Ropper, Alexander E.; Chi, John H.
The use of intracranial pressure (ICP) monitoring is a cornerstone of the management of the traumatic brain injury (TBI), however its efficacy has not been systematically evaluated in improving meaningful outcomes. In fact, some retrospective analyses have even proposed that monitoring leads to worse outcomes.1 Chestnut and colleagues designed and implemented the Benchmark Evidence from South America Trials: Treatment of Intracranial Pressure (BEST:TRIP) trial2 to test the hypothesis that management of TBI with ICP monitoring would improve survival and neuropsychological and functional recovery. The authors conducted a multi-center, randomized controlled trial of patients with severe TBI in 6 hospitals in Bolivia and Ecuador. Patients were assigned to either a management protocol in which ICP monitoring was utilized (pressure-monitoring arm) or a protocol in which therapy was guided by clinical exams and imaging studies (imaging-clinical examination arm). The primary outcome was a composite of survival time as well as neuropsychological and functional status at 6 months.
The study was a multicenter, parallel-group trial with randomization to the “pressure-monitoring” or “clinical and examination” groups. All sites were staffed with intensivists and computer tomography (CT) scanners, and non-neurological problems were treated aggressively in both groups. Eligibility criteria included age >13 years with a Glasgow Coma Score (GCS) between 3 and 8. Patients with bilateral fixed and dilated pupils and those with injuries deemed to be unsurvivable were excluded. A strict protocol was established for the management in both groups. All patients received CT scans at baseline, 48 hours and 5 to 7 days as well as standard supportive care including mechanical ventilation. Treatment in the pressure-monitoring group focused on initiating therapy when ICP exceeded 20 mm Hg based on established TBI guidelines.3 Therapies included sedation, hypertonic saline, mannitol, hyperventilation and optional ventricular drainage. Of note, all pressure was monitored with a parenchymal monitor. In the imaging-clinical exam group, CT scans were obtained with clinical worsening to drive decisions to escalate medical therapy for presumed increased ICPs. These treatments were then instituted on a scheduled basis.
There were 324 total patients enrolled in this study. There was no difference in 6-month mortality (39% in the pressure-monitoring group and 41% in the imaging-clinical examination group, P = .6). Nor was there a difference in the cumulative primary outcome measure (56th percentile in the pressure-monitoring group and 53rd in the imaging-clinical examination group, P = .49). The length of ICU stay did not statistically differ, but the number of days in the ICU with “brain-specific” treatments was lower in the pressure-monitoring group. Overall adverse event occurrence was also similar.
The need for craniotomies for mass lesions and decompressive hemicraniectomy was also similar in the 2 groups. However, the intensity of brain-specific treatments such as hypertonic saline, hyperventilation and barbiturates was significantly higher in the imaging-clinical examination group. The authors carefully state that the results of this study do not argue against the use of ICP-monitors in the management of these patients, but rather that the treatment algorithms based on established guidelines that use ICP measurements are not superior to an algorithm based on serial imaging and neurological examination.
The criticisms of this study has included a lack of generalizability, as it was conducted in South America, where ICU care may differ from that in the USA or Europe. The use of CSF drainage with ventriculostomies, a very common and efficacious method to lower ICPs, was sparsely used in either arm of the study (in 1% and 2% of patients, respectively). Despite possible shortcomings of the study, the authors should be commended for evaluating a long-held conception in trauma neurosurgery. And while other similar trials must be conducted to change practice, this article raises a number of interesting questions. Specifically, is 20 mm Hg the correct number at which to initiate therapy? Should all patients with TBI be treated in the same manner? Or can subsets of this population benefit more from direct ICP monitoring than others?
Figure. KaplanMeier ...Image Tools
1. Shafi S, Diaz-Arrastia R, Madden C, Gentilello L. Intracranial pressure monitoring in brain-injured patients is associated with worsening of survival. J Trauma. 2008;64(2):335–340.
2. Chesnut RM, Temkin N, Carney N, et al.. A trial of intracranial-pressure monitoring in traumatic brain injury. N Engl J Med. 2012;367(26):2471–2481.
3. Bullock MR, Povlishock JT. Guidelines for the management of severe traumatic brain injury. Editor's Commentary. J Neurotrauma. 2007;24(suppl 1):2 p preceding S1.