Incidence and Natural Progression of Neurogenic Shock after Traumatic Spinal Cord Injury

Neurogenic shock, a distributive type of circulatory shock after spinal cord injury (SCI), results in profound hypotension. The consequent hemodynamic instability complicates clinical management, delays surgical intervention, and impacts neurological outcome. Moreover, the reported incidence of this condition varies significantly. We establish the true incidence of neurogenic shock by comparing the most common clinical definitions used to diagnose the condition. Further, we characterize the acute progression and recovery of neurogenic shock. Daily blood pressure, heart rate, and fluid management as well as vasopressor therapy and neurologic status were collected over 30 days from 84 adults admitted to our tertiary trauma center after cervical (n = 56) and thoracic (n = 28) SCI. We found that the reported incidence of neurogenic shock varied greatly depending on which clinical definition was applied. By using a novel combination of hemodynamic and laboratory criteria to define neurogenic shock, the calculated incidence (29% cervical SCI) in our sample most appropriately reflects the true incidence, finding that hypovolemia was the primary factor responsible for the inconsistency in incidence reports between studies. In addition, we found a characteristic decline in blood pressure after the first week post-injury and that fluid management is not currently an integral aspect of clinical management (all persons were treated at a net fluid intake ≤ zero). The results demonstrate the need for accurate identification of neurogenic shock through consistent and appropriate criteria, which is not only important from a clinical point of view, but also in establishing accurate epidemiology to responsibly allocate resources to its management.