Intracranial pressure monitoring for traumatic brain injury: available evidence and clinical implications

Following traumatic brain injury, uncontrollable intracranial hypertension remains the most frequent cause of death. Despite general agreement on the deleterious effects of elevated intracranial pressure (ICP), however, the evidence supporting the use of ICP monitoring has recently been questioned. The aim of this review was to evaluate the pros and cons of ICP monitoring and to discuss the hypothetical desirability and feasibility of a trial testing the benefits of ICP monitoring.     

Relationship between intracranial pressure monitoring and outcomes in severe traumatic brain injury patients

Intracranial pressure (ICP) monitoring is recommended in patients with a severe traumatic brain injury (TBI) and an abnormal computed tomography (CT) scan. However, there is contradicting evidence about whether ICP monitoring improves outcome. The purpose of this study was to examine the relationship between ICP monitoring and outcomes in patients with severe TBI. From February 2001 to December 2008, a total of 477 consecutive adult (> or =18 years) patients with severe TBI were included retrospectively in the study. Patients who underwent ICP monitoring (n=52) were compared with those who did not (n=425). The primary outcome was hospital mortality. Secondary outcomes were ICU mortality, mechanical ventilation duration, the need for tracheostomy, and ICU and hospital length of stay (LOS). After adjustment for multiple potential confounding factors, ICP monitoring was not associated with significant difference in hospital or ICU mortality (odds ratio [OR] = 1.71, 95% confidence interval [CI] = 0.79 to 3.70, P = 0.17; OR = 1.01, 95% CI = 0.41 to 2.45, P = 0.99, respectively). ICP monitoring was associated with a significant increase in mechanical ventilation duration (coefficient = 5.66, 95% CI = 3.45 to 7.88, P < 0.0001), need for tracheostomy (OR = 2.02, 95% CI = 1.02 to 4.03, P = 0.04), and ICU LOS (coefficient = 5.62, 95% CI = 3.27 to 7.98, P < 0.0001), with no significant difference in hospital LOS (coefficient = 8.32, 95% CI = -82.6 to 99.25, P = 0.86). Stratified by the Glasgow Coma Scale score, ICP monitoring was associated with a significant increase in hospital mortality in the group of patients with Glasgow Coma Scale 7 to 8 (adjusted OR = 12.89, 95% CI = 3.14 to 52.95, P = 0.0004). In patients with severe TBI, ICP monitoring was not associated with reduced hospital mortality, however with a significant increase in mechanical ventilation duration, need for tracheostomy, and ICU LOS.     

Awareness and perceptions of outcomes after traumatic brain injury

Awareness or insight has been identified as a major factor in successful rehabilitation after traumatic brain injury TBI. Anecdotal evidence suggests people with TBI are more likely to be aware of residual physical disabilities, perhaps focusing on these to the exclusion of other issues in the psycho social and cognitive domains, for example. To investigate this more accurately, recovery and outcome questionnaires were administered to people with TBI and their nominated significant others, and, as appropriate, an assessment of their level of functioning was also recorded. Two and three way analyses t-tests, Kendall's and Wilcoxon's comparing these perceptions were then conducted. The results indicated a high level of agreement for basic demographic data and broad outcomes. It was found the subjects reported a lower rate of physical impairment and disability than the signifiant other or the author, suggesting that, as a group, they do not fixate on physical issues. Other areas of difference were found, such as a tendency for the significant other to perceive the subject as being more dependent in mobility and self care tasks, possibly because of their close involvement. Also the author reported more impairments, using clinical language and assessment that did not necessarilyhave meaning or significance for the other groups. There was also evidence to support the notion that there is an inherent hierarchy of needs ranging from the lower order, physiological or survival skills through to higher order, self actualizing areas. Because of the differing awareness and perceptions, care must be taken in service provision to identify the personal needs and values of each individual involved.     

