The work of this manuscript was supported by funding to Dr. Neal by the Vascular Medicine Institute Pilot Project Program in Hemostasis and Vascular Biology (P3HVB) and the AAST Research Fellowship. This work is supported by U.S. National Institutes of Health grants 1 R35 GM119526-01 and UM1HL120877-01.

Mice were housed in accordance with University of Pittsburgh (Pittsburgh, PA, USA) and National Institutes of Health (NIH; Bethesda, MD, USA) animal care guidelines in specific pathogen-free conditions with 12 h light-dark cycles and free access to standard feed and water. All animal experiments were approved and conducted in accordance with the guidelines set forth by the Animal Research and Care Committee at the University of Pittsburgh.
1. Surgical Field and Instrument Setup
<ol>
	<li><st...

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C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Animal+Models+for+Trauma+Research.">Animal Models for Trauma Research.</a> Shock. 31 (1), 3-10 (2009).</li><li>Darwiche, S. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pseudofracture:+an+acute+peripheral+tissue+trauma+model.">Pseudofracture: an acute peripheral tissue trauma model.</a> J Vis Exp. (50), (2011).</li><li>Lomas-Niera, J. L., Perl, M., Chung, C. -. S., Ayala, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Shock+and+Hemorrhage:+an+Overview+of+Animal+Models.">Shock and Hemorrhage: an Overview of Animal Models.</a> Shock. 24, 33-39 (2005).</li><li>Kohut, L. K., Darwiche, S. S., Brumfield, J. M., Frank, A. M., Billiar, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fixed+volume+or+fixed+pressure:+a+murine+model+of+hemorrhagic+shock.">Fixed volume or fixed pressure: a murine model of hemorrhagic shock.</a> J Vis Exp. (52), (2011).</li><li>Matsuoka, T., Hildreth, J., Wisner, D. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liver+injury+as+a+model+of+uncontrolled+hemorrhagic+shock:+resuscitation+with+different+hypertonic+regimens.">Liver injury as a model of uncontrolled hemorrhagic shock: resuscitation with different hypertonic regimens.</a> J Trauma. 39 (4), 674-680 (1995).</li><li>Komachi, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adhesive+and+Robust+Multilayered+Poly(lactic+acid)+Nanosheets+for+Hemostatic+Dressing+in+Liver+Injury+Model.">Adhesive and Robust Multilayered Poly(lactic acid) Nanosheets for Hemostatic Dressing in Liver Injury Model.</a> J. Biomed. Mater. Res. Part B Appl. Biomater. , (2016).</li><li>Orfanos, N. 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A., Yu, B., Raghavendran, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+murine+model+of+blunt+hepatic+trauma.">Development of a murine model of blunt hepatic trauma.</a> Comp Med. 63 (5), 398-408 (2013).</li><li>Vogel, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Platelet-derived+HMGB1+is+a+critical+mediator+of+thrombosis.">Platelet-derived HMGB1 is a critical mediator of thrombosis.</a> J Clin Invest. 125 (12), (2015).</li><li>Modery-Pawlowski, C. L., Tian, L. L., Ravikumar, M., Wong, T. L., Sen Gupta, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+and+in+vivo+hemostatic+capabilities+of+a+functionally+integrated+platelet-mimetic+liposomal+nanoconstruct.">In vitro and in vivo hemostatic capabilities of a functionally integrated platelet-mimetic liposomal nanoconstruct.</a> Biomaterials. 34 (12), 3031-3041 (2013).</li></ol>

The murine liver laceration model described here provides a reliable, consistent model of uncontrolled hemorrhage. This model is straightforward to perform but there are important steps that require meticulous consideration. The most technically challenging part of the model is cannulation of the femoral vessels for hemodynamic monitoring and fluid/drug administration. Care must be taken during the dissection of the nerve and the arteriotomy/venotomy. It is important to not touch the nerve during the dissection of the ve...

