Advancing critical care: joint combat casualty research team and joint theater trauma system

Prehospital Tourniquets in Civilians: A Systematic Review

OBJECTIVES

Terrorist attacks and civilian mass-casualty events are frequent, and some countries have implemented tourniquet use for uncontrollable extremity bleeding in civilian settings. The aim of this study was to summarize current knowledge on the use of prehospital tourniquets to assess whether their use increases the survival rate in civilian patients with life-threatening hemorrhages from the extremities.

DESIGN

Systematic literature review in Medline (Ovid), Embase (Ovid), Cochrane Library, and Epistemonikos was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Guidelines. The search was performed in January 2019.

SETTING

All types of studies that examined use of tourniquets in a prehospital setting published after January 1, 2000 were included.

PRIMARY/SECONDARY OUTCOMES

The primary outcome was mortality with and without tourniquet, while adverse effects of tourniquet use were secondary outcomes.

RESULTS

Among 3,460 screened records, 55 studies were identified as relevant. The studies were highly heterogeneous with low quality of evidence. Most studies reported increased survival in the tourniquet group, but few had relevant comparators, and the survival benefit was difficult to estimate. Most studies reported a reduced need for blood transfusion, with few and mainly transient adverse effects from tourniquet use.

CONCLUSION

Despite relatively low evidence, the studies consistently suggested that the use of commercial tourniquets in a civilian setting to control life-threatening extremity hemorrhage seemed to be associated with improved survival, reduced need for blood transfusion, and few and transient adverse effects.

Understanding blast-induced neurotrauma: how far have we come?

Blast injuries, including blast-induced neurotrauma (BINT), are caused by blast waves generated during an explosion. Accordingly, their history coincides with that of explosives. Hence, it is intriguing that, after more than 1000 years of using explosives, our understanding of the pathological consequences of blast and body/brain interactions is extremely limited. Postconflict recovery mechanisms seemingly include the suppression of painful experiences, such as explosive injuries. Unfortunately, ignoring the knowledge generated by previous generations of scientists retards research progress, leading to superfluous and repetitive studies. This article summarizes clinical and experimental findings published about blast injuries and BINT following the wars of the 20th and 21th centuries. Moreover, it offers a personal view on potential factors interfering with the progress of BINT research working toward providing better diagnosis, treatment and rehabilitation for military personnel affected by blast exposure.

[A new concept of organization and scope of neurosurgical care in the US army during armed conflicts in the early 2000s]

Military operations in various parts of the world in the early 2000s are becoming more regionalized; new warfare tactics emerge, which makes it necessary to review and modify the neurosurgical care system. The article reviews the results of original studies on this issue and summarizes the experience of the US Army medical service in Afghanistan and Iraq. The article discusses the structure of sanitary losses, organization and scope of medical and evacuation neurosurgical measures, types and techniques of surgical interventions, and the rate of complications. We describe five levels of neurosurgical care echelons and an implemented "injury control - neurosurgery" concept; particular attention is paid to the peculiarities of research and specialist training. We demonstrate that implementation of the new concept for organization and scope of neurosurgical care has improved treatment outcomes and reduced the mortality rate in the mentioned military conflicts of recent years compared to those in the Vietnam War. We may conclude that the described experience of the US Army can be used to improve the efficacy of neurosurgical care to the wounded and victims of armed conflicts.

Comparison of nurse burnout across Army hospital practice environments

PURPOSE

The primary purpose of this study was to examine the nursing practice environment and burnout of nursing personnel assigned to a deployed combat support hospital (CSH). A secondary aim was to compare differences in the level of burnout between the deployed Army nursing personnel and Army nursing personnel assigned to an Army hospital in the United States that served as the U.S. military's primary referral center for American combat casualties evacuated from Iraq.

DESIGN

A nonexperimental cross-sectional design was used for this study.

METHODS

The Maslach Burnout Inventory and the Practice Environment Scale were administered to 105 personnel who deployed with a CSH to Iraq. Data from this study were linked to data obtained from 152 nursing personnel who participated in an earlier burnout study at a large Army hospital in the United States. The linked datasets yielded a final sample of 257 Army nursing personnel. Analysis of variance and linear regression analysis were used to analyze these data.

FINDINGS

Emotional exhaustion was common across groups. For the deployed nursing personnel, emotional exhaustion was related to a perceived lack of support from management, foundations for quality of care, collegial relationships, and extended work schedules. The U.S.-based Army hospital group scored significantly higher emotional exhaustion, but it was related to the additional responsibilities associated with being an Army nurse, working extended schedules, and working with combat casualties for extended periods of time. The U.S.-based group perceived more personal accomplishment from the work they do.

CONCLUSIONS

Burnout was common across Army hospital settings. Emotional exhaustion was most problematic in the U.S.-based Army hospital; however, there was less cynicism toward patients and a greater perception of personal accomplishment associated with work.

CLINICAL RELEVANCE

This study supports the importance of a professional practice environment for Army nursing personnel both during deployment and in U.S.-based Army hospitals.