The impact of intracranial pressure monitoring on mortality after severe traumatic brain injury

Background

The effect of intracranial pressure (ICP) monitoring on mortality after severe traumatic brain injury (sTBI) remains unclear. We hypothesized that ICP monitoring would not be associated with improved survival in patients with sTBI.

Methods

A retrospective analysis was performed on sTBI patients, defined as admission Glasgow Coma Scale score of 8 or less with intracranial hemorrhage. Patients who underwent ICP monitoring were compared with patients who did not. The primary outcome measure was inhospital mortality.

Results

Of 123 sTBI patients meeting inclusion criteria, 40 (32.5%) underwent ICP monitoring. On bivariate and multivariate regression analyses, ICP monitoring was associated with decreased mortality (odds ratio = .32, 95% confidence interval = .10 to .99, P = .049). This finding persisted on propensity-adjusted analysis.

Conclusions

ICP monitoring is associated with improved survival in adult patients with sTBI. In addition, significant variability exists in the use of ICP monitoring among patients with sTBI.     

Asymmetry of pressure autoregulation after traumatic brain injury

OBJECT: The aim of this study was to assess the asymmetry of autoregulation between the left and right sides of the brain by using bilateral transcranial Doppler ultrasonography in a cohort of patients with head injuries. METHODS: Ninety-six patients with head injuries comprised the study population. All significant intracranial mass lesions were promptly removed. The patients were given medications to induce sedation and paralysis, and artificial ventilation. Arterial blood pressure (ABP) and intracranial pressure (ICP) were monitored in an invasive manner. A strategy based on the patient's cerebral perfusion pressure (CPP = ABP - ICP) was applied: CPP was maintained at a level higher than 70 mm Hg and ICP at a level lower than 25 mm Hg. The left and right middle cerebral arteries were insonated daily, and bilateral flow velocities (FVs) were recorded. The correlation coefficient between the CPP and FV, termed Mx, was calculated and time-averaged over each recording period on both sides. An Mx close to 1 signified that slow fluctuations in CPP produced synchronized slow changes in FV, indicating a defective autoregulation. An Mx close to 0 indicated preserved autoregulation. Computerized tomography scans in all patients were reviewed; the side on which the major brain lesion was located was noted and the extent of the midline shift was determined. Outcome was measured 6 months after discharge. The left-right difference in the Mx between the hemispheres was significantly higher in patients who died than in those who survived (0.16 +/- 0.04 compared with 0.08 +/- 0.01; p = 0.04). The left-right difference in the Mx was correlated with a midline shift (r = -0.42; p = 0.03). Autoregulation was worse on the side of the brain where the lesion was located (p < 0.035). CONCLUSIONS: The left-right difference in autoregulation is significantly associated with a fatal outcome. Autoregulation in the brain is worse on the side ipsilateral to the lesion and on the side of expansion in cases in which there is a midline shift.     

Management of head injury. Intracranial pressure monitoring.

The role of intracranial pressure monitoring as an adjunct to the clinical examination, CT scanning, and other diagnostic modalities has become increasingly recognized. This article presents a brief overview of the present status of this technique and touches on prospects for further developments.     

Clinical applications of intracranial pressure monitoring in traumatic brain injury

Background

Intracranial pressure (ICP) monitoring has been for decades a cornerstone of traumatic brain injury (TBI) management. Nevertheless, in recent years, its usefulness has been questioned in several reports. A group of neurosurgeons and neurointensivists met to openly discuss, and provide consensus on, practical applications of ICP in severe adult TBI.

Methods

A consensus conference was held in Milan on October 5, 2013, putting together neurosurgeons and intensivists with recognized expertise in treatment of TBI. Four topics have been selected and addressed in pro-con presentations: 1) ICP indications in diffuse brain injury, 2) cerebral contusions, 3) secondary decompressive craniectomy (DC), and 4) after evacuation of intracranial traumatic hematomas. The participants were asked to elaborate on the existing published evidence (without a systematic review) and their personal clinical experience. Based on the presentations and discussions of the conference, some drafts were circulated among the attendants. After remarks and further contributions were collected, a final document was approved by the participants.

