The IMPACT prognosis calculator used in patients with severe traumatic brain injury treated with an ICP-targeted therapy

Prognostic Models in Severe Traumatic Brain Injury: A Systematic Review and Meta-analysis

This review aimed to analyze the results of investigations that performed external validation or that compared prognostic models to identify the models and their variations that showed the best performance in predicting mortality, survival, and unfavorable outcome after severe traumatic brain injury. Pubmed, Embase, Scopus, Web of Science, Cumulative Index to Nursing and Allied Health Literature, Google Scholar, TROVE, and Open Grey databases were searched. A total of 1616 studies were identified and screened, and 15 studies were subsequently included for analysis after applying the selection criteria. The Corticosteroid Randomization After Significant Head Injury (CRASH) and International Mission for Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (IMPACT) models were the most externally validated among studies of severe traumatic brain injury. The results of the review showed that most publications encountered an area under the curve ≥ 0.70. The area under the curve meta-analysis showed similarity between the CRASH and IMPACT models and their variations for predicting mortality and unfavorable outcomes. Calibration results showed that the variations of CRASH and IMPACT models demonstrated adequate calibration in most studies for both outcomes, but without a clear indication of uncertainties in the evaluations of these models. Based on the results of this meta-analysis, the choice of prognostic models for clinical application may depend on the availability of predictors, characteristics of the population, and trauma care services.

Prognosis in moderate-severe traumatic brain injury in a Swedish cohort and external validation of the IMPACT models

Background

A major challenge in management of traumatic brain injury (TBI) is to assess the heterogeneity of TBI pathology and outcome prediction. A reliable outcome prediction would have both great value for the healthcare provider, but also for the patients and their relatives. A well-known prediction model is the International Mission for Prognosis and Analysis of Clinical Trials (IMPACT) prognostic calculator. The aim of this study was to externally validate all three modules of the IMPACT calculator on TBI patients admitted to Uppsala University hospital (UUH).

Method

TBI patients admitted to UUH are continuously enrolled into the Uppsala neurointensive care unit (NICU) TBI Uppsala Clinical Research (UCR) quality register. The register contains both clinical and demographic data, radiological evaluations, and outcome assessments based on the extended Glasgow outcome scale extended (GOSE) performed at 6 months to 1 year. In this study, we included 635 patients with severe TBI admitted during 2008–2020. We used IMPACT core parameters: age, motor score, and pupillary reaction.

Results

The patients had a median age of 56 (range 18–93), 142 female and 478 male. Using the IMPACT Core model to predict outcome resulted in an AUC of 0.85 for mortality and 0.79 for unfavorable outcome. The CT module did not increase AUC for mortality and slightly decreased AUC for unfavorable outcome to 0.78. However, the lab module increased AUC for mortality to 0.89 but slightly decreased for unfavorable outcome to 0.76. Comparing the predicted risk to actual outcomes, we found that all three models correctly predicted low risk of mortality in the surviving group of GOSE 2–8. However, it produced a greater variance of predicted risk in the GOSE 1 group, denoting general underprediction of risk. Regarding unfavorable outcome, all models once again underestimated the risk in the GOSE 3–4 groups, but correctly predicts low risk in GOSE 5–8.

Conclusions

The results of our study are in line with previous findings from centers with modern TBI care using the IMPACT model, in that the model provides adequate prediction for mortality and unfavorable outcome. However, it should be noted that the prediction is limited to 6 months outcome and not longer time interval.

Health and Well-Being of Persons of Working Age up to Seven Years after Severe Traumatic Brain Injury in Northern Sweden: A Mixed Method Study

Purpose: To explore the health and well-being of persons seven years after severe traumatic brain injury (STBI). Material and methods: Follow-up of 21 persons 1 and 7 years after STBI using surveys for functional outcome, anxiety/depression, health and mental fatigue. Interviews were conducted and analysed using qualitative content analysis. Convergent parallel mixed method then merged and analysed the results into an overall interpretation. Results: Good recovery, high functional outcome and overall good health were relatively unchanged between 1 and 7 years. Well-being was a result of adaptation to a recovered or changed life situation. Persons with good recovery had moved on in life. Persons with moderate disability self-estimated their health as good recovery but reported poorer well-being. For persons with severe disability, adaptation was an ongoing process and health and well-being were low. Only a few persons reported anxiety and depression. They had poorer health but nevertheless reported well-being. Persons with moderate and severe mental fatigue had low functional outcomes and overall health and none of them reported well-being. Conclusions: The life of a person who has suffered STBI is still affected to a lesser or greater degree several years after injury due to acceptance of a recovered or changed life situation. Further studies are needed on how health and well-being can be improved after STBI in the long-term perspective.

Selection of CT variables and prognostic models for outcome prediction in patients with traumatic brain injury

Background

Traumatic brain injuries (TBI) are associated with high risk of morbidity and mortality. Early outcome prediction in patients with TBI require reliable data input and stable prognostic models. The aim of this investigation was to analyze different CT classification systems and prognostic calculators in a representative population of TBI-patients, with known outcomes, in a neurointensive care unit (NICU), to identify the most suitable CT scoring system for continued research.

