PTXtensionA patient arrives in PEA arrest and you note that her left chest has no breath sounds or lung sliding on bedside ultrasound. You suspect a tension pneumothorax.

You insert a standard 14g angiocather in the left 2nd intercostal space (ICS). You don’t hear a rush of air. The patient’s clinical condition deteriorates to impending asystole. How sure are you that your angiocatheter actually reached the pleural space?

Trick of the Trade #1:

If aiming for the mid-clavicular 2nd ICS, go more lateral than you think. The clavicle ends in the shoulder, not the lateral chest wall! (1)

  • Ferrie et al study: Dots are where emergency physicians would have inserted an angiocatheter. Vertical line is the true mid-clavicular line.

Trick of the Trade #2:

Insert angiocatheter at the 5th ICS along the mid-axillary line, similar to the location of a chest tube.

  • Cadaver study by Inaba et al (2): Average chest wall thickness was 3.5 cm ± 0.9 cm at mid-axillary 5th ICS vs 4.5 cm ± 1.1 cm at mid-clavicular 2nd ICS
  • Success needle thoracostomy placement was 100% (5th ICS) vs 58% (2nd ICS)
  • Use at least a 5 cm angiocatheter.


Trick of the Trade #3:

Regardless of whether you use the mid-clavicular 2nd ICS or mid-axillary 5th ICS, use a longer angiocatheter than a traditional 3 cm IV angiocatheter. Otherwise it won’t reach the pleural space!

  • Example: Use the 6.3 cm angiocatheter often found in central line kits.
  • The average chest wall thickness at the 2nd ICS in a retrospective study in Canada was (3):

Thanks to Dr. Scott Weingart (@emcrit). Listen to the podcast for more tips and suggestions on this topic at his EMCrit blog!


  1. Ferrie EP, Collum N, McGovern S. The right place in the right space? Awareness of site for needle thoracocentesis. Emerg Med J. 2005 Nov;22(11):788-9. Pubmed. Free PDF article
  2. Inaba K, Branco BC, Eckstein M, Shatz DV, Martin MJ, Green DJ, Noguchi TT, Demetriades D. Optimal positioning for emergent needle thoracostomy: a cadaver-based study. J Trauma. 2011 Nov;71(5):1099-103; discussion 1103. Pubmed .
  3. Zengerink I, Brink PR, Laupland KB, Raber EL, Zygun D, Kortbeek JB. Needle thoracostomy in the treatment of a tension pneumothorax in trauma patients: what size needle? J Trauma. 2008 Jan;64(1):111-4. Pubmed .
Michelle Lin, MD
ALiEM Founder and CEO
Professor and Digital Innovation Lab Director
Department of Emergency Medicine
University of California, San Francisco
Michelle Lin, MD


Professor of Emerg Med at UCSF-Zuckerberg SF General. ALiEM Founder @aliemteam #PostitPearls at Bio:
Michelle Lin, MD