Isolated traumatic brain injury results in significant pre-hospital derangement of cardiovascular physiology

Brain Injury Associated Shock: An Under-Recognized and Challenging Prehospital Phenomenon

OBJECTIVE

Hemodynamic collapse in multi-trauma patients with severe traumatic brain injury (TBI) poses both a diagnostic and therapeutic challenge for prehospital clinicians. Brain injury associated shock (BIAS), likely resulting from catecholamine storm, can cause both ventricular dysfunction and vasoplegia but may present clinically in a manner similar to hemorrhagic shock. Despite different treatment strategies, few studies exist describing this phenomenon in the early post-injury phase. This retrospective observational study aimed to describe the frequency of shock in isolated TBI in prehospital trauma patients and to compare their clinical characteristics to those patients with hemorrhagic shock and TBI without shock.

METHODS

All prehospital trauma patients intubated by prehospital medical teams from New South Wales Ambulance Aeromedical Operations (NSWA-AO) with an initial Glasgow Coma Scale (GCS) of 12 or less were investigated. Shock was defined as a pre-intubation systolic blood pressure under 90mmHg and the administration of blood products or vasopressors. Injuries were classified from in-hospital computed tomography (CT) reports. From this, three study groups were derived: BIAS, hemorrhagic shock, and isolated TBI without shock. Descriptive statistics were then produced for clinical and treatment variables.

RESULTS

Of 1,292 intubated patients, 423 had an initial GCS of 12 or less, 24 patients (5.7% of the original cohort) had shock with an isolated TBI, and 39 patients had hemorrhagic shock. The hemodynamic parameters were similar amongst these groups, including values of tachycardia, hypotension, and elevated shock index. Prehospital clinical interventions including blood transfusion and total fluids administered were also similar, suggesting they were indistinguishable to prehospital clinicians.

CONCLUSIONS

Hemodynamic compromise in the setting of isolated severe TBI is a rare clinical entity. Current prehospital physiological data available to clinicians do not allow for easy delineation between these patients from those with hemorrhagic shock.

Predictive clinical utility of pre-hospital point of care lactate for transfusion of blood product in patients with suspected traumatic haemorrhage: derivation of a decision-support tool

INTRODUCTION

Pre-hospital emergency medical teams can transfuse blood products to patients with suspected major traumatic haemorrhage. Common transfusion triggers based on physiological parameters have several disadvantages and are largely unvalidated in guiding pre-hospital transfusion. The addition of pre-hospital lactate (P-LACT) may overcome these challenges. To date, the clinical utility of P-LACT to guide pre-hospital blood transfusion is unclear.

METHODS

A retrospective analysis of patients with suspected major traumatic haemorrhage attended by Air Ambulance Charity Kent Surrey Sussex (KSS) between 8 July 2017 and 31 December 2019. The primary endpoint was the accuracy of P-LACT to predict the requirement for any in-hospital (continued) transfusion of blood product.

RESULTS

During the study period, 306 patients with suspected major traumatic haemorrhage were attended by KSS. P-LACT was obtained in 194 patients. In the cohort 103 (34%) patients were declared Code Red. A pre-hospital transfusion was commenced in 124 patients (41%) and in-hospital transfusion was continued in 100 (81%) of these patients, in 24 (19%) patients it was ceased. Predictive probabilities of various lactate cut-off points for requirement of in-hospital transfusion are documented. The highest overall proportion correctly classified patients were found for a P-LACT cut-point of 5.4 mmol/L (76.50% correctly classified). Based on the calculated predictive probabilities, optimal cut-off points were derived for both the exclusion- and inclusion of the need for in-hospital transfusion. A P-LACT < 2.5 mmol/L had a sensitivity of 80.28% and a negative likelihood ratio [LR-] of 0.37 for the prediction of in-hospital transfusion requirement, whereas a P-LACT of 6.0 mmol/L had a specificity of 99.22%, [LR-] = 0.78.

CONCLUSION

Pre-hospital lactate measurements can be used to predict the need for (continued) in-hospital blood products in addition to current physiological parameters. A simple decision support tool derived in this study can help the clinician interpret pre-hospital lactate results and guide pre-hospital interventions in the major trauma patient.

Mortality and Risk Factors in Isolated Traumatic Brain Injury Patients: A Prospective Cohort Study

INTRODUCTION

Outcomes in patients with isolated traumatic brain injury (iTBI) have not been evaluated comprehensively in low-income and middle-income countries. We aimed to study the in-hospital iTBI mortality and its associated risk factors in a prospective multicenter Indian trauma registry.

METHODS

Patients with iTBI (head and neck Abbreviated Injury Score ≥2 and other region Abbreviated Injury Score ≤2) were included. Study variables comprised age, gender, mechanism of injury, systolic blood pressure (SBP) at arrival, Glasgow Coma Scale (GCS) score - classified as mild (13-15), moderate (9-12), and severe (3-8), transfer status, and time to presentation at any participating hospital. A multivariable logistic regression was performed to assess the impact of these factors on 24-h and 30-d mortality following iTBI.

RESULTS

Among 5042 included patients, 24-h and 30-d in-hospital mortalities were 5.9% and 22.4%. On a regression analysis, 30-d mortality was associated with age ≥45 y (odds ratio [OR] = 2.1 [1.6-2.7]), railway injury mechanisms (OR = 2.1 [1.3-3.5]), SBP <90 mmHg (OR = 2.6 [1.6-4.1]), and moderate (OR = 3.8 [3.0-5.0]) to severe (OR = 21.1 [16.8-26.7]) iTBI based on GCS scores. 24-h mortality showed similar trends. Patients transferred to the participating hospitals from other centers had higher odds of 30-d mortality (OR = 1.4 [1.2-1.8]) compared to those arriving directly. Those who received neurosurgical intervention had lower odds of 24-h mortality (0.3 [0.2-0.4]).

