Pulse oximetry for the diagnosis of vascular injury following limb trauma

Abstract

Prompt diagnosis and intervention are essential for acute limb ischaemia after trauma. Guidelines for diagnosis are changing with new evidence. Pulse oximetry may be a useful adjunct. We aim to assess the value of pulse oximetry and other common tests for diagnosing vascular injury.Electronic medical records of patients with limb injuries were identified. Patient demographics, the mechanism of injury, comorbidities, the results of diagnostic tests or examinations, and the end outcome were extracted. Receiver Operator Characteristics (ROC) curves were used to calculate cut-offs with optimum sensitivity and specificity for pulse oximetry. Performance characteristics to predict vascular injury for all documented tests were calculated and compared.SpO2 values were significantly different in the group with and without vascular disruption (p = 0.034). Using a cut-off of 96% calculated from ROC curve analysis, SpO2 had a sensitivity of 78% and a specificity of 90%. For the other techniques, abnormal pulse oximetry waveform, absent distal pulses, and capillary refill over 2 s were significantly different between the two groups. Abnormal pulse oximetry waveform had the highest specificity (100%) while SpO2 was the most sensitive (78%).We suggest that pulse oximetry is a useful adjunct for patients with limb trauma, an abnormal waveform or SpO2 value below 96% suggests vascular disruption is present. Capillary refill over 2 s and absent distal pulses can also be used; if either are positive, this suggests vascular disruption. No test or examination was shown to be able to exclude vascular injury.