A Pulseless Limb Poorly Predicts an Arterial Injury in Combat Trauma
Jacob F. Quail, Victoria S. McDonald, Kristina K. Carter, Jeffrey S. Weiss, and Kevin M. Casey, San Diego, California; and Kandahar, Afghanistan
Background: A pulseless limb is considered a hard sign of an arterial injury after penetrating trauma in the civilian population. However, the reliability of this finding has never been examined in combat trauma. The purpose of this study was to examine the reliability of the pulseless limb in the combat trauma population. Reasons for false positive physical examination findings were also identified.
Methods: The Joint Theater Trauma Registry identified all patients who presented to a military treatment facility (MTF) in Kandahar, Afghanistan, with a penetrating extremity injury over a 2year period. Patients found to have a pulse deficit on initial physical examination were followed, and the results of the subsequent computed tomographic angiogram or arteriogram recorded. Patient demographics, injury patterns, and physiological data were examined. Standard statistical analysis was performed. Results: From 2011 to 2012, 644 patients were treated at a single MTF for lower extremity penetrating injuries. The most common mechanisms of injury were explosions (62%) and gunshot wounds (20%). Of the 577 patients with complete medical records, 448 patients (78%) presented with palpable pulses, 115 patients (20%) presented with a pulseless limb, and 14 (2%) presented with hard signs of vascular injury. Of those with a pulseless limb and abnormal ankle-brachial index (ABI) or no ABI obtained who underwent further radiologic imaging, 38 patients (77%) had no arterial injury identified. Compared with those with a palpable pulse, patients with a pulseless limb without an arterial injury were more likely to have a higher Injury Severity Score (ISS), lower hematocrit, lower pH, greater base deficit, higher heart rate, more frequent use of tranexamic acid, and received greater volumes of packed red blood cells, plasma, and crystalloids.
Conclusions: Our results demonstrate that a pulseless limb is a poor predictor of arterial injury and should not be considered a hard sign of vascular injury in the combat population. Variables including a high ISS, anemia, acidosis, and need for resuscitation products, each a surrogate for injury severity, may contribute to the decreased accuracy of the physical examination in our troops. This may translate into unnecessary immediate exploration or other interventions in patients who present with more significant injuries from the battlefield. Future studies must continue to focus on improved algorithms for diagnostic accuracy of extremity vascular injuries in this population.
INTRODUCTION
Extremity injuries continue to predominate in the current war in Afghanistan and recently completed war in Iraq. Compared with prior conflicts, troops wounded during the Global War on Terror (GWOT) sustained a significant number of injuries to the extremities, often with a higher Injury Severity Score (ISS) and more significant soft tissue, osseous, and neurologic damage. The rate of vascular injury during Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF) is 5 times that of previous conflicts. The immediate threat to limb salvage is secondary to acute ischemia and warrants urgent evaluation and intervention. A pulseless limb has been considered a hard sign of vascular injury and historically warrants further imaging or even exploration in the operating room when advanced imaging modalities are not available. Computed tomographic angiography (CTA) and arteriography are considered the ‘‘gold standard’’ for diagnosing extremity arterial injuries. However, which patients are best served by invasive imaging remains controversial as most studies are based on data collected from civilian populations. One such study from Schwartz et al. concluded that a pulse deficit and an ankle-brachial index (ABI) <1 in an injured extremity were significant predictors of an arterial injury and warranted arteriography in a civilian trauma population. The military medical system consists of 5 levels of care which support the expeditious transport of troops from the battlefield to definitive care at stateside military medical treatment facilities (MTFs). Role III facilities, such as the MTF at Kandahar Air Field, are comparable to level I trauma centers and provide the highest level of medical care in combat theater. The role III facility has the ability to perform CTAs and arteriograms, allowing for identification and treatment of vascular injuries. In contrast, role I and II facilities have limited resources. Patients presentingtothesefacilities with a pulseless limb are frequently obligated to an operativeexploration. Reliance on aninaccurate pulse examination may lead to a significant number of unnecessary operative procedures which would delay patient transfer to the next level of care. The purpose of this study was to examine the accuracy of the pulseless limb in evaluating arterial injuries in a combat trauma population at an MTF in Kandahar, Afghanistan. Furthermore, as the war in Afghanistan continues to de-escalate, we sought to examine the role of the physical examination in future MTFs with limited resources and imaging modalities.
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