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Autonomic cardiovascular state after severe brain injury and brain death in children
B Goldstein1, D DeKing, D J DeLong
1Department of Pediatrics, University of Rochester School of Medicine and Dentistry, NY.
Insights
Autonomic cardiovascular testing reveals distinct differences between severe brain injury and brain death in children. Severe brain injury shows sympathetic damage, while brain death indicates complete autonomic pathway interruption.
Area of Science:
- Pediatric critical care medicine
- Neuroscience
- Cardiovascular physiology
Background:
- Assessing autonomic cardiovascular function is crucial in critically ill children.
- Distinguishing severe brain injury from brain death can be challenging.
Purpose of the Study:
- To compare the autonomic cardiovascular state in children with severe brain injury versus brain death.
- To explore the utility of autonomic testing in corroborating brain death determination.
Main Methods:
- Prospective clinical study in a pediatric intensive care unit.
- Involved pediatric patients with severe brain injury (trauma, anoxia, hemorrhage) and brain-dead patients.
- Evaluated cardiorespiratory parameters, heart rate power spectra, plasma catecholamines, and cold pressor test response.
Main Results:
- Significant differences observed in low-frequency heart rate power, peak amplitude, and plasma catecholamines between groups.
- Patients with severe brain injury exhibited significant changes in respiratory rate and heart rate power during cold pressor testing.
- Brain-dead patients showed no measurable changes in response to cold pressor testing.
Conclusions:
- Findings support a damaged sympathetic system in severe brain injury and interrupted autonomic pathways in brain death.
- Autonomic cardiovascular testing may serve as a valuable tool to corroborate the diagnosis of brain death.
- This research has implications for improving the accuracy and confidence in diagnosing brain death in pediatric patients.
Objective:
To study and compare the autonomic cardiovascular state of children after severe brain injury and brain death.
Design:
Prospective clinical study.
Setting:
Pediatric ICU.
Patients:
Pediatric patients suffering severe brain injury caused by trauma, anoxia, or hemorrhage.
Intervention:
None.
Measurements And Main Results:
We analyzed cardiorespiratory parameters, heart rate power spectra, plasma catecholamine concentrations, and the response to the cold pressor test in nine brain-dead patients and compared the results with the test findings of 11 patients with severe brain injury. Low-frequency total heart rate power (p < .03), peak amplitude (p < .02), and plasma catecholamine concentrations (p < .001) were different with no overlap of values between groups. Cold pressor testing in patients with severe brain injury showed changes in respiratory rate and low-frequency heart rate power that were +/- 20% to 100% from baseline values; however, there were no measurable changes in brain-dead patients.
Conclusions:
Our results support the concept of a damaged sympathetic cardiovascular system in severe brain injury and complete interruption of the autonomic cardiovascular pathways in brain death. Since determination of brain death may be difficult, our findings have implications for corroborating brain death using autonomic cardiovascular testing.