HOW SHOULD TRANEXAMIC ACID BE ADMINISTERED IN HEMORRHAGIC SHOCK? CONTINUOUS SERUM CONCENTRATION MEASUREMENTS IN A SWINE MODEL

ABSTRACT

Background : Tranexamic acid (TXA) reduces mortality in trauma patients. Intramuscular (IM) administration could be advantageous in low-resource and military settings. Achieving the same serum concentration as intravenous (IV) administration is important to achieve equal mortality reduction. Therefore, we aimed to investigate whether dividing an IM dose of TXA between two injection sites and whether an increase in dose would lead to serum concentrations comparable to those achieved by IV administration. Methods : Norwegian landrace pigs (n = 29) from a course in hemostatic emergency surgery were given TXA 1 h after start of surgery. Blood samples were drawn at 0, 5, 10, 15, 20, 25, 35, 45, 60, and 85 min. The samples were centrifuged and serum TXA concentrations quantified with liquid chromatography-tandem mass spectrometry. The use of two injection sites was compared with distributing the dose on one injection site, and a dose of 15 mg/kg was compared with a dose of 30 mg/kg. All IM groups were compared with IV administration. Results : The groups were in a similar degree of shock. Increasing the IM dose from the standard of 15 mg/kg to 30 mg/kg resulted in significantly higher serum concentrations of TXA, comparable to those achieved by IV administration. Distributing the IM dose on two injection sites did not affect drug uptake, as shown by equal serum concentrations. Conclusions : For IM administration of TXA, 30 mg/kg should be the standard dose. With a short delay, IM administration will provide equal serum concentrations as IV administration, above what is considered necessary to inhibit fibrinolysis.

Assessing bystander first aid: development and validation of a First Aid Quality Assessment (FAQA) tool

BACKGROUND

Injuries are one of the leading causes of death worldwide. Bystanders at the scene can perform first aid measures before the arrival of health services. The quality of first aid measures likely affects patient outcome. However, scientific evidence on its effect on patient outcome is limited. To properly assess bystander first aid quality, measure effect, and facilitate improvement, validated assessment tools are needed. The purpose of this study was to develop and validate a First Aid Quality Assessment (FAQA) tool. The FAQA tool focuses on first aid measures for injured patients based on the ABC-principle, as assessed by ambulance personnel arriving on scene.

METHODS

In phase 1, we drafted an initial version of the FAQA tool for assessment of airway management, control of external bleeding, recovery position and hypothermia prevention. A group of ambulance personnel aided presentation and wording of the tool. In phase 2 we made eight virtual reality (VR) films, each presenting an injury scenario where bystander performed first aid. In phase 3, an expert group discussed until consensus on how the FAQA tool should rate each scenario. Followingly, 19 respondents, all ambulance personnel, rated the eight films with the FAQA tool. We assessed concurrent validity and inter-rater agreement by visual inspection and Kendall's coefficient of concordance.

RESULTS

FAQA-scores by the expert group concurred with ± 1 of the median of the respondents on all first aid measures for all eight films except one case, where a deviation of 2 was seen. The inter-rater agreement was "very good" for three first aid measures, "good" for one, and "moderate" for the scoring of overall quality on first aid measures.

CONCLUSION

Our findings show that it is feasible and acceptable for ambulance personnel to collect information on bystander first aid with the FAQA tool and will be of importance for future research on bystander first aid for injured patients.

Epidemiology of trauma in the subarctic regions of the Nordic countries

BACKGROUND

The northern regions of the Nordic countries have common challenges of sparsely populated areas, long distances, and an arctic climate. The aim of this study was to compare the cause and rate of fatal injuries in the northernmost area of the Nordic countries over a 5-year period.

METHODS

In this retrospective cohort, we used the Cause of Death Registries to collate all deaths from 2007 to 2011 due to an external cause of death. The study area was the three northernmost counties in Norway, the four northernmost counties in Finland and Sweden, and the whole of Iceland.

