The authors would like to thank Custom Design &#38; Fabrication Inc. for their technical assistance and support. This work was funded by the National Institutes of Health grants R01NS120099-01A1 and R37HD059288-19.

1. Cleaning the LFPI cylinder
<ol>
	<li>Carefully detach the syringes attached to the transducer housing and fill port, as well as the cable connected to the pressure transducer (see Figure 1 for a schematic of injury device components).</li>
	<li>While being careful not to drop the cylinder, unscrew the hand knobs at the back of the device from the cylinder clamps to free the cylinder.</li>
	<li>Remove the piston at the end of the cylinder, transducer, transducer housing, and plunger O-rings.</li>
	<li>Drain fluid out of the cylinder.</li>
	<li>Add mild detergent, such as dish washing detergent, to the cylinder and scrub lightly using a dish or bottle brush13.</li>
	<li>To ensure that all the detergent is rinsed off, completely fill the cylinder with water and rinse thoroughly.</li>
</ol>
2. Degassing the fluid used to fill the cylinder
<ol>
	<li>Use a vacuum pump to degas the fluid before refilling the cylinder to prevent the formation of new bubbles and absorb existing bubbles. 
	NOTE: Approximately 1.5 L of fluid will be needed to fill the cylinder, although degassing approximately 2 L will leave a small supply for replacing any fluid lost during use and testing. 
	NOTE: House vacuums are too weak to effectively degas the fluid. The vacuum must be able to produce a pressure of 25-28 inHg.</li>
	<li>Add a stir bar to the fluid and place the fluid container on a stir plate. Stirring the fluid during the degassing process helps to stimulate bubbling and the release of gas. Stirring also prevents a large sudden increase in bubbling. 
	&#8203;NOTE: The degassing process should be over when very few bubbles are being produced; this occurs after roughly 45 min.</li>
</ol>
3. Reassembly of the LFPI device
<ol>
	<li>Apply a thin layer of petroleum jelly to the piston plunger.</li>
	<li>Attach the piston plunger with the plunger protruding approximately 32 mm from the cylinder14. 
	NOTE: Air frequently gets trapped at the plunger before the leading O-ring. To get rid of this excess air, twist the plunger while moving it in and out to work the air out of this gap.</li>
	<li>Apply a thin layer of petroleum jelly to the other O-rings as well and attach them to the cylinder, with exception to the O-ring on the fill port.</li>
	<li>Wrap Teflon tape twice around the transducer&#39;s threads.</li>
</ol>
4. Refilling the LFPI device and attachment to the base
<ol>
	<li>Connect a 10 mL syringe filled with degassed fluid and free of air bubbles to the Luer lock hub on the transducer housing.</li>
	<li>Hold the transducer with the threaded end pointing upward, and completely fill the well inside the threaded region of the transducer with the degassed fluid using a 10 mL syringe. The goal here is to fill the transducer well without introducing any air bubbles. Be careful not to damage the delicate membrane at the bottom of the transducer well.</li>
	<li>With the cylinder placed at an angle to prevent air from reentering the transducer housing, attach the transducer housing to the cylinder13 and use a wrench to tighten it snugly.</li>
	<li>Remove the cap from the fill port and cylinder once the degassed fluid reaches approximately 2/3 of the cylinder capacity.</li>
	<li>Place the cylinder horizontally and finish filling the cylinder with degassed fluid. 
	NOTE: To avoid the formation of air bubbles, pouring the fluid in slowly is recommended14.</li>
	<li>Replace the cap at the fill port and close all stopcocks.</li>
	<li>Manipulate the cylinder to work any air bubbles to the fill port14.</li>
	<li>Open the stopcock on the fill port and inject fluid using the syringe on the transducer housing to force any air bubbles out of the port14.</li>
	<li>Inspect the entire device and ensure that there are no air bubbles.</li>
	<li>Add a 10 mL syringe filled with degassed fluid to the Luer lock hub on the fill cap.</li>
	<li>Reattach the cylinder to the base using the hand screws.</li>
	<li>Ensure that the cylinder is horizontal and lined up with the center of the weighted hammer on the pendulum.</li>
</ol>