Materials and methods

We retrospectively included 158 consecutive patients with TBI admitted to the NICU at a level 1 trauma center in Sweden from 2012 to 2016. Baseline data on admission was recorded, CT scans were reviewed, and patient outcome one year after trauma was assessed according to Glasgow Outcome Scale (GOS). The Marshall classification, Rotterdam scoring system, Helsinki CT score and Stockholm CT score were tested, in addition to the IMPACT and CRASH prognostic calculators. The results were then compared with the actual outcomes.

Results

Glasgow Coma Scale score on admission was 3–8 in 38%, 9–13 in 27.2%, and 14–15 in 34.8% of the patients. GOS after one year showed good recovery in 15.8%, moderate disability in 27.2%, severe disability in 24.7%, vegetative state in 1.3% and death in 29.7%. When adding the variables from the IMPACT base model to the CT scoring systems, the Stockholm CT score yielded the strongest relationship to actual outcome. The results from the prognostic calculators IMPACT and CRASH were divided into two subgroups of mortality (percentages); ≤50% (favorable outcome) and > 50% (unfavorable outcome). This yielded favorable IMPACT and CRASH scores in 54.4 and 38.0% respectively.

Conclusion

The Stockholm CT score and the Helsinki score yielded the closest relationship between the models and the actual outcomes in this consecutive patient series, representative of a NICU TBI-population. Furthermore, the Stockholm CT score yielded the strongest overall relationship when adding variables from the IMPACT base model and would be our method of choice for continued research when using any of the current available CT score models.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00901-6.

Development of a Mortality Prediction Tool in Pediatric Severe Traumatic Brain Injury

Severe traumatic brain injury (sTBI) is a leading cause of pediatric death, yet outcomes remain difficult to predict. The goal of this study was to develop a predictive mortality tool in pediatric sTBI. We retrospectively analyzed 196 patients with sTBI (pre-sedation Glasgow Coma Scale [GCS] score <8 and head Maximum Abbreviated Injury Scale (MAIS) score >4) admitted to a pediatric intensive care unit (PICU). Overall, 56 patients with sTBI (29%) died during PICU stay. Of the survivors, 88 (63%) were discharged home, and 52 (37%) went to an acute care or rehabilitation facility. Receiver operating characteristic (ROC) curve analyses of admission variables showed that pre-sedation GCS score, Rotterdam computed tomography (CT) score, and partial thromboplastin time (PTT) were fair predictors of PICU mortality (area under the curve [AUC] = 0.79, 0.76, and 0.75, respectively; p < 0.001). Cutoff values best associated with PICU mortality were pre-sedation GCS score <5 (sensitivity = 0.91, specificity = 0.54), Rotterdam CT score >3 (sensitivity = 0.84, specificity = 0.53), and PTT >34.5 sec (sensitivity = 0.69 specificity = 0.67). Combining pre-sedation GCS score, Rotterdam CT score, and PTT in ROC curve analysis yielded an excellent predictor of PICU mortality (AUC = 0.91). In summary, pre-sedation GCS score (<5), Rotterdam CT score (>3), and PTT (>34.5 sec) obtained on hospital admission were fair predictors of PICU mortality, ranked highest to lowest. Combining these three admission variables resulted in an excellent pediatric sTBI mortality prediction tool for further prospective validation.

Prognosis in Moderate and Severe Traumatic Brain Injury: A Systematic Review of Contemporary Models and Validation Studies

Outcome prognostication in traumatic brain injury (TBI) is important but challenging due to heterogeneity of the disease. The aim of this systematic review is to present the current state-of-the-art on prognostic models for outcome after moderate and severe TBI and evidence on their validity. We searched for studies reporting on the development, validation or extension of prognostic models for functional outcome after TBI with Glasgow Coma Scale (GCS) ≤12 published between 2006-2018. Studies with patients age ≥14 years and evaluating a multi-variable prognostic model based on admission characteristics were included. Model discrimination was expressed with the area under the receiver operating characteristic curve (AUC), and model calibration with calibration slope and intercept. We included 58 studies describing 67 different prognostic models, comprising the development of 42 models, 149 external validations of 31 models, and 12 model extensions. The most common predictors were GCS (motor) score (n = 55), age (n = 54), and pupillary reactivity (n = 48). Model discrimination varied substantially between studies. The International Mission for Prognosis and Analysis of Clinical Trials (IMPACT) and Corticoid Randomisation After Significant Head injury (CRASH) models were developed on the largest cohorts (8509 and 10,008 patients, respectively) and were most often externally validated (n = 91), yielding AUCs ranging between 0.65-0.90 and 0.66-1.00, respectively. Model calibration was reported with a calibration intercept and slope for seven models in 53 validations, and was highly variable. In conclusion, the discriminatory validity of the IMPACT and CRASH prognostic models is supported across a range of settings. The variation in calibration, reflecting heterogeneity in reliability of predictions, motivates continuous validation and updating if clinical implementation is pursued.

