An Evaluation of a Novel Medical Device Versus Standard Interventions in the Treatment of Tension Pneumothorax in a Swine Model (Sus scrofa).

INTRODUCTION: Tension pneumothorax is a common cause of preventable death in trauma. Needle decompression is the traditional first-line intervention but has high failure rates. We sought to evaluate the effectiveness and expedience of needle thoracostomy, surgical tube thoracostomy, and Reactor™ thoracostomy - a novel spring-loaded trocar insertion device. MATERIALS AND METHODS: Yorkshire swine underwent controlled thoracic insufflation to create tension pneumothorax physiology for device comparison. Additional experiments were performed by increasing insufflation pressures to achieve pulseless electrical activity. Intervention was randomized to needle thoracostomy (14 gauge), tube thoracostomy (32Fr), or Reactor™ thoracostomy (36Fr). Air leak was simulated throughout intervention with 40-80 mL/kg/min insufflation. Intrathoracic pressure monitoring and hemodynamic parameters were obtained at 1 and 5 minutes. RESULTS: Tension physiology and tension-induced pulseless electrical activity were created in all iterations. Needle thoracostomy (n = 28) was faster at 7.04 ± 3.04 seconds than both Reactor thoracostomy (n = 32), 11.63 ± 5.30 (p < 0.05) and tube thoracostomy (n = 32), 27.06 ± 10.73 (p < 0.01); however, Reactor™ thoracostomy was faster than tube thoracostomy (p < 0.001). Physiological decompression was achieved in all patients treated with Reactor™ and tube thoracostomy, but only 14% of needle thoracostomy. Cardiac recovery to complete physiologic baseline occurred in only 21% (6/28) of those treated with needle thoracostomy whereas Reactor™ or tube thoracostomy demonstrated 88% (28/32) and 94% (30/32) response rates. When combined, needle thoracostomy successfully treated tension pneumothorax in only 4% (1/28) of subjects as compared to 88% (28/32) with Reactor™ thoracostomy and 94% (30/32) with tube thoracostomy (p < 0.01). CONCLUSIONS: Needle thoracostomy provides a rapid intervention for tension pneumothorax, but is associated with unacceptably high failure rates. Reactor™ thoracostomy was effective, expedient, and may provide a useful and technically simpler first-line treatment for tension pneumothorax or tension-induced pulseless electrical activity.

Lifesaving interventions in blackout conditions using night vision technology: Come to the dark side.

BACKGROUND: During military combat operations and civilian night-time aeromedical transport, medical providers are frequently required to perform lifesaving interventions (LSIs) in low-light environments. Because definitive surgical care is often delayed until a white light environment is permissible, we sought to determine if night optical device (NOD) technology could enable surgical capabilities in blackout conditions. METHODS: Using a crossover design, six surgeons performed 11 different procedures on six swine, three in normal light conditions (LC) and 3 in blackout conditions (BC) using two-chamber NODs after familiarization with the procedures in both conditions on manikins. Successful completion and procedural times were compared between groups. RESULTS: Blackout conditions were confirmed with ambient light reading of 0.2 lux during BC versus 3962.9 lux for LC (p < 0.001). There were no significant differences in success rates for any procedure. There were no differences in operative times between BC and LC for extremity tourniquet placement, femoral artery cut-down and clamping, resuscitative thoracotomy, or percutaneous resuscitative endovascular balloon occlusion of the aorta placement. The following procedures took significantly longer in BC vs. LC: Focused Assessment with Sonography for Trauma examination (98 seconds vs. 62 seconds), peripheral IV placement (140 seconds vs. 35 seconds), intraosseous access (51 seconds vs. 26 seconds), jugular vein cut-down and access (237 seconds vs. 104 seconds), laparotomy and packing (71 seconds vs. 51 seconds), stapled splenectomy (137 seconds vs. 74 seconds), resuscitative endovascular balloon occlusion of the aorta placement via cutdown (1,008 seconds vs. 338 seconds), and cricothyroidotomy (177 seconds vs. 109 seconds) (all p < 0.05). CONCLUSION: Lifesaving interventions can be safely and effectively performed in blackout conditions using NODs, although increased difficulty with select procedure types was identified. Focused training and technological improvements to currently available devices are needed. LEVEL OF EVIDENCE: Basic science.

