Prognostication of Mortality and Long-Term Functional Outcomes Following Traumatic Brain Injury: Can We Do Better?

Accurate prognostication of outcomes following traumatic brain injury (TBI) affects not only the aggressiveness of intervention and therapeutic decision-making but also clinicians' ability to provide reliable expectations. To investigate the relative ability of clinicians to accurately predict a patient's outcomes, compared with point-of-care prognostic models, we surveyed clinical providers of 86 patients with moderate-severe TBI at admission, Day 3, and Day 7 post-injury for a patient's predicted mortality and functional outcome at 6 months. The predicted mortality and functional outcomes were compared with actual occurrence of 14-day mortality and functional outcomes at six months. A prognostic score was then calculated utilizing the Corticoid Randomization After Significant Head Injury (CRASH) and International Mission on Prognosis and Analysis of Clinical Trials (IMPACT) models and categorized as high, intermediate, and low likelihood of mortality or poor functional outcome, and compared with clinical predictions. Overall, clinicians of varying backgrounds showed an accurate prediction of survival (87.2-97.4%) but struggled in prognosticating poor functional outcomes (24.3-36.6%). These values did not statistically improve over 7 days. Stratified CRASH (87.2%) and IMPACT (84.9%) accuracy rates were statistically better than clinical judgment alone in predicting functional outcomes (p < 0.0001). Prognostic models calculated at admission showed to be potentially useful, in conjunction with clinical judgment, in accurately predicting both survival and 6-month functional outcomes.

Open chest cardiac massage offers no benefit over closed chest compressions in patients with traumatic cardiac arrest.

BACKGROUND: Open chest cardiac massage (OCCM) is a commonly performed procedure after traumatic cardiac arrest (TCA). OCCM has been reported to be superior to closed chest compressions (CCC) in animal models and in non-TCA. The purpose of this study is to prospectively compare OCCM versus CCC in TCA using end-tidal carbon dioxide (ETCO2), the criterion standard for determining the effectiveness of chest compressions and detection of return of spontaneous circulation (ROSC), as the surrogate for cardiac output and marker for adequacy of resuscitation. METHODS: This prospective observational study enrolled patients over a 9-month period directly presenting to a level 1 trauma center after TCA. Continuous high-resolution ETCO2 measurements were collected every 6 seconds for periods of CCC and OCCM, respectively. Patients receiving CCC only were compared with patients receiving CCC followed by OCCM. Student's t tests were used to compare ETCO2 within and between groups. RESULTS: Thirty-three patients were enrolled (16 OCCM, 17 CCC-only). Mean time of CCC before OCCM was 66 seconds. Within the OCCM group, final, peak, mean, and median ETCO2 levels significantly increased when comparing the initial CCC period to the OCCM interval. Using a time-matched comparison, significant increases were observed in the final and peak but not mean and median values when comparing the first minute of CCC to the remaining time in the CCC-only group. However, when periods of OCCM were compared with equivalent periods of CCC-only, there were no differences in the initial, final, peak, mean, or median ETCO2 values. Correspondingly, no difference in rates of ROSC was observed between groups (OCCM 23.5% vs. CCC 38.9%; p = 0.53). CONCLUSION: Although we could not control for confounders, we found no significant improvement in ETCO2 or ROSC with OCCM. With newer endovascular techniques for aortic occlusion, thoracotomy solely for performing OCCM provides no benefit over CCC. LEVEL OF EVIDENCE: Therapeutic study, level III.

Dexmedetomidine as an adjunct for sedation in patients with traumatic brain injury.

BACKGROUND: In patients with traumatic brain injury (TBI), optimizing sedation is challenging because maintaining a clinical examination is important in being able to detect neurological deterioration. Propofol (PROP) is frequently used as a sedative in TBI since it has been shown to reduce the cerebral metabolic rate, but it may lead to PROP-related infusion syndrome and hemodynamic compromise. Dexmedetomidine (DEX) is a sedative that produces minimal respiratory depression with opioid-sparing effects. The purpose of this study was to determine whether sedation with DEX would be safe in patients with severe TBI. METHODS: This prospective observational single-center study was conducted from 2011 to 2013. Patients with severe TBI were treated according to standard of care per the Brain Trauma Foundation guidelines. Sedative agents were titrated using the Richmond Agitation Sedation Scale (RASS) while maintaining intracranial pressure of less than 20 mm Hg and cerebral perfusion pressure of greater than 60 mm Hg. The primary outcome measure was the mean time in target RASS (0 = alert and calm to -2 = light sedation). RESULTS: A total of 198 patients were enrolled in the study. Patient-days (1,028 in total) were stratified into four groups: DEX only (n = 222), DEX + PROP (n = 148), PROP only (n = 599), and NEITHER (n = 59). Regression analyses indicated a significant difference in target RASS between sedative agents (p = 0.001). The DEX-only group had the highest adjusted mean daily estimate of 16.0 hours in target RASS. Hypotension was significantly higher in both the DEX only (p = 0.01) and DEX + PROP (p = 0.01) groups than in the PROP-only group. CONCLUSIONS: Dexmedetomidine was found to be associated with significantly more hypotension. Therefore, larger studies are needed to identify the role of DEX in TBI. LEVEL OF EVIDENCE: Therapeutic study, level III.