<ol>
	<li>Centers for Disease Control and Prevention. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Surveillance+Report+of+Traumatic+Brain+Injury-related+Emergency+Department+Visits,+Hospitalizations,+and+Deaths.">Surveillance Report of Traumatic Brain Injury-related Emergency Department Visits, Hospitalizations, and Deaths.</a> Centers for Disease Control and Prevention, U.S. Department of Health and Human Services. , (2014).</li><li>Dewan, M. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Estimating+the+global+incidence+of+traumatic+brain+injury.">Estimating the global incidence of traumatic brain injury.</a> Journal of Neurosurgery. 130 (4), 1080-1097 (2018).</li><li>National Center for Injury Prevention and Control; Division of Unintentional Injury Prevention. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Traumatic Brain Injury in the United States: Epidemiology and Rehabilitation. , (2015).</li><li>Holm, L., Cassidy, J. D., Carroll, L. J., Borg, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Summary+of+the+WHO+Collaborating+Centre+for+neurotrauma+task+force+on+mild+traumatic+brain+injury.">Summary of the WHO Collaborating Centre for neurotrauma task force on mild traumatic brain injury.</a> Journal of Rehabilitation Medicine. 37 (3), 137-141 (2005).</li><li>Pavlovic, D., Pekic, S., Stojanovic, M., Popovic, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traumatic+brain+injury:+neuropathological,+neurocognitive+and+neurobehavioral+sequelae.">Traumatic brain injury: neuropathological, neurocognitive and neurobehavioral sequelae.</a> Pituitary. 22 (3), 270-282 (2019).</li><li>Dixon, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+fluid+percussion+model+of+experimental+brain+injury+in+the+rat.">A fluid percussion model of experimental brain injury in the rat.</a> Journal of Neurosurgery. 67 (1), 110-119 (1987).</li><li>McIntosh, T. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Traumatic+brain+injury+in+the+rat:+characterization+of+a+lateral+fluid-percussion+model.">Traumatic brain injury in the rat: characterization of a lateral fluid-percussion model.</a> Neuroscience. 28 (1), 233-244 (1989).</li><li>Ma, X., Aravind, A., Pfister, B. J., Chandra, N., Haorah, J. <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+of+traumatic+brain+injury+and+assessment+of+injury+severity.">Animal models of traumatic brain injury and assessment of injury severity.</a> Molecular Neurobiology. 56 (8), 5332-5345 (2019).</li><li>Nwafor, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Pediatric+traumatic+brain+injury:+an+update+on+preclinical+models,+clinical+biomarkers,+and+the+implications+of+cerebrovascular+dysfunction.">Pediatric traumatic brain injury: an update on preclinical models, clinical biomarkers, and the implications of cerebrovascular dysfunction.</a> Journal of Central Nervous System Disease. 14, (2022).</li><li>Turner, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+chronic+traumatic+encephalopathy:+the+way+forward+for+future+discovery.">Modeling chronic traumatic encephalopathy: the way forward for future discovery.</a> Frontiers in Neurology. 6, 223 (2015).</li><li>Petersen, A., Soderstrom, M., Saha, B., Sharma, P. <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+of+traumatic+brain+injury:+a+review+of+pathophysiology+to+biomarkers+and+treatments.">Animal models of traumatic brain injury: a review of pathophysiology to biomarkers and treatments.</a> Experimental Brain Research. 239 (10), 2939-2950 (2021).</li><li>Sullivan, H. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluid-percussion+model+of+mechanical+brain+injury+in+the+cat.">Fluid-percussion model of mechanical brain injury in the cat.</a> Journal of Neurosurgery. 45 (5), 521-534 (1976).</li><li>Pernici, C. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Longitudinal+optical+imaging+technique+to+visualize+progressive+axonal+damage+after+brain+injury+in+mice+reveals+responses+to+different+minocycline+treatments.">Longitudinal optical imaging technique to visualize progressive axonal damage after brain injury in mice reveals responses to different minocycline treatments.</a> Scientific Reports. 10, 7815-78 (2020).</li></ol>

No conflicts of interest declared.

