Hemodynamic and metabolic parameters in brain injury

Abstract

Introduction: Indirect monitoring of brain metabolism through parameters such as cerebral perfusion pressure (CPP), intracranial pressure (ICP), arterial CO2 partial pressure (PaCO2) and mean arterial blood pressure (MABP) is necessary to guide treatment and to prevent secondary cerebral ischemia. The aim of the present study was to analyze the association between cerebral hemodynamic and metabolic parameters and the occurrence of traumatic brain ischemia. Methods: Thirty-one patients were prospectively assessed in the pediatric or adult intensive care unit of Hospital de Pronto Socorro (HPS), in Porto Alegre, Brasil, from April to December, 2003. Patients were 23 adults (aged 17 to 66 years-old ) and eight children (aged 3 to 13 years-old) with severe traumatic brain injury( TBI ) . Mean age was 24 years. The inclusioncriteria were Glasgow coma scale (GCS) below 8 and abnormal cranial computed tomography (CT) results. Intracranial pressure, mean arterial blood pressure, arterial CO2 partial pressure and cerebral perfusion pressure were recorded. Results: Cerebral ischemia was identified in 13 adults (56.5%) and in seven children (87.5%). High MABP was associated with mortality (P<=0.005) in children. High ICP (P= 0.03) and low CPP (P=0.007) in adults were associated with cerebral ischemia. Fourteen patients (45.2%) died: 13 adults (56.5%) and one child (12.5%). Adult patients with low CPP had a worse outcome with higher mortality rate (P=0.045). Conclusions: High ICP, high MABP and low CPP were associated with traumatic brain ischemia and higher mortality rate in these patients.