assisted ventilation. This is a serious complication, which if untreated may lead to cardiac tamponade and death. Pneumomediastinum, which is the presence of air in the mediastinum, may mimic and also coexist with pneumopericardium.

It can be congenital, or introduced by a wound.

Treatment of TBI varies based on the location and severity of injury and whether the patient is stable or having trouble breathing, but ensuring that the airway is patent so that the patient can breathe is always of paramount importance. Ensuring an open airway and adequate ventilation may be difficult in people with TBI. Intubation, one method to secure the airway, may be used to bypass a disruption in the airway in order to send air to the lungs. If necessary, a tube can be placed into the uninjured bronchus, and a single lung can be ventilated. If there is a penetrating injury to the neck through which air is escaping, the trachea may be intubated through the wound. Multiple unsuccessful attempts at conventional (direct) laryngoscopy may threaten the airway, so alternative techniques to visualize the airway, such as fiberoptic or video laryngoscopy, may be employed to facilitate tracheal intubation. If the upper trachea is injured, an incision can be made in the trachea (tracheotomy) or the cricothyroid membrane (cricothyrotomy, or cricothyroidotomy) in order to ensure an open airway. However, cricothyrotomy may not be useful if the trachea is lacerated below the site of the artificial airway. Tracheotomy is used sparingly because it can cause complications such as infections and narrowing of the trachea and larynx. When it is impossible to establish a sufficient airway, or when complicated surgery must be performed, cardiopulmonary bypass may be used—blood is pumped out of the body, oxygenated by a machine, and pumped back in. If a pneumothorax occurs, a chest tube may be inserted into the pleural cavity to remove the air.

People with TBI are provided with supplemental oxygen and may need mechanical ventilation. Employment of certain measures such as Positive end-expiratory pressure (PEEP) and ventilation at higher-than-normal pressures may be helpful in maintaining adequate oxygenation. However, such measures can also increase leakage of air through a tear, and can stress the sutures in a tear that has been surgically repaired; therefore the lowest possible airway pressures that still maintain oxygenation are typically used. Mechanical ventilation can also cause pulmonary barotrauma when high pressure is required to ventilate the lungs. Techniques such as pulmonary toilet (removal of secretions), fluid management, and treatment of pneumonia are employed to improve pulmonary compliance (the elasticity of the lungs).

While TBI may be managed without surgery, surgical repair of the tear is considered standard in the treatment of most TBI. It is required if a tear interferes with ventilation; if mediastinitis (inflammation of the tissues in the mid-chest) occurs; or if subcutaneous or mediastinal emphysema progresses rapidly; or if air leak or large pneumothorax is persistent despite chest tube placement. Other indications for surgery are a tear more than one third the circumference of the airway, tears with loss of tissue, and a need for positive pressure ventilation. Damaged tissue around a rupture (e.g. torn or scarred tissue) may be removed in order to obtain clean edges that can be surgically repaired. Debridement of damaged tissue can shorten the trachea by as much as 50%. Repair of extensive tears can include sewing a flap of tissue taken from the membranes surrounding the heart or lungs (the pericardium and pleura, respectively) over the sutures to protect them. When lung tissue is destroyed as a result of TBI complications, pneumonectomy or lobectomy (removal of a lung or of one lobe, respectively) may be required. Pneumonectomy is avoided whenever possible due to the high rate of death associated with the procedure. Surgery to repair a tear in the tracheobronchial tree can be successful even when it is performed months after the trauma, as can occur if the diagnosis of TBI is delayed. When airway stenosis results after delayed diagnosis, surgery is similar to that performed after early diagnosis: the stenotic section is removed and the cut airway is repaired.

Different treatments have been used to manage pulmonary interstitial emphysema with variable success. Admission/transfer to a neonatal intensive care unit (NICU) is common and expected for patients with PIE.

