Acute Spinal Cord Injury Causes Cardiac Contractile Dysfunction that when Treated Aids Spinal Cord Oxygenation
Bibliographic record
Abstract
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 (β 1 ‐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, E es ) 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 E es of ~2.5–2.9 mmHg/ml (DOB) or pre‐SCI MAP of ~85–90 mmHg (NE). Results E es 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 .
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".