The role of cardiac troponin I in prognostication of patients with isolated severe traumatic brain injury.

BACKGROUND: Cardiac dysfunction is frequently observed after severe traumatic brain injury (sTBI); however, its significance is poorly understood. Our study sought to elucidate the association of cardiac troponin I (cTnI) elevation with all-cause in-hospital mortality following isolated sTBI (brain Abbreviated Injury Scale score ≥3 and admission Glasgow Coma Scale score ≤8, no Abbreviated Injury Scale score ≥3 to any other bodily regions). METHODS: We retrospectively reviewed all adult patients (aged ≥18 years) with isolated sTBI admitted to a Level I trauma center between June 2007 and January 2014. Patients must have cTnI values within 24 hours of admission. Mortality risks were examined by Cox proportional hazard model. RESULTS: Of 580 patients identified, 30.9% had detectable cTnI in 24 hours of admission. The median survival time was 4.19 days (interquartile range, 1.27-11.69). When adjusted for potential confounders, patients in the highest cTnI category (≥0.21 ng/mL) had a significantly higher risk of in-hospital mortality (hazard ratio, 1.39; 95% confidence interval, 1.04-1.88) compared with patients with undetectable cTnI. Mortality risk increased with higher troponin levels (p < 0.0001). This association was more pronounced in patients aged 65 years or younger (hazard ratio, 2.28; 95% confidence interval, 1.53-3.40; p < 0.0001) while, interestingly, insignificant in those older than 65 years (p = 0.0826). CONCLUSION: Among patients with sTBI, cTnI elevation is associated with all-cause in-hospital mortality via a nonlinear positive trend. Age modified the effect of cTnI on mortality. LEVEL OF EVIDENCE: Prognostic and epidemiologic study, level III.

Indirect signs of blunt duodenal injury on computed tomography: Is non-operative management safe?

INTRODUCTION: Clear signs of duodenal injury (DI) such as pneumoperitoneum and/or oral contrast extravasation mandate laparotomy. Management when computed tomography (CT) reveals indirect evidence of DI namely duodenal hematoma or periduodenal fluid is unclear. We evaluated the utility of indirect signs to identify DI and the success of expected management, hypothesizing patients with indirect evidence of DI on CT can be safely managed non-operatively. METHODS: We retrospectively reviewed patients with a computed tomography (CT) scan with periduodenal hematoma or periduodenal fluid treated between January 2003 and January 2013 at a level 1 Trauma Center. Demographics, injury characteristics, laboratory values, injury severity scores (ISS), and outcome measures were recorded. Patients having immediate laparotomy were compared to those initially managed nonoperatively. RESULTS: We identified 74 patients with indirect signs of DI, with 35 patients (47%) undergoing immediate operative exploration and 39 (53%) initially managed non-operatively. Lactate (4.5 mg/dL, standard deviation (SD) 2.1 vs 3.1 mg/dL, SD 1.4, p<0.001), ISS (median (IQR) 34 (27-44) vs. 24 (17-34), p=0.002) and abdominal AIS (3 (3-4) vs 2 (2-3), p<0.001) were higher in those with immediate operation. The incidence of DI requiring operative repair was 11% (8 of 74). Six of 35 (17%) explored urgently had a DI requiring repair while 29 of 35 (83%) had no DI or minor injury not requiring surgical therapy. Of those managed non-operatively, 7 of 39 (18%) failed observation but only two (5%) required duodenal repair. There was no significant difference in intensive care unit (ICU) (10.2 days, standard error [SE] 2.1 vs 9.7 days, SE 4.8, p=0.93) or hospital (22.5 days, SE 3.8 vs 23.6 days, SE 8.5, p=0.91) length of stay between those operated on immediately and those that failed non-operative management when adjusted for age, sex, and ISS. There was no mortality in the non-operative group related to an intra-abdominal injury. CONCLUSION: Observation of patients with indirect sign of DI fails in about 20% of patients, but failure rate due to DI is low at 5%. Conservative management in appropriately selected patients is reasonable with close observation.

Predictive value of hyperthermia and intracranial hypertension on neurological outcomes in patients with severe traumatic brain injury.