The techniques outlined above demonstrate how to properly maintain an LFPI device. Routine cleaning and monitoring are necessary to keep the LFPI device functioning correctly and reliably. Additionally, due to the invasive nature of the LFPI procedure, it is imperative that the device be cleaned thoroughly to prevent infection of laboratory animals. 
Avoiding the formation of air bubbles in the device is crucial for obtaining optimal injuries and pressure waveforms. Air bubbles alter the chara...

Traumatic brain injury (TBI) is caused by a sudden force applied to the head. Following primary injuries resulting from the physical impact, TBI survivors commonly experience secondary injuries, including cognitive deficits and neurological dysfunctions that are associated with physiological responses to the initial injury1. It is estimated that roughly 69 million individuals worldwide suffer from TBI annually2. In the United States alone, approximately 2.5 million TBI-related emergency room visits and hospitalizations occur each year, making TBI one of the leading causes of disability and death among children and young adults3. TBI can be classified as mild, moderate, or severe, with mild TBI (mTBI) accounting for approximately 70%-90% of TBI cases4. Histological and cognitive TBI pathology can occur within minutes to hours of injury, and the effects of TBI can persist for months to years after initial damage5.
The development of experimental models has been instrumental in understanding the effects and underlying mechanisms of TBI. One such model, the lateral fluid percussion injury (LFPI), is commonly used to assess TBI in vivo. LFPI closely reproduces pathologies associated with human TBI, including vascular disruptions, hemorrhages, neuronal loss, inflammation, gliosis, and molecular disturbances6,7,8. The LFPI technique is used for a diverse set of experimental applications, including modeling pediatric TBI, as well as chronic neurodegenerative conditions, such as chronic traumatic encephalopathy9,10. LFPI is a well-defined and reproducible method of experimental TBI that allows for the severity of the injury to be adjusted11. The LFPI device has several important components, including: a pendulum with a weighted hammer, a piston, a fluid-filled cylinder, a pressure transducer, a digital oscilloscope, and a small tube at the end of the cylinder with a Luer lock which attaches to a hub on the animal&#39;s skull (Figure 1). LFPI works by swinging the pendulum into the piston, creating a wave of pressure through the fluid (degassed deionized water or saline) into the brain of the attached animal; this increases intracranial pressure, thus replicating the mechanical features and biological changes of TBI12. Additionally, animals used in LFPI experiments undergo a craniectomy in order to expose the brain to the impact of the fluid pressure of the device.
Routine maintenance and monitoring are necessary to ensure that the LFPI device is accurately functioning. The following methods are vital in preventing the introduction of contaminating air bubbles into the device. Here, we demonstrate methods to properly clean, fill, and assemble the LFPI device. We will also discuss oscilloscope outputs and mouse righting times as ways to confirm the viability of the LFPI.

<table><tbody><tr><td>2 - 10 mL syringes with Luer lock capability</td><td></td><td></td><td>Ensures that needle is secure and reduces possible leaks of fluid&amp;nbsp;</td></tr><tr><td>Degassed fluid</td><td></td><td></td><td>Helps to reduce air bubble formation during injury procedure</td></tr><tr><td>Fluid Percussion Injury (FPI) device (Model 01-B)</td><td>Custom Designs &amp;amp; Fabrications Inc.</td><td>N/A</td><td>Injury device used to model TBI in rodents</td></tr><tr><td>Mild detergent</td><td></td><td></td><td>Allows to thoroughly clean the LFPI cylinder&amp;nbsp;</td></tr><tr><td>Petroleum Jelly</td><td></td><td></td><td>Used as a water-repellent and protects LFPI device form rust</td></tr><tr><td>Teflon tape</td><td></td><td></td><td>Helps with tight seal of pipe joints on the LFPI device</td></tr><tr><td>*Materials other than the LFPI device can be purchased from any reliable company.</td><td></td><td></td><td></td></tr></tbody></table>

