wiki:respiratory:pneumothorax

Pneumothorax

ie air in the pleural cavity with consequences and management dependent on the degree of lung collapse

spontaneous
- associated with smoking (in some studies >100x more likely), chronic lung disease eg COPD
- often taller patients
- NOT associated with exercise
- hereditary
- others - abnormal connective tissue, related to distal airway inflammation, apical ischaemia, low BMI etc
iatrogenic
traumatic
catamenial
- R sided pneumothorax, generally in women 30-40y with symptoms within 48/24 of menstruation
- cause unknown but many have associated endometriosis
- one theory suggest PGF2, which is elevated in ovulation, causes bronchoconstriction which may be associated with small ruptures

may or may not present with pain, SOB
examination findings of reduced air sounds, hyper-resonance on percussion rarely
deviated trachea (with tension), subcutaneous emphysema and pneumo-mediastinum on CXR
associated physiological signs - tachycardia, hypotension, pulsus paradoxus, ↑JVP
clinical symptoms associated with secondary pneumothorax are generally more severe than a similar sized primary pneumothorax
CXR should not demonstrate tension pneumothorax!! - this is a clinical finding and should have been treated before CXR!

BTS pleural disease guideline 2010

expiratory CXR no greater accuracy than inspiratory
size of pneumothorax generally not as important as clinical consequences, although 'large' is generally viewed as being >2cm at apex on PA CXR in UK and >3cm in USA
- methods of estimation of size are debatable. CT is better but exact estimation not necessarily important
- spontaneous resolution of primary spontaneous pneumothorax (PSP) - rate of ~2% per 24/24. Resolution 4x faster with O2 therapy and therefore reserved for IP Mx

Collins method - % = 4.2 + 4.7 (A + B + C)
A is the maximum apical interpleural distance B is the interpleural distance at midpoint of upper half of lung C is the interpleural distance at midpoint of lower half of lung

landmarks - ant to mid-axillary line, 5th ICS
remembering that neurovascular bundle lies 'below the rib above' with vein then artery then nerve. (VAN from above down)
2-3cm transverse incision in line with superior border of rib, to avoid the main N/vasc bundle. (there are smaller collateral branches here though)
blunt dissection to pleura and finger then to 'probe' canal
using forceps clamped on end of drain, insert into space
connect to drain bag
suturing and dressing to ensure confident fixing of drain to chest wall