Cerebral perfusion pressure, microdialysis biochemistry and clinical outcome in patients with traumatic brain injury

Abstract

BackgroundTraumatic Brain Injury (TBI) is a major cause of death and disability. It has been postulated that brain metabolic status, intracranial pressure (ICP) and cerebral perfusion pressure (CPP) are related to patients' outcome. The aim of this study was to investigate the relationship between CPP, ICP and microdialysis parameters and clinical outcome in TBIs.ResultsThirty four individuals with severe brain injury hospitalized in an intensive care unit participated in this study. Microdialysis data were collected, along with ICP and CPP values. Glasgow Outcome Scale (GOS) was used to evaluate patient outcome at 6 months after injury. Fifteen patients with a CPP greater than 75 mmHg, L/P ratio lower than 37 and Glycerol concentration lower than 72 mmol/l had an excellent outcome (GOS 4 or 5), as opposed to the remaining 19 patients. No patient with a favorable outcome had a CPP lower than 75 mmHg or Glycerol concentration and L/P ratio greater than 72 mmol/l and 37 respectively. Data regarding L/P ratio and Glycerol concentration were statistically significant at p = 0.05 when patients with favorable and unfavorable outcome were compared. In a logistic regression model adjusted for age, sex and Glasgow Coma Scale on admission, a CPP greater than 75 mmHg was marginally statistically significantly related to outcome at 6 months after injury.ConclusionsPatients with favorable outcome had certain common features in terms of microdialysis parameters and CPP values. An individualized approach regarding CPP levels and cut -off points for Glycerol concentration and L/P ratio are proposed.

Cerebral Microdialysis: Going Deep into Brain Biochemistry for a Better Understanding of Pathomechanisms of Acute Brain Injury

“…Parafarou et al suggested a CPP cutoff > 75 mm Hg, LPR < 37, and glycerol < 72 µmoles/L as markers of good outcome. 23 This study shows somewhat similar results (LPR < 45 and CPP 70 mm Hg).…”

“…Neuromonitoring can be a measure of the effect of treatment (i.e., DC) on cerebral ischemia and hypoxia, as it relates to neurologic outcomes. The results of neuromonitoring can offer clinicians a perspective on the appropriate time window for the investigated rescue treatment [21][22][23] (►Figs. 4, 5).…”

Systematic and Comprehensive Literature Review of Publications on Direct Cerebral Oxygenation Monitoring

“…There are publications also from Australia [38,[198][199][200], Austria [53,85], Brazil [58], Canada [93,118,132,135,139], China [9, 201,202], Croatia [203], the Czech Republic [204], Denmark [134]; Finland [134], France [43,77,114,205,206], Greece [207], Hungary [141], India [208], Japan [140,146,167,209], Portugal [64]; Russia [210,211], Singapore [2,4,10,16,74,212,213]; Serbia [214]; South Africa [26,28,35], South Korea [127], Sweden [90,134,215], Switzerland [11,216,217]...…”

ICU Management of Traumatic Brain Injury

“…Although changes in PaCO 2 may acutely change ICP for short periods, evidence suggests that the reduction in CBF associated with prolonged hyperventilation to a PaCO 2 below 34 mmHg may be deleterious [14]. In addition, physiologic compensatory mechanisms to ongoing hyperventilation return the systemic pH to normal within 6-8 h, and a rebound acute respiratory acidosis with the associated cerebral vasodilatation and increased ICP may occur upon return to normoventilation [32]. Hyperventilation is, therefore, only recommended as a short-duration temporizing measure, and hypoventilation should be aggressively avoided.…”

“…Nearly any molecule can conceivably be monitored, but glucose, lactate, pyruvate, glutamate, glycerol, and pH levels are most commonly evaluated. Although there is a growing body of data showing that disturbances in many of these parameters are associated with outcome independent of PbO 2 and other factors, whether goal-directed correction of the disturbances can be translated into improved outcomes remains unknown [6,[30][31][32].…”