Pharmacokinetics of Tranexamic Acid (TXA) Delivered by Expeditious Routes in a Swine Model of Polytrauma and Hemorrhagic Shock.

OBJECTIVE: Hemorrhage is the leading cause of preventable death in civilian trauma centers and on the battlefield. One of the emerging treatment options for hemorrhage in austere environments is tranexamic acid (TXA). However, the landscape is not amenable to the current delivery standard. This study compared the pharmacokinetics of TXA via a standard 10-minute intravenous infusion (IV infusion), intravenous rapid push over 10 s (IV push), and intramuscular injection (IM) in a swine polytrauma and hemorrhagic shock model (trauma group) compared to uninjured controls (control group). METHODS: Thirty swine were randomized to the trauma or control group. Following anesthesia, the trauma group experienced a simulated blast injury and 40% controlled hemorrhage. Subjects in both groups were then randomized to receive 1 g/10 mL TXA via IV infusion, IV push, or IM. Animals were monitored for four hours with serial blood sampling. Serum TXA concentrations were measured by liquid chromatography with tandem mass spectrometry (LC-MS/MS) and analyzed. RESULTS: The time to maximum TXA concentration (Tmax) was not affected by trauma in IV infusion or IV push, but was affected in the IM administration with Tmax significantly slower than the control group (p = 0.016). The minimum effective serum concentration of TXA (Ceff, 10 µg/mL) was reached in less than one minute with IV infusion and instantaneously with IV push. Despite lower bioavailability, the time to reach Ceff (Teff) was achieved via IM administration in less than 10 min for both groups (6.4 min trauma vs. 2.1 min control). CONCLUSIONS: In austere prehospital environments, an alternative to intravenous infusion of a life-saving medication is desired. Administration of TXA via all three methods reached the level needed to cause substantial inhibition of fibrinolysis within 10 min. The IV push method showed similar pharmacokinetics to IV infusion of TXA but can be delivered quickly without sacrificing an access site for 10 min.

Ultrasound Localization of Resuscitative Endovascular Balloon Occlusion of the Aorta in a Human Cadaver Model.

OBJECTIVE: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a method of gaining proximal control of noncompressible torso hemorrhage (NCTH). Catheter placement is traditionally confirmed with fluoroscopy, but few studies have evaluated whether ultrasound (US) can be used. METHODS: Using a pressurized human cadaver model, a certified REBOA placer was shown one of four randomized cards that instructed them to place the REBOA either correctly or incorrectly in Zone 1 (the distal thoracic aorta extending from the celiac artery to the left subclavian artery) or Zone 3 (in the distal abdominal aorta, from the aortic bifurcation to the lowest renal artery). Once the REBOA was placed, 10 US-trained locators were asked to confirm balloon placement via US. The participants were given 3 minutes to determine whether the catheter had been correctly placed, repeating this 20 times on two cadavers. RESULTS: Overall, US exhibited an average sensitivity of 83%, specificity of 76%, and accuracy of 80%. For Zone 1, US showed a sensitivity of 78% and specificity of 83%, and for Zone 3, a sensitivity of 88% and specificity of 76%. In addition, US exhibited a likelihood positive ratio (LR+) of 3.73 and a likelihood negative ratio (LR-) of 0.22 for either position, with similar numbers for Zone 1 (+4.57, -0.26) and Zone 3 (+3.16, -0.16). CONCLUSION: Ultrasound could prove to be a useful tool for confirming placement of a REBOA catheter, especially in austere environments.

Management of Coronary Artery Disease.

This article reviews the surgical management of coronary artery disease (CAD). The authors cover the background, presentation, diagnosis, heart team evaluation, and development of treatment strategies tailored to individual patients with significant CAD. Special attention is given to conduit selection and configuration as well as alternative revascularization approaches that differ from traditional coronary artery bypass grafting.

Single Versus Double Anatomic Site Intraosseous Blood Transfusion in a Swine Model of Hemorrhagic Shock.

