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

BACKGROUND

Severe trauma represents a major global public health burden and the management of post-traumatic bleeding continues to challenge healthcare systems around the world. Post-traumatic bleeding and associated traumatic coagulopathy remain leading causes of potentially preventable multiorgan failure and death if not diagnosed and managed in an appropriate and timely manner. This sixth edition of the European guideline on the management of major bleeding and coagulopathy following traumatic injury aims to advise clinicians who care for the bleeding trauma patient during the initial diagnostic and therapeutic phases of patient management.

METHODS

The pan-European, multidisciplinary Task Force for Advanced Bleeding Care in Trauma included representatives from six European professional societies and convened to assess and update the previous version of this guideline using a structured, evidence-based consensus approach. Structured literature searches covered the period since the last edition of the guideline, but considered evidence cited previously. The format of this edition has been adjusted to reflect the trend towards concise guideline documents that cite only the highest-quality studies and most relevant literature rather than attempting to provide a comprehensive literature review to accompany each recommendation.

RESULTS

This guideline comprises 39 clinical practice recommendations that follow an approximate temporal path for management of the bleeding trauma patient, with recommendations grouped behind key decision points. While approximately one-third of patients who have experienced severe trauma arrive in hospital in a coagulopathic state, a systematic diagnostic and therapeutic approach has been shown to reduce the number of preventable deaths attributable to traumatic injury.

CONCLUSION

A multidisciplinary approach and adherence to evidence-based guidelines are pillars of best practice in the management of severely injured trauma patients. Further improvement in outcomes will be achieved by optimising and standardising trauma care in line with the available evidence across Europe and beyond.

Programmed, intermittent boluses versus continuous infusion to the sciatic nerve - a non-inferiority randomized, controlled trial

BACKGROUND

Trials comparing programmed, intermittent boluses (PIB) and continuous infusion in catheter-based nerve blocks found no analgesic differences. However, as these trials used equal doses of local anesthetic (LA), the time of action of each bolus was not accounted for. Therefore, the dose-sparing benefits of PIB may have been overlooked. We compared the analgesic effect of boluses administered in intervals resembling the time of action of each bolus with continuous infusion. We hypothesized that PIB provided non-inferior analgesia despite consuming less LA.

METHODS

Eighty-one patients undergoing fore- and midfoot surgery receiving a catheter-based sciatic nerve block were randomized to ropivacaine 0.2% as PIB of 10 ml every 8th hour or as continuous infusion, 6 ml h^-1 . All participants could also receive boluses of 10 ml every 4th hour as needed. A non-inferiority randomized controlled design was used. Primary outcome was pain (VAS, 0-100 mm) for 72 h using area under curve (AUC) calculation. We assumed a linear relationship between mean VAS and AUC-VAS and used a non-inferiority margin of VAS = 20 mm, corresponding to AUC-VAS = 1440 mm h.

RESULTS

Mean difference in AUC-VAS was -416 mm h (95% CI -1076 to 244; p = .217) between continuous infusion (mean AUC-VAS 1206 mm h) and PIB (mean AUC-VAS 1621 mm h), establishing non-inferiority. Mean total LA consumption was significantly larger for continuous infusion compared to PIB ((468 ml (95% CI 458 to 478) vs. 136 ml (95% CI 123 to 148); p < 0.0001)).

CONCLUSIONS

PIB provided non-inferior analgesia compared to continuous infusion for 72 postoperative hours despite using significantly less LA.

Longitudinal neural exposure to local anesthetic and nerve block duration: a retrospective analysis of experimental data from healthy volunteer trials

Background and objectives

Characteristics of a nerve block depend on the distribution of local anesthetic (LA) close to the nerve. The relationship between longitudinal distribution of LA and nerve block characteristics has not been investigated in vivo, but one in vitro study showed decrements in action potential amplitudes with increasing exposure length. We describe the influence of longitudinal neural exposure to LA on nerve block duration adjusted for other likely influential factors.

