Tension pneumothorax is rare in civilian trauma care settings, but is one of the leading causes of preventable death on the modern battlefield. Without treatment, tension pneumothorax rapidly progresses to shock and death, and the first emergency treatment of choice is needle decompression.
Autopsy studies of chest wall thickness in military service members demonstrate that at least a 3.25 inch, 14-16 gauge angiocath is required to penetrate the chest wall and pleural cavity in most military casualties. This information is relevant to the civilian EMS and ED patient populations, since treatment must accommodate patients with all types of body habitus.
The standard civilian recommendation for needle decompression is needle placement into the affected side of the chest, at the second intercostal space in the midclavicular line, just above the rib to avoid the intercostal artery. However, several military studies support an alternative approach in the fourth or fifth intercostal space at the anterior axillary line . This placement recommendation is based on the relatively thinner chest wall at the anterior axillary line and the decreased chance of injuring vital organs in the lateral chest compared to the central chest .