Makindo Medical Notes.com

Related Subjects: Asthma |Acute Severe Asthma |Exacerbation of COPD |Pulmonary Embolism |Cardiogenic Pulmonary Oedema |Pneumothorax |Tension Pneumothorax |Respiratory (Chest) infections Pneumonia |Fat embolism |Hyperventilation Syndrome |ARDS |Respiratory Failure |Diabetic Ketoacidosis

Treatment depends critically on whether it is a primary or secondary pneumothorax. Underlying lung disease means it is secondary and it is treated far more cautiously. Suspect a pneumothorax in any mechanically ventilated patient whose respiratory function deteriorates. It may only be detected by an increase in resistance to ventilation

About

• Spontaneous presence of air in the pleural space.
• Aged over 50 or with lung disease are classed as secondary and need admitted

Mechanism

• Penetrating from a hole in the visceral pleura into the lung
• Penetrating wound from oesophagus, mediastinum, diaphragm and associated structures
• Gas forming bacteria within an empyema

Types

• Primary - defined as age less than 50y, no significant smoking history, and no evidence of underlying lung disease
• Secondary - due to known lung disease
• Traumatic (consider under Trauma)

Classification

• Primary Pneumothorax
  • Tall thin males aged 20-40 seem to be more at risk and commoner on right.
  • Commoner in smokers possibly have subclinical lung disease
  • Increased stresses on the lung apices in tall people cause a predisposition to subpleural bleb formation which can later cause a pneumothorax
  • Risk of recurrence is 40% within 2 years especially tall who smoke
• Secondary Pneumothorax
  • Trauma - especially penetrating chest trauma
  • Iatrogenic trauma - pleural biopsy, lung biopsy, central line insertion
  • High positive end-expiratory pressure ventilation
  • Asthma, Cystic fibrosis, Emphysema
  • Lung abscess, PCP pneumonia
  • Idiopathic pulmonary fibrosis, Sarcoidosis
  • Endometriosis/Catamenial pneumothorax - occurs within 72 hours of menses
  • Oesophageal rupture
  • Lymphangioleiomyomatosis, Lung carcinoma
  • Histiocytosis X, Eosinophilic granuloma
  • Marfan's syndrome, Homocystinuria
• Iatrogenic Pneumothorax
  • Attempted internal jugular/subclavian vein access
  • Pleural aspiration/biopsy
  • Percutaneous lung/liver biopsy
  • Transbronchial biopsy
  • Intermittent positive pressure ventilation

Clinical

• May be asymptomatic
• Breathless - may be mild in small PTX
• Tachycardia, hypotension, cyanosis when severe or tension
• Localised chest pain and even a click or added sounds
• Affected side is hyper resonant with decreased breath sounds
• Tension pneumothorax the trachea is pushed away

Investigations

• PA CXR shows an absence of lung markings between the ribs and a line demarcating the edge of the lung. Expiratory films are no longer advocated. Lateral CXR may help if PTX is suspected and the PA chest is not definitive.
• Size of Pneumothorax - For the purposes of the current guidelines, "small" is regarded as a pneumothorax of a rim of air <2 cm and "large" as a pneumothorax of > 2 cm.
• High resolution CT scan is becoming used for management and decisions on best place to place drain in complex cases and in detecting small pneumothoraxes and differentiating pneumothorax from bullae. Also the scanners are now much faster and a scan can be done in under a minute.

Left sided PTX with drain placed and possible blocked needing repositioned

Differential

• Bullous Disease: Do not confuse a large bulla with a pneumothorax: old CXRs on PACS archive may help. If in doubt, discuss with a radiologist and obtain a chest CT prior to drain insertion if appropriate.

