Background

gas in the pleural space can cause lung collapse and V:Q mismatch

Categorization and Etiology

Primary spontaneous pneumothorax (PSP)

no apparent lung disease, but majority of cases develop due to the rupture of subpleural blebs or bullae.
population/risk factors:
- characteristically affects men < 30 with asthenic body types
- smoking both cigarettes and cannabis is a risk factor (dose-dependent) --> smoking cessation management
very rare to present/convert to tension PTX

Secondary spontaneous pneumothorax (SSP)

occurs in patients with underlying lung disease
more likely to be symptomatic and lack the reserve to compensate for V:Q mismatch
most common in Chronic obstructive pulmonary disease (COPD), but also in:
- airway disease: chronic obstructive pulmonary disease, cystic fibrosis, status asthmaticus
- infectious lung disease:Pneumocystis carinii pneumonia, necrotizing pneumonias (caused by anaerobic, gram-negative bacteria or staphylococcus)
- interstitial lung disease: sarcoidosis, idiopathic pulmonary fibrosis, Langerhans’-cell granulomatosis, lymphangioleiomyomatosis, tuberous sclerosis
- connective-tissue disease: rheumatoid arthritis (causes pyopneumothorax), ankylosing spondylitis, polymyositis and dermatomyositis, scleroderma, Marfan syndrome, Ehlers–Danlos syndrome
- cancer: sarcoma, lung cancer
- thoracic endometriosis (related to menses; causes catamenial pneumothorax)

Traumatic (iatrogenic) pneumothorax

due to penetrating or blunt chest trauma
iatrogenic causes: chest tube), central line, etc.)

Examination/Investigations

look for: dyspnea, pleuritic chest pain [shoulder tip], decreased diaphragmatic excursion, decreased breath sounds, loss of tactile fremitus, hyperresonant percussion, subcutaneous emphysema, hemodynamic collapse.
imaging:
- CXR (upright is best)
- ultrasound (more sensitive, Sens/Spec > 90% in ICU patients)
- CT chest

Management of First PSP

Initial Assessment and Stabilization

Airway, Breathing, Circulation. Supplemental oxygen if hypoxemic.
Assess the size and stability of the issue:
- Size: small is < 2-3 cm between the pleural line and the chest wall at the level of the hilum, and large is >2-3 cm. This is done on CXR or CT.
- Stable: controlled respiratory rate, controlled HR and blood pressure, SpO2 > 90%, and able to speak in whole sentences. All other patients are defined as unstable.

Unstable Patients

Immediatechest tubed) thoracostomy, or if delayed, then needle decompression.
Tension PTX is rare in PSP

Initial Management

Primary Spontaneous Pneumothorax

Small PSP

If first episode of PSP, then these patients can be treated with observation +/- oxygen. Hospital admission generally not required.
Supplemental oxygen theoretically improves resolution of the PTX by promoting nitrogen/air absorption. Target SpO2 >96-100% (unclear evidence), avoid positive pressure if possible (HFNC, NIV). Try for about 4-6 hours then get a repeat CXR
if there are significant attributable symptoms, then consider aspiration ochest tubemd) thoracostomy (as well as searching for other lung disorders or diagnoses).

Large PSP

First episode of PSP: consider all of the following:
- aspiration. Most guidelines suggest the standard of care with a large stable first PSP is needle or catheter aspiration.
  - continue aspiration until resistance is felt or 2.5-4L of air is aspirated
  - Catheter could be left in place with a Heimlich valve (See below) chest tube.md) thoracostomy +/- ambulatory device
- Initial observation only approach is supported by the recent PSP trial (NEJM 2020) which suggests that conservative observational management of PSP is noninferior to interventional management, with a lower risk of serious adverse events. Patients should be generally healthy with mild symptoms, no hemodynamic compromise, no supplemental oxygen requirement, and ambulatory.

Heimlich valve Chest Tubes.md) Management

PSP

Size/Device:
- In most patients with PSP, a small-chest tubees.md) (≤22 Fr) or chest catheter (≤14 Fr) is placed. In most cases, a small caliber tube or catheter is sufficient for the drainage of air in patients with PSP. It is unusual in this population that an indication for a largechest tubeies.md) (eg, 22 to 28 Fr) is present unless the patient is unstable with tension pneumothorax, concomitant drainage of viscous pleural fluid (eg, empyema) or blood is needed, or small-bore catheter drainage is insufficient.
- One systematic review that compared smalpigtailmies.md) catheters with larchest tubesomies.md) in patients with both PSP and secondary spontaneous pneumothorax (SSP) reported that the success rate was similar in both groups (80 versus 83 percpigtailtomies.md) catheters had a lower complication rate (odds ratio 0.49) and shorter drainage duration (mean difference -1.51 days) and hospital stay (mean difference -2.54 days).
Suction
- For the majority of patients, suction is not initially applied and the tube or catheter is connected to a water seal device only. Lung re-expansion is achieved in 70 percent of patients within 72 hours without suction
- If the lung fails to re-expand within the subsequent 24 to 48 hours, worsenchest tubestomies.md) drainage, or develops a persistent air leak, low wall suction can be applied and, in some cases, a second drainage device may be needed. If suction is applied, we generally start with low rates of -10 cm H2O and increase to -20 cm H2O using a high pressure-low volume system; other forms of suction using high pressure-high volume or low pressure-high volume systems should be avoided.
  - prolonged use of suction may lead to a delay in definitive management by prolonging air flow through the leak, thereby slowing down the natural healing of a ruptured bleb
Followup thoracostomy management
- daily assessment of symptoms, air leak, complications of the chest thoracostomy (blockade, pain, bleeding). Daily CXR is not always required.
- once the air leak is sealed, then clamp the tube/catheter
  - serial assessment + followup CXR
  - if PTX not recurred, then the tube can be removed
  - if the PTX recurs, then unclamp and repeat the process

Management of Persistent or Recurrent PSP

indications for this strategy:
- prolonged air leak [PAL] (>5 days)
- recurrent PSP
therapeutic options:
- pleurodesis
- VATS > open thoracotomy

Air Travel

Recommendations for air travel passengers after pneumothorax are largely based on anecdotal case reports [110, 111]. A pneumothorax, especially an undrained pneumothorax, is however an absolute contraindication to commercial air travel [112]. Definitive treatment reduces the risk of recurrence and makes air travel safer [110]; however, an individual clinical decision is usually made by the treating clinician, taking into account both airline policy and details of relevant insurance.