Low-dose desmopressin improves hypothermia-induced impairment of primary haemostasis in healthy volunteers*

The use of impedance aggregometry to evaluate platelet function after the administration of DDAVP in healthy dogs treated with aspirin or clopidogrel

OBJECTIVE

To evaluate the effect of 1-Desamino-8-d-arginine vasopressin (DDAVP; desmopressin acetate) on platelet aggregation in healthy dogs receiving aspirin or clopidogrel.

ANIMALS

7 healthy staff-owned dogs.

PROCEDURES

In this randomized double-blinded crossover study, impedance aggregometry was performed on samples of lithium-heparinized whole blood samples from dogs before (T0) treatment with aspirin (1 mg/kg, PO, q 24 h for 4 days; ASP group) or clopidogrel (1 mg/kg, PO, q 24 h for 4 days; CLP group) and then before (T1) and after (T2) treatment with DDAVP (0.3 μg/kg, IV, once). There was a 14-day washout period before the crossover component. Aggregometry was performed with 4 different assays, each of which involved a different agonist reagent to stimulate platelet function: ADP, thrombin receptor activating peptide-6, arachidonic acid, or collagen type 1.

RESULTS

Median results for platelet aggregometry with agonist reagents ADP, arachidonic acid, or thrombin receptor activating peptide-6 significantly decreased between T0 and T1 for the CLP group; however, no meaningful difference in platelet aggregation was detected in the ASP group. Results for platelet aggregometry did not differ substantially between T1 and T2 regardless of treatment group or assay.

CONCLUSIONS AND CLINICAL RELEVANCE

Findings suggested that administration of DDAVP may have no effect on platelet aggregation (measured with platelet aggregometry) in healthy dogs treated with clopidogrel. Because no inhibition of platelet aggregation was detected for dogs in the ASP group, no conclusion could be made regarding the effects of DDAVP administered to dogs treated with aspirin.

Multiple trauma management in mountain environments - a scoping review : Evidence based guidelines of the International Commission for Mountain Emergency Medicine (ICAR MedCom). Intended for physicians and other advanced life support personnel

Background

Multiple trauma in mountain environments may be associated with increased morbidity and mortality compared to urban environments.

Objective

To provide evidence based guidance to assist rescuers in multiple trauma management in mountain environments.

Eligibility criteria

All articles published on or before September 30th 2019, in all languages, were included. Articles were searched with predefined search terms.

Sources of evidence

PubMed, Cochrane Database of Systematic Reviews and hand searching of relevant studies from the reference list of included articles.

Charting methods

Evidence was searched according to clinically relevant topics and PICO questions.

Results

Two-hundred forty-seven articles met the inclusion criteria. Recommendations were developed and graded according to the evidence-grading system of the American College of Chest Physicians. The manuscript was initially written and discussed by the coauthors. Then it was presented to ICAR MedCom in draft and again in final form for discussion and internal peer review. Finally, in a face-to-face discussion within ICAR MedCom consensus was reached on October 11th 2019, at the ICAR fall meeting in Zakopane, Poland.

Conclusions

Multiple trauma management in mountain environments can be demanding. Safety of the rescuers and the victim has priority. A crABCDE approach, with haemorrhage control first, is central, followed by basic first aid, splinting, immobilisation, analgesia, and insulation. Time for on-site medical treatment must be balanced against the need for rapid transfer to a trauma centre and should be as short as possible. Reduced on-scene times may be achieved with helicopter rescue. Advanced diagnostics (e.g. ultrasound) may be used and treatment continued during transport.

[Platelet function disorder in trauma patients, an underestimated problem? Results of a single center study]

BACKGROUND

Plasmatic coagulation disorders in trauma patients are common and their management is subject to current guidelines. Less evidence exists for platelet function. Although it is known that several trauma-associated factors have a negative influence on platelet function, routine monitoring has not yet become established.

METHODS

A retrospective single center study was carried out at a German level 1 trauma center from 2010 to 2016. In all patients fulfilling the requirements for the German Trauma Society (DGU) Traumaregister® who were admitted directly from the scene of the incident, platelet function was analyzed using the Platelet Function Analyzer (PFA 100®) with adenosine diphosphate (ADP) and epinephrine as activation factors. After exclusion of patients with intake of long-term anticoagulant and antiaggregant medication, possible influencing factors of a reduced platelet function were identified.