Simple Aspiration

• Explain and obtain consent. Use sterile gloves. Sterile field.
• Infiltrate with Lidocaine 5-10 ml down to pleura in 2nd ICS in MCL or use the safety triangle. Aspirate air with a green needle.
• Use a 16 FG cannula (or less) at least 3 cm long. Insert at 90 degrees to the skin. Advance plastic cannula to hilt
• Once in pleural space, begin and remove needle as soon as tip within chest space.
• Connect cannula via three-way tap to the chest, 50 mL syringe.
• Aspirate and expel the air until resistance is felt, or patient coughs or complains of discomfort, or when 2.5 L aspirated.
• Remove cannula and apply a dressing. Repeat CXR to see if partially re-expanded and assess the clinical state

Indications for Chest drain in Spontaneous Pneumothorax

• Large (> 2 cm) symptomatic Primary Pneumothorax, after failed aspiration
• Large (>2 cm) Secondary Pneumothorax
• 1-2 cm Symptomatic Secondary Pneumothorax, after failed aspiration (If shallow pneumothorax may need CT guided drain).
• Pneumothorax of any size in a ventilated patient
• Tension Pneumothorax
• Bilateral pneumothorax.

Management

• ABC. Oxygen 15L/min (caution if COPD) as this helps by a factor of four. Ensure adequate analgesia if the pain is an issue.
• No evidence that large chest drains are more effective except in trauma. Smaller drains (e.g. = 16 Fr) are easier to insert and better tolerated by the patient.
• Those with chest drains best managed in a ward used to dealing with them (e.g. respiratory ward) to minimise complications.
• Failure to respond to treatment within 48 hours, needs respiratory physician consult.
• Get an HRCT if needed to help differentiate PTX from bullous disease, where PTX complex and drain placement is difficult e.g. partial adherence of lung to the chest wall or Incorrect tube placement is suspected or CXR obscured by surgical emphysema.
• Primary Pneumothorax (Age < 50, No lung disease)
  • If <2 cm and not breathless: consider discharge. Referral to chest clinic in 2 weeks. Advise return to ED immediately if more breathless or chest pain. In meantime NO diving NO flying and NO smoking. Document this.
  • If Breathless and/or PTX >2 cm rim on CXR: Aspirate. If still unsuccessful: insert the intercostal drain
• Secondary Pneumothorax (Age > 50, Smoker/lung disease)
  • All require admission overnight for next day review and High flow oxygen unless COPD
  • If 1-2 cm: Aspirate and if now < 1 cm give Oxygen and keep overnight for review next day.
  • If 1-2 cm: Aspirate and if no change or worse then Chest drain 8-14 French and admit and give oxygen
  • If > 2 cm or breathless the Chest drain 8-14 French and admit and give oxygen
• Air will continue to leak into the pleural space until the bleb has sealed and closed. With a chest drain in any pleural air is expelled on inspiration through the one-way system and the drain will bubble when the patient is asked to cough. The swinging of the drain just reflects intra-pleural pressures and shows that the tube is not blocked. A bubbling chest drain should never be clamped.
• The administration of supplemental oxygen e.g. 100% accelerates the rate of pleural air absorption and can be given as long as the patient is hospitalized as the absence of Nitrogen will lower the partial pressures and greatly improve the diffusion gradient
• Persistent bubbling on coughing suggests discussion with the thoracic team and thoracic surgeons as a bronchopleural fistula may have formed and the patient may require video-assisted thorascopic surgery (VATS) to repair any persistent leak. Once the bleb has sealed and air has to stop accumulating in the pleural space the drain should be removed. A repeat CXR should be done. Removing the drain - remove the suture holding the chest drain in place, withdraw the tube while the patient holds their breath in full inspiration. Use the two remaining sutures to seal the wound.
• Patients discharged without intervention should avoid air travel until a CXR has confirmed resolution of the PTX and many airlines will want a gap of 6 weeks between a resolved PTX and flying. If no intervention is necessary then there is a risk of recurrence for up to 1 year. Diving should be permanently avoided after a PTX unless the patient has had a bilateral surgical pleurodesis
• Pleurodesis may be chemical using tetracycline or talc which induces an inflammatory reaction in the pleural space causing the pleural and visceral pleural to fuse. Alternatively, bilateral surgical pleurectomy can be undertaken.

References

• Management of spontaneous pneumothorax: British Thoracic Society pleural disease guideline 2010
• NHS Guidelines for Spontaneous Pneumothorax