Stem cell, Granulocyte-Colony Stimulating Factor and/or Dihexa to promote limb function recovery in a rat sciatic nerve damage-repair model: Experimental animal studies.

BACKGROUND: Optimizing nerve regeneration and re-innervation of target muscle/s is the key for improved functional recovery following peripheral nerve damage. We investigated whether administration of mesenchymal stem cell (MSC), Granulocyte-Colony Stimulating Factor (G-CSF) and/or Dihexa can improve recovery of limb function following peripheral nerve damage in rat sciatic nerve transection-repair model. MATERIALS AND METHODS: There were 10 experimental groups (n = 6-8 rats/group). Bone marrow derived syngeneic MSCs (2 × 106; passage≤6), G-CSF (200-400 µg/kg b.wt.), Dihexa (2-4 mg/kg b.wt.) and/or Vehicle were administered to male Lewis rats locally via hydrogel at the site of nerve repair, systemically (i.v./i.p), and/or to gastrocnemius muscle. The limb sensory and motor functions were assessed at 1-2 week intervals post nerve repair until the study endpoint (16 weeks). RESULTS: The sensory function in all nerve boundaries (peroneal, tibial, sural) returned to nearly normal by 8 weeks (Grade 2.7 on a scale of Grade 0-3 [0 = No function; 3 = Normal function]) in all groups combined. The peroneal nerve function recovered quickly with return of function at one week (∼2.0) while sural nerve function recovered rather slowly at four weeks (∼1.0). Motor function at 8-16 weeks post-nerve repair as determined by walking foot print grades significantly (P < 0.05) improved with MSC + G-CSF or MSC + Dihexa administrations into gastrocnemius muscle and mitigated foot flexion contractures. CONCLUSIONS: These findings demonstrate MSC, G-CSF and Dihexa are promising candidates for adjunct therapies to promote limb functional recovery after surgical nerve repair, and have implications in peripheral nerve injury and limb transplantation. IACUC No.215064.

Mobile Smartphone Thermal Imaging Characterization and Identification of Microvascular Flow Insufficiencies in Deep Inferior Epigastric Artery Perforator Free Flaps.

BACKGROUND: Mobile smartphone thermal imaging (MTI) devices correlate with blood flow, which makes them appealing adjuncts during reconstructive surgery. MTI was assessed in the setting of deep inferior epigastric artery perforator (DIEAP) free flaps. We hypothesized that MTI can be a surrogate for blood flow to identify microvascular flow insufficiencies. METHODS: Nineteen patients underwent 30 DIEAP flaps for breast reconstruction. Images were obtained preoperatively, intraoperatively, and at instances of concern for flap viability. Three groups were evaluated: normal DIEAP flaps (NDFs), flaps with arterial insufficiency (AI), and flaps with venous congestion (VC). RESULTS: All flaps were successful. There were significant temperature increases from max ischemia (24.5 ± 2.1°C) to 1 min after anastomosis (27.2 ± 1.6°C, P < 0.001). NDFs continued to warm until the final MTI was taken when leaving the operating room. There were no differences between MTI flap temperatures before transfer to the chest and after completion of microanastomosis. With questionable flap viability, VC and AI temperatures were found to be significantly colder than the NDF group (28.3 ± 1.9°C versus 32.2 ± 1.8°C, P = 0.003) in the VC group and (27.2 ± 0.7°C versus 32.2 ± 1.8°C, P = 0.001) in the AI group. After correction of the identified flow insufficiency, VC and AI rewarmed and temperatures were no different compared with NDF. CONCLUSIONS: MTI recognizes microanastomotic failure and is a practical adjunct in the evaluation of free flap perfusion.

Leclercia adecarboxylata causing necrotising soft tissue infection in an immunocompetent adult.