Mobile forward-looking infrared technology allows rapid assessment of resuscitative endovascular balloon occlusion of the aorta in hemorrhage and blackout conditions.

INTRODUCTION: Objective assessment of final resuscitative endovascular balloon occlusion of the aorta (REBOA) position and adequate distal aortic occlusion is critical in patients with hemorrhagic shock, especially as feasibility is being increasingly investigated in the prehospital setting. We propose that mobile forward-looking infrared (FLIR) thermal imaging is a fast, reliable, and noninvasive method to assess REBOA position and efficacy in scenarios applicable to battlefield and prehospital care. METHODS: Ten swine were randomized to a 40% hemorrhage group (H, n = 5) or nonhemorrhage group (NH, n = 5). Three experiments were completed after Zone I placement of a REBOA catheter. Resuscitative endovascular balloon occlusion of the aorta was deployed for 30 minutes in all animals followed by randomized continued deployment versus sham in both light and blackout conditions. Forward-looking infrared images and hemodynamic data were obtained. Images were presented to 62 blinded observers for assessment of REBOA inflation status. RESULTS: There was no difference in hemodynamic or laboratory values at baseline. The H group was significantly more hypotensive (mean arterial pressure 44 vs. 60 mm Hg, p < 0.01), vasodilated (systemic vascular resistance 634 vs. 938dyn·s/cm, p = 0.02), and anemic (hematocrit 12 vs. 23.2%, p < 0.01). Hemorrhage group animals remained more hypotensive, anemic, and acidotic throughout all three experiments. There was a significant difference in the temperature change (ΔTemp) measured by FLIR between animals with REBOA inflated versus not inflated (5.7°C vs. 0.7°C, p < 0.01). The H and NH animals exhibited equal magnitudes of ΔTemp in both inflated and deflated states. Blinded observer analysis of FLIR images correctly identified adequate REBOA inflation and aortic occlusion 95.4% at 5 minutes and 98.8% at 10 minutes (positive predictive value at 5 minutes = 99% and positive predictive value at 10 minutes = 100%). CONCLUSIONS: Mobile thermal imaging is an easy, rapid, and reliable method for assessing distal perfusion after occlusion by REBOA. Smartphone-based FLIR technology allows for confirmation of adequate REBOA placement at the point of care, and performance was not degraded in the setting of major hemorrhage or blackout conditions.

The effects of hemorrhage on the pharmacokinetics of tranexamic acid in a swine model.

BACKGROUND: The early use of tranexamic acid (TXA) is strongly advocated in patients who are likely to require massive transfusion to decrease mortality. This study determines the influence of hemorrhage on the pharmacokinetics of TXA in a porcine model. METHODS: The investigation was a prospective experimental study in Yucatan minipigs. First, in vitro plasma-cell partitioning of TXA was evaluated by inoculating whole blood with known aliquots, centrifuging, and measuring the supernatant with high-performance liquid chromatography with mass spectrometry (HPLC-MS). Then, using in vivo modeling, normovolemic and hypovolemic (35% reduction in blood volume) swine (n = 4 per group) received 1 g of intravenous TXA and had blood sampled at 14 time points over 4 hours to determine baseline clearance via HPLC-MS. Additional swine (n = 4) were hemorrhaged 35% of their blood volume, and TXA was administered as a 15 mg/kg infusion over 10 minutes followed by infusion of 1.875 mg/kg per hour to simulate massive hemorrhage scenario. During the first hour of TXA administration, one total blood volume was hemorrhaged and simultaneously replaced with TXA free blood. Serial blood samples and the hemorrhaged blood were analyzed by HPLC-MS to determine the percentage of dose lost via hemorrhage. RESULTS: Clearance of TXA was diminished in the hypovolemic group compared with the normovolemic group (115 ± 4 vs 70 ± 7 mL/min). Percentage of dose lost via hemorrhage averaged 25%. The lowest measured plasma level during the exchange transfusion was 34 µg/mL. CONCLUSION: Mean 25% of the present 2017 Joint Trauma System Clinical Practice Guideline dosing of TXA can be lost to hemorrhage if a blood volume is transfused within an hour of initiating therapy. In the case of TXA, which has limited distribution and is administered during active hemorrhage and massive blood transfusions, replacement strategies should be developed and tested to find simple methods of adjusting the current dosing guidelines to maintain therapeutic plasma concentrations. LEVEL OF EVIDENCE: Therapeutic, level II.