Trauma is the leading cause of death and disability among young people worldwide.1 Uncontrolled hemorrhage remains a leading cause of mortality among severely injured trauma patients.2 Management of the hemorrhaging trauma patient is two-fold: control of surgical bleeding, and resuscitation and replacement of lost blood.
Animal models of hemorrhagic shock have been the cornerstone in trauma research and can be used in the evaluation of the pathophysiology and treatment of traumatic/hemorrhagic shock.3,4 Shock in animal models can be achieved broadly by two methods: controlled-hemorrhage and uncontrolled-hemorrhage.5,6 Controlled-hemorrhage is performed by removal of a fixed volume of blood or by blood removal to achieve a certain blood pressure (fixed-pressure). While these models are useful in the evaluation in the mechanisms and immune alterations in hemorrhagic shock, they are not applicable to the testing of hemostatic agents and do not mimic the clinical scenario of hemorrhage following trauma. To this degree, we sought to develop a model of uncontrolled hemorrhage that would allow us to test hemostatic changes and pro-coagulant agents in a murine model. The liver is an attractive option for uncontrolled hemorrhage in part because of the dual blood supply to the liver and it is one of the most commonly injured intrabdominal organs in both blunt and penetrating trauma. Given the high clinical relevance, the liver has been utilized as a model of uncontrolled hemorrhage, most commonly in rat and porcine models but recently in primates as well.7,8,9,10,11,12 Murine models have also incorporated liver injury, such as a crush model or blunt trauma; however, these models do not result in hemorrhagic shock secondary to the liver injury.13,14
The rat and porcine models of uncontrolled liver hemorrhage, while valuable in looking at resuscitation practices and hemodynamic monitoring, are less advantageous than a murine model for various reasons such as cost, number of animals utilized, and importantly the relative lack transgenic lines available for analysis of specific cellular and molecular signaling. The present murine model shares important similarities to existing liver hemorrhage models including standardized liver laceration, blood loss quantification, hemodynamic monitoring, and the ability to perform survival analysis. Many existing models only incorporate some of these aspects whereas our model was developed to measure many of the physiologic variables simultaneously and in multiple mice. As well, development of a murine model opens the door to investigations beyond resuscitation and into greater pathophysiology mechanisms in uncontrolled hemorrhage with the potential of a cost efficient, high-throughput model using advanced molecular techniques.