A 72-year-old woman presented with concern for a necrotising soft tissue infection (NSTI) 6 days after a tree branch impaled her left lower extremity while hiking in Hawaii. The wound was irrigated and closed at a local clinic in Hawaii. She completed a 5-day course of clindamycin. She presented to our emergency department 1 day after completion of antibiotics due to worsening erythema and malodorous drainage. Local wound exploration revealed bullae and easy dissection of fascial planes. CT scan revealed complex heterogeneous fluid and inflammatory stranding in the posterior calf. Clinical and radiographic findings raised concern for NSTI prompting initiation of broad spectrum antibiotics and urgent operative debridement. Wound cultures and deep tissues cultures returned positive for pansusceptible Leclercia adecarboxylata She underwent two additional operative debridements and transitioned to negative pressure wound therapy during her hospitalisation. She was discharged home on oral amoxicillin/clavulanate on hospital day 6.

Senior surgical resident autonomy and teaching assistant cases: A prospective observational study.

INTRODUCTION: Teaching assistant (TA) cases allow senior residents (SR) to gain autonomy. We compared the safety profiles of TA cases performed under direct vs. indirect staff supervision. METHODS: Prospective observational study of operative cases where a SR served as the TA between 7/2014-6/2017 (n = 161). Patient/operative characteristics, 30-day outcomes, and SR survey data were compared by level of supervision. RESULTS: Case mix included 68 laparoscopic appendectomies (42%), 49 laparoscopic cholecystectomies (30%), 10 I&Ds (6%), 10 umbilical hernia repairs (6%), 4 port placements (3%), and 11 others. Indirectly supervised cases were shorter (61 vs. 76 min, p < 0.01), with less blood loss (11 vs. 24 ml, p < 0.05), and lower conversion rates (0% vs. 5.7%, p < 0.05). Perceived difficulty was high in 20% of cases with indirect vs. 49% with direct supervision (p < 0.01). Mean SR comfort was high (4.4 vs. 4.6 out of 5) regardless of level of staff supervision. 30-day complications did not differ for indirect vs. direct supervision (all p = NS). DISCUSSION: Carefully selected TA cases offer SRs opportunities to practice autonomy without sacrificing operative time or patient safety.

Efficacy of intermittent versus standard resuscitative endovascular balloon occlusion of the aorta in a lethal solid organ injury model.

BACKGROUND: High-grade solid organ injury is a major cause of mortality in trauma. Use of resuscitative endovascular balloon occlusion of the aorta (REBOA) can be effective but is limited by ischemia-reperfusion injury. Intermittent balloon inflation/deflation has been proposed as an alternative, but the safety and efficacy prior to operative hemorrhage control is unknown. METHODS: Twenty male swine underwent standardized high-grade liver injury, then randomization to controls (N = 5), 60-min continuous REBOA (cR, n = 5), and either a time-based (10-minute inflation/3-minute deflation, iRT = 5) or pressure-based (mean arterial pressure<40 during deflation, iRP = 5) intermittent schedule. Experiments were concluded after 120 minutes or death. RESULTS: Improved overall survival was seen in the iRT group when compared to cR (p < 0.01). Bleeding rate in iRT (5.9 mL/min) was significantly lower versus cR and iRP (p = 0.02). Both iR groups had higher final hematocrit (26% vs. 21%) compared to cR (p = 0.03). Although overall survival was lower in the iRP group, animals surviving to 120 minutes with iRP had decreased end organ injury (Alanine aminotransferase [ALT] 33 vs. 40 in the iRT group, p = 0.03) and lower lactate levels (13 vs. 17) compared with the iRT group (p = 0.03). No differences were seen between groups in terms of coagulopathy based on rotational thromboelastometry. CONCLUSION: Intermittent REBOA is a potential viable adjunct to improve survival in lethal solid organ injury while minimizing the ischemia-reperfusion seen with full REBOA. The time-based intermittent schedule had the best survival and prolonged duration of tolerable zone 1 placement. Although the pressure-based schedule was less reliable in terms of survival, when effective, it was associated with decreased acidosis and end-organ injury.

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.