Treatments include:

- Lateral decubitus position with the affected side down

- High-frequency ventilation

- Lobectomy

- Selective Main Bronchial Intubation and Occlusion

Barrel chest generally refers to a , deep chest found on a man. A man described as barrel chested will usually have a naturally large ribcage, very round torso, large lung capacity, and can potentially have great upper body strength. It can sometimes be a sign of acromegaly (a syndrome resulting from excess levels of human growth hormone (HGH) in the body). It is most commonly related to osteoarthritis as individuals age. Arthritis can stiffen the chest causing the ribs to become fixed in their most expanded position, giving the appearance of a barrel chest.

Barrel chest also refers to an increase in the anterior posterior diameter of the chest wall resembling the shape of a barrel, most often associated with emphysema. There are two main causes of the barrel chest phenomenon in emphysema:

1. Increased compliance of the lungs leads to the accumulation of air pockets inside the thoracic cavity.

2. Increased compliance of the lungs increases the intrathoracic pressure. This increase in pressure allows the chest wall to naturally expand outward.

Barrel chest occurs naturally in native people who live at altitudes of over 5500 m, e.g. the Himalayas or the Andes. These natives also have polycythemia and other accommodations for high altitude life.

Pulmonary interstitial emphysema often resolves gradually and may take 2–3 weeks. For longer durations of PIE the length of time of mechanical ventilation needed may increase and the incidence of bronchopulmonary dysplasia becomes higher. Some infants may develop chronic lobar emphysema, which may require surgical lobectomies.

Symptoms are usually relieved with radiation therapy within one month of treatment. However, even with treatment, 99% of patients die within two and a half years. This relates to the cancerous causes of SVC that are 90% of the cases. The average age of onset of disease is 54 years of age.

Several methods of treatment are available, mainly consisting of careful drug therapy and surgery. Glucocorticoids (such as prednisone or methylprednisolone) decrease the inflammatory response to tumor invasion and edema surrounding the tumor. Glucocorticoids are most helpful if the tumor is steroid-responsive, such as lymphomas. In addition, diuretics (such as furosemide) are used to reduce venous return to the heart which relieves the increased pressure.

In an acute setting, endovascular stenting by an interventional radiologist may provide relief of symptoms in as little as 12–24 hours with minimal risks.

Should a patient require assistance with respiration whether it be by bag/valve/mask, BiPAP, CPAP or mechanical ventilation, extreme care should be taken. Increased airway pressure will tend to further compress an already compromised SVC and reduce venous return and in turn cardiac output and cerebral and coronary blood flow. Spontaneous respiration should be allowed during endotracheal intubation until sedation allows placement of an ET tube and reduced airway pressures should be employed when possible.

The mechanism responsible for pneumopericardium is the ‘Macklin effect’ – There is initially an increased pressure gradient between the alveoli and the interstitial space. Increased pressure leads to alveolar rupture, resulting in air getting through to the pericapillary interstitial pulmonary space. This space is continuous with the peribronchial and pulmonary perivascular sheaths. From here, the air tracks to the hilum of the lung and then to the mediastinum. In case of a pericardial tear, this air enters the pericardial cavity and pneumopericardium develops. The condition may remain asymptomatic or may progress to life-threatening conditions like tension pneumopericardium or cardiac tamponade.

Respiratory disease is a common and significant cause of illness and death around the world. In the US, approximately 1 billion "common colds" occur each year. A study found that in 2010, there were approximately 6.8 million emergency department visits for respiratory disorders in the U.S. for patients under the age of 18. In 2012, respiratory conditions were the most frequent reasons for hospital stays among children.

In the UK, approximately 1 in 7 individuals are affected by some form of chronic lung disease, most commonly chronic obstructive pulmonary disease, which includes asthma, chronic bronchitis and emphysema.

Respiratory diseases (including lung cancer) are responsible for over 10% of hospitalizations and over 16% of deaths in Canada.

In 2011, respiratory disease with ventilator support accounted for 93.3% of ICU utilization in the United States.

The primary medications for lung barotrauma are oxygen, oxygen-helium or nitrox, isotonic fluids, anti-inflammatory medications, decongestants, and analgesics.

