Peter A. Ferrazzano, Bedda L. Rosario, Stephen R. Wisniewski, Nadeem I. Shafi, Heather M. Siefkes, Darryl K. Miles, Andrew L. Alexander, Michael J. Bell and for the Investigators of the ADAPT Trial
There is no consensus on the optimal timing and specific brain MRI sequences in the evaluation and management of severe pediatric traumatic brain injury (TBI), and information on current practices is lacking. The authors performed a survey of MRI practices among sites participating in a multicenter study of severe pediatric TBI to provide information for designing future clinical trials using MRI to assess brain injury after severe pediatric TBI.
Information on current imaging practices and resources was collected from 27 institutions participating in the Approaches and Decisions after Pediatric TBI Trial. Multiple-choice questions addressed the percentage of patients with TBI who have MRI studies, timing of MRI, MRI sequences used to investigate TBI, as well as the magnetic field strength of MR scanners used at the participating institutions and use of standardized MRI protocols for imaging after severe pediatric TBI.
Overall, the reported use of MRI in pediatric patients with severe TBI at participating sites was high, with 40% of sites indicating that they obtain MRI studies in > 95% of this patient population. Differences were observed in the frequency of MRI use between US and international sites, with the US sites obtaining MRI in a higher proportion of their pediatric patients with severe TBI (94% of US vs 44% of international sites reported MRI in at least 70% of patients with severe TBI). The reported timing and composition of MRI studies was highly variable across sites. Sixty percent of sites reported typically obtaining an MRI study within the first 7 days postinjury, with the remainder of responses distributed throughout the first 30-day postinjury period. Responses indicated that MRI sequences sensitive for diffuse axonal injury and ischemia are frequently obtained in patients with TBI, whereas perfusion imaging and spectroscopy techniques are less common.
Results from this survey suggest that despite the lack of consensus or guidelines, MRI is commonly obtained during the acute clinical setting after severe pediatric TBI. The variation in MRI practices highlights the need for additional studies to determine the utility, optimal timing, and composition of clinical MRI studies after TBI. The information in this survey describes current clinical MRI practices in children with severe TBI and identifies important challenges and objectives that should be considered when designing future studies.
Martina Stippler, Veronica Ortiz, P. David Adelson, Yue-Fang Chang, Elizabeth C. Tyler-Kabara, Stephen R. Wisniewski, Ericka L. Fink, Patrick M. Kochanek, S. Danielle Brown and Michael J. Bell
Minimizing secondary brain injuries after traumatic brain injury (TBI) in children is critical to maximizing neurological outcome. Brain tissue oxygenation monitoring (as measured by interstitial partial pressure of O2 [PbO2]) is a new tool that may aid in guiding therapies, yet experience in children is limited. This study aims to describe the authors' experience of PbO2 monitoring after TBI. It was hypothesized that PbO2 thresholds could be established that were associated with favorable neurological outcome, and it was determined whether any relationships between PbO2 and other important clinical variables existed.
Forty-six children with severe TBI (Glasgow Coma Scale score ≤ 8 after resuscitation) who underwent PbO2 and brain temperature monitoring between September 2004 and June 2008 were studied. All patients received standard neurocritical care, and 24 were concurrently enrolled in a trial of therapeutic early hypothermia (n = 12/group). The PbO2 was measured in the uninjured frontal cortex. Hourly recordings and calculated daily means of various variables including PbO2, intracranial pressure (ICP), cerebral perfusion pressure (CPP), mean arterial blood pressure, partial pressure of arterial O2, and fraction of inspired O2 were compared using several statistical approaches. Glasgow Outcome Scale scores were determined at 6 months after injury.
The mean patient age was 9.4 years (range 0.1–16.5 years; 13 girls) and 8554 hours of monitoring were analyzed (PbO2 range 0.0–97.2 mm Hg). A PbO2 of 30 mm Hg was associated with the highest sensitivity/specificity for favorable neurological outcome at 6 months after TBI, yet CPP was the only factor that was independently associated with favorable outcome. Surprisingly, instances of preserved PbO2 with altered ICP and CPP were observed in some children with unfavorable outcomes.
Monitoring of PbO2 demonstrated complex interactions with clinical variables reflecting intracranial dynamics using this protocol. A higher threshold than reported in studies in adults was suggested as a potential therapeutic target, but this threshold was not associated with improved outcomes. Additional studies to assess the utility of PbO2 monitoring after TBI in children are needed.