Background: The utility of prehospital thoracic needle decompression (ND) for tension physiology in the civilian setting continues to be debated. We attempted to provide objective evidence for clinical improvement when ND is performed and determine whether technical success is associated with provider factors. We also attempted to determine whether certain clinical scenarios are more predictive than others of successful improvement in symptoms when ND is performed. Methods: Prehospital ND data acquired from one air ambulance service serving 79 trauma centers consisted of 143 patients (n = 143; ND attempts = 172). Demographic and clinical outcome data were retrospectively reviewed. Patients were stratified by prehospital characteristics and indications. Objective outcomes were measured as improvement in vital signs, subjective patient assessment, and physical examination findings. Univariate analysis was performed using chi-square for variable proportions and unpaired Student's t-test for variable means; p < .05 was considered statistically significant. Results: The success rate of ND performed for hypoxia (70.5%) was notably higher than ND performed for hemodynamic instability (20.3%; p < .01) or cardiac arrest (0%; p < .01). Compared to vital sign parameters, clinical examination findings as part of the indication for ND did not reliably predict technical success (p > .52 for all indications). No difference was observed comparing registered nurse versus paramedic (p = .23), diameter of catheter (p < .13 for all), or length of catheter (p = .12). Conclusion: Prehospital ND should be considered in the appropriate clinical setting. Outcomes are less reliable in cases of cardiopulmonary arrest or hypotension with respiratory symptoms; however, this should not deter prehospital providers from attempting ND when clinically indicated. Additionally, the success rate of prehospital ND does not appear to be related to catheter type or the role of the performing provider.