Background: Tension pneumothorax is a prominent cause of potentially survivable death on the battlefield. Field management for suspected tension pneumothorax is immediate needle thoracostomy (NT). Recent data noted higher NT success rates and ease of insertion at the fifth intercostal space, anterior axillary line (5th ICS AAL), leading to an amendment of the Committee on Tactical Combat Casualty Care recommendations on managing suspected tension pneumothorax to include the 5th ICS AAL as a viable alternative site for NT placement. The objective of this study was to assess the overall accuracy, speed, and ease of NT site selection and compare these outcomes between the second intercostal space, midclavicular line (2nd ICS MCL) and 5th ICS AAL among a cohort of Army medics.
Methods: We designed a prospective, observational, comparative study and recruited a convenience sample of US Army medics from a single military installation to localize and mark the anatomic location where they would perform an NT at the 2nd ICS MCL and 5th ICS AAL on 6 live human models. The marked site was compared for accuracy to an optimal site predetermined by investigators. We assessed the primary outcome of accuracy via concordance with the predetermined NT site location at the 2nd ICS MCL and 5th ICS MCL. Secondarily, we compared time to final site marking and the influence of model body mass index (BMI) and gender on accuracy of selection between sites.
Results: A total of 15 participants performed 360 NT site selections. We found a significant difference between participants' ability to accurately target the 2nd ICS MCL compared to the 5th ICS AAL (42.2% versus 10% respectively, p is less than 0.001). The overall accuracy rate among all NT site selections was 26.1%. We also found a significant difference in time-to-site identification between the 2nd ICS MCL and 5th ICS AAL in favor of the 2nd ICS MCL (median [IQR] 9 [7.8] seconds versus 12 [12] seconds, p is less than 0.001).
Conclusions: US Army medics may be more accurate and faster at identifying the 2nd ICS MCL when compared to the 5th ICS AAL. However, overall site selection accuracy is unacceptably low, highlighting an opportunity to enhance training for this procedure.
Keywords: training; performance; pneumothorax; procedural skills.