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			<td>SS/45 dumonts</td>
			<td>Fine Science Tools</td>
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			<td>surgical scissors</td>
			<td>Fine Science Tools</td>
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			<td>hemostats</td>
			<td>Fine Science Tools</td>
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			<td>microscissors</td>
			<td>Fine Science Tools</td>
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			<td>Fine Science Tools</td>
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			<td>suture reel 6-0</td>
			<td>Fine Science Tools</td>
			<td>18020-60</td>
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			<td>suture 4-0 silk w/ needle</td>
			<td>Owens Minor</td>
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			<td>gauze 4x4</td>
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			<td>cotton-tip applicator</td>
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			<td>30G needle</td>
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			<td>23G needle</td>
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			<td>10cc syringe</td>
			<td colspan="2">can be purchased through any global vendor</td>
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			<td>50cc conical tube</td>
			<td colspan="2">can be purchased through any global vendor</td>
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			<td>1cc syringe w/ 25G needle</td>
			<td>Fisher Scientific</td>
			<td>14-826-88</td>
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			<td>Polyethylene 10 tubing 100`(PE-10)</td>
			<td>Fisher Scientific</td>
			<td>14-170-12P</td>
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			<td>Polyethylene 50 tubing 100`(PE-50)</td>
			<td>Fisher Scientific</td>
			<td>14-170-12B</td>
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			<td>3-way stopcock</td>
			<td>Fisher Scientific</td>
			<td>NC9779127</td>
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			<td>surgical blue pad</td>
			<td>Fisher Scientific</td>
			<td>50-7105</td>
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			<td>Sterile Field dressings</td>
			<td>Fisher Scientific</td>
			<td>NC9517505</td>
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			<td>tape rolls 1&#34;</td>
			<td>Corporate Express</td>
			<td>MMM26001</td>
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			<td>straight side wide mouth jars</td>
			<td>VWR</td>
			<td>159000-058</td>
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			<td>stainless steel tray 8&#34; x 11&#34;</td>
			<td>VWR</td>
			<td>62687-049</td>
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		<tr>
			<td>male-male leur lock 3-way</td>
			<td>VWR</td>
			<td>20068-909</td>
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			<td>sterilization pouch 3&#34;x8&#34;</td>
			<td>VWR</td>
			<td>24008</td>
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			<td>sterilization pouch 5&#34;x10&#34;</td>
			<td>VWR</td>
			<td>24010</td>
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			<td>absorption triangles</td>
			<td>Fine Science Tools</td>
			<td>18105-03</td>
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			<td>7mm wound clip applier</td>
			<td>Fisher Scientific</td>
			<td>E0522687</td>
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			<td>1000 7mm wound clips</td>
			<td>Fisher Scientific</td>
			<td>E0522687</td>
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			<td>betadine (4oz)</td>
			<td colspan="2">can be purchased through any global vendor</td>
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			<td>sterile gloves</td>
			<td colspan="2">can be purchased through any global vendor</td>
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			<td>eppendorfs&#160;</td>
			<td colspan="2">can be purchased through any global vendor</td>
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			<td>1/2cc Lo-Dose insulin syringe</td>
			<td>Fisher Scientific</td>
			<td>12-826-79</td>
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			<td>small weigh boat</td>
			<td colspan="2">can be purchased through any global vendor</td>
		</tr>
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			<td>lactated ringers</td>
			<td colspan="2">can be purchased through any global vendor</td>
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			<td>hepranized saline solution (.1&#181; hep + 9.9&#181;NaCl)</td>
			<td colspan="2">can be purchased through any global vendor</td>
		</tr>
		<tr>
			<td>phosphate buffered saline&#160;</td>
			<td colspan="2">can be purchased through any global vendor</td>
		</tr>
		<tr>
			<td>pentobarbital&#160;</td>
			<td colspan="2">can be purchased through any global vendor</td>
		</tr>
		<tr>
			<td>Wild M650 microscope w/ boom stand</td>
			<td>Leica</td>
			<td></td>
		</tr>
		<tr>
			<td>Digi-Med BPA-400 analyzer &#38; systems integrator</td>
			<td>Micro-Med</td>
			<td>SYS-400</td>
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			<td>TXD-310 (Digi-Med Transducer)&#160;</td>
			<td>Micro-Med</td>
			<td>TXD-300</td>
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			<td>Computer</td>
			<td>Dell</td>
			<td></td>
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			<td>microbead instrument sterilizer</td>
			<td>VWR</td>
			<td>11156-002</td>
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		<tr>
			<td>Oster A5 clippers w. size 40 blade</td>
			<td>VWR</td>
			<td>10749-020</td>
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			<td>circulating heating pad 18x26</td>
			<td>Harvard</td>
			<td>py872-5272</td>
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			<td>rectal thermometer</td>
			<td>Kent Scientific</td>
			<td>RET-3</td>
		</tr>
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uncontrolled hemorrhagic shock modeled via liver laceration in mice with real time hemodynamic monitoring

Uncontrolled hemorrhage is an important cause of preventable deaths among trauma patients. We have developed a murine model of uncontrolled hemorrhage via a liver laceration that results in consistent blood loss, hemodynamic alterations, and survival.
Mice undergo a standardized resection of the left-middle lobe of the liver. They are allowed to bleed without mechanical intervention. Hemostatic agents can be administered as pre-treatment or rescue therapy depending on the interest of the investigator. During the time of hemorrhage, real-time hemodynamic monitoring via a left femoral arterial line is performed. Mice are then sacrificed, blood loss is quantified, blood is collected for further analysis, and organs are harvested for analysis of injury. Experimental design is described to allow for simultaneous testing of multiple animals.
Liver hemorrhage as a model of uncontrolled hemorrhage exists in the literature, primarily in rat and porcine models. Some of these models utilize hemodynamic monitoring or quantify blood loss but lack consistency. The present model incorporates quantification of blood loss, real-time hemodynamic monitoring in a murine model that offers the advantage of using transgenic lines and a high-throughput mechanism to further investigate the pathophysiologic mechanisms in uncontrolled hemorrhage.

The liver laceration model results in reproducible and consistent blood loss in mice. Figure 1A demonstrates the consistent weight of lacerated liver that can be obtained with a standard deviation of only 0.02 g. This consistency in lacerated liver weight allows the ability to reproduce the model between mice and in different experimental set-ups such as different resuscitative protocols. As well, the reproducible weight of the lacerated liver, with a standard error of on...

Watch this Scientific Journal Video about Uncontrolled Hemorrhagic Shock Modeled via Liver Laceration in Mice with Real Time Hemodynamic Monitoring at JoVE.com

Uncontrolled Hemorrhagic Shock Modeled via Liver Laceration in Mice with Real Time Hemodynamic Monitoring

Uncontrolled hemorrhage, an important cause of mortality among trauma patients, can be modeled using a standard liver laceration in a murine model. This model results in consistent blood loss, survival, and allows for testing hemostatic agents. This article provides the step-by-step process to perform this valuable model.

