Cerebral perfusion pressure directed therapy following traumatic brain injury and hypotension in swine

Ajai K. Malhotra, John B. Schweitzer, Jerry L. Fox, Timothy C. Fabian, Kenneth G Proctor

Research output: Contribution to journalArticle

22 Scopus citations

Abstract

There is a paucity of studies, clinical and experimental, attesting to the benefit of cerebral perfusion pressure (CPP) directed pressor therapy following traumatic brain injury (TBI). The current study evaluates this therapy in a swine model of TBI and hypotension. Forty-five anesthetized and ventilated swine received TBI followed by a 45% blood volume bleed. After 1 h, all animals were resuscitated with 0.9% sodium chloride equal to three times the shed blood volume. The experimental group (PHE) received phenylephrine to maintain CPP > 80 mm Hg; the control group (SAL) did not. Outcomes in the first phase (n = 33) of the study were as follows: cerebro-venous oxygen saturation (S cvO2), cerebro-vascular carbon dioxide reactivity (δScvO2), and brain structural damage (β-amyloid precursor protein [βAPP] immunoreactivity). In the second phase (n = 12) of the study, extravascular blood free water (EVBFW) was measured in the brain and lung. After resuscitation, intracranial and mean arterial pressures were >15 and >80 mm Hg, respectively, in both groups. CPP declined to 64 ± 5 mm Hg in the SAL group, despite fluid supplements. CPP was maintained at >80 mm Hg with pressors in the PHE group. PHE animals maintained better ScvO2 (p < 0.05 at 180, 210, 240, 270, and 300 min post-TBI). At baseline, 5% CO2 evoked a 16 ± 4% increase in ScvO2, indicating cerebral vasodilatation and luxury perfusion. By 240 min, this response was absent in SAL animals and preserved in PHE animals (p < 0.05). Brain EVBFW was higher in SAL animals; however, lung EVBFW was higher in PHE animals. There was no difference in βAPP immunoreactivity between the SAL and PHE groups (p > 0.05). In this swine model of TBI and hypotension, CPP directed pressor therapy improved brain oxygenation and maintained cerebro-vascular CO2 reactivity. Brain edema was lower, but lung edema was greater, suggesting a higher propensity for pulmonary complications.

Original languageEnglish
Pages (from-to)827-839
Number of pages13
JournalJournal of Neurotrauma
Volume20
Issue number9
StatePublished - Sep 1 2003

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Keywords

  • Beta-amyloid precursor protein
  • Brain edema
  • Brain injury
  • Cerebral oxygenation
  • Cerebral perfusion pressure
  • Cerebro-vascular CO reactivity
  • Pressor

ASJC Scopus subject areas

  • Clinical Neurology
  • Neuroscience(all)

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