The FAST D protocol: a simple method to rule out traumatic vascular injuries of the lower extremities

Background

The aim of this study is to assess the accuracy of a Fast Doppler protocol for the examination of an injured lower limb, namely 2-Point Fast Doppler (2PFD), in order to rapidly triage arterial lesions after penetrating trauma.

Methods

The presence of flow and the aspects of the Doppler waveform of the dorsalis pedis artery (DPA) and posterior tibial artery (PTA) of the injured lower limb (2PFD) were evaluated immediately before the execution of a standardized Color Duplex Doppler (SD) evaluation in 149 limbs of 140 patients with gunshot penetrating injuries. We considered 2PFD normal exams as the ones with triphasic patterns in both the DPA and PTA, and 2PFD pathologic exams as the ones with absent, biphasic, or monophasic flow patterns in the DPA and/or PTA. 2PFD data were then analyzed to assess accuracy variables, using SD results as matching test reference. According to the trauma center standard protocols, SD positive cases underwent also angiography and surgical exploration, whose findings were used to further match the 2PFD specificity.

Results

The 2PFD protocol showed a sensitivity of 100%, and a specificity of 100% compared with the SD, in the diagnostic workup of arterial injuries of the lower limbs after penetrating trauma. Furthermore, all the pathologic cases that resulted in all true positives (TP), compared with SD, were confirmed as TP also when matched with the angiography evaluation results.

Conclusions

The 2PFD protocol can rapidly identify arterial flow and differentiate between normal and pathologic spectral Doppler analyses in distal arteries. The presence of the normal triphasic flows in DPA and PTA is as sensitive as the standardized Color Doppler Duplex assessment of the entire limb in ruling out arterial lesions in lower-limb penetrating trauma. The absence of flow or the presence of a biphasic or monophasic pathologic flow in DPA and PTA is pathologic and should be always followed by further investigation. 2PFD is faster and easier to perform compared with the SD approach. It could become a new first-line screening technique, both in pre-hospital and hospital critical scenarios, particularly in contexts where advanced diagnostic performance is limited by time concerns or scarce resources.

Point-of-care ultrasound and Doppler ultrasound evaluation of vascular injuries in penetrating and blunt trauma

BACKGROUND

The aim of this study is to describe point-of-care ultrasound and Color flow Duplex Doppler characteristics of penetrating and blunt trauma-related vascular injuries of the limbs and neck.

METHODS

Penetrating and blunt trauma-related vascular injuries such as vein disruption, intimal flap, deep vein thrombosis, arterial dissection, pseudoaneurysm, and arteriovenous fistulae are discussed in this manuscript. Images of the most significant lesions of our personal clinical experience are presented to illustrate point-of-care ultrasound and Color flow Duplex Doppler ultrasound findings.

RESULTS

Penetrating and blunt trauma-related vascular injuries represent a big challenge. While patients with hard signs of arterial damage must be sent immediately to surgical exploration, when there are soft signs or no clear signs of vascular injury at the physical examination, and the patient is stable, imaging investigation and observation can be useful in the diagnosis and management of these patients. Although angiography is the gold standard of the imaging methods, point-of-care ultrasound and Color flow Duplex Doppler ultrasound are widely available, cheaper, noninvasive, and faster to obtain. They can provide bedside valuable information for the identification of some vascular injuries allowing to an integrated management of the trauma patient, enriched by the use of ultrasound.

CONCLUSIONS

Point-of-care ultrasound and Color flow Duplex Doppler examination are increasingly used in the decision making process of trauma-related vascular injuries.