maintenance of a lateral fluid percussion injury device

Traumatic brain injury (TBI) accounts for roughly 2.5 million emergency room visits and hospitalizations annually and is a leading cause of death and disability in children and young adults. TBI is caused by a sudden force applied to the head and, to better understand human TBI and its underlying mechanisms, experimental injury models are necessary. Lateral fluid percussion injury (LFPI) is a commonly used injury model due to similarities in the pathological changes found in human TBI compared to LFPI, including hemorrhages, vascular disruption, neurological deficits, and neuron loss. LFPI employs a pendulum and a fluid-filled cylinder, the latter having a moveable piston at one end, and a Luer lock connection to stiff, fluid-filled tubing at the other end. Preparation of the animal involves performing a craniectomy and attaching a Luer hub over the site. The next day, the tubing from the injury device is connected to the Luer hub on the animal's skull and the pendulum is raised to a specified height and released. The impact of the pendulum with the piston generates a pressure pulse which is transmitted to the intact dura mater of the animal via the tubing and produces the experimental TBI. Proper care and maintenance are essential for the LFPI device to function reliably, as the character and severity of the injury can vary greatly depending on the condition of the device. Here, we demonstrate how to properly clean, fill, and assemble the LFPI device, and ensure that it is adequately maintained for optimal results.

We tested the effects of air bubble contamination in an LFPI device on waveform formation. We injected air bubbles into the device and compared the oscilloscope outputs with oscilloscope data collected from a non-contaminated LFPI device. Conditions were as follows: non-contaminated, injection of 5 mL of air, injection of 10 mL of air, and injection of 15 mL of air. We kept the pendulum at a consistent height for all impacts for all conditions, and we performed 15 impacts per condition.
When p...

Watch this Scientific Journal Video about Maintenance of a Lateral Fluid Percussion Injury Device at JoVE.com

Maintenance of a Lateral Fluid Percussion Injury Device

Proper care and maintenance are essential for a lateral fluid percussion injury (LFPI) device to function reliably. Here, we demonstrate how to properly clean, fill, and assemble an LFPI device, and ensure that it is adequately maintained for optimal results.

Traumatic brain injury (TBI) accounts for roughly 2.5 million emergency room visits and hospitalizations annually and is a leading cause of death and ...

maintenance-of-a-lateral-fluid-percussion-injury-device

Research

JoVE Journal

Neuroscience

836 Views.  Children’s Hospital of Philadelphia. Ons protocol laat zien hoe u het LFPI-apparaat op de juiste manier kunt onderhouden. Het benadrukt het belang van routinematige reiniging en monitoring om storingen van het apparaat bij inconsistente verwondingen te voorkomen. LFPI is dus een letselmodel dat wordt gebruikt om TBI in vivo te beoordelen.Het reproduceert nauw pathologieën die geassocieerd zijn met menselijke TBI, waardoor het een van de best gedefinieerde methoden van experimentele TBI is. Aangezien de LFPI wordt gebruik...

Video: Maintenance of a Lateral Fluid Percussion Injury Device

Lateral Fluid Percussion: Model of Traumatic Brain Injury in Mice

Traumatic brain injury (TBI) research has attained renewed momentum due to the increasing awareness of head injuries, which result in morbidity and mortality. Based on the nature of primary injury following TBI, complex and heterogeneous secondary consequences result, which are followed by regenerative processes 1,2. Primary injury can be induced by a direct contusion to the brain from skull fracture or from shearing and stretching of tissue causing displacement of brain due to movement 3,4. The resulting hematomas and lacerations cause a vascular response 3,5, and the morphological and functional damage of the white matter leads to diffuse axonal injury 6-8. Additional secondary changes commonly seen in the brain are edema and increased intracranial pressure 9. Following TBI there are microscopic alterations in biochemical and physiological pathways involving the release of excitotoxic neurotransmitters, immune mediators and oxygen radicals 10-12, which ultimately result in long-term neurological disabilities 13,14. Thus choosing appropriate animal models of TBI that present similar cellular and molecular events in human and rodent TBI is critical for studying the mechanisms underlying injury and repair.
Various experimental models of TBI have been developed to reproduce aspects of TBI observed in humans, among them three specific models are widely adapted for rodents: fluid percussion, cortical impact and weight drop/impact acceleration 1. The fluid percussion device produces an injury through a craniectomy by applying a brief fluid pressure pulse on to the intact dura. The pulse is created by a pendulum striking the piston of a reservoir of fluid. The percussion produces brief displacement and deformation of neural tissue 1,15. Conversely, cortical impact injury delivers mechanical energy to the intact dura via a rigid impactor under pneumatic pressure 16,17. The weight drop/impact model is characterized by the fall of a rod with a specific mass on the closed skull 18. Among the TBI models, LFP is the most established and commonly used model to evaluate mixed focal and diffuse brain injury 19. It is reproducible and is standardized to allow for the manipulation of injury parameters. LFP recapitulates injuries observed in humans, thus rendering it clinically relevant, and allows for exploration of novel therapeutics for clinical translation 20.
We describe the detailed protocol to perform LFP procedure in mice. The injury inflicted is mild to moderate, with brain regions such as cortex, hippocampus and corpus callosum being most vulnerable. Hippocampal and motor learning tasks are explored following LFP.