Methods

We analyzed data from an ethical board approved prospective consecutive collected dataset of 180 healthy volunteers with a common peroneal nerve block (2.5–20 mL, 5–40 mg of ropivacaine). Data were retrieved from three independent randomized controlled trials. The longitudinal neural exposure to LA in millimeters was evaluated using ultrasound. Interventional covariates and demographics were retrieved. Nerve block duration, the dependent variable in the primary assessment, was defined as time of insensitivity to a cold stimulus and was evaluated blinded to all other covariates. Using a multiple linear mixed-effects model, we explored the association between neural exposure to LA and nerve block duration.

Results

We found a significant positive association between longitudinal neural exposure to LA and block duration (p<0.01). A 10% increase in longitudinal exposure resulted in an 8.7 (2.5; 15) min increase in block duration. LA dose was associated to block duration (p<0.001) but LA volume had no impact (p=0.93).

Conclusions

Longitudinal neural exposure to LA was significantly associated with nerve block duration. LA dose was the strongest determinant for block duration whereas LA volume had no influence.

Magnetic Field Tuning and Quantum Interference in a Cooper Pair Splitter

Cooper pair splitting (CPS) is a process in which the electrons of the naturally occurring spin-singlet pairs in a superconductor are spatially separated using two quantum dots. Here, we investigate the evolution of the conductance correlations in an InAs CPS device in the presence of an external magnetic field. In our experiments the gate dependence of the signal that depends on both quantum dots continuously evolves from a slightly asymmetric Lorentzian to a strongly asymmetric Fano-type resonance with increasing field. These experiments can be understood in a simple three-site model, which shows that the nonlocal CPS leads to symmetric line shapes, while the local transport processes can exhibit an asymmetric shape due to quantum interference. These findings demonstrate that the electrons from a Cooper pair splitter can propagate coherently after their emission from the superconductor and how a magnetic field can be used to optimize the performance of a CPS device. In addition, the model calculations suggest that the estimate of the CPS efficiency in the experiments is a lower bound for the actual efficiency.

Gigahertz Quantized Charge Pumping in Bottom-Gate-Defined InAs Nanowire Quantum Dots

Semiconducting nanowires (NWs) are a versatile, highly tunable material platform at the heart of many new developments in nanoscale and quantum physics. Here, we demonstrate charge pumping, that is, the controlled transport of individual electrons through an InAs NW quantum dot (QD) device at frequencies up to 1.3 GHz. The QD is induced electrostatically in the NW by a series of local bottom gates in a state of the art device geometry. A periodic modulation of a single gate is enough to obtain a dc current proportional to the frequency of the modulation. The dc bias, the modulation amplitude and the gate voltages on the local gates can be used to control the number of charges conveyed per cycle. Charge pumping in InAs NWs is relevant not only in metrology as a current standard, but also opens up the opportunity to investigate a variety of exotic states of matter, for example, Majorana modes, by single electron spectroscopy and correlation experiments.

Epitaxy of semiconductor-superconductor nanowires

Controlling the properties of semiconductor/metal interfaces is a powerful method for designing functionality and improving the performance of electrical devices. Recently semiconductor/superconductor hybrids have appeared as an important example where the atomic scale uniformity of the interface plays a key role in determining the quality of the induced superconducting gap. Here we present epitaxial growth of semiconductor-metal core-shell nanowires by molecular beam epitaxy, a method that provides a conceptually new route to controlled electrical contacting of nanostructures and the design of devices for specialized applications such as topological and gate-controlled superconducting electronics. Our materials of choice, InAs/Al grown with epitaxially matched single-plane interfaces, and alternative semiconductor/metal combinations allowing epitaxial interface matching in nanowires are discussed. We formulate the grain growth kinetics of the metal phase in general terms of continuum parameters and bicrystal symmetries. The method realizes the ultimate limit of uniform interfaces and seems to solve the soft-gap problem in superconducting hybrid structures.

