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1.
J Am Assoc Lab Anim Sci ; 59(3): 322-327, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32204749

RESUMO

Accurate assessment of coagulation in porcine studies is essential. We sought to establish normal values for porcine rotational thromboelastometry (ROTEM) according to the American Society for Veterinary Clinical Pathology guidelines and to assess the effects of various preanalytical parameters on those measurements. Healthy Yorkshire-cross pigs (n = 81; 46 males and 35 females) were anesthetized. By using a 18-gauge needle attached to a vacuum phlebotomy tube, blood was acquired from the cranial vena cava. Tubes were filled in the following order: evacuation clot tube, EDTA tube, heparin tube, and 2 citrate tubes. The citrate tubes were randomly assigned to 30 min with or without constant agitation on a rocker. The following parameters were reported according to the manufacturer's recommendations: clotting time, clot formation time, α, (tangent to the clot formation curve when the clot firmness is 20 mm), clot firmness after 10 and 20 min, maximal clot firmness, maximum lysis, and lysis indexes at 30 and 45 min. Reference intervals were reported as mean ± 2 SD (parametric distribution) or 2.5th and 97.5th percentile of the population's results (nonparametric distribution). The effects of sex, sampling order, and agitation on ROTEM results were analyzed through linear regression. Neither sex nor sample agitation influenced any of the ROTEM parameters. Combined reference intervals were established for each ROTEM parameter by pooling data from the nonagitated tubes for both male and female pigs. This study is the first to establish ROTEM reference intervals from a large number of male and female adult Yorkshire-cross pigs and to provide a detailed description of preanalytical sample processing.

2.
Mil Med ; 185(Suppl 1): 42-49, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-32074339

RESUMO

INTRODUCTION: External cooling of ischemic limbs has been shown to have a significant protective benefit for durations up to 4 hours. MATERIALS AND METHODS: It was hypothesized that this benefit could be extended to 8 hours. Six swine were anesthetized and instrumented, then underwent a 25% total blood volume hemorrhage. Animals were randomized to hypothermia or normothermia followed by 8 hours of Zone 3 resuscitative endovascular balloon occlusion of the aorta, then resuscitation with shed blood, warming, and 3 hours of critical care. Physiologic parameters were continuously recorded, and laboratory specimens were obtained at regular intervals. RESULTS: There were no significant differences between groups at baseline. There were no significant differences between creatine kinase in the hypothermia group when compared to the normothermia group (median [IQR] = 15,206 U/mL [12,476-19,987] vs 23,027 U/mL [18,745-26,843]); P = 0.13) at the end of the study. Similarly, serum myoglobin was also not significantly different in the hypothermia group after 8 hours (7,345 ng/mL [5,082-10,732] vs 5,126 ng/mL [4,720-5,298]; P = 0.28). No histologic differences were observed in hind limb skeletal muscle. CONCLUSION: While external cooling during prolonged Zone 3 resuscitative endovascular balloon occlusion of the aorta appears to decrease ischemic muscle injury, this benefit appears to be time dependent. As the ischemic time approaches 8 hours, the benefit from hypothermia decreases.

3.
Artigo em Inglês | MEDLINE | ID: mdl-32068720

RESUMO

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is recommended in adults with a non-compressible torso hemorrhage with occlusion times of less than 60 minutes. The tolerable duration in children is unknown. We used a pediatric swine controlled hemorrhage model to evaluate the physiologic effects of 30 and 60 minutes of REBOA. METHODS: Pediatric swine weighing 20-30kg underwent a splenectomy and a controlled 60% total blood volume hemorrhage over 30 minutes, followed by either Zone 1 REBOA for 30 minutes (30R) or 60 minutes (60R). Swine were then resuscitated with shed blood and received critical care for 240 minutes. RESULTS: During critical care, the 30R group's (n=3) pH, bicarbonate, base excess and lactate were no different than baseline, while at the end of critical care, these variables continued to differ from baseline in the 60R group (n=5) and were worsening (7.4 vs 7.2, p<0.001, 30.4 vs 18.4mmol/L, p<0.0001, 5.6 vs -8.5mmol/L, p<0.0001, 2.4 vs 5.7mmol/L, p<0.001, respectively). Compared to baseline, end creatinine and creatinine kinase were elevated in 60R swine (1.0 vs 1.7mg/dL, p<0.01 and 335.4 vs 961.0U/L, p<0.001, respectively), but not 30R swine (0.9 vs 1.2 mg/dL, p=0.06 and 423.7 vs 769.5U/L, p=0.15, respectively). There was no difference in survival time between the 30R and 60R pediatric swine, p=0.99. CONCLUSION: The physiologic effects of 30 minutes of Zone 1 REBOA in pediatric swine mostly resolved during the subsequent 4 hours of critical care, whereas the effects of 60 minutes of REBOA persisted and worsened after 4 hours of critical care. Sixty minutes of Zone 1 REBOA may create an irreversible physiologic insult in a pediatric population. LEVEL OF EVIDENCE: Not applicable, translational animal scienceOriginal article.

