Using Ultrasound to Determine Optimal Location for Needle Decompression of Tension Pneumothorax: A Pilot Study.

Background: Chest injury can result in life-threatening complications like tension pneumothorax, in which rapid deterioration can occur without decompression. Traditionally, the second intercostal space (ICS) along the mid-clavicular line is taught as the site for decompression. However, this has been questioned due to high rates of treatment failure. The fifth ICS on the mid-axillary line (MAL) is hypothesized to have a shorter distance from skin to pleura based on recent studies.

Objective: The purpose of this study was to use point-of-care ultrasound (POCUS) to compare chest wall thickness at these two locations. The primary objective was to evaluate the distance from skin to pleura line at the second ICS along the mid-clavicular line and the fifth ICS along the MAL. Secondarily, we aimed to evaluate inter-rater reliability of the two assessments.

Methods: This was a single-center, observational, pilot study. POCUS was performed using a linear transducer. Measurements of skin to pleura line were obtained at the right second ICS and fifth ICS. These measurements were then repeated by a blinded second ultrasonographer. Intraclass correlations (ICCs) for each measurement site were calculated to determine the inter-rater reliability.

Results: Ninety-three percent of volunteers had a smaller chest wall distance at the fifth ICS-MAL. The median distance at the second and fifth ICS was 2.28 cm and 1.80 cm. The ICC for second ICS was 0.75 (95% CI 0.54-0.87), and 0.90 for the fifth ICS (95% CI 0.81-0.95), both indicating good reliability.

Conclusions: The data support that patients have a smaller chest wall distance at the fifth ICS vs. the second ICS. We support performing needle decompression at the fifth ICS and believe POCUS can be used to determine the optimal location for decompression.