BACKGROUND: Blood transfusion via single site intraosseous access is a critical modality when caring for a trauma victim that lacks intravascular access. Flow rates and potential clinical complications when utilizing two sites of intraosseous access are not well known. MATERIALS AND METHODS: Anesthetized adult female Yorkshire swine (Sus scrofa; n = 48; 76.7 ± 1.75kg; range 66-90kg) were cannulated and then bled approximately 30% total blood volume. Swine were randomly assigned to treatment groups: single sited humerus, single sited sternum, dual sited humerus or dual sited humerus and sternum. Flow rates, hemolysis, physiologic measurements, biochemical variables, and pulmonary histologic inflammation and occlusion were contrasted between groups. RESULTS: Dual sited intraosseous transfusion flow rates (128ml/min, 95% CI 123-132) were double the flow rates of single sites (65ml/min, 95% CI 60-70), P < .0001.Single sited humeral flow rates were greater than sternal flow rates, with respective averages of 74ml/min and 55ml/min, though not reaching statistical significance (P < 0.17). There was no significant elevation of plasma free hemoglobin in any group after transfusion as compared to baseline (P = 0.7). Groups did not significantly differ in vitals or biochemical variables. Most pulmonary specimens had some intraparenchymal fat embolism, however no animals had evidence of occlusive intra-arterial fat embolism. CONCLUSIONS: Dual anatomic site, pressure bag driven, intraosseous blood transfusion approximately doubles flow rates without evidence of clinical complications or hemolysis. Further research using a survivability model is needed to characterize long-term complications from pressurized IO transfusions.

More Than Just Torsion: An Unusual Case of Testicular Pain.

Testicular pain has a wide differential and the nonspecific presentation should be triaged rapidly for urgent diagnosis and treatment. Scrotal pyoceles are uncommon collections of purulent fluid between the visceral and parietal tunica vaginalis, usually secondary to acute epididymo-orchitis, intra-abdominal infection, or trauma. Epididymitis and epididymo-orchitis are generally secondary to sexually transmitted infections or urinary tract pathogens. Epidymo-orchitis can compromise the testicular blood supply, leading to a microinfarction and rupture through the tunica albuginea; inflammatory and infectious material then translocate into the tunica vaginalis leading to the formation of a pyocele. Ultrasonography is the preferred method of diagnostic imaging, which can show a classic "falling snow" sign, loculations, or gas. The treatment for a scrotal pyocele is pain control, fluid resuscitation, broad-spectrum antibiotics, and early urology/general surgery consultation. In such cases, Fournier gangrene (FG) should be clinically ruled out and the presence of signs of Fournier gangrene should be met with an urgent surgical consult.

Elevated Liver Enzymes: Emergency Department-Focused Management.

BACKGROUND: Liver function test (LFT) abnormalities are a common problem faced by emergency physicians. This has become more common with the introduction of laboratory panels and automated routine laboratory testing. Fortunately, not all patients with irregularities in liver enzymes possess underlying pathology. This emergency medicine focused review provides a discussion of the various biochemical tests, their underlying biological basis, and an algorithmic approach to the interpretation of abnormalities. OBJECTIVE: Our aim was to provide emergency physicians with an overview of the evaluation and management of patients with elevated LFTs. DISCUSSION: The liver is a complex organ with multiple roles. The key biochemical markers of hepatic function can be organized into the groupings of hepatocellular, cholestatic, or functioning liver, based on underlying enzymatic roles. Pathologic alterations to these markers can be algorithmically assessed by separating disease processes of these groupings, followed by assessment of the magnitude of enzymatic elevation. This review conducts an in-depth evaluation of the differential diagnosis and emergency department-centered clinical response of elevated LFTs based on subcategories of mild, moderate, and severe transaminase elevation. CONCLUSIONS: By understanding the biochemical basis of each LFT, it is possible to correlate laboratory findings to a patient's clinical presentation. An algorithmic approach can be taken to help narrow the spectrum of a differential diagnosis. This may assist providers in ensuring appropriate management and evaluation of the patient with elevated LFTs.