CONCLUSIONS

Age ≥45 y, GCS score ≤12, and SBP <90 mmHg at arrival increased the risk of in-hospital mortality from iTBI.

Prehospital activation of a coordinated multidisciplinary hospital response in preparation for patients with severe hemorrhage. A state-wide data linkage study of the New South Wales "Code Crimson" pathway

BACKGROUND

Hemorrhage is a leading cause of preventable death in trauma. Prehospital medical teams can streamline access to massive transfusion and definitive hemorrhage control by alerting in-hospital trauma teams of suspected life-threatening bleeding in unstable patients. This study reports the initial experience of an Australian "Code Crimson" pathway facilitating early multidisciplinary care for these patients.

METHODS

This data-linkage study combined prehospital databases with a trauma registry of patients with an ISS > 12 between 2017 and 2019. Four groups were created; prehospital Code Crimson (CC) activation with and without in-hospital links and patients with inpatient treatment consistent with CC, without one being activated. Diagnostic accuracy was estimated using capture-recapture methodology to replace the missing cell (no prehospital CC and ISS < 12).

RESULTS

Of 72 prehospital CC patients, 50 were linked with hospital data. Of 154 potentially missed patients, 42 had a prehospital link. Most CC patients were young males who sustained blunt trauma and required more prehospital interventions than non-CC patients. CC patients had more multisystem trauma, especially complex thoracic injuries (80%), while missed-CC patients more frequently had single organ injuries (59%). CC patients required fewer hemorrhage control procedures (60% vs 86%). Lower mortality was observed in CC patients despite greater hospital and ICU length of stay. Despite a low sensitivity (0.49, 95%CI 0.38-0.61) and good specificity (0.92, 95%CI 0.86-0.96), the positive likelihood ratio was acceptable (6.42, 95%CI 3.30-12.48).

CONCLUSIONS

The initiation of a state-wide Code Crimson process was highly specific for the need for hemorrhage control intervention in hospital, but further work is required to improve the sensitivity of prehospital activation. Patients who had a Code Crimson activation sustained more multisystem trauma but had lower mortality than those who did not. These results guide measures to improve this pathway.

LEVEL OF EVIDENCE

Level III, Therapeutic/Care management.

A multicenter evaluation of the accuracy of prehospital eFAST by a physician-staffed helicopter emergency medical service

PURPOSE

The purpose of this study is to report the relative accuracy of prehospital extended focused assessment with sonography in trauma (eFAST) examinations performed by HEMS physicians.

METHODS

Trauma patients who received prehospital eFAST by HEMS clinicians between January 2013 and December 2017 were reviewed. The clinician's interpretations of these ultrasounds were compared to gold standard references of CT imaging or operating room findings. The outcomes measured include the calculated accuracy of eFAST for detecting intraperitoneal free fluid (IPFF), pneumothorax, hemothorax, and pericardial fluid compared to available gold standard results.

RESULTS

Of the 411 patients with adequate data for comparison, the median age was 39.5 years with 73% male and 98% sustaining blunt force trauma. For the detection of IPFF, eFAST had a sensitivity of 25% (95% CI 16-36%) and specificity of 96% (95% CI 93-98%). Sensitivities and specificities were calculated for pneumothorax (38% and 96% respectively), hemothorax (17% and 97% respectively), and pericardial effusion (17% and 100% respectively). These results did not change significantly when reassessed with several sensitivity analyses.

CONCLUSION

Prehospital eFAST is reliable for detecting the presence of intraperitoneal free fluid. This finding should inform receiving trauma teams to prepare for early definitive care in these patients. The low sensitivities across all components of the eFAST highlight the importance of cautiously interpreting negative studies while prompting the need for further studies.

TRIAL REGISTRATION

ACTRN12618001973202 (Registered on 06/12/2018).

Hypotension on admission in patients with isolated traumatic brain injury: contemporary examination of the incidence and outcomes using a national registry

PURPOSE

This study was primarily aimed at establishing the incidence and impact of hypotension in patients with blunt traumatic brain injury based on National Trauma Registry Database.

METHODS

A retrospective cohort study using the National Trauma Registry was conducted. Patients with TBI following blunt mechanisms of injury were examined, comparing those with and without hypotension (SBP < 90 mm Hg) on arrival.

RESULTS

During the period from 1998 to 2017, the registry included 437.354 blunt trauma patients. Of them, 7818 patients were hemodynamically unstable (SBP < 90 mm Hg) on admission. 513 met the inclusion criteria. Significant percentages of patients with high grade injures (ISS≥16) and low admission's GCS 3-12 (46% vs 16.4%), were found in the group of hypotensive TBI patients (p<0.0001). 323 (62.9%) patients had head AIS score 3-4 and only 190 (37.1%) patients AIS 5-6 (p<0.0001). Mortality in the hypotensive TBI group was 32.3%, whereas 6.1% patients died in the TBI hemodynamically stable group (p<0.0001).

CONCLUSION

TBI patients presenting with hypotension represent an appreciable portion blunt trauma patients. Prompt brain CT, expedient efforts at optimal resuscitation and possibly early inotropic and vasopressors agents use may have an impact on final outcome in these patients.