4.
J Trauma Acute Care Surg ; 88(2): 298-304, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31996655

RESUMO

BACKGROUND: Partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) and intermittent REBOA (iREBOA) are techniques to extend the therapeutic duration of REBOA by balloon titration for distal flow or cyclical balloon inflation/deflation to allow transient distal flow, respectively. We hypothesized that manually titrated pREBOA would reduce blood losses and ischemic burden when compared with iREBOA. METHODS: Following 20% blood volume controlled hemorrhage, 10 anesthetized pigs underwent uncontrolled hemorrhage from the right iliac artery and vein. Once in hemorrhagic shock, animals underwent 15 minutes of complete zone 1 REBOA followed by 75 minutes of either pREBOA or iREBOA (n = 5/group). After 90 minutes, definitive hemorrhage control was obtained, animals were resuscitated with the remaining collected blood, and then received 2 hours of critical care. RESULTS: There were no differences in mortality. Animals randomized to iREBOA spent a larger portion of the time at full occlusion when compared with pREBOA (median, 70 minutes; interquartile range [IQR], 70-80 vs. median, 20 minutes; IQR, 20-40, respectively; p = 0.008). While the average blood pressure during the intervention period was equivalent between groups, this was offset by large fluctuations in blood pressure and significantly more rescue occlusions for hypotension with iREBOA. Despite lower maximum aortic flow rates, the pREBOA group tolerated a greater total amount of distal aortic flow during the intervention period (median, 20.9 L; IQR, 20.1-23.0 vs. median, 9.8 L; IQR, 6.8-10.3; p = 0.03) with equivalent abdominal blood losses. Final plasma lactate and creatinine concentrations were equivalent, although iREBOA animals had increased duodenal edema on histology. CONCLUSION: Compared with iREBOA, pREBOA reduced the time spent at full occlusion and the number of precipitous drops in proximal mean arterial pressure while delivering more distal aortic flow but not increasing total blood loss in this highly lethal injury model. Neither technique demonstrated a survival benefit. Further refinement of these techniques is necessary before clinical guidelines are issued.


Assuntos
Oclusão com Balão/métodos , Procedimentos Endovasculares/métodos , Ressuscitação/métodos , Choque Hemorrágico/terapia , Ferimentos e Lesões/terapia , Animais , Aorta/cirurgia , Oclusão com Balão/efeitos adversos , Oclusão com Balão/instrumentação , Modelos Animais de Doenças , Procedimentos Endovasculares/efeitos adversos , Procedimentos Endovasculares/instrumentação , Humanos , Masculino , Ressuscitação/efeitos adversos , Ressuscitação/instrumentação , Choque Hemorrágico/etiologia , Choque Hemorrágico/mortalidade , Análise de Sobrevida , Sus scrofa , Fatores de Tempo , Índices de Gravidade do Trauma , Resultado do Tratamento , Ferimentos e Lesões/complicações , Ferimentos e Lesões/diagnóstico
5.
J Pediatr Surg ; 55(2): 346-352, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31787320

RESUMO

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) has not been studied in children. We hypothesized that REBOA was feasible and would improve hemorrhage control and survival time, compared to no aortic occlusion, in a pediatric swine liver injury model. METHODS: Pediatric swine were randomized to Zone 1 REBOA or no intervention (control). Piglets underwent a partial liver amputation and free hemorrhage followed by either REBOA or no intervention for 30 min, then a damage control laparotomy and critical care for 4 h. RESULTS: Compared to control piglets (n = 5), REBOA piglets (n = 6) had less blood loss (34.0 ±â€¯1.6 vs 61.3 ±â€¯2.5 mL/kg, p < 0.01), higher end hematocrit (28.1 ±â€¯2.1 vs 17.1 ±â€¯4.1%, p = 0.03), higher end creatinine (1.4 ±â€¯0.1 vs 1.2 ±â€¯0.1 mg/dL, p = 0.05), higher end ALT and AST (56 ±â€¯4 vs 32 ±â€¯6 U/L, p = 0.01 and 155 ±â€¯26 vs 69 ±â€¯25 U/L, p = 0.05) and required more norepinephrine during critical care (1.4 ±â€¯0.3 vs 0.3 ±â€¯0.3 mg/kg, p = 0.04). All REBOA piglets survived, whereas 2 control piglets died, p = 0.10. CONCLUSION: In pediatric swine, 30 min of REBOA is feasible, decreases blood loss after liver injury and may improve survival. LEVEL OF EVIDENCE: Level 1.

6.
Artigo em Inglês | MEDLINE | ID: mdl-31804420

RESUMO

BACKGROUND: Partial resuscitative endovascular balloon occlusion of the aorta (pREBOA) and intermittent-REBOA (iREBOA) are techniques to extend the therapeutic duration of REBOA by balloon titration for distal flow or cyclical balloon inflation/deflation to allow transient distal flow, respectively. We hypothesized that manually-titrated pREBOA would reduce blood losses and ischemic burden when compared to iREBOA. METHODS: Following 20% blood volume controlled hemorrhage, 10 anesthetized pigs underwent uncontrolled hemorrhage from the right iliac artery and vein. Once in hemorrhagic shock, animals underwent 15 minutes of complete Zone 1 REBOA followed by 75 minutes of either pREBOA or iREBOA (N=5/group). After 90 minutes, definitive hemorrhage control was obtained, animals were resuscitated with the remaining collected blood, and then received 2 hours of critical care. RESULTS: There were no differences in mortality. Animals randomized to iREBOA spent a larger portion of the time at full occlusion when compared to pREBOA (median [IQR]; 70 minutes [70, 80] versus 20 minutes [20, 40] respectively; p=0.008). While the average blood pressure during the intervention period was equivalent between groups, this was offset by large fluctuations in blood pressure and significantly more rescue occlusions for hypotension with iREBOA. Despite lower maximum aortic flow rates, the pREBOA group tolerated a greater total amount of distal aortic flow during the intervention period (median [IQR]; 20.9 L [20.1-23.0] vs 9.8 L [6.8-10.3]; p=0.03) with equivalent abdominal blood losses. Final plasma lactate and creatinine concentrations were equivalent, although iREBOA animals had increased duodenal edema on histology. CONCLUSION: Compared to iREBOA, pREBOA reduced the time spent at full occlusion and the number of precipitous drops in proximal MAP while delivering more distal aortic flow but not increasing total blood loss in this highly lethal injury model. Neither technique demonstrated a survival benefit. Further refinement of these techniques is necessary before clinical guidelines are issued. LEVEL OF EVIDENCE: III STUDY TYPE: Therapeutic.

