Acute Spinal Cord Injury Causes Cardiac Contractile Dysfunction that when Treated Aids Spinal Cord Oxygenation
Authors: West Christopher , Williams Alex , Manouchehri Neda , Tauh Keerit , Poormasjedi‐Meibod Malihe , Boushel Robert , So Kitty , Shortt Katelyn , Streijger Femke , Kwon Brian 
Published: June 2021

Objective

In chronically injured humans and rodents with spinal cord injury (SCI) cardiac function is impaired. It is unknown whether such dysfunction is present acutely post‐SCI and if so whether it contributes to reduced spinal cord oxygenation. The aims of the present study, therefore, were to 1) define the acute cardiac and hemodynamic response to SCI, and 2) test the efficacy of a cardiac‐centered hemodynamic management strategy (β1‐receptor agonist dobutamine, DOB) vs. a traditional vasopressor‐based strategy (norepinephrine, NE) on intraparenchymal spinal cord oxygenation.

Design

To address aim 1, 7 Yucatan mini‐pigs received a T2 contusion SCI with 2 hours of compression and underwent measures of left‐ventricular (LV) function and spinal cord oxygenation pre‐ and up to 4 hrs post‐SCI. Pigs were instrumented with 1) a left‐ventricular (LV) pressure‐volume catheter for assessment of contractility (i.e., end‐systolic elastance, Ees) and LV hemodynamics, 2) a Swan‐Ganz pulmonary artery catheter for assessment of cardiac output (Q), 3) an inferior vena cava occlusion catheter, 4) a femoral arterial catheter to monitor mean arterial pressure (MAP), and 5) an intraparenchymal spinal cord oxygen sensor. To address aim 2, an additional 14 pigs were evenly assigned to either dobutamine (DOB, cardiac‐centered therapy), or norepinephrine (NE, vasopressor therapy) and were instrumented in the same way as aim 1. Drug infusions began 30 mins post‐SCI, and were continuously titrated to attain a targeted “normal” pre‐SCI Ees of ~2.5–2.9 mmHg/ml (DOB) or pre‐SCI MAP of ~85–90 mmHg (NE).

Results

Ees and MAP were significantly reduced 4 hrs post‐SCI vs. pre‐ SCI (all p<0.048), while Q was unchanged. When titrating DOB infusions to a pre‐established range of “normal” LV contractility, 3 animals received higher doses (≥3 mcg/kg/min) and 4 received lower doses (≤1 mcg/kg/min). Relative to their own pre‐drug baseline, animals receiving high‐dose DOB had significant increases in intraparenchymal spinal cord oxygenation at 4hr post‐SCI (p=0.014), whereas those treated with low‐dose DOB, NE or CON did not.

Conclusions

SCI is associated with reductions to cardiac contractility in the acute setting. Normalizing reduced contractility with high‐dose DOB increased spinal cord oxygenation, whereas low‐dose DOB, NE or CON did not alter cord oxygenation. These findings have important clinical implications as a reduction in spinal cord oxygenation post‐SCI is known to be a major contributing factor the development of the secondary injury and poor neurological recovery.

Support or Funding Information

US Department of Defense, Craig Nielsen Foundation, Rick Hansen Institute, Michael Smith Foundation for Health Research

This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.