Estrogen-containing medications can exacerbate LAM and are contraindicated. Agents that antagonize the effects of estrogen have not been proven to be effective for treatment, but no proper trials have been done. A trial of bronchodilators should be considered in LAM patients, because up to 17% to 25% have bronchodilator-responsive airflow obstruction. Oxygen should be administered to maintain oxyhemoglobin saturations of greater than 90% with rest, exercise and sleep. Bone densitometry should be considered in all patients who are immobilized and/or on antiestrogen therapies, and appropriate therapy instituted for osteoporotic patients. Proper attention should be paid to cardiovascular health following natural or induced menopause. Immunizations for pneumococcus and influenza should be kept up to date. Pulmonary rehabilitation seems to be particularly rewarding in young, motivated patients with obstructive lung disease, but studies to assess this intervention's effect on exercise tolerance, conditioning and quality of life have not been done.

Isolated mechanical forces may not adequately explain ventilator induced lung injury (VILI). The damage is affected by the interaction of these forces and the pre-existing state of the lung tissues, and dynamic changes in alveolar structure may be involved. Factors such as plateau pressure and positive end-expiratory pressure (PEEP) alone do not adequately predict injury. Cyclic deformation of lung tissue may play a large part in the cause of VILI, and contributory factors probably include tidal volume, positive end-expiratory pressure and respiratory rate. There is no protocol guaranteed to avoid all risk in all applications.

The National Institute of Occupational Safety and Health, Japan (JNIOSH) set limits for acceptable exposure at 0.0003 mg/m after the discovery of indium lung. Methods for reducing indium exposure are thought to be the best mode of protection. Medical surveillance of indium workers is also a method of prevention.

There is no standardized treatment for indium lung disease. Treatment options include pulmonary lavage and corticosteroid therapy. Prognostic factors were a matter of research as of 2012, but preliminary evidence suggests that duration of employment and reported use of respiratory protection are not prognostic factors, but the serum level of indium may be a prognostic factor - higher levels of serum indium have been associated with worse prognoses. Indium lung disease has been fatal in several cases.

Lung cancer may be related to indium lung disease, though indium is not a known carcinogen.

The mediastinum (from Medieval Latin "mediastinus", "midway") is the central compartment of the thoracic cavity surrounded by loose connective tissue, as an undelineated region that contains a group of structures within the thorax. The mediastinum contains the heart and its vessels, the esophagus, trachea, phrenic and cardiac nerves, the thoracic duct, thymus and lymph nodes of the central chest.

Tumor-like disorders of the lung pleura are a group of conditions that on initial radiological studies might be confused with malignant lesions. Radiologists must be aware of these conditions in order to avoid misdiagnosing patients. Examples of such lesions are: pleural plaques, thoracic splenosis, catamenial pneumothorax, pleural pseudotumor, diffuse pleural thickening, diffuse pulmonary lymphangiomatosis and Erdheim-Chester Disease.

Sirolimus is an mTOR inhibitor that stabilizes lung function and improves some measures of life in LAM patients. It is approved by the FDA for use in LAM, based on the results of the Multicenter International LAM Efficacy and Safety of Sirolimus (MILES) Trial. MILES data supports the use of sirolimus in patients who have abnormal lung function (i.e. FEV1<70% predicted). Whether the benefits of treatment outweigh the risks for asymptomatic LAM patients with normal lung function is not clear, but some physicians consider treatment for declining patients who are approaching the abnormal range for FEV1. Sirolimus also appears to be effective for the treatment chylous effusions and lymphangioleiomyomatosis. The benefits of sirolimus only persist while treatment continues. The safety of long term therapy has not been studied.

Potential side effects from mTOR inhibitors include swelling in the ankles, acne, oral ulcers, dyspepsia, diarrhea, elevation of cholesterol and triglycerides, hypertension and headache. Sirolimus pneumonitis and latent malignancy are more serious concerns, but occur infrequently. Sirolimus inhibits wound healing. It is important to stop therapy with the drug for 1–2 weeks before and after elective procedures that require optimal wound healing. Precautions must be taken to avoid prolonged sun exposure due to increased skin cancer risk.