7.
Shock ; 2019 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-31389905

RESUMO

INTRODUCTION: Tranexamic acid (TXA) improves survival in traumatic hemorrhage, but difficulty obtaining intravenous (IV) access may limit its use in austere environments, given its incompatibility with blood products. The bioavailability of intramuscular (IM) TXA in a shock state is unknown. We hypothesized that IM and IV administration have similar pharmacokinetics and ability to reverse in vitro hyperfibrinolysis in a swine controlled-hemorrhage model. METHODS: Twelve Yorkshire cross swine were anesthetized, instrumented, and subjected to a 35% controlled hemorrhage, followed by resuscitation. During hemorrhage, they were randomized to receive a 1 g IV TXA infusion over 10 minutes, 1 g IM TXA in two 5 mL injections, or 10 mL normal saline IM injection as a placebo group to assess model adequacy. Serum TXA concentrations were determined using liquid chromatography-mass spectrometry, and plasma samples supplemented with tissue plasminogen activator (tPA) were analyzed by rotational thromboelastometry (ROTEM). RESULTS: All animals achieved class III shock. There was no difference in the concentration-time areas under the curve (AUC) between TXA given by either route. The absolute bioavailability of IM TXA was 97%. IV TXA resulted in a higher peak serum concentration during the infusion, with no subsequent differences. Both IV and IM TXA administration caused complete reversal of in vitro tPA-induced hyperfibrinolysis. CONCLUSION: The pharmacokinetics of IM TXA were similar to IV TXA during hemorrhagic shock in our swine model. IV administration resulted in a higher serum concentration only during the infusion, but all levels were able to successfully correct in vitro hyperfibrinolysis. There was no difference in total body exposure to equal doses of TXA between the two routes of administration. IM TXA may prove beneficial in scenarios where difficulty establishing dedicated IV access could otherwise limit or delay its use.

8.
Injury ; 50(11): 1908-1914, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31466700

RESUMO

INTRODUCTION: Trauma patients are predisposed to kidney injury. We hypothesized that in shock, zone 3 REBOA would increase renal blood flow (RBF) compared to control and that a period of zone 3 occlusion following zone 1 occlusion would improve renal function compared to zone 1 occlusion alone. MATERIALS AND METHODS: Twenty-four anesthetized swine underwent hemorrhagic shock, 45 min of zone 1 REBOA (Z1, supraceliac), zone 3 REBOA (Z3, infrarenal), or no intervention (control) followed by resuscitation with shed blood and 5 h of critical care. In a fourth group (Z1Z3), animals underwent 55 min of zone 3 REBOA following zone 1 occlusion. Physiologic parameters were recorded, blood and urine were collected at specified intervals. RESULTS: During critical care, there were no differences in RBF between the Z1 and Z3 groups. The average RBF during critical care in Z1Z3 was significantly lower than in Z3 alone (98.2 ±â€¯23.9 and 191.9 ±â€¯23.7 mL/min; p = 0.046) and not different than Z1. There was no difference in urinary neutrophil gelatinase-associated lipocalin-to-urinary creatinine ratio between Z1 and Z1Z3. Animals in the Z1Z3 group had a significant increase in the ratio at the end of the experiment compared to baseline [median (IQR)] [9.2 (8.2-13.2) versus 264.5 (73.6-1174.6)]. Following Z1 balloon deflation, RBF required 45 min to return to baseline. CONCLUSION: Neither zone 3 REBOA alone nor zone 3 REBOA following zone 1 REBOA improved renal blood flow or function. Following zone 1 occlusion, RBF is restored to baseline levels after approximately 45 min.

9.
Front Vet Sci ; 6: 197, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31275952

RESUMO

While hemorrhagic shock might be the result of various conditions, hemorrhage control and resuscitation are the corner stone of patient management. Hemorrhage control can prove challenging in both the acute care and surgical settings, especially in the abdomen, where no direct pressure can be applied onto the source of bleeding. Resuscitative endovascular balloon occlusion of the aorta (REBOA) has emerged as a promising replacement to resuscitative thoracotomy (RT) for the management of non-compressible torso hemorrhage in human trauma patients. By inflating a balloon at specific levels (or zones) of the aorta to interrupt blood flow, hemorrhage below the level of the balloon can be controlled. While REBOA allows for hemorrhage control and augmentation of blood pressure cranial to the balloon, it also exposes caudal tissue beds to ischemia and the whole body to reperfusion injury. We aim to introduce the advantages of REBOA while reviewing known limitations. This review outlines a step-by-step approach to REBOA implementation, and discusses common challenges observed both in human patients and during translational large animal studies. Currently accepted and debated indications for REBOA in humans are discussed. Finally, we review possible applications for veterinary patients and how REBOA has the potential to be translated into clinical veterinary practice.

