Research questions in pre-hospital trauma care

Randomised controlled trials in pre-hospital trauma: a systematic mapping review

BACKGROUND

Trauma is a leading cause of morbidity and mortality worldwide with about 5.8 million deaths globally and the leading cause of death in those aged 45 and younger. The pre-hospital phase of traumatic injury is particularly important as care received during this phase has effects on survival. The need for high quality clinical trials in this area has been recognised for several years as a key priority to improve the evidence base and, ultimately, clinical care in prehospital trauma. We aimed to systematically map the existing evidence base for pre-hospital trauma trials, to identify knowledge gaps and inform decisions about the future research agenda.

METHODS

A systematic mapping review was conducted first employing a search of key databases (MEDLINE, CINAHL, EMBASE, and Cochrane Library from inception to March 23rd 2020) to identify randomised controlled trials within the pre-hospital trauma and injury setting. The evidence 'map' identified and described the characteristics of included studies and compared these studies against existing priorities for research. Narrative description of studies informed by analysis of relevant data using descriptive statistics was completed.

RESULTS

Twenty-three eligible studies, including 10,405 participants across 14 countries, were identified and included in the systematic map. No clear temporal or geographical trends in publications were identified. Studies were categorised into six broad categories based on intervention type with evaluations of fluid therapy and analgesia making up 60% of the included trials. Overall, studies were heterogenous with regard to individual interventions within categories and outcomes reported. There was poor reporting across several studies. No studies reported patient involvement in the design or conduct of the trials.

CONCLUSION

This mapping review has highlighted that evidence from trials in prehospital trauma is sparse and where trials have been completed, the reporting is generally poor and study designs sub-optimal. There is a continued need, and significant scope, for improvement in a setting where high quality evidence has great potential to make a demonstrable impact on care and outcomes.

Influence of prehospital physician presence on survival after severe trauma: Systematic review and meta-analysis

BACKGROUND

As trauma is one of the leading causes of death worldwide, there is great potential for reducing mortality in trauma patients. However, there is continuing controversy over the benefit of deploying emergency medical systems (EMS) physicians in the prehospital setting. The objective of this systematic review and meta-analysis is to assess how out-of-hospital hospital management of severely injured patients by EMS teams with and without physicians affects mortality.

METHODS

PubMed and Google Scholar were searched for relevant articles, and the search was supplemented by a hand search. Injury severity in the group of patients treated by an EMS team including a physician had to be comparable to the group treated without a physician. Primary outcome parameter was mortality. Helicopter transport as a confounder was accounted for by subgroup analyses including only the studies with comparable modes of transport. Quality of all included studies was assessed according to the Cochrane handbook.

RESULTS

There were 2,249 publications found, 71 full-text articles assessed, and 22 studies included. Nine of these studies were matched or adjusted for injury severity. The odds ratio (OR) of mortality was significantly lower in the EMS physician-treated group of patients: 0.81; 95% confidence interval (CI): 0.71-0.92. When analysis was limited to the studies that were adjusted or matched for injury severity, the OR was 0.86 (95% CI, 0.73-1.01). Analyzing only studies published after 2005 yielded an OR for mortality of 0.75 (95% CI, 0.64-0.88) in the overall analysis and 0.81 (95% CI, 0.67-0.97) in the analysis of adjusted or matched studies. The OR was 0.80 (95% CI, 0.65-1.00) in the subgroup of studies with comparable modes of transport and 0.74 (95% CI, 0.53-1.03) in the more recent studies.

CONCLUSION

Prehospital management of severely injured patients by EMS teams including a physician seems to be associated with lower mortality. After excluding the confounder of helicopter transport we have shown a nonsignificant trend toward lower mortality.

LEVEL OF EVIDENCE

Systematic review and meta-analysis, level III.

Physician Prehospital Care in Mexico City: Retrospective Analysis of Endotracheal Intubation in Patients with Severe Head Trauma

INTRODUCTION

In Mexico, physicians have become part of public service prehospital care. Head injured patients are a sensitive group that can benefit from early advanced measures to protect the airway, with the objective to reduce hypoxia and maintain normocapnia.

