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pneumothorax

pneumothorax

introduction

  • spontaneous pneumothorax:
    • can be divided into:
      • primary:
        • no clinically evident underlying lung pathology and no inciting event
        • most are aged 18-40 years and have subclinical lung pathology
        • most young persons are tall and thin, but other risk factors include smoking (91% smoke!), family history (eg. Birt-Hogg-Dube sydrome and other familial clustering conditions), Marfan syndrome, homocystinuria, malnutrition (eg. anorexia nervosa), and thoracic endometriosis
        • usually occurs at rest
        • recurrence occurs in 25-50% of patients
      • secondary:
        • occurs in those with underlying lung disease such as emphysema, cystic fibrosis, tuberculosis, or almost any other lung disease
        • pneumothorax in HIV / AIDS patients is potentially fatal and may be caused by intravenous drug users (IVDU) or injection drug use (IDU), Pneumocystis jirovecii pneumonia with use of aerosilised pentamidine, Kaposi's sarcoma, toxoplasmosis, and a range of other infections
  • iatrogenic or traumatic pneumothorax:
    • may result from inadvertent penetration into the pleura during medical procedures such as central venous line placement
    • may result from mechanical ventilation
    • may result from blunt or penetrating trauma to the chest
  • tension pneumothorax:
    • particularly a risk in pneumothorax patients who either:
      • open chest trauma
      • lung injury with persistent air leak
      • mechanical ventilation
    • but can occur in any pneumothorax (1-2% of primary spontaneous pneumothoraces)
    • it is a risk following clamping of an intercostal catheter
    • results from increasing air pressure within the pleural space which causes decreased venous return to the heart, collapse of the ipsilateral lung, mediastinum pushed to contralateral side with increasing difficulty in respiration and resultant congested neck veins, severe hypotension and cyanosis, leading to death if not treated.
    • this is a true medical emergency which requires treatment before investigations as it is essentially a clinical bedside diagnosis.

ED Mx of spontaneous pneumothorax

  • if clinical tension pnumothorax
    • immediate decompression with 10-14G needle into 2nd ICS MCL and leave in situ until chest drain inserted
  • inspiratory CXR to confirm pneumothorax
  • 100% oxygen
  • consider chest drain and underwater seal and possible admit under thoracic medicine or respiratory medicine unit for further Mx if either:
    • tension pneumothorax
    • positive pressure ventilation
    • a secondary pneumothorax or recurrent primary pneumothorax with either:
      • breathlessness
      • SaO2 < 95%, or,
      • > 2cm intrapleural space at hilum
    • deterioration after simple aspiration
    • high risk for large air leak
  • if above are not present but either > 2cm intrapleural gap at hilum, SaO2 < 95%, or patient is breathless then needle-catheter aspiration:
    • consider Cook's catheter placement into 4th or 5th ICS AAL or MAL then either:
      • attach stopcock, secure catheter to chest wall and close after aspiration of < 2.5L air, repeat CXR in 4 hours, if adequate expansion, then remove catheter. Repeat CXR 2 hours later and if all well, discharge home.
      • attach Heimlich valve, secure catheter to chest wall, check CXR, if all well, discharge home and r/v within 48hrs for repeat CXR and removal of catheter.
  • expectant Mx with no aspiration if above features are not present
    • ie. intrapleural space < 2cm at hilum AND not breathless AND SaO2 > 94%
    • NB. consider aspiration for secondary pneumothoraces with intrapleural gap at hilum 1-2cm
    • primary cases can be discharged home if no deterioration after 4-6hrs post-onset (consider admission to ED observation unit)
    • secondary cases should probably be admitted to an inpatient ward for prolonged observation and given oxygen if tolerated
  • most believe patients are safe to go on commercial air flights after 2 weeks of resolution of pneumothorax
  • patients should be advised to stop smoking
  • outpatient follow up:
    • 1st presentation pneumothorax: refer to respiratory outpatients
    • recurrent pneumothorax: refer to thoracic surgery outpatients for consideration for pleurodesis

British Thoracic Society guidelines

    • if tension pneumothorax is present, a cannula of adequate length should be promptly inserted into the second intercostal space in the mid clavicular line and left in place until a functioning intercostal tube can be positioned.
    • the size of a pneumothorax is divided into “small” or “large” depending on the presence of a visible rim of <2 cm or >2 cm between the lung margin and the chest wall.
    • patients with small (<2 cm) primary pneumothoraces not associated with breathlessness should be considered for discharge with early outpatient review. These patients should receive clear written advice to return in the event of worsening breathlessness.
      • patients discharged without intervention should avoid air travel until a chest radiograph has confirmed resolution of the pneumothorax.
    • if a patient with a pneumothorax is admitted overnight for observation, high flow (10 l/min) oxygen should be administered, with appropriate caution in patients with COPD who may be sensitive to higher concentrations of oxygen.
      • the normal rate of resorption is approximately 1.25 percent of the volume of the hemithorax per 24 hours, the rate of resorption increases six-fold if humidified 100 percent oxygen is administered in an animal model.
    • breathless patients should not be left without intervention regardless of the size of the pneumothorax on a chest radiograph.
    • simple aspiration is recommended as first line treatment for all primary pneumothoraces requiring intervention.
    • primary pneumothorax patients treated successfully by simple aspiration should be observed to ensure clinical stability before discharge.
    • repeated aspiration is reasonable for primary pneumothorax when the first aspiration has been unsuccessful (i.e. patient still symptomatic) and a volume of <2.5 l has been aspirated on the first attempt.
    • catheter aspiration of pneumothorax (CASP) can be used where the equipment and experience is available.
    • catheter aspiration kits with an integral one way valve system may reduce the need for repeat aspiration.
    • if simple aspiration or catheter aspiration drainage of any pneumothorax is unsuccessful in controlling symptoms, then an intercostal tube should be inserted.
    • intercostal tube drainage is recommended in secondary pneumothorax except in patients who are not breathless and have a very small (<1 cm or apical) pneumothorax.
    • there is no evidence that large tubes (20–24 F) are any better than small tubes (10–14 F) in the management of pneumothoraces. The initial use of large (20–24 F) intercostal tubes is not recommended, although it may become necessary to replace a small chest tube with a larger one if there is a persistent air leak.
    • suction to an intercostal tube should not be applied directly after tube insertion, but can be added after 48 hours for persistent air leak or failure of a pneumothorax to re-expand.
    • a bubbling chest tube should never be clamped.
    • a chest tube which is not bubbling should not usually be clamped.
    • if a chest tube for pneumothorax is clamped, this should be under the supervision of a respiratory physician or thoracic surgeon, the patient should be managed in a specialist ward with experienced nursing staff, and the patient should not leave the ward environment.
    • if a patient with a clamped drain becomes breathless or develops subcutaneous emphysema, the drain must be immediately unclamped and medical advice sought.
    • diving should be permanently avoided after a pneumothorax, unless the patient has had bilateral surgical pleurectomy.

References

pneumothorax.txt · Last modified: 2014/04/07 12:38 by gary1