10.
J Trauma Acute Care Surg ; 86(4): 694-701, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30633103

RESUMO

BACKGROUND: Potassium-binding polymers have shown promising results in an anephric porcine hyperkalemia model. The benefits of the polymer in a clinically relevant injury model remain unknown. We hypothesized that potassium-binding cartridges would control serum potassium concentration in a porcine hemorrhagic shock model with supraceliac aortic occlusion and a limb crush injury. METHODS: Ten Yorkshire-cross swine were anesthetized and instrumented. Pigs underwent splenectomy and bilateral nephrectomy. Hemorrhagic shock was induced for 30 minutes while a leg compression device was applied. Pigs underwent supraceliac aortic occlusion for 60 minutes and were resuscitated with shed blood. The leg compression device was removed 20 minutes after balloon deflation. After 20 minutes of reperfusion, animals were randomized to extracorporeal circulation with (treatment) or without (control) the potassium binding cartridges. In both groups, blood was circulated through a hemodialyzer with a peristaltic pump. In the treatment group, the ultrafiltrate was diverted from the hemodialyzer through cartridges containing the polymer and returned to the extracorporeal circuit. Animals were resuscitated with 0.9% saline boluses and a norepinephrine infusion. The change in serum potassium concentration (ΔK) was calculated as serum [K]T390 - serum [K]T0. RESULTS: There was a significant difference in serum potassium concentration between groups (p < 0.001). ΔK was significantly higher in the control than the treatment group (3.75 [3.27-4.42] and 1.15 [0.62-1.59] mmol/L, respectively; p = 0.03). There were no differences in mean arterial pressure (p = 0.14), isotonic crystalloids requirement (p = 0.51), or norepinephrine dose (p = 0.83) between groups. Serum lactate concentration was significantly higher in the control group (p < 0.001). At the end of the experiment, the [K] was reduced by 25% (24.9%-27.8%) across the cartridges. CONCLUSION: The cartridges controlled serum potassium concentrations without dialysate and retained potassium binding capabilities over 4 hours. There were no deleterious effects on hemodynamic parameters. Those cartridges might be beneficial adjuncts for hyperkalemia management in austere environments. LEVEL OF EVIDENCE: Translational science study, level I.

11.
Mil Med ; 184(5-6): e298-e302, 2019 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-30371879

RESUMO

INTRODUCTION: Low distal aortic flow via partial aortic occlusion (AO) may mitigate ischemia induced by resuscitative endovascular balloon occlusion of the aorta (REBOA). We compared endocrine effects of a novel simulated partial AO strategy, endovascular variable aortic control (EVAC), with simulated REBOA in a swine model. MATERIALS AND METHODS: Aortic flow in 20 swine was routed from the supraceliac aorta through an automated extracorporeal circuit. Following liver injury-induced hemorrhagic shock, animals were randomized to control (unregulated distal flow), simulated REBOA (no flow, complete AO), or simulated EVAC (distal flow of 100-300 mL/min after 20 minutes of complete AO). After 90 minutes, damage control surgery, resuscitation, and full flow restoration ensued. Critical care was continued for 4.5 hours or until death. RESULTS: Serum angiotensin II concentration was higher in the simulated EVAC (4,769 ± 624 pg/mL) than the simulated REBOA group (2649 ± 429) (p = 0.01) at 180 minutes. There was no detectable difference in serum renin [simulated REBOA: 231.3 (227.9-261.4) pg/mL; simulated EVAC: 294.1 (231.2-390.7) pg/mL; p = 0.27], aldosterone [simulated EVAC: 629 (454-1098), simulated REBOA: 777 (575-1079) pg/mL, p = 0.53], or cortisol (simulated EVAC: 141 ± 12, simulated REBOA: 127 ± 9 ng/mL, p = 0.34) concentrations between groups. CONCLUSIONS: Simulated EVAC was associated with higher serum angiotensin II, which may have contributed to previously reported cardiovascular benefits. Future studies should evaluate the renal effects of EVAC and the concomitant therapeutic use of angiotensin II.


Assuntos
Aorta/cirurgia , Oclusão com Balão/efeitos adversos , Sistema Endócrino/enzimologia , Aldosterona/análise , Aldosterona/sangue , Angiotensina II/análise , Angiotensina II/sangue , Animais , Aorta/enzimologia , Oclusão com Balão/métodos , Modelos Animais de Doenças , Sistema Endócrino/irrigação sanguínea , Hidrocortisona/análise , Hidrocortisona/sangue , Renina/análise , Renina/sangue , Estatísticas não Paramétricas , Suínos
12.
Shock ; 51(5): 659-666, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-29877961