RESULTS

A total of 4308 deaths were included in the analysis. Low energy trauma comprised 24% of deaths and high energy trauma 76% of deaths. Northern Finland had the highest incidence of both high and low energy trauma deaths. Iceland had the lowest incidence of high and low energy trauma deaths. Iceland had the lowest prehospital share of deaths (74%) and the lowest incidence of injuries leading to death in a rural location. The incidence rates for high energy trauma death were 36.1/100000/year in Northern Finland, 15.6/100000/year in Iceland, 27.0/100000/year in Northern Norway, and 23.0/100000/year in Northern Sweden.

CONCLUSION

We found unexpected differences in the epidemiology of trauma death between the countries. The differences suggest that a comparison of the trauma care systems and preventive strategies in the four countries is required.

Intramuscular uptake of tranexamic acid during haemorrhagic shock in a swine model

Background

Tranexamic acid (TXA) reduce mortality in bleeding trauma patients, with greater effect if administered early. Serum concentrations above 10 µg/mL are considered sufficient to inhibit fibrinolysis. Normally administered intravenously (i.v.), TXA can also be administered intramuscularly (i.m.). This could be advantageous in low resource and military settings, if sufficient serum concentrations can be reached in shocked patients with reduced muscular blood perfusion. Accordingly, we aimed to: (1) Determine the impact of shock on the pharmacokinetics of i.m. TXA, and (2) Compare the pharmacokinetics of i.v. versus i.m. TXA in ongoing shock.

Materials and methods

In a prospective experimental study, N = 18 Norwegian landrace pigs (40–50 kg), utilised in a surgical course in haemostatic emergency surgery, were subjected to various abdominal and thoracic trauma. After 1 h of surgery the animals were given 15 mg/kg TXA either i.v. or i.m. A control group without injury, or surgery, received intramuscular TXA. Blood samples were drawn at 0, 5, 15, 25, 35, 45, 60 and 85 min. The samples were centrifuged and analysed with liquid chromatography–tandem mass spectrometry (LC–MS/MS) for TXA serum-concentrations.

Results

In shocked pigs, i.m. administration resulted in a mean maximum serum concentration (C_max) of 20.9 µg/mL, and i.v. administration a C_max of 48.1 µg/mL. C_max occurred 15 min after i.m. administration and 5 min after i.v. administration. In non-shocked swine, i.m. administration resulted in a C_max of 36.9 µg/mL after 15 min. In all groups, mean TXA serum concentrations stayed above 10 µg/mL from administration to end of experiments.

Conclusions

I.m. administration of TXA in shocked pigs provides serum concentrations associated with inhibition of fibrinolysis. It may be an alternative to i.v. and intraosseous administration during stabilisation and transport of trauma patients to advanced medical care.

Do pre-hospital poisoning deaths differ from in-hospital deaths? A retrospective analysis

Background

Most fatal poisonings occur outside the hospital and the victims found dead. The purpose of this study was to determine the general pattern and patient demographics of fatal poisonings in Northern Finland. In particular, we wanted to analyze differences between pre-hospital and in-hospital deaths.

Methods

All fatal poisonings that occurred in Northern Finland in 2007–2011 were retrieved from the Cause of Death Registry provided by Statistics Finland. We noted the patient demographics, causal agents, and other characteristics of the poisoning events.

Results

A total of 689 fatal poisonings occurred during the study period, of which only 42 (6.1%) reached the hospital alive. Those who died pre-hospital were significantly younger (50 vs. 56 years, p = 0.04) and more likely to be male (77% vs. 57%, p = 0.003). Cardiopulmonary resuscitation was attempted less often in pre-hospital cases (9.9% vs. 47.6%, p < 0.001). Ethanol was more frequently the main toxic agent in pre-hospital deaths (58.4% vs. 26.2%, p < 0.001), and multiple ingestions were more common (52.2% vs. 35.7%, p < 0.001) in pre-hospital deaths.

Discussion

Most of the pre-hospital fatal poisoning victims are found dead and the majority of in-hospital victims are admitted to hospital in an already serious condition. According to results of this and former studies, prevention seems to be the most important factor in reducing deaths due to poisoning.