PROBLEM

The occurrence of endotracheal intubation to patients with severe head injuries by prehospital physicians working at Mexico City's Service of Emergency Medical Care (SAMU) is unknown.

METHODS

A retrospective analysis of five-year data (2012-2016) from Mexico City's Medical Emergencies Regulation Center was performed. Only SAMU ambulance services were analyzed. Adult patients with a prehospital diagnosis of head injury based on mechanism of injury and physical examination with a Glasgow Coma Scale (GCS) <nine were included.

RESULTS

A total of 293 cases met the inclusion criteria; the mean GCS was five points. Of those, 150 (51.1%) patients were intubated. There was no difference in the occurrence of intubation among the different GCS scales, or if the patient was considered to have isolated head trauma versus polytrauma. Fifteen patients were intubated using sedation and neuromuscular blockage. Four patients were intubated with sedation alone and six patients with neuromuscular blockage alone. One patient was intubated using opioid analgesia, sedation, and neuromuscular blockage.

CONCLUSIONS

Patients with severe head injuries cared by prehospital physicians in Mexico City were intubated 51.1% of the time and were more likely to be intubated without the assistance of anesthetics.

Outcomes following trauma laparotomy for hypotensive trauma patients: A UK military and civilian perspective

BACKGROUND

The management of trauma patients has changed radically in the last decade, and studies have shown overall improvements in survival. However, reduction in mortality for the many may obscure a lack of progress in some high-risk patients. We sought to examine the outcomes for hypotensive patients requiring laparotomy in UK military and civilian cohorts.

METHODS

We undertook a review of two prospectively maintained trauma databases: the UK Joint Theatre Trauma Registry for the military cohort (February 4, 2003, to September 21, 2014) and the trauma registry of the Royal London Hospital major trauma center (January 1, 2012, to January 1, 2017) for civilian patients. Adults undergoing trauma laparotomy within 90 minutes of arrival at the emergency department (ED) were included.

RESULTS

Hypotension was present on arrival at the ED in 155 (20.4%) of 761 military patients. Mortality was higher in hypotensive casualties (25.8% vs. 9.7% in normotensive casualties; p < 0.001). Hypotension was present on arrival at the ED in 63 (35.7%) of 176 civilian patients. Mortality was higher in hypotensive patients (47.6% vs. 12.4% in normotensive patients; p < 0.001). In both cohorts of hypotensive patients, neither the average injury severity, the prehospital time, the ED arrival systolic blood pressure, nor mortality rate changed significantly during the study period.

CONCLUSIONS

Despite improvements in survival after trauma for patients overall, the mortality for patients undergoing laparotomy who arrive at the ED with hypotension has not changed and appears stubbornly resistant to all efforts. Specific enquiry and research should continue to be directed at this high-risk group of patients.

LEVEL OF EVIDENCE

Prognostic/Epidemiologic, level IV.

Research challenges in prehospital care: the need for a simulation-based prehospital research laboratory

There is a need for improved research in the field of prehospital care. At the same time, there are many barriers in prehospital research due to the complex context, posing unique challenges for research, development, and evaluation. The present paper argues for the potential of simulation for prehospital research, e.g., through the development of an advanced simulation-based prehospital research laboratory. However, the prehospital context is different from other healthcare areas, which implies special requirements for the design of this type of laboratory, in terms of simulation width (including the entire prehospital work process) and depth (level of scenario detail). A set of features pertaining to simulation width, scenario depth, equipment, and personnel and competence are proposed. Close tailoring between these features and the prehospital research problems and context presents great potential to improve and further prehospital research.

Patient-centred outcomes for prehospital trauma trials: A systematic review and patient involvement exercise

Introduction

Outcome measures are used in clinical trials to determine efficacy of interventions. We aimed to determine which outcome measures in prehospital major trauma trials have been reported in the literature, and which of these are most patient-centred.