RESUMO

BACKGROUND: The resuscitation of patients in shock is materially intensive and many patients are refractory to maximal therapy. We hypothesized that partial inflation of an intra-aortic balloon, termed Endovascular Perfusion Augmentation for Critical Care (EPACC), would minimize material requirements while improving physiologic metrics. METHODS: Swine underwent a 25% controlled bleed and 45 min of complete aortic occlusion to create a severe ischemia-reperfusion shock state. Animals received either standardized critical care (SCC) composed of IV fluids and norepinephrine delivered through an algorithmically controlled platform or EPACC in addition to SCC. Physiologic parameters were collected, and blood was sampled for analysis. Primary outcomes were total IV fluids and average MAP during the critical care phase. Differences (P < 0.05) were measured with t test (continuous data) and Wilcoxon rank-sum test (ordinal data). RESULTS: There were no differences in baseline characteristics. There were no differences in the maximum lactate; however, animals in the EPACC group had a higher average MAP (EPACC 65 mmHg, 95% confidence interval [CI], 65-66; SCC 60 mmHg, 95% CI, 57-63; P < 0.01) and remained within goal MAP for a greater period of time (EPACC 95.3%, 95% CI, 93.2-97.4; SCC 51.0%, 95% CI, 29.5-72.6; P < 0.01). EPACC animals required less IV fluids when compared with the SCC group (EPACC 21 mL/kg, 95% CI, 0-42; SCC 96 mL/kg, 95% CI, 76-117; P < 0.01). There were no differences in final lactate. Animals in the EPACC group had a higher final creatinine (EPACC 2.3 mg/dL, 95% CI, 2.1-2.5; SCC 1.7 mg/dL, 95% CI, 1.4-2.0; P < 0.01), but there were no differences in renal cellular damage on histology (P = 0.16). CONCLUSION: Using a swine model of severe shock, the addition of EPACC to SCC significantly reduced fluid resuscitation requirements and improved blood pressure. This is the first description of a new therapy for patients in refractory shock or in resource-limited settings.

13.
J Spec Oper Med ; 19(4): 80-84, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31910476

RESUMO

BACKGROUND: Intravenous (IV) tranexamic acid (TXA) is an adjunct for resuscitation in hemorrhagic shock; however, IV access in these patients may be difficult or impossible. Intraosseous (IO) or intramuscular (IM) administration could be quickly performed with minimal training. We investigated the pharmacokinetics of TXA via IV, IO, and IM routes in a swine model of controlled hemorrhagic shock. METHODS: Fifteen swine were anesthetized and bled of 35% of their blood volume before randomization to a single 1g/10mL dose of IV, IO, or IM TXA. Serial serum samples were obtained after TXA administration. These were analyzed with high-pressure liquid chromatography-mass spectrometry to determine drug concentration at each time point and define the pharmacokinetics of each route. RESULTS: There were no significant differences in baseline hemodynamics or blood loss between the groups. Peak concentration (Cmax) was significantly higher in IV and IO routes compared with IM (p = .005); however, the half-life of TXA was similar across all routes (p = .275). CONCLUSION: TXA administration via IO and IM routes during hemorrhagic shock achieves serum concentrations necessary for inhibition of fibrinolysis and may be practical alternatives when IV access is not available.


Assuntos
Choque Hemorrágico/tratamento farmacológico , Ácido Tranexâmico/administração & dosagem , Ácido Tranexâmico/farmacocinética , Administração Intravenosa , Animais , Modelos Animais de Doenças , Humanos , Infusões Intraósseas , Injeções Intramusculares , Suínos
14.
Shock ; 50(6): 677-683, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30427323

RESUMO

INTRODUCTION: The standard of care for refractory hyperkalemia is renal replacement therapy (RRT). However, traditional RRT requires specialized equipment, trained personnel, and large amounts of dialysate. It is therefore poorly suited for austere environments. We hypothesized that a simplified hemoperfusion system could control serum potassium concentration in a swine model of acute hyperkalemia. METHODS: Ten pigs were anesthetized and instrumented. A dialysis catheter was inserted. After bilateral nephrectomy, animals received intravenous potassium chloride and were randomized to the control or treatment group. In both groups, blood was pumped through an extracorporeal circuit (EC) with an in-line hemodialyzer. In the treatment arm, ultrafiltrate from the hemodialyzer was diverted through cartridges containing novel potassium binding beads and returned to the EC. Blood samples were obtained every 30 min for 6 h. RESULTS: Serum potassium concentration was significantly lower in the treatment than in the control group over time (P = 0.02). There was no difference in serum total calcium concentration for group or time (P = 0.13 and 0.44, respectively) or platelet count between groups or over time (P = 0.28 and 1, respectively). No significant EC thrombosis occurred. Two of five animals in the control group and none in the treatment group developed arrhythmias. All animals survived until end of experiment. CONCLUSIONS: A simplified hemoperfusion system removed potassium in a porcine model. In austere settings, this system could be used to temporize patients with hyperkalemia until evacuation to a facility with traditional RRT.


