Background: Prehospital tourniquet use is now standard in trauma patients with diagnosed or suspected extremity vascular injuries. Tourniquet-related vasospasm is an understudied phenomenon that may confound management by causing erroneous arterial pressure indices (APIs) and abnormalities on computed tomography angiography (CTA) that do not reflect true arterial injuries. We hypothesized that shorter intervals between tourniquet removal and CTA imaging and longer total tourniquet times would be correlated with a higher likelihood of false positive CTA.
Materials and methods: We performed a single-institution retrospective cohort study of patients presenting to a busy, urban Level 1 Trauma Center with prehospital tourniquets from 2019 to 2021. Patients who presented with a tourniquet disengaged upon arrival or who died prior to admission to the Trauma Unit were excluded. Tourniquet duration, time between tourniquet removal and CTA imaging (CTA interval), CTA findings, and management of extremity arterial injuries were extracted. The proportion of false positive injuries on CTA was assessed for correlation with increasing time interval from tourniquet removal to CTA imaging and correlation with increasing total tourniquet time using multivariable logistic regression.
Results: 251 patients were identified with prehospital tourniquets. 127 underwent CTA of the affected extremity, 96 patients had an abnormal CTA finding, and 57 (45% of total CTA patients) had false positive arterial injuries on imaging. Using multivariable logistic regression, neither the CTA interval nor the tourniquet duration was associated with false positive CTA injuries. Female sex was associated with false positive injuries on CTA (OR 2.91, 95% CI: 1.01 - 8.39). Vasospasm was cited as a possible explanation by radiologists in 40% of false positive CTA reports.
Conclusions: Arterial vasospasm is a frequent finding on CTA after tourniquet use for extremity trauma, but concerns regarding tourniquet-related vasospasm should not alter trauma patient management. Neither the duration of tourniquet application nor the time interval since removal is associated with decreased CTA accuracy, and any delay in imaging does not appear to reduce the likelihood of vasospasm. These findings are important for supporting expedited care of trauma patients with severe extremity injuries.
Keywords: ABI; API; Ankle brachial index; Arterial pressure index; CTA; Computed tomography angiography; Extremity trauma; Tourniquet; Vasospasm.
Copyright © 2023. Published by Elsevier Ltd.