Abstract / Summary
Background/Objectives: Accurate assessment of distal circulation is essential for confirming effective arterial occlusion after tourniquet application in patients with life-threatening extremity hemorrhage. Although distal pulse palpation is commonly used in prehospital settings, its accuracy may be affected by examiner experience and environmental conditions. This study aimed to compare manual pulse palpation and paramedic-performed Doppler ultrasonography for assessing distal circulation after tourniquet application, using assessor-performed Doppler ultrasonography as the reference assessment. Methods: A prospective randomized crossover study was conducted among 41 actively practicing paramedics. Participants were randomly assigned to one of two assessment sequences: pulse palpation followed by Doppler ultrasonography or Doppler ultrasonography followed by pulse palpation. After standardized tourniquet application to the upper extremity, distal circulation was independently assessed using both methods. Assessor-performed Doppler ultrasonography served as the reference assessment. Sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) were calculated for each method. Agreement between the two index tests was evaluated using percent agreement and Cohen’s kappa, and assessment times were compared between methods. Results: Among the 41 participants, the reference standard identified distal flow in 18 (43.9%) and absence of distal flow in 23 (56.1%). Relative to the assessor-performed Doppler reference assessment, pulse palpation demonstrated a sensitivity of 66.7% (95% CI, 41.0–86.7), specificity of 87.0% (95% CI, 66.4–97.2), and accuracy of 78.0% (95% CI, 62.4–89.4). In comparison, paramedic-performed Doppler ultrasonography demonstrated a sensitivity of 88.9% (95% CI, 65.3–98.6), specificity of 91.3% (95% CI, 72.0–98.9), and accuracy of 90.2% (95% CI, 76.9–97.3). The PPV and NPV were 80.0% and 76.9% for pulse palpation and 88.9% and 91.3% for Doppler ultrasonography, respectively. Agreement between the two methods was 82.9%, with a Cohen’s kappa of 0.65. Mean assessment time was 14.2 ± 6.1 s for pulse palpation and 28.5 ± 10.4 s for Doppler ultrasonography. Conclusions: Paramedic-performed Doppler ultrasonography showed greater concordance with assessor-performed Doppler ultrasonography than pulse palpation for assessing distal circulation after tourniquet application, although it required additional assessment time. Because assessor-performed Doppler ultrasonography served as the reference assessment rather than an independent physiological gold standard, these findings should be interpreted as reflecting agreement with the reference Doppler assessment rather than definitive diagnostic superiority. Handheld Doppler ultrasonography may therefore have a potential role as an adjunct to pulse palpation, particularly when palpation findings are equivocal or objective reassessment of distal flow is required. Further studies using independent reference standards and conducted in real-world prehospital environments are warranted to evaluate its clinical utility, feasibility, and safety.