Assuntos
Hiperpotassemia/sangue , Hiperpotassemia/terapia , Animais , Pressão Arterial/fisiologia , Glicemia/efeitos dos fármacos , Glucose/uso terapêutico , Hemodinâmica/efeitos dos fármacos , Hemoperfusão , Hiperpotassemia/fisiopatologia , Masculino , Fenilefrina/farmacologia , Potássio/sangue , Taxa Respiratória/fisiologia , Suínos
15.
J Trauma Acute Care Surg ; 85(3): 519-526, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-30142105

RESUMO

BACKGROUND: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is effective at limiting hemorrhage from noncompressible sources and restoring but causes progressive distal ischemia, supraphysiologic pressures, and increased cardiac afterload. Endovascular variable aortic control (EVAC) addresses these limitations, while still controlling hemorrhage. Previous work demonstrated improved outcomes following a 90-minute intervention period in an uncontrolled hemorrhage model. The present study compares automated EVAC to REBOA over an occlusion period reflective of contemporary REBOA usage. METHODS: Following instrumentation, 12 Yorkshire-cross swine underwent controlled 25% hemorrhage, a 45-minute intervention period of EVAC or REBOA, and subsequent resuscitation with whole blood and critical care for the remainder of a 6-hour experiment. Hemodynamics were acquired continuously, and laboratory parameters were assessed at routine intervals. Tissue was collected for histopathologic analysis. RESULTS: No differences were seen in baseline parameters. During intervention, EVAC resulted in more physiologic proximal pressure augmentation compared with REBOA (101 vs. 129 mm Hg; 95% confidence interval [CI], 105-151 mm Hg; p = 0.04). During critical care, EVAC animals required less than half the amount of crystalloid (3,450 mL; 95% CI, 1,215-5,684 mL] vs. 7,400 mL [95% CI, 6,148-8,642 mL]; p < 0.01) and vasopressors (21.5 ng/kg [95% CI, 7.5-35.5 ng/kg] vs. 50.5 ng/kg [95% CI, 40.5-60.5 ng/kg]; p = 0.05) when compared with REBOA animals. Endovascular variable aortic control resulted in lower peak and final lactate levels. Endovascular variable aortic control animals had less aortic hyperemia from reperfusion with aortic flow rates closer to baseline (36 mL/kg per minute [95% CI, 30-44 mL/kg per minute] vs. 51 mL/kg per minute [95% CI, 41-61 mL/kg per minute]; p = 0.01). CONCLUSIONS: For short durations of therapy, EVAC produces superior hemodynamics and less ischemic insult than REBOA in this porcine-controlled hemorrhage model, with improved outcomes during critical care. This study suggests EVAC is a viable strategy for in-hospital management of patients with hemorrhagic shock from noncompressible sources. Survival studies are needed to determine if these early differences persist over time.


Assuntos
Oclusão com Balão/métodos , Procedimentos Endovasculares/instrumentação , Traumatismo por Reperfusão/terapia , Animais , Aorta/patologia , Oclusão com Balão/efeitos adversos , Modelos Animais de Doenças , Feminino , Hemodinâmica/fisiologia , Hemorragia/prevenção & controle , Hemorragia/terapia , Ácido Láctico/metabolismo , Masculino , Reperfusão , Ressuscitação/métodos , Choque Hemorrágico/terapia , Suínos
16.
J Trauma Acute Care Surg ; 85(1): 101-107, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29965941

RESUMO

OBJECTIVES: Resuscitative endovascular balloon occlusion of the aorta (REBOA) is an emerging technology to augment proximal blood pressure during the resuscitation of patients with noncompressible torso hemorrhage. Currently, placement choice, supraceliac (Zone 1) versus infrarenal (Zone 3) aorta, depends on injury patterns, but remains a highly debated topic. We sought to compare the proximal hemodynamic support provided by Zone 1 versus Zone 3 REBOA placement and the degree of hemodynamic instability upon reperfusion following intervention. METHODS: Eighteen anesthetized swine underwent controlled hemorrhage of 25% total blood volume, followed by 45 minutes of Zone 1 REBOA, Zone 3 REBOA, or no intervention (control). They were then resuscitated with shed blood, aortic balloons were deflated, and 5 hours of critical care ensued prior to euthanasia. Physiologic parameters were recorded continuously, and blood was drawn for analysis at specified intervals. Significance was defined as p < 0.05. RESULTS: There were no significant differences between groups at baseline or during the initial 30 minutes of hemorrhage. During the intervention period, average proximal MAP was significantly greater in Zone 1 animals when compared with Zone 3 animals (127.9 ± 1.3 vs. 53.4 ± 1.1 mm Hg) and greater in Zone 3 animals when compared with control animals (42.9 ± 0.9 mm Hg). Lactate concentrations were significantly higher in Zone 1 animals (9.6 ± 0.4 mmol/L) when compared with Zone 3 animals (5.1 ± 0.3 mmol/L) and control animals (4.2 ± 0.8 mmol/L). CONCLUSIONS: In our swine model of hemorrhagic shock, Zone 3 REBOA provided minimal proximal hemodynamic support when compared with Zone 1 REBOA, albeit with less ischemic burden and instability upon reperfusion. In cases of impending hemodynamic collapse, Zone 1 REBOA placement may be more efficacious regardless of injury pattern, whereas Zone 3 should be reserved only for relatively stable patients with ongoing distal hemorrhage.