Conclusions

The majority of poisoning-related deaths occur pre-hospital and are related to alcohol intoxication and multiple ingestions.

We need to include bystander first aid in trauma research

Background

The chain of trauma survival is a concept that originated in the area of out-of-hospital cardiac arrest (OHCA) and was adapted to the treatment of trauma. In out-of-hospital cardiac arrest research into bystander first aid has resulted in improved outcome. Whereas, in trauma research the first link of the chain of survival is almost ignored.

Methods

In OHCA, cardiopulmonary resuscitation (CPR) from bystanders has been subject of a vast amount of research, as well as measures and programs to raise the rate of bystander CPR to cardiac arrest victims. These efforts have resulted in improved survival. The research effort has been well grounded in the research community, as demonstrated by its natural inclusion in the uniform reporting template (Utstein) for the treatment of OHCA. In trauma the bystander may contribute by providing an open airway, staunch bleedings, or prevent hypothermia. In trauma however, while the chain of survival has been adopted along with it distinct links, including bystander first aid, the consensus-based uniform reporting template for trauma (the Utstein template) does not include the bystander first aid efforts. There is extremely little research on what first aid measures bystanders provide to trauma victims, and on what impact such measures have on outcome. An important step to improve research on bystander first aid in trauma would be to include this as part of the uniform reporting template for trauma

Conclusion

The lack of research on bystander first aid makes the first link in the trauma chain of survival the weakest link. We, the trauma research community, should either improve our research and knowledge in this area, or remove the link from the chain of survival

Effect and accuracy of emergency dispatch telephone guidance to bystanders in trauma: post-hoc analysis of a prospective observational study

BACKGROUND

Emergency medical communication centres (EMCCs) dispatch and allocate ambulance resources, and provide first-aid guidance to on-scene bystanders. We aimed to 1) evaluate whether dispatcher guidance improved bystander first aid in trauma, and 2) to evaluate whether dispatchers and on-scene emergency medical services (EMS) crews identified the same first aid measures as indicated.

METHODS

For 18 months, the crew on the first EMS crew responding to trauma calls used a standard form to assess bystander first aid. Audio recordings of the corresponding telephone calls from bystanders to the EMCC were reviewed.

RESULTS

A total of 311 trauma calls were included. The on-scene EMS crew identified needs for the following first-aid measures: free airway in 26 patients, CPR in 6 patients, and hypothermia prevention in 179 patients. EMCC dispatchers advised these measures, respectively, in 16 (62%), 5 (83%), and 54 (30%) of these cases. Dispatcher guidance was not correlated with correctly performed bystander first aid. For potentially life saving first aid measures, all (20/20) callers who received dispatcher guidance attempted first aid, while only some few (4/22) of the callers who did not receive dispatcher guidance did not attempt first aid.

DISCUSSION

Overall, the EMCC dispatchers had low sensitivity and specificity for correctly identifying trauma patients requiring first-aid measures. Dispatcher guidance did not significantly influence whether on-scene bystander first aid was performed correctly or attempted in this study setting, with a remarkably high willingness to perform first-aid. However, the findings for potentially lifesaving measures suggests that there may be differences that this study was unable to detect.

CONCLUSION

This study found a high rate of first-aid willingness and performance, even without dispatcher prompting, and a low precision in dispatcher advice. This underlines the need for further knowledge about how to increase EMCC dispatchers' possibility to identify trauma patients in need of first aid. The correlation between EMCC-guidance and bystander first aid should be investigated in study settings with lower spontaneous first-aid rates.

A nationwide survey of first aid training and encounters in Norway

Background

Bystander first aid can improve survival following out-of-hospital cardiac arrest or trauma. Thus, providing first aid education to laypersons may lead to better outcomes. In this study, we aimed to establish the prevalence and distribution of first aid training in the populace, how often first aid skills are needed, and self-reported helping behaviour.

Methods

We conducted a telephone survey of 1000 respondents who were representative of the Norwegian population. Respondents were asked where and when they had first aid training, if they had ever encountered situations where first aid was necessary, and stratified by occupation. First aid included cardio-pulmonary resuscitation (CPR) and basic life support (BLS). To test theoretical first aid knowledge, respondents were subjected to two hypothetical first aid scenarios.

