The effect of ICP monitoring in severe traumatic brain injury: a propensity score–weighted and adjusted regression approach

Restricted access


The use of intracranial pressure (ICP) monitoring has been postulated to be beneficial in patients with severe traumatic brain injury (TBI), although studies investigating this hypothesis have reported conflicting results. The objective of this study was to evaluate the effect of inserting an ICP monitor on survival in patients with severe TBI.


The Oslo University Hospital trauma registry was searched for the records of all patients admitted between January 1, 2002, and December 31, 2013, who fulfilled the Brain Trauma Foundation criteria for intracranial hypertension and who survived at least 24 hours after admission. The impact of ICP monitoring was investigated using both a logistic regression model and a multiple imputed, propensity score–weighted logistic regression analysis.


The study involved 1327 patients, in which 757 patients had an ICP monitor implanted. The use of ICP monitors significantly increased in the study period (p < 0.01). The 30-day overall mortality was 24.3% (322 patients), divided into 35.1% (200 patients, 95% confidence interval [CI] 31.3%–39.1%) in the group without an ICP monitor and 16.1% (122 patients, 95% CI 13.6%–18.9%) in the group with an ICP monitor. The impact of ICP monitors on 30-day mortality was found to be beneficial both in the complete case analysis logistic regression model (odds ratio [OR] 0.23, 95% CI 0.16–0.33) and in the adjusted, aggregated, propensity score–weighted imputed data sets (OR 0.22, 95% CI 0.15–0.35; both p < 0.001). The sensitivity analysis indicated that the findings are robust to unmeasured confounders.


The authors found that the use of an ICP monitor is significantly associated with improved survival in patients with severe head injury.

ABBREVIATIONS AIS = Abbreviated Injury Scale; ASA = American Society of Anesthesiologists Physical Status Classification; BEST-TRIP = Benchmark Evidence from South American Trials: Treatment of Intracranial Pressure; BTF = Brain Trauma Foundation; CI = confidence interval; CPP = cerebral perfusion pressure; EVD = external ventricular drain; GB = generalized boosting; GCS = Glasgow Coma Scale; ICP = intracranial pressure; ISS = Injury Severity Score; OR = odds ratio; OUH-U = Oslo University Hospital, Ullevål; TBI = traumatic brain injury.

Article Information

Correspondence Pål Rønning: Oslo University Hospital, Oslo, Norway.

INCLUDE WHEN CITING Published online December 21, 2018; DOI: 10.3171/2018.7.JNS18270.

Disclosures The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.

© AANS, except where prohibited by US copyright law.



  • View in gallery

    The left panel demonstrates the effect of weighting the propensity score obtained from the GB model on standardized differences between the ICP-monitored and -nonmonitored groups. The different points indicate the different results from the 10 imputed data sets. The right panel indicates the relative influence of the variable on the final multivariate model from the GB model. BP = blood pressure; fx = fracture.

  • View in gallery

    A weighted Kaplan-Meier curve (using the aggregated, propensity score, multiple-imputed data set) demonstrating improved survival in the ICP-monitored cohort.

  • View in gallery

    Coefficient plot. The unadjusted and adjusted b-coefficients and their associated 95% CIs from the complete case data set using logistic regression are contrasted with the b-coefficients from the imputed, propensity score–weighted logistic regression analysis. The effect of ICP monitor insertion is significant for the adjusted analyses in both data sets (OR 0.23, 95% CI 0.16–0.33, and OR 0.22, 95% CI 0.15–0.35; both p < 0.001).



Alali ASFowler RAMainprize TGScales DCKiss Ade Mestral C: Intracranial pressure monitoring in severe traumatic brain injury: results from the American College of Surgeons Trauma Quality Improvement Program. J Neurotrauma 30:173717462013


Association for the Advancement of Automotive Medicine: The Abbreviated Injury Scale 1990 Revision: Update 98. Barrington, IL: Association for the Advancement of Automotive Medicine1998


Baker SPO’Neill BHaddon W JrLong WB: The injury severity score: a method for describing patients with multiple injuries and evaluating emergency care. J Trauma 14:1871961974


Brain Trauma Foundation: Guidelines for the management of severe traumatic brain injury. J Neurotrauma 24 (Suppl 1):S1S1062007


Carney NTotten AMO’Reilly CUllman JSHawryluk GWBell MJ: Guidelines for the Management of Severe Traumatic Brain InjuryFourth Edition. Neurosurgery 80:6152017


Chesnut RMTemkin NCarney NDikmen SRondina CVidetta W: A trial of intracranial-pressure monitoring in traumatic brain injury. N Engl J Med 367:247124812012