Assuntos
Aorta/cirurgia , Oclusão com Balão/métodos , Procedimentos Endovasculares/métodos , Ressuscitação/métodos , Choque Hemorrágico/cirurgia , Animais , Oclusão com Balão/veterinária , Cuidados Críticos/métodos , Modelos Animais de Doenças , Procedimentos Endovasculares/veterinária , Feminino , Hemodinâmica/fisiologia , Masculino , Traumatismo por Reperfusão/etiologia , Ressuscitação/veterinária , Choque Hemorrágico/fisiopatologia , Choque Hemorrágico/veterinária , Suínos
17.
J Trauma Acute Care Surg ; 85(3): 512-518, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29847535

RESUMO

BACKGROUND: New strategies to mitigate ischemia during REBOA and to prolong its maximal duration are needed. We hypothesized that simple external cooling of the hind limbs would decrease ischemia-reperfusion injury following prolonged Zone 3 REBOA. METHODS: Twelve swine were anesthetized, instrumented, splenectomized, and then underwent 15% total blood volume hemorrhage. Animals were randomized to hypothermia or control followed by 4 hours of Zone 3 REBOA, resuscitation with shed blood, and 3 hours of critical care. Physiologic parameters were continuously recorded, and laboratory specimens were obtained at regular intervals. Baseline and end-of-study muscle biopsies were obtained for histologic analysis. RESULTS: There were no significant differences between groups at baseline or after hemorrhage. Maximum creatine kinase was significantly lower in the hypothermia group compared with the normothermia group (median [interquartile range] = 3,445 U/mL [3,380-4,402 U/mL] vs. 22,544 U/mL [17,030-24,981 U/mL]; p < 0.01). Maximum serum myoglobin was also significantly lower in the hypothermia group (1,792 ng/mL [1,250-3,668 ng/mL] vs. 21,186 ng/mL [14,181-24,779 ng/mL]; p < 0.01). Fascial compartment pressures were significantly lower during critical care in the hypothermia group (p = 0.03). No histologic differences were observed in hind limb skeletal muscle. CONCLUSIONS: External cooling during prolonged Zone 3 REBOA decreased ischemic muscle injury and resulted in lower compartment pressures following reperfusion. Hypothermia may be a viable option to extend the tolerable duration of Zone 3 occlusion, beyond what is currently achievable. Future survival studies are required to assess functional outcomes.


Assuntos
Temperatura Baixa/efeitos adversos , Procedimentos Endovasculares/instrumentação , Extremidade Inferior/irrigação sanguínea , Traumatismo por Reperfusão/prevenção & controle , Animais , Oclusão com Balão/métodos , Creatina Quinase/metabolismo , Modelos Animais de Doenças , Feminino , Hemorragia/prevenção & controle , Membro Posterior/irrigação sanguínea , Membro Posterior/fisiopatologia , Hipotermia/complicações , Isquemia , Extremidade Inferior/fisiopatologia , Masculino , Músculos/irrigação sanguínea , Músculos/metabolismo , Músculos/patologia , Mioglobina/sangue , Reperfusão/efeitos adversos , Ressuscitação/instrumentação , Choque Hemorrágico , Suínos
18.
Vet Surg ; 47(4): 524-535, 2018 May.
Artigo em Inglês | MEDLINE | ID: mdl-29603757

RESUMO

OBJECTIVE: Large muscular or musculotendinous defects present a dilemma because of the inadequacies of current treatment strategies. Extracellular matrices (ECM) are potential clinically applicable regenerative biomaterials. This review summarizes information from the preclinical literature evaluating the use of ECM for muscle regeneration in animal models of volumetric muscle loss (VML). STUDY DESIGN: Literature review. SAMPLE POPULATION: Animal models of VML in which surgical repair was performed with an ECM product, with or without added cell populations. METHODS: PubMed, Google Scholar, CAB abstracts, and Scopus were searched for preclinical studies using ECM in animal models of VML. The search terms "extracellular matrix," "VML," "muscle regeneration," "cell seeded," and "scaffold" identified 40 articles that met inclusion criteria of an animal model of VML in which surgical repair was performed with an ECM product, with or without added cell populations. Key skeletal muscle repair mechanisms and experimental findings on scaffold type, VML location, and experimental animal species were summarized. CONCLUSIONS: Satellite cells and basal lamina are key endogenous contributors to skeletal muscle regeneration. ECM as a dynamic tissue component may provide structural integrity, signaling molecules, and a 3-dimensional topography conducive to muscle regeneration. Preclinical models of muscle repair most commonly used mice and rats (88%). Most experimental lesions were created in abdominal wall (33%), anterior tibialis (33%), latissimus dorsi (10%), or quadriceps (10%) muscles. Matrices varied markedly in source and preparation. Experimental outcomes of ECM and cell-seeded ECM implantation for muscle regeneration in VML were highly variable and dependent on matrix tissue source, preparation method, and anatomic site of injury. Scar tissue formation likely contributes to load transfer. Nonappendicular lesions had better regenerative results compared with appendicular VML. CLINICAL SIGNIFICANCE: The preponderance of current evidence supports the use of ECM for muscle defect repair only in specific instances, such as nonappendicular and/or partial-thickness defects. Consequently, clinical use of ECM in veterinary patients requires careful consideration of the specific ECM product, lesion size and location, and loading circumstances.