Lateral fluid percussion (LFP), an established model of traumatic brain injury in mice, is demonstrated. LFP fulfills three major criteria for animal models: validity, reliability and clinical relevance. The procedure, consisting of surgical craniotomy, fixation of hub followed by induction of injury, resulting in focal and diffuse injuries, is described.

Traumatic brain injury (TBI) research has attained renewed momentum due to the increasing awareness of head injuries, which result in morbidity and ...

Use of a Wireless Video-EEG System to Monitor Epileptiform Discharges Following Lateral Fluid-Percussion Induced Traumatic Brain Injury

The lateral fluid percussion injury (FPI) model is well established and has been used to study TBI and post-traumatic epilepsy (PTE). However, considerable variability has been reported for the specific parameters used in different studies that have employed this model, making it difficult to harmonize and interpret the results between laboratories. For example, variability has been reported regarding the size and location of the craniectomy, how the Luer lock hub is placed relative to the craniectomy, the atmospheric pressure applied to the dura and the duration of the pressure pulse. Each of these parameters can impact injury severity, which directly correlates with the incidence of PTE. This has been manifested as a wide range of mortality rates, righting reflex times and incidence of convulsive seizures reported. Here we provide a detailed protocol for the method we have used to help facilitate harmonization between studies. We used FPI in combination with a wireless EEG telemetry system to continuously monitor for electrographic changes and detect seizure activity.&#160; FPI is induced by creating a 5 mm craniectomy over the left hemisphere, between the Bregma and Lambda and adjacent to the lateral ridge. A Luer lock hub is secured onto the skull over the craniectomy. This hub is connected to the FPI device, and a 20-millisecond pressure pulse is delivered directly to the intact dura through pressure tubing connected to the hub via a twist lock connector. Following recovery, rats are re-anesthetized to remove the hub. Five 0.5 mm, stainless steel EEG electrode screws are placed in contact with the dura through the skull and serve as four recording electrodes and one reference electrode. The electrode wires are collected into a pedestal connector which is secured into place with bone cement. Continuous video/EEG recordings are collected for up to 4 weeks post TBI.

Here we present a protocol to induce severe TBI with the lateral fluid percussion injury (FPI) model in adult, male Wistar rats. We also demonstrate the use of a wireless telemetry system to collect continuous video-EEG recordings and monitor for epileptiform discharges consistent with post-traumatic epileptogenesis.&#160;

The lateral fluid percussion injury (FPI) model is well established and has been used to study TBI and post-traumatic epilepsy (PTE). However, ...