Results

Among the respondents, 90% had received first aid training, and 54% had undergone first aid training within the last 5 years. The workplace was the most common source of first aid training. Of the 43% who had been in a situation requiring first aid, 89% had provided first aid in that situation. There were considerable variations among different occupations in first aid training, and exposure to situations requiring first aid. Theoretical first aid knowledge was not as good as expected in light of the high share who had first aid training. In the presented scenarios 42% of respondent would initiate CPR in an unconscious patient not breathing normally, and 46% would provide an open airway to an unconscious road traffic victim. First aid training was correlated with better theoretical knowledge, but time since first aid training was not.

Conclusions

A high proportion of the Norwegian population had first aid training, and interviewees reported high willingness to provide first aid. Theoretical first aid knowledge was worse than expected. While first aid is part of national school curriculum, few have listed school as the source for their first aid training.

Electronic supplementary material

The online version of this article (doi:10.1186/s12873-017-0116-7) contains supplementary material, which is available to authorized users.

Fatal injury as a function of rurality-a tale of two Norwegian counties

BACKGROUND

Many studies indicate rural location as a separate risk for dying from injuries. For decades, Finnmark, the northernmost and most rural county in Norway, has topped the injury mortality statistics in Norway. The present study is an exploration of the impact of rurality, using a point-by-point comparison to another Norwegian county.

METHODS

We identified all fatalities following injury occurring in Finnmark between 2000 and 2004, and in Hordaland, a mixed rural/urban county in western Norway between 2003 and 2004 using data from the Norwegian Cause of Death Registry. Intoxications and low-energy trauma in patients aged over 64 years were excluded. To assess the effect of a rural locale, Hordaland was divided into a rural and an urban group for comparison. In addition, data from Statistics Norway were analysed.

RESULTS

Finnmark reported 207 deaths and Hordaland 217 deaths. Finnmark had an injury death rate of 33.1 per 100,000 inhabitants. Urban Hordaland had 18.8 deaths per 100,000 and rural Hordaland 23.7 deaths per 100,000. In Finnmark, more victims were male and were younger than in the other areas. Finnmark and rural Hordaland both had more fatal traffic accidents than urban Hordaland, but fewer non-fatal traffic accidents.

CONCLUSIONS

This study illustrates the disadvantages of the most rural trauma victims and suggests an urban-rural continuum. Rural victims seem to be younger, die mainly at the site of injury, and from road traffic accident injuries. In addition to injury prevention, the extent and possible impact of lay people's first aid response should be explored.

Rural high north: a high rate of fatal injury and prehospital death

Background

Finnmark County is the northernmost county in Norway. For several decades, the rate of mortality after injury in this sparsely inhabited region has remained above the national average. Following documentation of this discrepancy for the period 1991–1995, improvements to the trauma system were implemented. The present study aims to assess whether trauma-related mortality rates have subsequently improved.

Methods

All injury-associated fatalities in Finnmark from 1995–2004 were identified retrospectively from the National Registry of Death and reviewed. Low-energy trauma in elderly individuals and poisonings were excluded.

Results

A total of 453 cases of trauma-related death occurred during the study period, and 327 of those met the inclusion criteria. Information was retrievable for 266 cases. The majority of deaths (86%) occurred in the prehospital phase. The main causes of death were suicide (33%) and road traffic accidents (21%). Drowning and snowmobile injuries accounted for an unexpectedly high proportion (12 and 8%, respectively). The time of death did not show trimodal distribution. Compared to the previous study period, there was a significant overall decline in injury-related mortality, yet there was no change in place of death, mechanism of injury, or time from injury until death.

Conclusions

Changes in injury-related mortality cannot be linked to improvements in the trauma system. There was no change in the epidemiological patterns of injury. The high rate of on-scene mortality indicates that any major improvement in the number of injury-related deaths lies in targeted prevention.

