Neurogenic shock is on our differential for hypotension and hemodynamic instability in trauma patients. Today, we discuss this condition as well as the use of vasopressors for hemorrhagic shock.
Neurogenic Shock is not Spinal Shock
Spinal Shock is a loss of reflexes below the level of the injury
Preganglionic sympathetic neurons originating in the hypothalamus, pons and medulla are located in the intermediolateral cell column of the spinal cord between the first thoracic (T1) and second lumbar (L2) vertebrae. Theoretically, any SCI within or above this could cause sympathetic disruption. Since sympathetic innervation of the heart only occurs from T1 to T5, it is often said that neurogenic shock can only occur when the lesion is above the mid-thoracic (T6) level. [ 27697845]
- Doesn't necessarily happen instantly
- Won't always have bradycardia
- Move arms and legs during primary survey
- dopamine is bad–diuresis
- 85 for 7 days???
- UPDATE: Recently published cohort trial supports this practice (but not great evidence here) [Journal of Trauma and Acute Care Surgery Issue: Volume 90(1), January 2021, p 97-106]
Should we be using Vasopressors in Hemorrhagic Shock?
I listened to a thought-provoking episode of Traumacast today. It was an interview with Dr. Carrie Sims on the use of Vasopressin after Hemorrhagic Shock.
The contention is that Vasopressin at the 0.03-0.04 unit/minute dose will not affect blood pressure unless the patient is actually vasopressin deficient.
5th-10th Unit of blood, vasopressin levels begin to drop
Are we diluting out our stress hormones?
RCT by Carrie Sims et al. (PMID: 31461138)
vasopressin (bolus 4 IU) and i.v. infusion of 200 mL/h (vasopressin 2.4 IU/h) for 5 h after pts who received 6 units of product
Vasopressors are associated with worse otucome after blunt trauma shock (PMID: 18188092), but little can be taken from this study
Spahn, D.R., Bouillon, B., Cerny, V. et al. The European guideline on management of major bleeding and coagulopathy following trauma: fifth edition. Crit Care 23, 98 (2019). https://doi.org/10.1186/s13054-019-2347-3
If they are warm, give them vasoconstriction