Uncontrolled hemorrhage is an important cause of preventable deaths among trauma patients. We have developed a murine model of uncontrolled hemorrhage via ...

The overall goal of this murine liver laceration model is to induce uncontrolled hemorrhage for the study of resuscitation practices and the pathophysiologic mechanisms of uncontrolled hemorrhage. This method can help answer key questions in the hemorrhagic shock field about resuscitation practices, new hemostatic drugs, and the molecular mechanisms that follow uncontrolled hemorrhage. The main advantage of this technique are that it is reproducible, high throughput, and takes advantage of available transgenic mouse strains.Demonstrating the procedure will be Shannon Haldeman, a technician from the Neal Laboratory. Before beginning the procedure, place a sterile drape on top of a blue surgical pad over a 37 degree Celsius water-circulating heat pad. Secure the anesthetized mouse onto a surgical board with tape, and use a razor to shave the abdomen and bilateral groins.Using sterile gauze, disinfect the exposed skin with Betadine and insert a rectal temperature probe. Place the mouse under a dissecting microscope and make a four to five millimeter longitudinal incision over the groin muscle. Using Dumont forceps, grab the adipose tissue connected to the adductor muscle and pull the muscle laterally to cleanly expose the femoral bundle.Use the forceps to carefully dissect away from the artery and vein until the fat pad adjacent to the nerve is observed. Pull the pad laterally with the forceps to move the nerve away from the artery and use a second pair of Dumont forceps to bluntly dissect the connective tissue between the nerve and the artery. Next, loop one loose 6-0 silk suture around both vessels proximal to the profunda femoris takeoff, placing a second suture distal to the first.After immediately tying the second suture, place a third loose suture between the first two sutures and use microvascular scissors to make an arteriotomy on the ventral surface of the vessel. Insert a three-way catheter into the artery and tie the proximal and middle suture to secure the catheter. Connect the three-way catheter to a sterile transducer and collect the baseline blood pressure data.To lacerate the liver, first make a ventral midline laparotomy incision starting at the xiphoid process and extending caudally to allow complete exposure of the liver. Then insert one pre weighed absorption triangle against each of the right and left sides of the abdominal wall, taking care that the triangles are not against the liver to avoid liver hemostasis. Next, carefully grab the left middle lobe of the liver and use surgical Iris scissors to lacerate 75%of the tissue.Place the lacerated segment into a pre weighed tube containing 0.5 milliliters of PBS, and immediately use a staple applicator to close the skin and muscle together. Then, after the appropriate time of interest for hemorrhage, remove the staples and the absorption triangles. Use the third triangle to collect excess blood in the peritoneal cavity.Then weigh all three of the absorption filters to calculate the total blood loss. The liver laceration model results in reproducible and consistent blood loss in mice with a standard deviation of only 0.02 grams between animals, allowing the reproducible results to be obtained between mice and between different experimental setups. Pretreatment with heparin as a positive control for blood loss, an antifibrinolytic as a negative control, or a validated prohemostatic nanoparticle previously tested in murine tail vein bleeding assays demonstrates the ability of this model to be used to assess the hemostatic or anticoagulant effects on a hemorrhage setting.Uncontrolled hemorrhage is often accompanied by hemodynamic derangements that are important to monitor. For example, the mean arterial blood pressure of individual mice following liver laceration demonstrates precipitous and reproducible drops in pressure after laceration, resulting in a hemorrhagic shock state and allowing the hemodynamic effects of different resuscitative or interventional measures to be assessed. Although there are significant hemodynamic effects following liver laceration, the model can be used to evaluate survival effects out to 72 hours with a 56%survival rate at three days post laceration.Once mastered, this technique can be completed in 30 minutes if it is properly performed. This procedure readily combines with other models including soft tissue injury or polytrauma, and is easily adapted for testing topical hemostatic agents. While attempting this procedure, it's important to remember to avoid nerve damage during the vascular dissections and to avoid packing hemostasis when placing the filter triangles, and to quickly close the abdomen following the liver laceration.This technique provides a highly reproducible, high throughput uncontrolled hemorrhage model for the investigation of resuscitation practices similar to large animal models of uncontrolled hemorrhage, while allowing greater mechanistic investigations of the underlying pathophysiology following hemorrhagic shock. After watching this video, you should have a good understanding on how to cannulate the femoral vessels for hemodynamic monitoring and drug administration, and to reproducibly perform a liver laceration for the induction of hemorrhagic shock.