BACKGROUND: Intracranial hypertension (ICH) and hyperthermia are common after traumatic brain injury (TBI) and associated with worse neurological outcomes. This study sets out to determine the combined power of temperature and intracranial pressure (ICP) for predicting neurologic outcomes and prolonged length of stay (LOS) following severe TBI. METHODS: High resolution (every 6 seconds) temperature and ICP data were collected in adults with severe TBI from 2008-2010. Temperatures were plotted against concurrent ICP and divided based on breakpoints (Temperature: <36, 36-38.5 or >38.5 °C, ICP: <20, 20-30 or >30 mmHg). The percentage of time spent in each section, as well as several pooled unfavourable conditions (hyperthermia ± ICH), were then evaluated for predictive value for ICU-LOS > 7 days and short-term (<6 months) vs. long-term (>6 months) dichotomized neurologic outcomes. RESULTS: Fifty patients were included for analysis with severe TBI. Evaluation of the area under the operating receiver curve (AUC) showed significant periods of fever and high ICP (<30 mmHg) had a strong association with poor long-term neurological outcomes (Day 3, AUC = 0.71, p = 0.04) and were higher than either condition alone. ICU-LOS > 7 days was increased when hyperthermia and/or ICH remained uncontrolled by Day 5 (AUC = 0.82, p = 0.02). SUMMARY: Hyperthermia combined with ICH were shown to be significant prognostic indicators of future poor neurologic outcomes in patients with severe traumatic brain injury.

Predicting secondary insults after severe traumatic brain injury.

BACKGROUND: Secondary insults such as hypotension, hypoxia, cerebral hypoperfusion, and intracranial hypertension are associated with poor outcome following severe traumatic brain injury (TBI). Preventing and minimizing the effect of secondary insults are essential in the management of severe TBI. At present, clinicians have no way to predict the development of these events, limiting their ability to plan appropriate timing of interventions. We hypothesized that processing continuous vital signs (VS) data using machine learning methods could predict the development of future intracranial hypertension. METHODS: Continuous VS including intracranial pressure (ICP), heart rate, systolic blood pressure, and mean arterial pressure data were collected from adult patients admitted to a single Level I trauma center requiring an ICP monitor. We tested the ability of Nearest Neighbor Regression (NNR) to predict changes in ICP by algorithmically learning from the patients' past physiology. RESULTS: Continuous VS were collected on 132 adult patients over a minimum of 3 hours per patient (5,466 hours total; 65,600 data points). Bland-Altman plots show that NNR provides good agreement in predicting actual ICP with a bias of 0.02 (±2 SD = 4 mm Hg) for the subsequent 5 minutes and -0.02 (±2 SD = 10 mm Hg) for the subsequent 2 hours. CONCLUSION: We have demonstrated that with the use of physiologic data, it is possible to predict with reasonable accuracy future ICP levels following severe TBI. NNR predicts ICP changes in clinically useful time frames. This ability to predict events may allow clinicians to make better decisions about the timing of necessary interventions, and this method could support the future development of minimally invasive ICP monitoring systems, which may lead to better overall clinical outcomes after severe TBI. LEVEL OF EVIDENCE: Prognostic study, level III.

Intracranial pressure response after pharmacologic treatment of intracranial hypertension.

BACKGROUND: The accepted treatment of increased intracranial pressure (ICP) in patients experiencing severe traumatic brain injury is multimodal and algorithmic, obscuring individual effects of treatment. Using continuous vital signs monitoring, we sought to measure treatment effect and ascertain the accuracy of manual data recording. METHODS: Patients older than 17 years, admitted and requiring ICP monitoring between 2008 and 2010 at a high-volume urban trauma center, were retrospectively evaluated. Timing and dose of ICP-directed therapy were recorded from paper and electronic medical records. ICP data were collected automatically at 6-second intervals and from manual charts. A statistical mixed model was applied to all data to account for multiple sampling. RESULTS: A total of 117 patients met inclusion criteria; 450 treatments were administered when nursing records indicate an ICP greater than 20 mm Hg, while 968 treatments were given when ICP was greater than 20 mm Hg by automated data. Pharmacologic treatments identified include hypertonic saline (HTS), mannitol, barbiturates, and dose escalations of propofol or fentanyl infusions. Treatment with HTS resulted in the largest ICP decrease of the treatments examined, with a 1-hour ICP reduction of 8.8/9.9 mm Hg (for a small/large dose) according to manual data and a reduction of 3.0/2.4 mm Hg according to automated data. Propofol and fentanyl escalations resulted in smaller but significant ICP reductions. Mannitol (n = 8) resulted in statistically insignificant trends down in the first hour but rebounded by the second hour after administration. The average ICP in the hour before medication administration was higher for barbiturates (27 mm Hg) and mannitol (32 mm Hg) than for the other interventions (18-19 mm Hg). CONCLUSION: ICP fell after administration of HTS, mannitol, or barbiturates and showed continued improvement after 2 hours. ICP fell initially after treatment with short-acting propofol and fentanyl but trended back up after 2 hours. Manually recorded data consistently overestimated treatment effectiveness. Automated data collection gives a more accurate assessment of patient status and responsiveness to treatment. LEVEL OF EVIDENCE: Therapeutic study, level IV.