Use of serum biomarkers to predict cerebral hypoxia after severe traumatic brain injury

The management of severe traumatic brain injury (TBI) focuses on prevention and treatment of secondary insults such as cerebral hypoxia (CH). There are a number of biomarkers that are thought to play a part in secondary injury following severe TBI. This study evaluates the association between S100β, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP), detected in the serum of severe TBI patients and CH as measured by brain tissue oxygen partial pressure (Pbo(2)). Patients with severe TBI were prospectively enrolled. Pressure times time (PTD; mm Hg*h), measuring the depth and duration of CH, was calculated for 12-h periods for episodes of moderate (Pbo(2) < 20 mm Hg) and severe (Pbo(2) < 15 mm Hg) CH, and compared to serum levels of S100β, NSE, and GFAP drawn prior to periods of monitoring. An adjusted mixed model analysis was applied as was receiver operating characteristic (ROC) curve analysis. Of 76 patients enrolled, 24 had Pbo(2) monitoring. One hundred and thirty serum samples were matched with 12-h periods of monitoring. Significant associations were found in adjusted analyses between increasing serum levels of S100β (coefficient=0.57, 0.56; p<0.001), NSE (coefficient=0.48, 0.52; p<0.001), and GFAP (coefficient=0.29, 0.30; p=0.003 and 0.002), and increasing PTD of moderate (Pbo(2)<20 mm Hg) and severe (Pbo(2)<15 mm Hg) CH. AUCs for the prediction of moderate and severe CH were 0.62 and 0.66 for S100β, 0.55 and 0.71 for NSE, and 0.50 and 0.62 for GFAP, respectively. Specificities were between 76% and 90% for S100β and NSE. S100β, NSE, and GFAP demonstrate promise as candidate serum markers of impending CH. The fact that these biomarker elevations occur prior to the onset of clinical manifestations suggests that we may be able to predict imminent events following TBI. Given the morbidity of CH, early intervention and prevention may have a significant impact on outcomes and help guide decisions about the timing of interventions.

Association of CSF biomarkers and secondary insults following severe traumatic brain injury

BACKGROUND

Management of severe traumatic brain injury (TBI) focuses on mitigating secondary insults. There are a number of biomarkers that are thought to play a part in secondary injury following severe TBI. Two of these, S100β and neuron-specific enolase (NSE), have been extensively studied in the setting of neurological injury. This pilot study was undertaken to investigate the relationship of S100β and NSE to clinical markers of severity and poor outcome: intracranial hypertension (ICH), and cerebral hypoperfusion (CH).

METHODS

Patients at the R Adams Cowley Shock Trauma Center were prospectively enrolled over an 18-month period. Inclusion criteria were: age > 18, admission within the first 6 h after injury, Glasgow Coma Scale (GCS) < 9 on admission, isolated TBI, and placement of an intraventricular catheter (IVC). Patients were managed according to an institutional protocol based on the Brain Trauma Foundation Guidelines. CSF was collected from the IVC on admission and twice daily for 7 days. S100β and NSE levels were analyzed by ELISA. CSF levels drawn before (PRE) and after (POST) 12-h time periods were compared to percentage time intracranial pressure (ICP) > 20 mmHg (% ICP(20)) and cerebral perfusion pressure (CPP) < 60 mmHg (% CPP(60)), and cumulative "Pressure times Time Dose" (PTD) for episodes of ICP > 20 mmHg (PTD ICP(20)) and CPP < 60 mmHg (PTD CPP(60)). Statistical analysis was performed using the Student's t test to compare means and non-parametric Wilcoxon statistic to compare ranked data. Linear regression methods were applied to compare levels of S100β and NSE with ICP and CPP(.)

RESULTS

Twenty-three patients were enrolled. The cohort of patients was severely injured and neurologically compromised on admission (admission GCS = 5.6 ± 3.1, Injury Severity Score (ISS) = 31.9 ± 10.6, head Abbreviated Injury Scale (AIS) = 4.4 ± 0.7, Marshall score = 2.6 ± 0.9). Elevated levels of S100β and NSE were found in all 223 CSF samples analyzed. ICH was found to be associated with PRE and POST S100β levels when measured as % ICP(20) (r = 0.20 and r = 0.23, P < 0.01) and PTD ICP(20) (r = 0.35 and r = 0.26, P < 0.001). POST increasing NSE levels were weakly correlated with increasing PTD ICP(20) (r = 0.17, P = 0.01). PRE S100β levels were associated with episodes of CH as measured by % CPP(60) (r = 0.20, P = 0.002) and both PRE and POST S100β levels were associated with PTD CPP(60) (r = 0.24 and r = 0.23, P < 0.001). PRE and POST NSE levels were also associated with episodes of CH as measured by % CPP(60) (r = 0.22 and r = 0.18, P < 0.01) and PTD CPP(60) (r = 0.20 and r = 0.21, P < 0.01).

CONCLUSIONS

In this preliminary analysis, S100β levels were associated with ICH and CH over a full week of ICP monitoring. We also found associations between CH and NSE levels in CSF of patients with severe TBI. Our results suggest that there is an association between levels of ICH and CH and these biomarkers when measured before episodes of clinically significant secondary insults. These markers of neuronal cell death demonstrate promise as both indicators of impending clinical deterioration and targets of future therapeutic interventions.