Esophageal Magnetic Sphincter Augmentation as a Novel Approach to Post-bariatric Surgery Gastroesophageal Reflux Disease.

BACKGROUND: We sought to evaluate the safety and effectiveness of magnetic sphincter augmentation (MSA) in patients with GERD after bariatric surgery. METHODS: Pre- and post-operative GERD quality of life (G-QOL) surveys were conducted. Standard indications (SI) group or the post-bariatric group (PB) created. Outcomes were compared between groups. RESULTS: Twenty-eight patients analyzed with no losses to follow-up. All patients had preoperative testing confirming normal motility and presence of GERD. No patients were lost to follow-up. The PB group (N = 10) were mostly prior sleeve gastrectomies (N = 8) with two previous gastric bypasses. PB patients required larger MSA device size (16 beads) compared to the SI group (14 beads, p < 0.001). Outcomes were no different with percent improvement between pre- and post-operative G-QOL survey scores with 70% improvement for PB and 84% for SI (p = 0.13). Medication cessation was possible in 90% for PB versus 94% for SI (p = 0.99). Rates of post-operative dysphagia were similar between the two groups. CONCLUSIONS: Although larger prospective randomized studies are needed, there is an exciting potential for the role of MSA, providing surgeons a new and much needed tool in their armamentarium against refractory or de novo GERD after bariatric procedures.

Smartphone-based mobile thermal imaging technology to assess limb perfusion and tourniquet effectiveness under normal and blackout conditions.

BACKGROUND: Over the past decade, there has been a resurgence of tourniquet use in civilian and military settings. Several key challenges include assessment of limb perfusion and adequacy of tourniquet placement, particularly in the austere or prehospital environments. We investigated the utility of thermal imaging to assess adequacy of tourniquet placement. METHODS: The FLIR ONE smartphone-based thermal imager was utilized. Ten swine underwent tourniquet placement with no associated hemorrhage (n = 5) or with 40% hemorrhage (n = 5). Experiment 1 simulated proper tourniquet application, experiment 2 had one of two tourniquets inadequately tightened, and experiment 3 had one of two tourniquets inadequately tightened while simulating blackout-combat conditions. Static images were taken at multiple time points up to 30 minutes. Thermal images were then presented to blinded evaluators who assessed adequacy of tourniquet placement. RESULTS: The mean core temperature was 38.3 °C in non-hemorrhaged animals versus 38.2 °C in hemorrhaged animals. Hemorrhaged animals were more hypotensive (p = 0.001), anemic (p < 0.001), vasodilated (p = 0.008), and had a lower cardiac output (p = 0.007) compared to non-hemorrhaged animals. The thermal imaging temperature reading decreased significantly after proper tourniquet placement in all animals, with no difference between hemorrhaged and non-hemorrhaged groups at 30 minutes (p = 0.23). Qualitative thermal image analysis showed clearly visible perfusion differences in all animals between baseline, adequate tourniquet, and inadequate tourniquet in both hemorrhaged and non-hemorrhaged groups. Ninety-eight percent of blinded evaluators (n = 62) correctly identified adequate and inadequate tourniquet placement at 5 minutes. Images in blackout conditions showed no adverse impact on thermal measurements or in the ability to accurately characterize perfusion and tourniquet adequacy. CONCLUSIONS: A simple handheld smartphone-based forward looking infrared radiometry device demonstrated a high degree of accuracy, reliability, and ease of use for assessing limb perfusion. Forward looking infrared radiometry also allowed for rapid and reliable identification of adequate tourniquet placement that was not affected by major hemorrhage or blackout conditions.