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Published on: March 26, 2019
Monitoring cerebrovascular reactivity in pediatric traumatic brain injury: comparison of three methods
Francisco Abecasis1, Celeste Dias2, Agnieszka Zakrzewska3
1Pediatric Intensive Care Unit, Faculdade de Medicina, Centro Hospitalar Universitário Lisboa Norte, Universidade de Lisboa, Lisbon, Portugal. francisco.abecasis@chln.min-saude.pt.
Insights
The pressure-reactivity index (PRx) is a reliable method for monitoring cerebral autoregulation in children with severe traumatic brain injury (TBI). This index also shows potential for predicting long-term outcomes in pediatric TBI patients.
Area of Science:
- Pediatric Intensive Care
- Neurocritical Care
- Traumatic Brain Injury
Background:
- Severe traumatic brain injury (TBI) in children presents unique challenges in monitoring and management.
- Cerebral autoregulation, the brain's ability to maintain stable blood flow despite changes in blood pressure, is crucial for TBI patients.
- Assessing cerebral autoregulation aids in optimizing cerebral perfusion pressure (CPP) and improving outcomes.
Purpose of the Study:
- To evaluate and compare three methods for monitoring cerebral autoregulation in pediatric patients with severe TBI.
- To determine the most robust index for assessing cerebrovascular reactivity in this population.
- To investigate the prognostic value of these indices and their utility in calculating optimal CPP.
Main Methods:
- A prospective cohort study was conducted over 4 years in a pediatric intensive care unit.
- Included were children aged 5 months to 17 years with severe TBI.
- Three monitoring methods were assessed: pressure-reactivity index (PRx), transcranial Doppler-derived mean flow velocity index (Mx), and near-infrared spectroscopy-derived cerebral oximetry index (COx).
Main Results:
- The pressure-reactivity index (PRx) demonstrated a classic U-shaped distribution concerning cerebral perfusion pressure (CPP), with intact autoregulation observed at CPP levels of 50-100 mmHg.
- Optimal CPP for both PRx and COx was determined to be between 75-80 mmHg.
- Significant correlations were found between PRx and Mx (r=0.56, p<0.0001), and PRx and COx (r=0.16, p<0.0001).
- The mean PRx, with a cutoff of 0.3, accurately predicted long-term outcomes (p=0.015).
Conclusions:
- The pressure-reactivity index (PRx) appears to be the most reliable index for assessing cerebrovascular reactivity in children with TBI.
- PRx holds significant promise as a prognostic tool in pediatric TBI.
- Calculating optimal CPP is feasible using PRx and COx indices.
Purpose:
To study three different methods of monitoring cerebral autoregulation in children with severe traumatic brain injury.
Methods:
Prospective cohort study of all children admitted to the pediatric intensive care unit at a university-affiliated hospital with severe TBI over a 4-year period to study three different methods of monitoring cerebral autoregulation: pressure-reactivity index (PRx), transcranial Doppler derived mean flow velocity index (Mx), and near-infrared spectroscopy derived cerebral oximetry index (COx).
Results:
Twelve patients were included in the study, aged 5 months to 17 years old. An empirical regression analyzing dependence of PRx on cerebral perfusion pressure (CPP) displayed the classic U-shaped distribution, with low PRx values (< 0.3) reflecting intact auto-regulation, within the CPP range of 50-100 mmHg. The optimal CPP was 75-80 mmHg for PRx and COx. The correlation coefficients between the three indices were as follows: PRx vs Mx, r = 0.56; p < 0.0001; PRx vs COx, r = 0.16; p < 0.0001; and COx vs Mx, r = 0.15; p = 0.022. The mean PRx with a cutoff value of 0.3 predicted correctly long-term outcome (p = 0.015).
Conclusions:
PRx seems to be the most robust index to access cerebrovascular reactivity in children with TBI and has promising prognostic value. Optimal CPP calculation is feasible with PRx and COx.