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Research

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Medicine

8.4K ビュー.  University of Pittsburgh. The overall goal of this murine liver laceration model is to induce uncontrolled hemorrhage for the study of resuscitation practices and the pathophysiologic mechanisms of uncontrolled hemorrhage. This method can help answer key questions in the hemorrhagic shock field about resuscitation practices, new hemostatic drugs, and the molecular mechanisms that follow uncontrolled hemorrhage. The main advantage of this technique are that it is reproducible, high throughput, and takes advantage of av...

ビデオ: Uncontrolled Hemorrhagic Shock Modeled via Liver Laceration in Mice with Real Time Hemodynamic Monitoring

Controlled Cervical Laceration Injury in Mice

Use of genetically modified mice enhances our understanding of molecular mechanisms underlying several neurological disorders such as a spinal cord injury (SCI). Freehand manual control used to produce a laceration model of SCI creates inconsistent injuries often associated with a crush or contusion component and, therefore, a novel technique was developed. Our model of cervical laceration SCI has resolved inherent difficulties with the freehand method by incorporating 1) cervical vertebral stabilization by vertebral facet fixation, 2) enhanced spinal cord exposure, and 3) creation of a reproducible laceration of the spinal cord using an oscillating blade with an accuracy of &plusmn;0.01 mm in depth without associated contusion. Compared to the standard methods of creating a SCI laceration such as freehand use of a scalpel or scissors, our method has produced a consistent lesion. This method is useful for studies on axonal regeneration of corticospinal, rubrospinal, and dorsal ascending tracts.

A novel technique to create a reproducible in vivo model of cervical spinal cord laceration injury in the mouse is described. This technique is based on spine stabilization by fixation of the cervical facets and laceration of the spinal cord using an oscillating blade with an accuracy of &plusmn;0.01 mm.

Use of genetically modified mice enhances our  understanding of molecular mechanisms underlying several neurological disorders  such as a spinal cord ...

Monitoring of Systemic and Hepatic Hemodynamic Parameters in Mice

The use of mouse models in experimental research is of enormous importance for the study of hepatic physiology and pathophysiological disturbances. However, due to the small size of the mouse, technical details of the intraoperative monitoring procedure suitable for the mouse were rarely described. Previously we have reported a monitoring procedure to obtain hemodynamic parameters for rats. Now, we adapted the procedure to acquire systemic and hepatic hemodynamic parameters in mice, a species ten-fold smaller than rats. This film demonstrates the instrumentation of the animals as well as the data acquisition process needed to assess systemic and hepatic hemodynamics in mice. Vital parameters, including body temperature, respiratory&#160;rate&#160;and heart&#160;rate were recorded throughout the whole procedure. Systemic hemodynamic parameters consist of carotid artery pressure (CAP) and central venous pressure (CVP). Hepatic perfusion parameters include portal vein pressure (PVP), portal flow rate as well as the flow rate of the common hepatic artery (table 1). Instrumentation and data acquisition to record the normal values was completed within 1.5 h. Systemic and hepatic hemodynamic parameters remained within normal ranges during this procedure.
This procedure is challenging but feasible. We have already applied this procedure to assess hepatic hemodynamics in normal mice as well as during 70% partial hepatectomy and in liver lobe clamping experiments. Mean PVP after resection (n= 20), was 11.41&#177;2.94 cmH2O which was significantly higher (P&#60;0.05) than before resection (6.87&#177;2.39 cmH2O). The results of liver lobe clamping experiment indicated that this monitoring procedure is sensitive and suitable for detecting small changes in portal pressure and portal flow rate. In conclusion, this procedure is reliable in the hands of an experienced micro-surgeon but should be limited to experiments where mice are absolutely needed.

This film demonstrates how to acquire systemic and hepatic hemodynamics in mice. The whole monitoring includes acquisition of vital parameters, systemic blood pressure, central venous pressure, common hepatic artery flow rate, and portal vein pressure as well as the portal flow rate in mice.

The use of mouse models in experimental research is of enormous importance for the study of hepatic physiology and pathophysiological disturbances. ...