Restraint stress in biomedical research: an update

Since the publication of our initial review of restraint stress in 1986, much work has continued with this technique, either as a tool for the investigation of other pharmacological, physiological, or pathologic phenomena or with restraint stress itself serving as the object of the study. As we noted in 1986, the major use of restraint has been for the induction of stress responses in animals and, more specifically, for the investigation of drug effects, particularly as they affect typical stress-related pathology--gastrointestinal, neuroendocrine, and immunological agents have been extensively studied. In compiling this update on restraint stress and its effects, we noted an increasing emphasis on central nervous system mechanisms in peripheral disease, especially gastrointestinal disease. In particular, many CNS-active agents have been tested for their effects on gastric and duodenal lesion formation and gastric secretion, including antidepressants, antipsychotics, anxiolytics, noradrenergic, serotonergic, dopaminergic, and peptidergic compounds. Some of these agents are especially active in the gastrointestinal tract even when administered centrally, further solidifying the concept of a brain-gut axis. The present update includes studies of: methods and procedures, pre-restraint manipulations, post-restraint/healing effects, and drug effects. In addition, a current bibliography of reports that have employed restraint is included.

CNS effects on gastric functions: from clinical observations to peptidergic brain-gut interactions

Clinical observations as early as the last century pointed to the stomach's link to the brain. Animal studies in this century have given us detailed information about the neuroanatomical and neurophysiological basis of brain-gut interactions. Psychological stress models and stereotaxic brain procedures have been important tools in gaining this information. During the last 10 years, there has been much focus on the effects of neuropeptides on gastric functions. Several CNS-peptides have indeed been shown to influence multiple gastric functions such as: acid secretion, bicarbonate secretion, mucus secretion, motility, blood flow and prostaglandin synthesis. Accordingly, direct CNS-application of these peptides also influences the development of gastric erosions during experimental stress procedures.

The neurobiology of stress ulcers

We have reviewed the neurobiology of stress ulcers from animal models to potential pharmacotherapeutic mechanisms. The evidence strongly supports the hypothesis that certain stress-related gastric lesions are 'brain-driven' events which may be more effectively managed through central manipulations than by altering local, gastric factors. Recent advances in the use of anxiolytic and antidepressant drugs in the management of stress-related gastric mucosal injury further supports the contention that a brain-gut axis, which may have nervous, peptidergic and classic monoaminergic components, modulates the intricate and complicated pattern of communication between the brain and the stomach. Delineation of the precise pathways which make up this communication as well as their manipulation by various pharmacological agents will be the focus of future research endeavour.

Studies on the interaction between ICV effects of CRF and CNS noradrenaline depletion

The role of an intact locus coeruleus (LC) noradrenergic system for the central effects of corticotropin-releasing factor (CRF) was studied. Rats were treated with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride (DSP-4), a highly selective noradrenergic neurotoxin permanently affecting mainly the LC system. This procedure did not affect the activation of the sympathetic nervous system, as measured by plasma catecholamine levels, after either intracerebroventricular (ICV) or intraperitoneal (IP) administration of 8-micrograms CRF. Neither was the increased emotionality seen in an open field test after ICV injection of CRF altered. However, the ulceroprotective effect of 8-micrograms CRF ICV during a 2-hr water restraint stress was significantly antagonized by pretreatment with DSP-4, while CRF did exhibit an ulceroprotective effect after IP administration to DSP-4-treated animals. Our data indicate that the ulceroprotective effect of CRF under restraint stress is, at least partly, dependent on an intact locus coeruleus noradrenergic system.

Paradoxical DSP-4 effects: protection against gastric erosions and depletion of mucosal glycoproteins

We have previously reported that rats pretreated with the central noradrenergic neurotoxin DSP-4 are protected against 23 h restraint-induced gastric erosions. To elucidate the peripheral mechanisms of this protection, we undertook direct biochemical analyses of the gastric mucosa in terms of glycoproteins and proteins. A simple method for preparation of gastric mucosa devoid of the muscular stomach wall tissue is described. A restraint-induced decrease in gastric mucosal wet weight and mucosal glycoprotein content was revealed. Restraint had no effect on mucosal protein content, and no changes were found in gastric wall glycoprotein or protein content. Despite showing protection against restraint-induced gastric erosions, unrestrained DSP-4-treated animals exhibited reduced mucosal wet weight and mucosal glycoprotein content when compared to unrestrained controls. After the stress period, no significant differences on mucosal weight or glycoproteins could be detected between control and DSP-4-treated animals. The results indicate that the protective effect of DSP-4 in this paradigm is not due to enhanced gastric mucosal protection against erosive factors. We suggest that an additional effect of central nervous NA depletion by DSP-4 may be elimination of aggressive factors which precipitate overt ulcers.