Summary and conclusions

The group made the following recommendations: 1) in comatose TBI patients, in case of normal computed tomography (CT) scan, there is no indication for ICP monitoring; 2) ICP monitoring is indicated in comatose TBI patients with cerebral contusions in whom the interruption of sedation to check neurological status is dangerous and when the clinical examination is not completely reliable. The probe should be positioned on the side of the larger contusion; 3) ICP monitoring is generally recommended following a secondary DC in order to assess the effectiveness of DC in terms of ICP control and guide further therapy; 4) ICP monitoring after evacuation of an acute supratentorial intracranial hematoma should be considered for salvageable patients at increased risk of intracranial hypertension with particular perioperative features.     

Blood pressure and outcome after severe pediatric traumatic brain injury

BACKGROUND: The relationship between systolic blood pressure and outcome in children after severe traumatic brain injury (TBI) is unclear. We examined the relationship between age-appropriate systolic blood pressure (AASBP) percentile and outcome after severe pediatric TBI. METHODS: We examined the association between AASBP percentiles and outcome in 172 children younger than 14 years of age with a Glasgow Coma Scale score < 9. Outcome was evaluated using discharge Glasgow Outcome Scale score. Poor outcome was defined as a Glasgow Outcome Scale score < 4. RESULTS: Poor outcome was associated with AASBP < 75th percentile (odds ratio, 4.2; 95% confidence interval, 2.1-8.3). Patients with systolic blood pressure (SBP) > or = 90 mm Hg and AASBP < 75th percentile had a higher odds for poor outcome compared with patients with SBP > or = 90 mm Hg and AASBP > or = 75th percentile (odds ratio, 3.5; 95% confidence interval, 1.7-7.3). CONCLUSION AASBP < 75th percentile was associated with poor outcome after severe pediatric TBI, even when SBP was > or = 90 mm Hg.     

Neurobehavioral outcomes after early versus late childhood traumatic brain injury

OBJECTIVES: To examine differences in outcomes at transition age (17-21 years) between individuals who sustained complicated mild-to-severe traumatic brain injury (TBI) in early or middle childhood and those who were injured in late adolescence. PARTICIPANTS: Fifteen persons who sustained TBI between the ages of 6 and 12 years (early-onset) and 30 persons who sustained TBI between the ages of 16 and 20 years (late-onset). MEASURES: Peabody Picture Vocabulary Test-Third Edition, Trail-Making Test, Buschke Selective Reminding Test, Benton Visual Retention Test, Dysexecutive Questionnaire, Community Integration Questionnaire, Satisfaction with Life Scale. RESULTS: The groups did not differ in overall cognitive ability level, postinjury education or vocational accomplishments, or current living situation. However the early-onset group demonstrated worse outcomes in higher-level cognitive skills, social integration, driving, and legal guardianship. CONCLUSIONS: Complicated mild-to-severe TBI earlier in childhood is associated with worse long-term neurocognitive and psychosocial outcomes than injury sustained in late adolescence. Findings provide further support for theories that early brain injury onset interferes with development of immature or rapidly developing skills, and may be associated with further magnification of deficits during the course of later development.     

Impact of concomitant injuries on outcomes after traumatic brain injury

Background

Patients with traumatic brain injury (TBI) frequently have concomitant injuries; we aimed to investigate their impact on outcomes.

Methods

Between February 2002 and April 2010, 17 Austrian centers prospectively enrolled 863 patients with moderate and severe TBI into observational studies. Data on accident, treatment, and outcomes were collected. Patients who survived until intensive care unit (ICU) admission and had survivable TBI were selected, and were assigned to “isolated TBI” or “TBI + injury” groups. Six-month outcomes were classified as “favorable” if Glasgow Outcome Scale (GOS) scores were five or four, and were classified as “unfavorable” if GOS scores were three or less. Univariate statistics (Fisher’s exact test, t test, χ²-test) and logistic regression were used to identify factors associated with hospital mortality and unfavorable outcome.