A novel suture method to place and adjust peripheral nerve catheters

We have developed a peripheral nerve catheter, attached to a needle, which works like an adjustable suture. We used in‐plane ultrasound guidance to place 45 catheters close to the femoral, saphenous, sciatic and distal tibial nerves in cadaver legs. We displaced catheters after their initial placement and then attempted to return them to their original positions. We used ultrasound to evaluate the initial and secondary catheter placements and the spread of injectate around the nerves. In 10 cases, we confirmed catheter position by magnetic resonance imaging. We judged 43/45 initial placements successful and 42/43 secondary placements successful by ultrasound, confirmed in 10/10 cases by magnetic resonance imaging.

Experimental determination of the ²⁴Mg I (3s3p)³P₂ lifetime

We present the first experimental determination of the electric-dipole forbidden (3s3p)³P₂→(3s²)¹S₀ (M2) transition rate in ²⁴Mg and compare to state-of-the-art theoretical predictions. Our measurement exploits a magnetic trap isolating the sample from perturbations and a magneto-optical trap as an amplifier converting each ³P₂→¹S₀ decay event into millions of photons readily detected. The transition rate is determined to be (4.87 ± 0.3)×10⁻⁴  s⁻¹ corresponding to a ³P₂ lifetime of 2050(-110)(+140) sec. This value is in agreement with recent theoretical predictions, and to our knowledge the longest lifetime ever determined in a laboratory environment.

Absence of high‐affinity calreticulin autoantibodies in patients with systemic rheumatic diseases and coeliac disease

Calreticulin has been reported to be an autoantigen in various autoimmune connective tissue diseases and in coeliac disease. Previous studies have used incubation buffers with low salt and low detergent concentrations (low stringency conditions) with serum albumin or other proteins as a blocking agent. Using these conditions we found a relatively high level of non-specific binding in many sera. Antibodies to proteins that are used as blocking reagents in ELISA (bovine serum albumin (BSA), ovalbumin, skimmed milk powder) are frequently present in sera, and these may cause false-positive results. Moreover, the low isoelectric point of calreticulin and its chaperone properties may give rise to false-positive results under low stringency conditions. We report that the use of a simple buffer without protein (50 mM Tris, pH 7.5, 1% Tween 20, 0.3 M NaCl) removes most of the problems with unwanted binding (high stringency conditions). Using the high stringency conditions, we screened sera from 107 patients with systemic lupus erythematosus, sera from patients with other systemic autoimmune diseases and from children with coeliac disease for the presence of high-affinity calreticulin autoantibodies by immunoblotting and ELISA. None of the sera contained high-affinity calreticulin antibodies. It is concluded that calreticulin is not a common autoantigen in patients with autoimmune connective tissue diseases or coeliac disease.

Discrepancy between haemagglutination and radioimmunological techniques for measurement of serum thyroglobulin autoantibodies

Recently, it has been suggested that in some patients with autoimmune thyroid diseases the tanned red cell (TRC) method for detection of thyroglobulin autoantibodies (TgAb) is negative where TgAb measured by radioimmunoassay (RIA) show positive values. To investigate this further, patients with thyroid diseases, pernicious anaemia and a control group were studied for serum concentrations of TgAb by TRC and by quantitative RIA, calibrated against MRC Standard A65/93. Antibodies for microsomes (MAb) were measured immunofluoretically. There was in all patient groups (Hashimoto's thyroiditis (n = 41), Graves' disease (n = 50), idiopathic myxoedema (n = 12), euthyroid Graves' disease (n = 7), pernicious anaemia (n = 81) a discrepancy between TgAb measured by TRC and RIA, respectively, whereas there was a reasonable correlation between the presence of TgAb by RIA and the presence of MAb. A possible interference from antinuclear antibodies and rheumatoid factors was ruled out. There was no increased frequency of TgAb measured by RIA in the control group. Fractionation of TRC negative sera revealed macromolecular TRC-activity, whereas TgAb positive sera by both methods had almost exclusively RIA and TRC activity corresponding to IgG. Based on these results and others it seems that the TRC method for measurement of serum TgAb is of limited diagnostic value. Furthermore, the TRC method is in many cases not sensitive enough for screening for TgAb prior to measurement of serum Tg, which is of importance as this method shows false values in the presence of TgAb due to methodological interference.