Plasma corticosterone and restraint induced gastric pathology: age-related differences after administration of corticotropin releasing factor

Corticotropin releasing factor (CRF) or saline was administered i.p. to rats aged either 100 or 220 days, followed by either brief handling or water immersion restraint. Plasma corticosterone was measured 75 min. later. Age of the animals in itself was not a significant factor either for basal levels of plasma corticosterone or for extent of restraint induced gastric pathology. However after CRF administration, young but not older animals revealed a significant increase in plasma corticosterone levels, and post restraint gastric ulcerations were more severe in older than young animals. CRF significantly decreased the number of restraint induced ulcers in young rats, while the cumulative ulcer length was increased in older animals.

Effect of central noradrenaline depletion on corticosterone levels and gastric ulcerations in rats

Effects of central noradrenergic depletion on the stress responses of rats were explored using the new selective neurotoxin (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4)). Noradrenergic depletion using DSP-4 was followed by a reduction in basal corticosterone levels after 7 days. Three weeks after DSP-4 treatment, animals exhibited less severe and fewer gastric ulcerations than control animals following 23 h immobilization stress, but stress levels of corticosterone were similar for the two groups. No differences could be found in the peripheral gastric levels of noradrenaline between experimental and control animals, while central noradrenaline was reduced to approximately 30% of control levels. The data support previous findings using other methods that central noradrenaline is an important factor in stress-induced gastric ulceration. The peripheral mechanisms for the protective effects of DSP-4 remain to be elucidated, and studies of these may cast light on the efferent pathways between the central nervous system and gastric mucosa which are involved in stress-induced gastric pathology.

Comparison of electrolytic and ibotenic acid lesions in the lateral hypothalamus

Electrolytic lesions in the lateral hypothalamus (LH) seriously affect ingestive behavior and sensorimotor functions in the rat. We here report that bilateral infusions of the neurotoxin, ibotenic acid (IBO) in the LH yield a decrease in body weight, but not to the same extent as electrolytic lesions. The sensorimotor impairments were most severe after electrolytic lesions. When tested in a residential maze on days 5-7 and 18-20 after surgery, both lesioned groups showed no lack of motivation to seek food and water. Histological examination of the LH following IBO exposure revealed extensive degeneration of neuronal cell bodies with little evidence of non-specific damage. Biochemical analysis of the rostral forebrain content of norepinephrine (NE) and serotonin (5-HT) revealed that the fibers passing through the LH remained largely intact in the IBO treated rats. The results suggest that the observed aphagia and adipsia is not due to a lack of motivation, but rather reflects changes in the process which operate to initiate eating and drinking. Furthermore, selective neuronal degeneration induced the same behavioral changes as the electrolytic ones, though not to the same extent.

Passive avoidance after ibotenic acid and radio frequency lesions in the rat amygdala

Ibotenic acid (IBO) is assumed to lesion neurons and to spare fibers of passage. The effects of such lesions in the amygdaloid complex of rats were compared to those of radio frequency lesions (RF) on a passive avoidance task. Both lesions impaired the acquisition of the passive avoidance response. Plasma corticosterone levels were measured after a retention test in which no electrical shocks were applied. None of the lesion groups showed reduced corticosterone levels, the IBO lesioned rats actually showed significantly higher corticosterone levels than both RF lesioned and control animals. The corticosterone results are not consistent with a general reduction in fear. The slower avoidance learning may be a conditioning deficit due to impaired sensory information processing in the amygdaloid complex.