Metabolic Crisis in Severely Head-Injured Patients: Is Ischemia Just the Tip of the Iceberg?

Emilie Carre,Risso Jean-Jacques,Ambroise Montcriol,Lionel Bourdon,Henry Boret,Michael Ogier

doi:10.3389/fneur.2013.00146

Abstract

Ischemia and metabolic crisis are frequent post-traumatic secondary brain insults that negatively influence outcome. Clinicians commonly mix up these two types of insults, mainly because high lactate/pyruvate ratio (LPR) is the common marker for both ischemia and metabolic crisis. However, LPR elevations during ischemia and metabolic crisis reflect two different energetic imbalances: ischemia (Type 1 LPR elevations with low oxygenation) is characterized by a drastic deprivation of energetic substrates, whereas metabolic crisis (Type 2 LPR elevations with normal or high oxygenation) is associated with profound mitochondrial dysfunction but normal supply of energetic substrates. The discrimination between ischemia and metabolic crisis is crucial because conventional recommendations against ischemia may be detrimental for patients with metabolic crisis. Multimodal monitoring, including microdialysis and brain tissue oxygen monitoring, allows such discrimination, but these techniques are not easily accessible to all head-injured patients. Thus, a new “gold standard” and adapted medical education are required to optimize the management of patients with metabolic crisis.

Highlights

Managing traumatic brain injury is like navigating the ocean
CONFUSING DEFINITION OF METABOLIC CRISIS IN THE LITERATURE In Intensive Care Unit (ICU), cerebral post-traumatic metabolic disturbances have commonly been characterized by an increase of the lactate/pyruvate ratio (LPR) above 40, as measured by clinical intracerebral microdialysis
Three different types of metabolic disturbances, all characterized by a LPR > 40, have been reported: hyperglycolysis, ischemia, and a pattern described by Vespa and colleagues initially called “metabolic crisis without brain ischemia” [2]

Summary

Introduction

Managing traumatic brain injury is like navigating the ocean. Dangers (secondary insults) are everywhere, but, usually, easy to prevent. CONFUSING DEFINITION OF METABOLIC CRISIS IN THE LITERATURE In Intensive Care Unit (ICU), cerebral post-traumatic metabolic disturbances have commonly been characterized by an increase of the lactate/pyruvate ratio (LPR) above 40, as measured by clinical intracerebral microdialysis. Three different types of metabolic disturbances, all characterized by a LPR > 40, have been reported: hyperglycolysis, ischemia, and a pattern described by Vespa and colleagues initially called “metabolic crisis without brain ischemia” [2].

Results

Conclusion