Behavior

Anterior Segment Organ Culture Platform for Tracking Open Globe Injuries and Therapeutic Performance

Open globe injuries have poor visual outcomes, often resulting in permanent loss of vision. This is partly due to an extended delay between injury and medical intervention in rural environments and military medicine applications where ophthalmic care is not readily available. Untreated injuries are susceptible to infection after the eye has lost its watertight seal, as well as loss of tissue viability due to intraocular hypotension. Therapeutics to temporarily seal open globe injuries, if properly developed, may be able to restore intraocular pressure and prevent infection until proper ophthalmic care is possible. To facilitate product development, detailed here is the use of an anterior segment organ culture open globe injury platform for tracking therapeutic performance for at least 72 h post-injury. Porcine anterior segment tissue can be maintained in custom-designed organ culture dishes and held at physiological intraocular pressure. Puncture injuries can be created with a pneumatic-powered system capable of generating injury sizes up to 4.5 mm in diameter, similar to military-relevant injury sizes. Loss of intraocular pressure can be observed for 72 h post-injury confirming proper injury induction and loss of the eye&#39;s watertight seal. Therapeutic performance can be tracked by application to the eye after injury induction and then tracking intraocular pressure for multiple days. Further, the anterior segment injury model is applicable to widely used methods for functionally and biologically tracking anterior segment physiology, such as assessing transparency, ocular mechanics, corneal epithelium health, and tissue viability. Overall, the method described here is a necessary next step toward developing biomaterial therapeutics for temporarily sealing open globe injuries when ophthalmic care is not readily available.

Open globe eye injuries may go untreated for multiple days in rural or military-relevant scenarios, resulting in blindness. Therapeutics are needed to minimize loss of vision. Here, we detail an organ culture open globe injury model. With this model, potential therapeutics for stabilizing these injuries can be properly evaluated.

Open globe injuries have poor visual outcomes, often resulting in permanent loss of vision. This is partly due to an extended delay between injury and ...

Bioengineering

A Saline/Bipolar Radiofrequency Energy Device As an Adjunct for Hemostasis in Solid Organ Injury/Trauma

Solid organ (liver, spleen, and kidney) hemorrhage is often life-threatening and can be difficult to stop in critically ill patients. Traditional techniques for arresting this ongoing bleeding include coagulation by high voltage electrocautery, topical hemostatic application, and the delivery of ignited argon gas. The goal of this study/video was to demonstrate the efficacy of a new energy device for arresting persistent solid organ hemorrhage.A novel instrument utilizing bipolar radiofrequency (RF) energy which acts to ignite/boil dripping saline from a simple handpiece is employed to arrest ongoing bleeding from solid organ injuries in a porcine model. This instrument is extrapolated from experience within elective hepatic resections. An escalating series of injuries to solid organs within a porcine model will be created. This will be followed by arresting hemorrhage with this novel energy device in sequence. A standard suction device will also be employed. This simple saline/RF energy instrument has the potential to arrest ongoing solid organ surface/capsular bleeding, as well as moderate hemorrhage associated with deep lacerations.

The goal of this publication is to demonstrate the potential application of a novel device using simulated solid organ injuries in a porcine model.

Solid organ (liver, spleen, and kidney) hemorrhage is often life-threatening and can be difficult to stop in critically ill patients. Traditional ...

Medicine

A Bedside, Single Burr Hole Approach to Multimodality Monitoring in Severe Brain Injury

Intracranial pressure (ICP) monitoring is a cornerstone of the intensive care management of patients with severe acute brain injuries, including traumatic brain injury. While elevations in ICP are common, data regarding the measurement and treatment of these ICP elevations are conflicting. There is increasing recognition that changes in the balance between supply and demand of brain tissue are critically important and therefore the measurement of multiple modalities is required. Approaches are not standard, and therefore this article provides a description of a bedside, single burr hole approach to multimodality monitoring that allows the passage of probes designed to measure not only ICP but brain tissue oxygen, blood flow, and intracranial electroencephalography. Patient selection criteria, operative procedures, and practical considerations for securing probes during critical care are described. This method is readily performed, safe, secure, and flexible for the adoption of a variety of multimodality monitoring approaches aimed at detecting or preventing secondary brain injuries.

A method of recording multimodality monitoring signals in patients with severe brain injuries using a bedside, single burr hole technique is described.

Intracranial pressure (ICP) monitoring is a cornerstone of the intensive care management of patients with severe acute brain injuries, including traumatic ...