Results

Of the 767 patients, 403 (52.5 %) had isolated TBI, 364 (47.5 %) had concomitant injuries. Patients with isolated TBI had higher mean age (53 vs. 44 years, P = 0.001); hospital mortality (30.0 vs. 27.2 %, P = 0.42) and rate of unfavorable outcome (50.4 vs. 41.8 %, P = 0.02) were higher, too. There were no significant mortality differences for factors like age groups, trauma mechanisms, neurologic status, CT findings, or treatment factors. Concomitant injuries were associated with higher mortality (33.3 vs. 12.5 %, P = 0.05) in patients with moderate TBI, and were significantly associated with more ventilation, ICU, and hospitals days. Logistic regression revealed that age, Glasgow Coma Scale score, pupillary reactivity, severity of TBI and CT score were the main factors that influenced outcomes.

Conclusions

Concomitant injuries have a significant effect upon the mortality of patients with moderate TBI. They do not affect the mortality in patients with severe TBI.

Level of evidence and study type

Evidence level 2; prospective, observational prognostic study.     

Slope of the intracranial pressure waveform after traumatic brain injury

BACKGROUND: The measurement and treatment of ICP within the management of TBI generally focuses on keeping the mean ICP to less than 20 mm Hg. More sophisticated analysis of the intracranial pressure waveform has yielded important relationships, but those methods have not gained widespread use. Prior analysis of the slope of the ICP waveform during inspiration and expiration in patients with hydrocephalus has provided valuable information that has never been applied to patients with TBI. This study used digital methods to examine ICP and the slope of the ICP waveform in relation to the respiratory cycle in subjects with TBI. METHODS: Intracranial pressure was monitored in 6 randomly selected patients admitted with acute TBI. In the first 3 subjects, a single 5-minute recording was analyzed. In 3 subsequent subjects, 4 nonsequential 5-minute epochs were analyzed during periods of varying ICP. The systolic slope of the ICP waveform was compared during inspiration and expiration, and then evaluated in relation to simultaneous mean ICP. RESULTS: The slope of the systolic ICP waveform was significantly greater during inspiration than during expiration (P < .0001 for 5 subjects and P < .03 for 1 subject). Within each subject, the ICP slope was positively correlated with simultaneous ICP (P < .0001 in all 6 cases). CONCLUSION: Greater systolic ICP waveform slope during inspiration has not been described previously after TBI and is consistent with prior observations in subjects with hydrocephalus. The strong correlation between ICP slope and simultaneous mean ICP suggests that increasing ICP slope might indicate loss of intracranial compliance after TBI.     

Intracranial pressure monitoring in severe traumatic brain injury in latin america: process and methods for a multi-center randomized controlled trial

In patients with severe traumatic brain injury (TBI), the influence on important outcomes of the use of information from intracranial pressure (ICP) monitoring to direct treatment has never been tested in a randomized controlled trial (RCT). We are conducting an RCT in six trauma centers in Latin America to test this question. We hypothesize that patients randomized to ICP monitoring will have lower mortality and better outcomes at 6-months post-trauma than patients treated without ICP monitoring. We selected three centers in Bolivia to participate in the trial, based on (1) the absence of ICP monitoring, (2) adequate patient accession and data collection during the pilot phase, (3) preliminary institutional review board approval, and (4) the presence of equipoise about the value of ICP monitoring. We conducted extensive training of site personnel, and initiated the trial on September 1, 2008. Subsequently, we included three additional centers. A total of 176 patients were entered into the trial as of August 31, 2010. Current enrollment is 81% of that expected. The trial is expected to reach its enrollment goal of 324 patients by September of 2011. We are conducting a high-quality RCT to answer a question that is important globally. In addition, we are establishing the capacity to conduct strong research in Latin America, where TBI is a serious epidemic. Finally, we are demonstrating the feasibility and utility of international collaborations that share resources and unique patient populations to conduct strong research about global public health concerns.