J Spec Oper Med. Winter 2018;18(4):18-23.

# Larger-Caliber Alternative Devices for Decompression of Tension Hemopneumothorax in the Setting of Hemorrhagic Shock.

McEvoy CS, Leatherman ML, Held JM, Fluke LM, Ricca RL, Polk T.

BACKGROUND: The 14-gauge (14G) angiocatheter (AC) has an unacceptably high failure rate in treatment of tension pneumothorax (tPTX). Little is known regarding the interplay among hemorrhage, hemothorax (HTX), and tPTX. We hypothesized that increased hemorrhage predisposes tension physiology and that needle decompression fails more often with increased HTX.

METHODS: This is a planned secondary analysis of data from our recent comparison of 14G AC with 10-gauge (10G) AC, modified 14G Veress needle, and 3mm laparoscopic trocar conducted in a positive pressure ventilation tension hemopneumothorax model using anesthetized swine. Susceptibility to tension physiology was extrapolated from volume of carbon dioxide (CO2) instilled and time required to induce 50% reduction in cardiac output. Failures to rescue and recover were compared between the 10% and 20% estimated blood volume (EBV) HTX groups and across devices.

RESULTS: A total of 196 tension hemopneumothorax events were evaluated. No differences were noted in the volume of CO2 instilled nor time to tension physiology. HTX with 10% EBV had fewer failures compared with 20% HTX (7% versus 23%; p = .002). For larger-caliber devices, there was no difference between HTX groups, whereas smaller-caliber devices had more failures and longer time to rescue with increased HTX volume as well as increased variability in times to rescue in both HTX volume groups.

CONCLUSION: Increased HTX volume did not predispose tension physiology; however, smaller-caliber devices were associated with more failures and longer times to rescue in 20% HTX as compared with 10% HTX. Use of larger devices for decompression has benefit and further study with more profound hemorrhage and HTX and spontaneous breathing models is warranted.