Radiologic assessment of potential sites for needle decompression of a tension pneumothorax.

BACKGROUND: The recommended treatment of suspected tension pneumothorax is immediate needle decompression. Recommended sites and needle sizes for this procedure vary, and there are published reports of failed decompression as well as iatrogenic hemothorax. We investigated the optimal needle length and relative safety of three potential needle decompression sites.
METHODS: Using thoracic computed tomography scans of 100 adults, we measured the distance from skin surface to pleura and to intrathoracic structures at the level of the sternal angle at the midhemithoracic line (MHL), and at the level of the xiphoid process at the anterior axillary and midaxillary lines, as well as the distance from the sternal midline to internal mammary vessels.
RESULTS: Median distances from the midline to the MHL and internal mammary vessels were 6.1 and 3.0 cm, respectively. Median (range) depth-to-pleura below the skin surface at the MHL, midaxillary lines, and anterior axillary line sites was 3.1 (1.4-6.9), 3.5 (1.7-9.3+), and 2.6 (1.0-7.7+) cm, respectively. Overall, there was a lower margin of safety on the left side compared with the right side, and the MHL site was safest on both sides.
CONCLUSIONS: Needle decompression of suspected tension pneumothorax should be attempted in the MHL at the level of the sternal angle using a needle at least 7 cm long inserted perpendicular to the horizontal plane. This approach should yield the highest success rate and margin of safety compared with other sites.