Insulin differentially influences brain glucose and lactate in traumatic brain injured patients.
Summary of "Insulin differentially influences brain glucose and lactate in traumatic brain injured patients."
Hypo- and hyperglycemia must be avoided to prevent additional brain damage following traumatic brain injury (TBI). However, the optimal blood glucose range requiring insulin remains unknown. Cerebral microdialysis is helpful in unmasking signs of metabolic impairment, thereby identifying deleterious blood glucose levels.
A retrospective analysis of prospectively collected cerebral microdialysis samples obtained from 20 non-diabetic patients with severe TBI treated at the trauma surgical intensive care unit at the University Hospital Zürich, Switzerland.
The impact of different arterial blood glucose values and concomitant insulin administration on cerebral interstitial glucose and lactate levels was investigated. In addition, energetic impairment was determined by calculating lactate-to-glucose ratios. Insulin administration was associated with significantly reduced cerebral glucose concentrations and significantly increased lactate-to-glucose ratios with arterial blood glucose levels <5 mM. At arterial blood glucose levels >7 mM, insulin administration was associated with significantly increased interstitial glucose values, significantly decreased lactate concentrations, and markedly diminished lactate-to-glucose ratios.
Insulin exerts differential effects that depend strongly on the underlying arterial blood glucose concentrations. To avoid energetic impairment, insulin should not be administered at arterial blood glucose levels <5 mM. However, at arterial blood glucose levels >7-8 mM, insulin administration appears to be encouraged to increase extracellular glucose concentrations and decrease energetic impairment reflected by reduced interstitial brain lactate and decreased lactate-to-glucose ratios. Nevertheless, frequent analysis is required to minimize the risk of inducing impaired brain metabolism.
Surgical Intensive Care, University Hospital Zürich, Zürich, Switzerland - firstname.lastname@example.org.
This article was published in the following journal.
Name: Minerva anestesiologica
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Medical and Biotech [MESH] Definitions
Bleeding within the brain as a result of penetrating and nonpenetrating CRANIOCEREBRAL TRAUMA. Traumatically induced hemorrhages may occur in any area of the brain, including the CEREBRUM; BRAIN STEM (see BRAIN STEM HEMORRHAGE, TRAUMATIC); and CEREBELLUM.
A ubiquitously expressed glucose transporter that is important for constitutive, basal GLUCOSE transport. It is predominately expressed in ENDOTHELIAL CELLS and ERYTHROCYTES at the BLOOD-BRAIN BARRIER and is responsible for GLUCOSE entry into the BRAIN.
Acute and chronic (see also BRAIN INJURIES, CHRONIC) injuries to the brain, including the cerebral hemispheres, CEREBELLUM, and BRAIN STEM. Clinical manifestations depend on the nature of injury. Diffuse trauma to the brain is frequently associated with DIFFUSE AXONAL INJURY or COMA, POST-TRAUMATIC. Localized injuries may be associated with NEUROBEHAVIORAL MANIFESTATIONS; HEMIPARESIS, or other focal neurologic deficits.
Prolonged unconsciousness from which the individual cannot be aroused, associated with traumatic injuries to the BRAIN. This may be defined as unconsciousness persisting for 6 hours or longer. Coma results from injury to both cerebral hemispheres or the RETICULAR FORMATION of the BRAIN STEM. Contributing mechanisms include DIFFUSE AXONAL INJURY and BRAIN EDEMA. (From J Neurotrauma 1997 Oct;14(10):699-713)
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