Cerebral Perfusion Pressure Directed-Therapy Modulates Cardiac Dysfunction After Traumatic Brain Injury to Influence Cerebral Autoregulation in Pigs

Neurocrit Care. 2019 Dec;31(3):476-485. doi: 10.1007/s12028-019-00735-2.

Abstract

Background: Traumatic brain injury (TBI) is an important contributor to morbidity and mortality. Low cerebral perfusion pressure (CPP, mean arterial pressure [MAP] minus intracranial pressure) after TBI is associated with cerebral ischemia, impaired cerebral autoregulation, and poor outcomes. Normalization of CPP and limitation of cerebral autoregulation impairment is a key therapeutic goal. However, some vasoactive agents used to elevate MAP such as phenylephrine (Phe) improve outcome in females but not male piglets after TBI while dopamine (DA) does so in both sexes. Clinical evidence has implicated neurological injuries as a cause of cardiac dysfunction, and we recently described cardiac dysfunction after TBI. Cardiac dysfunction may, in turn, influence brain health. One mechanism of myocyte injury may involve catecholamine excess. We therefore tested the hypothesis that TBI caused cardiac dysfunction and catecholamine excess which may reciprocally be modulated by vasoactive agent choice to normalize CPP and prevent impairment of cerebral autoregulation after injury.

Methods: TBI was produced in anesthetized pigs equipped with a closed cranial window, and Phe or DA administered to normalize CPP.

Results: Plasma cardiac enzymes troponin and creatine kinase and catecholamines epinephrine and norepinephrine were elevated by TBI, such release potentiated by Phe in males but blocked in female piglets and blocked in both sexes after DA. Cerebral autoregulation was impaired after TBI, worsened by Phe in males but protected in females and males treated with DA. Papaverine-induced dilation was unchanged by fluid percussion brain injury, DA, and Phe.

Conclusions: These data indicate that pressor choice in elevation of CPP is important in limiting cardiac dysfunction and suggest that DA protects cerebral autoregulation in both sexes via reduction of cardiac biomarkers of injury and catecholamines released after TBI.

Keywords: Catecholamines; Cerebral autoregulation; Creatine kinase; Traumatic brain injury.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Animals, Newborn
  • Arterial Pressure / drug effects*
  • Brain Injuries, Traumatic / blood
  • Brain Injuries, Traumatic / physiopathology*
  • Cerebrovascular Circulation / drug effects*
  • Creatine Kinase, MB Form / blood
  • Creatine Kinase, MB Form / drug effects
  • Dopamine / pharmacology*
  • Epinephrine / blood
  • Female
  • Heart / drug effects*
  • Heart / physiopathology
  • Homeostasis / drug effects*
  • Intracranial Pressure
  • Male
  • Norepinephrine / blood
  • Papaverine / pharmacology
  • Phenylephrine / pharmacology*
  • Random Allocation
  • Sex Factors
  • Sus scrofa
  • Swine
  • Sympathomimetics / pharmacology*
  • Troponin I / blood
  • Troponin I / drug effects
  • Vasodilator Agents / pharmacology

Substances

  • Sympathomimetics
  • Troponin I
  • Vasodilator Agents
  • Phenylephrine
  • Papaverine
  • Creatine Kinase, MB Form
  • Dopamine
  • Norepinephrine
  • Epinephrine