BackgroundNeedle decompression is a useful tool in the pre-hospital setting for treating tension pneumothorax. However the specific improvements in vital signs that determine a successful decompression are only reported in a few studies and Emergency Medical Services (EMS) self-reported assessments of improvement are more commonplace. We hypothesize that EMS reports may exaggerate improvement when compared to objective vital sign changes. MethodologyThis is a retrospective cohort study using the National Emergency Medicine Information System (NEMSIS) for the year 2020. Vital signs recorded as objective endpoints include systolic blood pressure (SBP), pulse (HR), respiratory rate (RR), and oxygen saturation (SpO 2 ). Univariate analysis was performed using the t-test for continuous variables and the chi-square test for categorical variables. ResultsA total of 8,219 calls were included in the sample size analyzed. Most patients were white (2,911, 35.4%) and male (6,694, 81.4%). Abnormal vitals recorded as indications for needle decompression included SBP <100 mmHg, HR <60 or >100 beats/minute, RR <12 or >20 breaths/minute, and SpO 2 <93%. Statistically significant improvements were seen in the number of abnormal vital signs after the procedure. The percentage of improvement was higher in the EMS self-reported assessment than in objective findings for oxygen saturation and SBP. ConclusionsOur analysis shows objective improvement of hypoxia and hypotension after field needle decompression, supporting the efficacy of the procedure. The improvement based on vital sign change is modest and is less than that reported by EMS assessment of global improvement. This represents a target for quality improvement in EMS practice.