Real-time Pressure-volume Analysis of Acute Myocardial Infarction in Mice

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any potential therapeutic approach directed against acute left ventricular (LV) dysfunction. Current imaging modalities (e.g., echocardiography and magnetic resonance imaging) have several limitations since data on LV pressure cannot directly be measured. LV catheterization in mice undergoing coronary artery occlusion could serve as a novel method for a real-time evaluation of LV function.
At the beginning of the procedure, mice were anesthetized followed by endotracheal intubation. For LV catheterization, the right carotid artery was exposed via middle-neck incision. The catheter was introduced and placed into the LV cavity. Left thoracotomy was conducted and the left main coronary artery (LCA) was ligated. To induce reperfusion, the suture was released after 45 min. Pressure-volume data was recorded at all times.
Ligation of the LCA caused a decrease in LV systolic function as evidenced by a 30% reduction in stroke volume, LV ejection fraction (EF), and cardiac output. Maximum dP/dt as a parameter for LV contractility was also significantly reduced and diastolic function was severely impaired (minimum dP/dt -40%). Reperfusion over a period of 20 min did not lead to a complete recovery of LV function.
Real-time pressure-volume analysis served as a valid procedure for monitoring cardiac function during acute myocardial infarction in mice. Maintaining stable anesthesia and a standardized surgical approach was crucial to ensure valid results. As the early phase of acute myocardial infarction is critical for morbidity and mortality, the delineated method could be beneficial for preclinical evaluation of new strategies for cardioprotection.

Acute myocardial infarction in mice induces acute but incompletely characterized changes in left ventricular (LV) function. LV catheterization in mice undergoing coronary artery occlusion serves as a novel method for a real-time evaluation of LV function.

Acute myocardial infarction can lead to acute heart failure and cardiogenic shock. The evaluation of hemodynamics is critical for the evaluation of any ...

Complete and Partial Aortic Occlusion for the Treatment of Hemorrhagic Shock in Swine

Hemorrhage remains the leading cause of preventable deaths in trauma. Endovascular management of non-compressible torso hemorrhage has been at the forefront of trauma care in recent years. Since complete aortic occlusion presents serious concerns, the concept of partial aortic occlusion has gained a growing attention. Here, we present a large animal model of hemorrhagic shock to investigate the effects of a novel partial aortic balloon occlusion catheter and compare it with a catheter that works on the principles of complete aortic occlusion. Swine are anesthetized and instrumented in order to conduct controlled fixed-volume hemorrhage, and hemodynamic and physiological parameters are monitored. Following hemorrhage, aortic balloon occlusion catheters are inserted and inflated in the supraceliac aorta for 60 min, during which the animals receive whole-blood resuscitation as 20% of the total blood volume (TBV). Following balloon deflation, the animals are monitored in a critical care setting for 4 h, during which they receive fluid resuscitation and vasopressors as needed. The partial aortic balloon occlusion demonstrated improved distal mean arterial pressures (MAPs) during the balloon inflation, decreased markers of ischemia, and decreased fluid resuscitation and vasopressor use. As swine physiology and homeostatic responses following hemorrhage have been well-documented and are like those in humans, a swine hemorrhagic shock model can be used to test various treatment strategies. In addition to treating hemorrhage, aortic balloon occlusion catheters have become popular for their role in cardiac arrest, cardiac and vascular surgery, and other high-risk elective surgical procedures.

Here, we present a protocol demonstrating a hemorrhagic shock model in swine that uses aortic occlusion as a bridge to definitive care in trauma. This model has application in testing a wide range of surgical and pharmacological therapeutic strategies.

Hemorrhage remains the leading cause of preventable deaths in trauma. Endovascular management of non-compressible torso hemorrhage has been at the ...

Standardized Hemorrhagic Shock Induction Guided by Cerebral Oximetry and Extended Hemodynamic Monitoring in Pigs

Hemorrhagic shock ranks among the main reasons for severe injury-related death. The loss of circulatory volume and oxygen carriers can lead to an insufficient oxygen supply and irreversible organ failure. The brain exerts only limited compensation capacities and is particularly at high risk of severe hypoxic damage.This article demonstrates the reproducible induction of life-threatening hemorrhagic shock in a porcine model by means of calculated blood withdrawal. We titrate shock induction guided by near-infrared spectroscopy&#160;and extended hemodynamic monitoring to display systemic circulatory failure, as well as cerebral microcirculatory oxygen depletion. In comparison to similar models that primarily focus on predefined removal volumes for shock induction, this approach highlights a titration by means of the resulting failure of macro- and microcirculation.