Treatment with another mTOR inhibitor, everolimus, was reported in a small, open-label trial to be associated with improvement in FEV1 and six-minute walk distance. Serum levels of VEGF-D and collagen IV were reduced by treatment. Adverse events were generally consistent with those known to be associated with mTOR inhibitors, although some were serious and included peripheral edema, pneumonia, cardiac failure and "Pneumocystis jirovecii" infection. Escalating doses of everolimus were used, up to 10 mg per day; higher than what is typically used clinically for LAM.

Serum VEGF-D concentration is useful, predictive and prognostic biomarker. Higher baseline VEGF-D levels predicts more rapid disease progression and a more robust treatment response.

Hormonal approaches to treatment have never been tested in proper trials. In the absence of proven benefit, therapy with progesterone, GnRh agonists (e.g., Lupron, goserelin) and tamoxifen are not routinely recommended. Doxycycline had no effect on the rate of lung function decline in a double blind trial.

Sirolimus is often effective as first-line management for chylothorax. If chylous leakage or accumulations persist despite treatment, imaging with heavy T2 weighted MRI, MRI lymphangiography or thoracic duct lymphangiography can be considered. Pleural fusion procedures can be considered in refractory cases.

Infliximab, an immune-suppressing antibody, has been tested in COPD; there was a possibility of harm with no evidence of benefit.

Roflumilast, cilomilast, and phosphodiesterase 4 inhibitors act as a bronchodilator and as an anti-inflammatory. They show promise in decreasing the rate of exacerbations, but do not appear to change a persons quality of life. Roflumilast and cilomilast may be associated with side effects such as gastrointestinal issues and weight loss. Sleep disturbances and mood disturbances related to roflumilast have also been reported.

Several new long-acting agents are under development. Treatment with stem cells is under study. While there is tentative data that it is safe, and the animal data is promising, there is little human data as of 2017. The human data has shown poor results.

A procedure known as target lung denervation, which involves decreasing the parasympathetic nervous system supply of the lungs, is being studied but does not have sufficient data to determine its use. The effectiveness of alpha-1 antitrypsin augmentation treatment for people who have alpha-1 antitrypsin deficiency is unclear.

Research continues into the use of telehealthcare to treat people with COPD when they experience episodes of shortness of breath; treating people remotely may reduce the number of emergency-room visits and improve the person's quality of life.

Respiratory disease is a medical term that encompasses pathological conditions affecting the organs and tissues that make gas exchange possible in higher organisms, and includes conditions of the upper respiratory tract, trachea, bronchi, bronchioles, alveoli, pleura and pleural cavity, and the nerves and muscles of breathing. Respiratory diseases range from mild and self-limiting, such as the common cold, to life-threatening entities like bacterial pneumonia, pulmonary embolism, acute asthma and lung cancer.

The study of respiratory disease is known as pulmonology. A doctor who specializes in respiratory disease is known as a pulmonologist, a chest medicine specialist, a respiratory medicine specialist, a respirologist or a thoracic medicine specialist.

Respiratory diseases can be classified in many different ways, including by the organ or tissue involved, by the type and pattern of associated signs and symptoms, or by the cause of the disease.

Supplemental oxygen is recommended in those with low oxygen levels at rest (a partial pressure of oxygen less than 50–55 mmHg or oxygen saturations of less than 88%). In this group of people, it decreases the risk of heart failure and death if used 15 hours per day and may improve people's ability to exercise. In those with normal or mildly low oxygen levels, oxygen supplementation may improve shortness of breath when given during exercise, but may not improve breathlessness during normal daily activities or affect the quality of life. A risk of fires and little benefit exist when those on oxygen continue to smoke. In this situation, some recommend against its use. During acute exacerbations, many require oxygen therapy; the use of high concentrations of oxygen without taking into account a person's oxygen saturations may lead to increased levels of carbon dioxide and worsened outcomes. In those at high risk of high carbon dioxide levels, oxygen saturations of 88–92% are recommended, while for those without this risk, recommended levels are 94–98%.