Patient and Physician Perspectives in a Case of Severe Traumatic Brain Injury

Traumatic brain injury is a challenge for general practitioners and specialists worldwide due to the heterogeneous clinical picture, secondary injuries and complex treatment including surgery, medication, intensive care, nutrition and rehabilitation. This case report is about a TBI patient with a score of four on the Glasgow Coma Scale when she was transferred from the primary hospital to our center. Her condition, treatment options and expectations were discussed with the relatives. The patient was subjected to surgery and received pharmacologic intervention including a neurotrophic drug and extensive rehabilitation measures including occupational therapy. Considering the patient's remarkable recovery, a combination of multiple treatment approaches seems promising in patients with severe traumatic brain injury.

The aggressiveness of neurotrauma practitioners and the influence of the IMPACT prognostic calculator

Published guidelines have helped to standardize the care of patients with traumatic brain injury; however, there remains substantial variation in the decision to pursue or withhold aggressive care. The International Mission for Prognosis and Analysis of Clinical Trials in TBI (IMPACT) prognostic calculator offers the opportunity to study and decrease variability in physician aggressiveness. The authors wish to understand how IMPACT’s prognostic calculations currently influence patient care and to better understand physician aggressiveness. The authors conducted an anonymous international, multidisciplinary survey of practitioners who provide care to patients with traumatic brain injury. Questions were designed to determine current use rates of the IMPACT prognostic calculator and thresholds of age and risk for death or poor outcome that might cause practitioners to consider withholding aggressive care. Correlations between physician aggressiveness, putative predictors of aggressiveness, and demographics were examined. One hundred fifty-four responses were received, half of which were from physicians who were familiar with the IMPACT calculator. The most frequent use of the calculator was to improve communication with patients and their families. On average, respondents indicated that in patients older than 76 years or those with a >85% chance of death or poor outcome it might be reasonable to pursue non-aggressive care. These thresholds were robust and were not influenced by provider or institutional characteristics. This study demonstrates the need to educate physicians about the IMPACT prognostic calculator. The consensus values for age and prognosis identified in our study may be explored in future studies aimed at reducing variability in physician aggressiveness and should not serve as a basis for withdrawing care.

Computed tomography and clinical outcome in patients with severe traumatic brain injury

OBJECTIVE

To study: (i) acute computed tomography (CT) characteristics and clinical outcome; (ii) clinical course and (iii) Corticosteroid Randomisation after Significant Head Injury acute calculator protocol (CRASH) model and clinical outcome in patients with severe traumatic brain injury (sTBI).

METHODS

Initial CT (CT_i) and CT 24 hours post-trauma (CT₂₄) were evaluated according to Marshall and Rotterdam classifications. Rancho Los Amigos Cognitive Scale-Revised (RLAS-R) and Glasgow Outcome Scale Extended (GOSE) were assessed at three months and one year post-trauma. The prognostic value of the CRASH model was evaluated.

RESULTS

Thirty-seven patients were included. Marshall CT_i and CT₂₄ were significantly correlated with RLAS-R at three months. Rotterdam CT₂₄ was significantly correlated with GOSE at three months. RLAS-R and the GOSE improved significantly from three months to one year. CRASH predicted unfavourable outcome at six months for 81% of patients with bad outcome and for 85% of patients with favourable outcome according to GOSE at one year.

CONCLUSION

Neither CT nor CRASH yielded clinically useful predictions of outcome at one year post-injury. The study showed encouragingly many instances of significant recovery in this population of sTBI. The combination of lack of reliable prognostic indicators and favourable outcomes supports the case for intensive acute management and rehabilitation as the default protocol in the cases of sTBI.

Use of the CRASH study prognosis calculator in patients with severe traumatic brain injury treated with an intracranial pressure-targeted therapy

Based on the Corticosteroid Randomisation after Significant Head Injury (CRASH) trial database, a prognosis calculator has been developed for the prediction of outcome in an individual patient with a head injury. In 47 patients with severe traumatic brain injury (sTBI) prospectively treated using an intracranial pressure (ICP) targeted therapy, the individual prognosis for mortality at 14 days and unfavourable outcome at 6 months was calculated and compared with the actual outcome. An overestimation of the risk of mortality and unfavourable outcome was found. The mean risk for mortality and unfavourable outcome were estimated to be 44.6±32.5% (95% confidence interval [CI], 35.1-54.2%) and 69.3±23.7% (95% CI, 62.3-76.2%). The actual outcome was 4.3% and 42.6% respectively. The absolute risk reduction (ARR) for mortality was 33.1% and for unfavourable outcome 29.8%. A logistic fit for outcome at 6 months shows a statistically significant difference (p<0.01). A receiver operating characteristic (ROC) curve analysis shows an area under the curve (AUC) of 0.691. The CRASH prognosis calculator overestimates the risk of mortality and unfavourable outcome in patients with sTBI treated with an ICP-targeted therapy based on the Lund concept. We do not advocate the use of the calculator for treatment decisions in individual patients. We further conclude that patients with blunt sTBI admitted within 8 hours of trauma should be treated regardless of their clinical status as long as the initial cerebral perfusion pressure is >10 mmHg.