Cremer OLvan Dijk GWvan Wensen EBrekelmans GJMoons KGLeenen LP: Effect of intracranial pressure monitoring and targeted intensive care on functional outcome after severe head injury. Crit Care Med 33:220722132005


Dawes AJSacks GDCryer HGGruen JPPreston CGorospe D: Intracranial pressure monitoring and inpatient mortality in severe traumatic brain injury: a propensity score-matched analysis. J Trauma Acute Care Surg 78:4925022015


Fakhry SMTrask ALWaller MAWatts DD: Management of brain-injured patients by an evidence-based medicine protocol improves outcomes and decreases hospital charges. J Trauma 56:4925002004


Griesdale DEMcEwen JKurth TChittock DR: External ventricular drains and mortality in patients with severe traumatic brain injury. Can J Neurol Sci 37:43–482010


Harrell JFE: Regression Modeling Strategies: With Applications to Linear Models Logistic and Ordinal Regression and Survival Analysis. Cham, Switzerland: Springer International Publishing2015


Hutchinson PJKolias AGCzosnyka MKirkpatrick PJPickard JDMenon DK: Intracranial pressure monitoring in severe traumatic brain injury. BMJ 346:f10002013


Jones JMSkaga NOSøvik SLossius HMEken T: Norwegian survival prediction model in trauma: modelling effects of anatomic injury, acute physiology, age, and co-morbidity. Acta Anaesthesiol Scand 58:3033152014


Kostić AStefanović INovak VVeselinović DIvanov GVeselinović A: Prognostic significance of intracranial pressure monitoring and intracranial hypertension in severe brain trauma patients. Med Pregl 64:4614652011


Lane PLSkoretz TGDoig GGirotti MJ: Intracranial pressure monitoring and outcomes after traumatic brain injury. Can J Surg 43:4424482000


Maas AIRRoozenbeek BManley GT: Clinical trials in traumatic brain injury: past experience and current developments. Neurotherapeutics 7:1151262010


MacLaughlin BWPlurad DSSheppard WBricker SBongard FNeville A: The impact of intracranial pressure monitoring on mortality after severe traumatic brain injury. Am J Surg 210:108210872015


Marmarou AAnderson RLWard JDChoi SCYoung HFEisenberg HM: Impact of ICP instability and hypotension on outcome in patients with severe head trauma. J Neurosurg 75 Suppl:S59S661991


McCaffrey DFRidgeway GMorral AR: Propensity score estimation with boosted regression for evaluating causal effects in observational studies. Psychol Methods 9:4034252004


Murray GDButcher IMcHugh GSLu JMushkudiani NAMaas AIR: Multivariable prognostic analysis in traumatic brain injury: results from the IMPACT study. J Neurotrauma 24:3293372007


Rønning PGunstad POSkaga NOLangmoen IAStavem KHelseth E: The impact of blood ethanol concentration on the classification of head injury severity in traumatic brain injury. Brain Inj 29:164816532015


Roozenbeek BMaas AIMenon DK: Changing patterns in the epidemiology of traumatic brain injury. Nat Rev Neurol 9:2312362013


Shafi SDiaz-Arrastia RMadden CGentilello L: Intracranial pressure monitoring in brain-injured patients is associated with worsening of survival. J Trauma 64:3353402008


Shen LWang ZSu ZQiu SXu JZhou Y: Effects of intracranial pressure monitoring on mortality in patients with severe traumatic brain injury: a meta-analysis. PLoS One 11:e01689012016


Søvik SSkaga NOHanoa REken T: Sudden survival improvement in critical neurotrauma: an exploratory analysis using a stratified statistical process control technique. Injury 45:172217302014


Stocchetti NMaas AIR: Traumatic intracranial hypertension. N Engl J Med 370:212121302014


Stuart EA: Matching methods for causal inference: A review and a look forward. Stat Sci 25:1212010


van Buuren SGroothuis-Oudshoorn K: mice: Multivariate Imputation by Chained Equations in R. J Stat Softw 45:1672011


Vik ANag TFredriksli OASkandsen TMoen KGSchirmer-Mikalsen K: Relationship of “dose” of intracranial hypertension to outcome in severe traumatic brain injury. J Neurosurg 109:6786842008


You WFeng JTang QCao JWang LLei J: Intraventricular intracranial pressure monitoring improves the outcome of older adults with severe traumatic brain injury: an observational, prospective study. BMC Anesthesiol 16:352016


Yuan QWu XCheng HYang CWang YWang E: Is intracranial pressure monitoring of patients with diffuse traumatic brain injury valuable? An observational multicenter study. Neurosurgery 78:3613692016




All Time Past Year Past 30 Days
Abstract Views 176 176 108
Full Text Views 289 289 36
PDF Downloads 128 128 25
EPUB Downloads 0 0 0


Google Scholar