Methods

A systematic review identified outcomes reported in prehospital clinical trials of major trauma patients. A search was undertaken using Medline, Embase, clinicaltrials.gov, Web of Science and Google Scholar. Data were summarised by dividing outcomes into common themes which were presented to a Patient and Public Involvement group consisting of trauma survivors and their relatives. This group ranked the categories of outcomes in order of most importance, and agreed consensus statements regarding these outcome measures.

Results

There were 27 eligible studies, including 9,537 patients. Outcome measures were divided into nine categories: quality of life; length of stay; mortality/survival; physiological parameters; fluid/blood product requirements; complications; health economics; safety and feasibility; and intervention success. Of these, mortality/survival was the most commonly reported category, but over multiple timescales. The Patient and Public Involvement group agreed that the most important category was quality of life, and that mortality/survival should only be reported if concurrently reported with longer term quality of life. Length of stay and health economics were not considered important.

Conclusions

Outcome measures in prehospital clinical trials in major trauma have been heterogeneous, inconsistent, and not necessarily patient-centred. Trauma survivors considered quality of life and mortality most important when combined. Consensus is required for consistent, patient-centred, outcome measures in order to investigate interventions of meaningful impact to patients.

Mortality of civilian patients with suspected traumatic haemorrhage receiving pre-hospital transfusion of packed red blood cells compared to pre-hospital crystalloid

Background

Major haemorrhage is a leading cause of mortality following major trauma. Increasingly, Helicopter Emergency Medical Services (HEMS) in the United Kingdom provide pre-hospital transfusion with blood products, although the evidence to support this is equivocal. This study compares mortality for patients with suspected traumatic haemorrhage transfused with pre-hospital packed red blood cells (PRBC) compared to crystalloid.

Methods

A single centre retrospective observational cohort study between 1 January 2010 and 1 February 2015. Patients triggering a pre-hospital Code Red activation were eligible. The primary outcome measure was all-cause mortality at 6 hours (h) and 28 days (d), including a sub-analysis of patients receiving a major and massive transfusion. Multivariable regression models predicted mortality. Multiple Imputation was employed, and logistic regression models were constructed for all imputed datasets.

Results

The crystalloid (n = 103) and PRBC (n = 92) group were comparable for demographics, Injury Severity Score (p = 0.67) and mechanism of injury (p = 0.73). Observed 6 h mortality was smaller in the PRBC group (n = 10, 10%) compared to crystalloid group (n = 19, 18%). Adjusted OR was not statistically significant (OR 0.48, CI 0.19–1.19, p = 0.11). Observed mortality at 28 days was smaller in the PRBC group (n = 21, 26%) compared to crystalloid group (n = 31, 40%), p = 0.09. Adjusted OR was not statistically significant (OR 0.66, CI 0.32–1.35, p = 0.26). A statistically significant greater proportion of the crystalloid group required a major transfusion (n = 62, 60%) compared to the PRBC group (n = 41, 40%), p = 0.02. For patients requiring a massive transfusion observed mortality was smaller in the PRBC group at 28 days (p = 0.07).

Conclusion

In a single centre UK HEMS study, in patients with suspected traumatic haemorrhage who received a PRBC transfusion there was an observed, but non-significant, reduction in mortality at 6 h and 28 days, also reflected in a massive transfusion subgroup. Patients receiving pre-hospital PRBC were significantly less likely to require an in-hospital major transfusion. Further adequately powered multi-centre prospective research is required to establish the optimum strategy for pre-hospital volume replacement in patients with traumatic haemorrhage.

Airway management in pre-hospital critical care: a review of the evidence for a 'top five' research priority

The conduct and benefit of pre-hospital advanced airway management and pre-hospital emergency anaesthesia have been widely debated for many years. In 2011, prehospital advanced airway management was identified as a ‘top five’ in physician-provided pre-hospital critical care. This article summarises the evidence for and against this intervention since 2011 and attempts to address some of the more controversial areas of this topic.