Pneumothorax Flashcards
What is a pneumothorax?
Pneumothorax occurs when air gains access to, and accumulates in, the pleural space- the potential space between visceral and parietal pleura
Explain the consequences of a pneumothorax
- Usually there is a balance b/t 2 opposing forces: the muscle tension of the diaphragm & chest wall and the elastic recoil of the lungs
- The muscle tension expands outwards whilst the elastic recoil of the lungs pulls inwards and this creates a vaccum in pleural space
- When air moves in the balance is lost: the lungs pull in and collapse and the chest wall springs out
- This decreases oxygen and increases CO2
What are the different causes/ types of pneumothorax?
- Spontaneous:
o Occurs in people with typically normal lungs
o Typically in tall, thin males
o It is probably caused by the rupture of a subpleural bleb (bulla- usually formed from a leak from an alveoli)
- can be primary or secondary - Traumatic:
o Caused by penetrating injury to the chest (stab wound, gunshot)
o Often iatrogenic (e.g. during jugular venous cannulation, thoracocentesis, transbronchial biopsy, subclavian CVP line insertion, +ve pressure ventilation) - Tension:
- life-threatening variant.
- Complication of primary + secondary spontaneous pneumothorax & traumatic pneumothorax.
- Creates one way valve, air can enter pleural space, but not leave hence shifts trachea and can press on heart (reducing cardiac output
What is a spontaneous pneumothorax?
- Spontaneous:
o Occurs in people with typically normal lungs
o Typically in tall, thin males
o It is probably caused by the rupture of a subpleural bleb (bulla- usually formed from a leak from an alveoli)
- can be:
a. PRIMARY: in patients without underlying lung disease:
- thin, tall, adolescent (16-25 yrs old), male, holding breath
OR
b. SECONDARY: complication of underlying lung disease (eg. COPD, Marfan’s syndrome, Cystic fibrosis, Emphysema, Lung cancer)
What is a traumatic pneumothorax?
Traumatic:
o Caused by penetrating injury to the chest (stab wound, gunshot)
o Often iatrogenic (e.g. during jugular venous cannulation, thoracocentesis, transbronchial biopsy, subclavian CVP line insertion, +ve pressure ventilation)
What is a tension pneumothorax?
Tension:
- life-threatening variant.
- Complication of primary + secondary spontaneous pneumothorax & traumatic pneumothorax.
- Creates one way valve, air can enter pleural space, but not leave hence shifts trachea and can press on heart (reducing cardiac output):
- Will cause hypotension due to cardiac outflow obstruction (due to mediastinal shift). Severe hypotension is what causes death.
- Suspect if sudden deterioration following intubation
What are the risk factors for a pneumothorax?
Smoking, FH, Tall & Slender body, <40 years, Recent invasive medical procedure (Chest drain), Chest Trauma, COPD, Cystic Fibrosis, Marfan’s Disease
What presenting symptoms of a pneumothorax can be found in the history?
- May be ASYMPTOMATIC if the pneumothorax is small
- Sudden-onset breathlessness (dyspnoea)
- Pleuritic chest pain
- Sweating, tachypnoea, tachycardia
- Distress with rapid shallow breathing in tension pneumothorax
- Patients on ventilation may present with hypoxia or increase in ventilation pressures
What signs of a pneumothorax can be found on physical examination?
● There may be NO signs if the pneumothorax is small
● Signs of respiratory distress
● Reduced expansion on affected side
● Hyper-resonance to percussion on affected side
● Reduced breath sounds on affected side
- Decreased fremitus/ vocal resonanse
- Tachycardic & tachypnoeic
What signs of a tension pneumothorax can be found on physical examination?
o Severe respiratory distress
o Tachycardia
o Hypotension- circulatory shock
o Cyanosis
o Distended neck veins
o Tracheal deviation away from the side of the pneumothorax
o Increased percussion note, reduced air entry/breath sounds on affected side
What investigations are used to diagnose/ monitor a pneumothorax?
- Chest X-Ray → first line in stable patient who can sit upright (Order an erect PA x-ray in inspiration) ⇒ visible rim between the lung margin and chest wall + absence of lung markings between the lung margin and chest wall
- FBC & Clotting Screen → should all be normal
- Chest Ultrasound → can be done if patients are immobilised following trauma and CXR can not be done. Requires specialist expertise.
- CT Chest- gold standard but not routinely performed
- ABG - Check for hypoxaemia (respiratory failure)
- ECG- to rule out cardiac cause
How is a pneumothorax managed?
Primary Pneumothorax w/o SOB + <2cm ⇒ discharge and review in 2-4 wks (follow up as outpatient)
Primary Pneumothorax w/ SOB or >2cm ⇒ aspiration. If unsuccessful, then chest drain.
Secondary Pneumothorax w/o SOB + 1-2cm ⇒ aspiration
(If w/o SOB + <1cm, then give oxygen and admit for 24 hours)
Secondary Pneumothorax >2cm or SOB ⇒ chest drain
Chest Drain Borders = anterior border of latissimus dorsi, lateral border of pectoralis major, line level at 4/5th intercostal space, apex below the axilla
Tension Pneumothorax → insert large bore cannula (14G-16G) in 5th ICS, MCL (needle decompression) (on ipsilateral side)
Discharge Advice → stop smoking, scuba diving should be permanently avoided.
Identify the possible complications of pneumothorax
● Recurrent pneumothoraces
● Bronchopleural fistula
Summarise the prognosis for patients with pneumothorax
● After having one pneumothorax, at least 20% will have another
● Frequency increases with repeated pneumothoraces
What is done in this case of a “persistent alveolar leak”?
persistent alveolar leak, defined as an ongoing pneumothorax lasting 48 hours or greater. In these cases, intervention may be required by thoracic surgery, such as a VATS pleurodesis.