RESULTS

The results from 310 patients (44.0 ± 14.7 years, 76% male, Injury Severity Score, ISS 28.4 ± 14.2 points) were available. A delayed platelet activation was found in 25.5% using ADP and 31% using epinephrine. Laboratory parameters indicated a greater blood loss. Prolonged closure times were associated with an increased transfusion rate of packed red blood cell concentrates and a higher mortality rate. Logistic regression revealed hemoglobin (Hb) and fibrinogen levels at admission to be independent predictors for a decreased platelet activation in the assay with ADP (p < 0.001, Cohen's f = 0.61) and with epinephrine (p < 0.001, f = 0.42).

CONCLUSION

Approximately one quarter to one third of primarily admitted trauma patients without long-term anticoagulation medication showed a delayed platelet activation in the PFA-100 test. By considering all trauma patients an even higher rate can be expected. The Hb and fibrinogen levels at admission can be helpful to estimate platelet disorders. The development of platelet assays to guide the resuscitation of individual patients seems to be absolutely necessary. The contribution of platelet disorders to trauma-induced coagulopathy is not sufficiently understood. Regarding the importance assigned to platelet transfusion or administration of desmopressin, these aspects should be the subject of further research.

The European guideline on management of major bleeding and coagulopathy following trauma: fifth edition

BACKGROUND

Severe traumatic injury continues to present challenges to healthcare systems around the world, and post-traumatic bleeding remains a leading cause of potentially preventable death among injured patients. Now in its fifth edition, this document aims to provide guidance on the management of major bleeding and coagulopathy following traumatic injury and encourages adaptation of the guiding principles described here to individual institutional circumstances and resources.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004, and the current author group included representatives of six relevant European professional societies. The group applied a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were re-examined and revised based on scientific evidence that has emerged since the previous edition and observed shifts in clinical practice. New recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated.

RESULTS

Advances in our understanding of the pathophysiology of post-traumatic coagulopathy have supported improved management strategies, including evidence that early, individualised goal-directed treatment improves the outcome of severely injured patients. The overall organisation of the current guideline has been designed to reflect the clinical decision-making process along the patient pathway in an approximate temporal sequence. Recommendations are grouped behind the rationale for key decision points, which are patient- or problem-oriented rather than related to specific treatment modalities. While these recommendations provide guidance for the diagnosis and treatment of major bleeding and coagulopathy, emerging evidence supports the author group's belief that the greatest outcome improvement can be achieved through education and the establishment of and adherence to local clinical management algorithms.

CONCLUSIONS

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. If incorporated into local practice, these clinical practice guidelines have the potential to ensure a uniform standard of care across Europe and beyond and better outcomes for the severely bleeding trauma patient.

The European guideline on management of major bleeding and coagulopathy following trauma: fourth edition

BACKGROUND

Severe trauma continues to represent a global public health issue and mortality and morbidity in trauma patients remains substantial. A number of initiatives have aimed to provide guidance on the management of trauma patients. This document focuses on the management of major bleeding and coagulopathy following trauma and encourages adaptation of the guiding principles to each local situation and implementation within each institution.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma was founded in 2004 and included representatives of six relevant European professional societies. The group used a structured, evidence-based consensus approach to address scientific queries that served as the basis for each recommendation and supporting rationale. Expert opinion and current clinical practice were also considered, particularly in areas in which randomised clinical trials have not or cannot be performed. Existing recommendations were reconsidered and revised based on new scientific evidence and observed shifts in clinical practice; new recommendations were formulated to reflect current clinical concerns and areas in which new research data have been generated. This guideline represents the fourth edition of a document first published in 2007 and updated in 2010 and 2013.

RESULTS

The guideline now recommends that patients be transferred directly to an appropriate trauma treatment centre and encourages use of a restricted volume replacement strategy during initial resuscitation. Best-practice use of blood products during further resuscitation continues to evolve and should be guided by a goal-directed strategy. The identification and management of patients pre-treated with anticoagulant agents continues to pose a real challenge, despite accumulating experience and awareness. The present guideline should be viewed as an educational aid to improve and standardise the care of the bleeding trauma patients across Europe and beyond. This document may also serve as a basis for local implementation. Furthermore, local quality and safety management systems need to be established to specifically assess key measures of bleeding control and outcome.

