Neurogenic Shock
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
What Level?
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]
Presentation
- Doesn't necessarily happen instantly
- Won't always have bradycardia
- Move arms and legs during primary survey
Fluids
InoPressors
- dopamine is bad–diuresis
MAP Push
- 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]
- Saadeh, Yamaan S., Brandon W. Smith, Jacob R. Joseph, Sohaib Y. Jaffer, Martin J. Buckingham, Mark E. Oppenlander, Nicholas J. Szerlip, and Paul Park. “The Impact of Blood Pressure Management after Spinal Cord Injury: A Systematic Review of the Literature.” Neurosurgical Focus 43, no. 5 (November 2017): E20. https://doi.org/10.3171/2017.8.FOCUS17428.
- Sabit, Behzad, Frederick A. Zeiler, and Neil Berrington. “The Impact of Mean Arterial Pressure on Functional Outcome Post-Acute Spinal Cord Injury: A Scoping Systematic Review of Animal Models.” Journal of Neurotrauma 34, no. 18 (September 15, 2017): 2583–94. https://doi.org/10.1089/neu.2016.4735.
More Reading
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
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I really really like these topic reviews. TBH Im a no pressors ALL HAIL BLOOD in the trauma bay type of guy in general but I do use some as a bridge if it clearly looks neurogenic. The rationale I use is early ( and admittedly pretty badly designed) studies showed worse outcomes with first line vaso pressor use. The mechanism that would snap your back will make you loose blood. Dont get me wrong, Im currently working a setting where I have people trained from all over and so when I teach for the boards I present both arguements… Read more »
I have zero problem with temporary vasopressors for hemorrhagic shock while you transfuse, and I never understood people’s issue with it – sounds like one of those things that got taught as “vasopressors aren’t a long term solution for hemorrhagic shock” (which is true) but then became “you can’t give one drop of Levo”. to me, patients make their own vasopressors when they are hemorrhaging. When we do something like give (some) induction meds for intubation or sedation, we take some of their endogenous response to their hemorrhage away. It seems fine to me to supplement with exogenous vasopressors just… Read more »