Utilizing Percutaneous Ventricular Assist Devices in Acute Myocardial Infarction Complicated by Cardiogenic Shock

Cardiogenic shock is defined as persistent hypotension, accompanied by evidence of end organ hypo-perfusion. Percutaneous ventricular assist devices (PVADs) are used for the treatment of cardiogenic shock in an effort to improve hemodynamics. Impella is currently the most common PVAD and actively pumps blood from the left ventricle into the aorta. PVADs unload the left ventricle, increase cardiac output and improve coronary perfusion. PVADs are typically placed in the cardiac catheterization laboratory under fluoroscopic guidance via the femoral artery when feasible. In cases of severe peripheral arterial disease, PVADs can be implanted through an alternative access. In this article, we summarize the mechanism of action of PVAD and the data supporting their use in the treatment of cardiogenic shock.

Percutaneous ventricular assist devices are increasingly being utilized in patients with acute myocardial infarction and cardiogenic shock. Herein, we discuss the mechanism of action and hemodynamic effects of such devices. We also review algorithms and best practices for the implantation, management and weaning of these complex devices.

Cardiogenic shock is defined as persistent hypotension, accompanied by evidence of end organ hypo-perfusion. Percutaneous ventricular assist devices ...

Assessing Changes in Synaptic Plasticity Using an Awake Closed-Head Injury Model of Mild Traumatic Brain Injury

Mild traumatic brain injuries (mTBIs) are a prevalent health issue in North America. There is increasing pressure to utilize ecologically valid models of closed-head mTBI in the preclinical setting to increase translatability to the clinical population. The awake closed-headed injury (ACHI) model uses a modified controlled cortical impactor to deliver closed-headed injury, inducing clinically relevant behavioral deficits without the need for a craniotomy or the use of an anesthetic.
This technique does not normally induce fatalities, skull fractures, or brain bleeds, and is more consistent with being a mild injury. Indeed, the mild nature of the ACHI procedure makes it ideal for studies investigating repetitive mTBI (r-mTBI). Growing evidence indicates that r-mTBI can result in a cumulative injury that produces behavioral symptoms, neuropathological changes, and neurodegeneration. r-mTBI is common in youths playing sports, and these injuries occur during a period of robust synaptic reorganization and myelination, making the younger population particularly vulnerable to the long-term influences of r-mTBI.
Further, r-mTBI occurs in cases of intimate partner violence, a condition for which there are few objective screening measures. In these experiments, synaptic function was assessed in the hippocampus in juvenile rats that had experienced r-mTBI using the ACHI model. Following the injuries, a tissue slicer was utilized to make hippocampal slices to evaluate bidirectional synaptic plasticity in the hippocampus at either 1 or 7 days following the r-mTBI. Overall, the ACHI model provides researchers with an ecologically valid model to study changes in synaptic plasticity following mTBI and r-mTBI.

Here, it is demonstrated how an awake closed-head injury model can be used for examining the effects of repeated mild traumatic brain injury (r-mTBI) on synaptic plasticity in the hippocampus. The model replicates important features of r-mTBI in patients and is used in conjunction with in vitro electrophysiology.

Mild traumatic brain injuries (mTBIs) are a prevalent health issue in North America. There is increasing pressure to utilize ecologically valid models of ...

Insertion, Maintenance, and Removal of the Percutaneous Dual Lumen Cannula Right Ventricular Assist Device

Right ventricular (RV) shock, classically characterized by elevated central venous pressure (CVP) with&#160;normal to low pulmonary artery (PA) and pulmonary capillary wedge pressures (PCWP),&#160;remains a significant cause of morbidity and mortality worldwide if left untreated.&#160;Therapies for the treatment of RV shock range&#160;from medical management to durable or percutaneous mechanical circulatory support (MCS). A unique MCS device, a percutaneous right ventricular assist device (pRVAD), approved for use by the Food and Drug Administration (FDA) in 2014, works by temporarily off-loading the RV through a single, dual lumen catheter with extracorporeal mechanical support and is capable of shunting blood from the right atrium (RA) to the main PA. Although initially approved as venous-venous extracorporeal membrane oxygenation (VV-ECMO) device, this work will focus on the use of RV support, as ambulatory VV-ECMO strategies have been described previously. The catheter is most commonly inserted through the right internal jugular (IJ) vein into the PA and connected to an external pump, allowing flow up to 5 L/min. This device may be an attractive choice for the treatment of RV shock due to its percutaneous, minimally invasive insertion and removal and its ability to allow patient ambulation while the device is in place. This protocol discusses in detail the equipment, hemodynamic effects, indications, contraindications, complications, currently available research in the literature, and step-by-step instructions on how to implant, manage, and extract the device, along with the guidance on use and troubleshooting complications from one of the largest, single-center experiences with the device.