CONCLUSIONS

A multidisciplinary approach and adherence to evidence-based guidance are key to improving patient outcomes. The implementation of locally adapted treatment algorithms should strive to achieve measureable improvements in patient outcome.

The effectiveness of low-dose desmopressin in improving hypothermia-induced impairment of primary haemostasis under influence of aspirin - a randomized controlled trial

BACKGROUND

Mild hypothermia (34-35 °C) increases perioperative blood loss. Our previous studies showed that desmopressin could have in vitro beneficial effects on hypothermia-induced primary haemostasis impairment. In this study, we investigate the in vitro effects of desmopressin on hypothermia-induced primary haemostasis impairment under the influence of aspirin in healthy volunteers.

METHODS

Sixty healthy volunteers were randomly allocated to taking aspirin 100 mg or placebo for three days. On the sixth day blood samples were taken before and after the injection of desmopressin (1.5 microgram or 5 microgram) or normal saline subcutaneously. Measurements including Platelet Function Analyzer (PFA-100®) closure times, plasma von Willebrand Factor antigen, haemoglobin and platelet levels were made at 32 °C and 37 °C respectively.

RESULTS

Collagen/epinephrine closure time (EPICT) was significantly prolonged by 21.13 % (95 %CI 2.34-39.74 %, p = 0.021) in aspirin group at 37 °C. While hypothermia alone prolonged both collagen/adenosine diphosphate (ADPCT) and EPICT by 17.63 % (95 %CI 13.5-20.85 %, p < 0.001) and 8.0 % (95 %CI 6.38-10.04 %, p = 0.024) respectively, addition of aspirin only further prolonged EPICT by 19.9 % (95 %CI 3.32-36.49 %, p = 0.013). In aspirin group, desmopressin 1.5 microgram and 5 microgram significantly reduced ADPCT to below baseline levels at 37 °C (p = 0.025 and <0.001 respectively), whereas reduction in EPICT was seen with desmopressin 5 microgram (p =0.008). The effect was less pronounced at 32 °C, with a significant reduction in EPICT obtained with a dosage of 5 microgram only (p = 0.011).

CONCLUSION

It was shown that aspirin could further potentiate the hypothermia-induced closure time prolongations. Low dose desmopressin (1.5 microgram) reduced PFA-100® closure times towards baseline. A higher dosage (5 microgram) further reduced the closure times below baseline. Therefore low dose desmopressin (1.5 microgram) might have the potential to correct hypothermia-induced primary haemostasis impairment under the influence of aspirin during the perioperative period.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT01382134.

Correction of hypothermic and dilutional coagulopathy with concentrates of fibrinogen and factor XIII: an in vitro study with ROTEM

BACKGROUND

Fibrinogen concentrate treatment can improve coagulation during massive traumatic bleeding. The aim of this in vitro study was to determine whether fibrinogen concentrate, or a combination of factor XIII and fibrinogen concentrates, could reverse a haemodilution-induced coagulopathy during hypothermia.

METHODS

Citrated venous blood from 10 healthy volunteers was diluted in vitro by 33% with 130/0.42 hydroxyethyl starch (HES) or Ringer's acetate (RAc). The effects of fibrinogen concentrate corresponding to 4 gram per 70 kg, or a combination of the same dose of fibrinogen with factor XIII (20 IU per kg), were measured using rotational thromboelastometry (ROTEM). The blood was analysed at 33°C or 37°C with ROTEM EXTEM and FIBTEM reagents. Clotting time (CT), clot formation time (CFT), alpha angle (AA) and maximal clot formation (MCF) were recorded.

RESULTS

Fibrinogen with or without factor XIII improved all ROTEM parameters in either solution irrespective of temperature, with the exception of EXTEM-AA and EXTEM-CFT in HES haemodilution. Fibrinogen increased FIBTEM-MCF more in the samples diluted with RAc than HES, particularly in presence of factor XIII.

CONCLUSIONS

Fibrinogen improved in vitro haemodilution-induced coagulopathy at both 33°C and 37°C, though more efficiently after crystalloid than HES haemodilution. Factor XIII had an additional effect on FIBTEM-MCF, but only after crystalloid dilution.