Hemorrhagic shock is a severe complication in seriously injured patients, which leads to life-threatening oxygen undersupply. We present a standardized method to induce hemorrhagic shock via blood withdrawal in pigs that is guided by hemodynamics and microcirculatory cerebral oxygenation.

Hemorrhagic shock ranks among the main reasons for severe injury-related death. The loss of circulatory volume and oxygen carriers can lead to an ...

Real-Time Monitoring of Neurocritical Patients with Diffuse Optical Spectroscopies

Neurophysiological monitoring is an important goal in the treatment of neurocritical patients, as it may prevent secondary damage and directly impact morbidity and mortality rates. However, there is currently a lack of suitable non-invasive, real-time technologies for continuous monitoring of cerebral physiology at the bedside. Diffuse optical techniques have been proposed as a potential tool for bedside measurements of cerebral blood flow and cerebral oxygenation in case of neurocritical patients. Diffuse optical spectroscopies have been previously explored to monitor patients in several clinical scenarios ranging from neonatal monitoring to cerebrovascular interventions in adults. However, the feasibility of the technique to aid clinicians by providing real-time information at the bedside remains largely unaddressed. Here, we report the translation of a diffuse optical system for continuous real-time monitoring of cerebral blood flow, cerebral oxygenation, and cerebral oxygen metabolism during intensive care. The real-time feature of the instrument could enable treatment strategies based on patient-specific cerebral physiology rather than relying on surrogate metrics, such as arterial blood pressure. By providing real-time information on the cerebral circulation at different time scales with relatively cheap and portable instrumentation, this approach may be especially useful in low-budget hospitals, in remote areas and for&#160;monitoring in open fields (e.g., defense and sports).

Presented here is a protocol for non-invasively monitoring cerebral hemodynamics of neurocritical patients in real-time and at the bedside using diffuse optics. Specifically, the proposed protocol uses a hybrid diffuse optical systems to detect and display real-time information on cerebral oxygenation, cerebral blood flow and cerebral metabolism.

Neurophysiological monitoring is an important goal in the treatment of neurocritical patients, as it may prevent secondary damage and directly impact ...

Complete and Partial Resuscitative Endovascular Balloon Occlusion of the Aorta for Hemorrhagic Shock

Resuscitative endovascular balloon occlusion of the aorta (REBOA) devices grew out of a military-civilian partnership to develop new capabilities for hemorrhage control. With the advent of purpose-built devices, REBOA has become increasingly common in civilian trauma and acute care settings. Currently available REBOA catheters were designed as complete aortic occlusion devices. However, the therapeutic window for complete aortic occlusion is time-limited due to ischemia-reperfusion injury. The partial procedure allows blood flow past the level of occlusion while maintaining targeted proximal pressure, which has been shown to reduce distal ischemia and adjunctive resuscitation requirements in preclinical studies with prolonged occlusion times as compared to traditional complete occlusion.
pREBOA-PRO is the first catheter designed to enable partial and complete aortic occlusion and is currently in limited market release at seven Level I trauma centers in North America. This paper will focus on procedural considerations for REBOA, including patient selection criteria and a comparison of complete and partial aortic occlusion in a simulator, along with highlighting critical steps to improve clinical outcomes. Additionally, this paper reviews a contrast-enhanced CT scan from a trauma patient that shows distal perfusion after 2 h of partial aortic occlusion using this newly designed catheter and discusses representative results from the limited market release to highlight the profound effect of technological innovation on outcomes in vascular emergencies.

A commercial catheter was designed to facilitate true partial resuscitative endovascular balloon occlusion of the aorta (REBOA) and address the complications associated with complete aortic occlusion. Initial clinical reports indicate that partial REBOA improves transition to reperfusion, reduction of distal ischemia, and extension of safe occlusion time compared to complete occlusion.

Resuscitative endovascular balloon occlusion of the aorta (REBOA) devices grew out of a military-civilian partnership to develop new capabilities for ...