Assuntos
Matriz Extracelular , Músculo Esquelético/lesões , Tecidos Suporte , Cicatrização , Animais , Músculo Esquelético/fisiologia
19.
J Trauma Acute Care Surg ; 83(3): 457-463, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28846579

RESUMO

INTRODUCTION: The small diameter of temporary vascular shunts for vascular trauma management may restrict flow and result in ischemia or early thrombosis. We have previously reported a clinical experience with direct, open surgical reconstruction using expandable polytetrafluoroethylene stent grafts to create a "sutureless" anastomosis as an alternative to standard temporary vascular shunts. We sought to characterize patency and flow characteristics of these grafts compared with standard shunts in a survival model of porcine vascular injury. METHODS: Twelve Yorkshire-cross swine received a 2-cm-long near-circumferential defect in the bilateral iliac arteries. A 14 Fr Argyle shunt was inserted into one randomly assigned artery, with a self-expanding expandable polytetrafluoroethylene stent deployed in the other. At 72 hours, conduit patency was evaluated by angiography. Arterial flow measurements were obtained at baseline, immediately after intervention, and after 72 hours via direct measurement with perivascular flow meters. Blood pressure proximal and distal to the conduits and arterial samples for histopathology were obtained during the terminal procedure. RESULTS: Angiography revealed no difference in patency at 72 hours (p = 1.0). While there was no difference in baseline arterial flow between arteries (p = 0.63), the stent grafts demonstrated significantly improved blood flow compared with shunts both immediately after intervention (390 ± 36 mL/min vs. 265 ± 25 mL/min, p = 0.002) and at 72 hours (261 ± 29 mL/min vs. 170 ± 36 mL/min, p = 0.005). The pressure gradient across the shunts was greater than that of the stent grafts (11.5 mm Hg [interquartile range, 3-19 mm Hg] vs. 3 mm Hg [interquartile range, 3-5 mm Hg], p = 0.013). The speed of deployment was similar between the two devices. CONCLUSIONS: Open "sutureless" direct site repair using commercially available stent grafts to treat vascular injury is a technically feasible strategy for damage control management of peripheral vascular injury and offers increased blood flow when compared with temporary shunts. Furthermore, stent grafts may offer improved durability to extend the window until definitive vascular repair. The combination of these traits may improve outcomes after vascular injury. LEVEL OF EVIDENCE: Epidemiologic/Prognostic, level III.


Assuntos
Implante de Prótese Vascular/métodos , Procedimentos Endovasculares , Artéria Ilíaca/cirurgia , Politetrafluoretileno , Stents , Lesões do Sistema Vascular/cirurgia , Angiografia , Animais , Velocidade do Fluxo Sanguíneo , Prótese Vascular , Modelos Animais de Doenças , Artéria Ilíaca/diagnóstico por imagem , Artéria Ilíaca/lesões , Desenho de Prótese , Suínos , Grau de Desobstrução Vascular
20.
J Trauma Acute Care Surg ; 83(1): 61-70, 2017 07.
Artigo em Inglês | MEDLINE | ID: mdl-28632582

RESUMO

BACKGROUND: Despite clinical reports of poor outcomes, the degree to which resuscitative endovascular balloon occlusion of the aorta (REBOA) exacerbates traumatic brain injury (TBI) is not known. We hypothesized that combined effects of increased proximal mean arterial pressure (pMAP), carotid blood flow (Qcarotid), and intracranial pressure (ICP) from REBOA would lead to TBI progression compared with partial aortic occlusion (PAO) or no intervention. METHODS: Twenty-one swine underwent a standardized TBI via computer Controlled cortical impact followed by 25% total blood volume rapid hemorrhage. After 30 minutes of hypotension, animals were randomized to 60 minutes of continued hypotension (Control), REBOA, or PAO. REBOA and PAO animals were then weaned from occlusion. All animals were resuscitated with shed blood via a rapid blood infuser. Physiologic parameters were recorded continuously and brain computed tomography obtained at specified intervals. RESULTS: There were no differences in baseline physiology or during the initial 30 minutes of hypotension. During the 60-minute intervention period, REBOA resulted in higher maximal pMAP (REBOA, 105.3 ± 8.8; PAO, 92.7 ± 9.2; Control, 48.9 ± 7.7; p = 0.02) and higher Qcarotid (REBOA, 673.1 ± 57.9; PAO, 464.2 ± 53.0; Control, 170.3 ± 29.4; p < 0.01). Increases in ICP were greatest during blood resuscitation, with Control animals demonstrating the largest peak ICP (Control, 12.8 ± 1.2; REBOA, 5.1 ± 0.6; PAO, 9.4 ± 1.1; p < 0.01). There were no differences in the percentage of animals with hemorrhage progression on CT (Control, 14.3%; 95% confidence interval [CI], 3.6-57.9; REBOA, 28.6%; 95% CI, 3.7-71.0; and PAO, 28.6%; 95% CI, 3.7-71.0). CONCLUSION: In an animal model of TBI and shock, REBOA increased Qcarotid and pMAP, but did not exacerbate TBI progression. PAO resulted in physiology closer to baseline with smaller increases in ICP and pMAP. Rapid blood resuscitation, not REBOA, resulted in the largest increase in ICP after intervention, which occurred in Control animals. Continued studies of the cerebral hemodynamics of aortic occlusion and blood transfusion are required to determine optimal resuscitation strategies for multi-injured patients.


Assuntos
Oclusão com Balão/métodos , Transfusão de Sangue , Lesões Encefálicas Traumáticas/complicações , Hemorragia/complicações , Hemorragia/terapia , Ressuscitação/métodos , Animais , Aorta Torácica , Modelos Animais de Doenças , Progressão da Doença , Hemodinâmica , Distribuição Aleatória , Suínos , Tomografia Computadorizada por Raios X
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