The present protocol provides a detailed description of a percutaneous dual lumen right ventricular assist device and illustrates step-by-step instructions on the safe implanting, managing, and removing the device. Guidance on its use and troubleshooting complications from one of the most significant single-center experiences is also included.

Right ventricular (RV) shock, classically characterized by elevated central venous pressure (CVP) with&#160;normal to low pulmonary artery (PA) and ...

rmTBI Induction in Mice via a Closed-Head Injury Method

Modified Mouse Model of Repetitive Mild Traumatic Brain Injury Incorporating Thinned-Skull Window and Fluid Percussion

Mild traumatic brain injury is a clinically highly heterogeneous neurological disorder. Highly reproducible traumatic brain injury (TBI) animal models with well-defined pathologies are urgently needed for studying the mechanisms of neuropathology after mild TBI and testing therapeutics. Replicating the entire sequelae of TBI in animal models has proven to be a challenge. Therefore, the availability of multiple animal models of TBI is necessary to account for the diverse aspects and severities seen in TBI patients. CHI is one of the most common methods for fabricating rodent models of rmTBI. However, this method is susceptible to many factors, including the impact method used, the thickness and shape of the skull bone, animal apnea, and the type of head support and immobilization utilized. The aim of this protocol is to demonstrate a combination of the thinned-skull window and fluid percussion injury (FPI) methods to produce a precise mouse model of CHI-associated rmTBI. The primary objective of this protocol is to minimize factors that could impact the accuracy and consistency of CHI and FPI modeling, including skull bone thickness, shape, and head support. By utilizing a thinned-skull window method, potential inflammation due to craniotomy and FPI is minimized, resulting in an improved mouse model that replicates the clinical features observed in patients with mild TBI. Results from behavior and histological analysis using hematoxylin and eosin (HE) staining suggest that rmTBI can lead to a cumulative injury that produces changes in both behavior and gross morphology of the brain. Overall, the modified CHI-associated rmTBI presents a useful tool for researchers to explore the underlying mechanisms that contribute to focal and diffuse pathophysiological changes in rmTBI.

Author Spotlight: Optimizing Rodent Models for Investigating the Mechanisms and Rehabilitation in Repeated Mild Traumatic Brain Injury

This protocol presents a modified mouse model of repetitive mild traumatic brain injury (rmTBI) induced via a closed-head injury (CHI) method. The approach features a thinned-skull window and fluid percussion to reduce the inflammation commonly caused by meninges exposure, along with improved reproducibility and accuracy in modeling rmTBI in rodents.

Mild traumatic brain injury is a clinically highly heterogeneous neurological disorder. Highly reproducible traumatic brain injury (TBI) animal models ...

Induction of Traumatic Brain Injury in a Rat Model Using a Lateral Fluid Percussion Device

Source: McGuire, M. J., et al. <a href="https://app.jove.com/v/59637">Use of a Wireless Video-EEG System to Monitor Epileptiform Discharges Following Lateral Fluid-Percussion Induced Traumatic Brain Injury.</a> J. Vis. Exp. (2019)
This video demonstrates the induction of traumatic brain injury (TBI) in a rat using a lateral fluid percussion injury (FPI) device. The procedure involves creating a hole in the skull of an anesthetized rat to expose the dura mater, onto which a cannula is attached. The rat is then connected to the device, which generates a pressure wave that reaches the brain, mimicking TBI by causing neural cell death and vascular damage

Source: McGuire, M. J., et al. Use of a Wireless Video-EEG System to Monitor Epileptiform Discharges Following Lateral Fluid-Percussion Induced Traumatic ...

Maintenance of a Lateral Fluid Percussion Injury Device

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