Real-Time Electrocardiogram Monitoring During Treadmill Training in Mice

Regular physical exercise is a major contributor to cardiovascular health, influencing various metabolic as well as electrophysiological processes. However, in certain cardiac diseases such as inherited arrhythmia syndromes, e.g., arrhythmogenic cardiomyopathy (ACM) or myocarditis, physical exercise may have negative effects on the heart leading to a proarrhythmogenic substrate production. Currently, the underlying molecular mechanisms of exercise-related proarrhythmogenic remodeling are largely unknown, thus it remains unclear which frequency, duration, and intensity of exercise can be considered safe in the context of disease(s).
The proposed method allows to study proarrhythmic/antiarrhythmic effects of physical exercise by combining treadmill training with real-time monitoring of the ECG. Implantable telemetry devices are used to continuously record the ECG of freely moving mice over a period of up to 3 months both at rest and during treadmill training. Data acquisition software with its analysis modules is used to analyze basic ECG parameters such as heart rate, P wave duration, PR interval, QRS interval, or QT duration at rest, during and after training. Furthermore, heart rate variability (HRV) parameters and occurrence of arrhythmias are evaluated. In brief, this manuscript describes a step-by-step approach to experimentally explore exercise induced effects on cardiac electrophysiology, including potential proarrhythmogenic remodeling in mouse models.

Electrocardiogram (ECG) is the key variable to understanding cardiac electrophysiology. Physical exercise has beneficial effects but may also be harmful in the context of cardiovascular diseases. This manuscript provides a method of recording real-time ECG during exercise, which can serve to investigate its effects on cardiac electrophysiology in mice.

Regular physical exercise is a major contributor to cardiovascular health, influencing various metabolic as well as electrophysiological processes. ...

Description of a Swine Infant Model of Volume-Controlled Hemorrhagic Shock

Hemorrhagic shock is a leading cause of morbidity and mortality in pediatric patients. Interpretation of the clinical indicators validated in adults to guide resuscitation and comparison between different therapies is difficult in children due to the inherent heterogeneity of this population. As a result, compared to adults, appropriate management of pediatric hemorrhagic shock is still not well established. In addition, the scarcity of pediatric patients with hemorrhagic shock precludes the development of clinically relevant studies. For this reason, an experimental pediatric animal model is necessary to study the effects of hemorrhage in children as well as their response to different therapies. We present an infant animal model of volume-controlled hemorrhagic shock in anesthetized young pigs. Hemorrhage is induced by withdrawing a previously calculated blood volume, and the pig is subsequently monitored and resuscitated with different therapies. Here, we describe a precise and highly reproducible model of hemorrhagic shock in immature swine. The model yields hemodynamic data that characterizes compensatory mechanisms that are activated in response to severe hemorrhage.

This article aims to provide researchers with a detailed and accessible guide to set up an infant porcine model of hemorrhagic shock.

Hemorrhagic shock is a leading cause of morbidity and mortality in pediatric patients. Interpretation of the clinical indicators validated in adults to ...

Dosage-Dependent Induction of Endotoxemia in Pigs via LPS Infusion

Lipopolysaccharide Infusion as a Porcine Endotoxemic Shock Model

Sepsis and septic shock are frequently encountered in patients treated in intensive care units (ICUs) and are among the leading causes of death in these patients. It is caused by a dysregulated immune response to an infection. Even with optimized treatment, mortality rates remain high, which makes further insights into the pathophysiology and new treatment options necessary. Lipopolysaccharide (LPS) is a component of the cell membrane of gram-negative bacteria, which are often responsible for infections causing sepsis and septic shock. 
The severity and high mortality of sepsis and septic shock make standardized experimental studies in humans impossible. Thus, an animal model is needed for further studies. The pig is especially well suited for this purpose as it closely resembles humans in anatomy, physiology, and size. 
This protocol provides an experimental model for endotoxemic shock in pigs by LPS infusion. We were able to reliably induce changes frequently observed in septic shock patients, including hemodynamic instability, respiratory failure, and acidosis. This will allow researchers to gain valuable insight into this highly relevant condition and evaluate new therapeutic approaches in an experimental setting.

Author Spotlight: Induction of Experimental Endotoxemic Shock in Pigs for Studying Hemodynamic and Respiratory Failure

We provide a protocol for an experimental endotoxemic shock model in pigs by infusion of lipopolysaccharide.

Sepsis and septic shock are frequently encountered in patients treated in intensive care units (ICUs) and are among the leading causes of death in these ...