The work in this grant is funded by the University of Utah Clinical and Translational Science Institute through the Translational and Clinical Studies Pilot Program and the Department of Defense office of&#160;the Congressionally Directed Medical Research Programs (PR192745).

The Institutional Animal Care and Use Committee of the University of Utah approved all experimental protocols described here. Prior to the experiment, a total of 12 castrated male or non-pregnant female Yorkshire swine weighing 50-75 kg and between 6-8 months old were acclimated in their enclosures for at least 7 days. During this period, all care is directed by a veterinarian and in accordance with the Guide for the Care and Use of Laboratory Animals and the Animal Welfare Act Regulations and Standards. The animals are ...

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B., 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=Trauma+induced+acute+kidney+injury.">Trauma induced acute kidney injury.</a> Plos One. 14 (1), 0211001 (2019).</li><li>Lai, W. 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W., Shaw, G. M., Endre, Z. 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P. C., Ngo, J. P., Ullah, M. M., Hilliard, L. M., Evans, R. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Renal+hypoxia+in+kidney+disease:+Cause+or+consequence.">Renal hypoxia in kidney disease: Cause or consequence.</a> Acta Physiologica. 222 (4), 12999 (2018).</li><li>Leonhardt, K. O., Landes, R. R., McCauley, R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomy+and+physiology+of+intrarenal+oxygen+tension:+Preliminary+study+of+the+effets+of+anesthetics.">Anatomy and physiology of intrarenal oxygen tension: Preliminary study of the effets of anesthetics.</a> Anesthesiology. 26 (5), 648-658 (1965).</li><li>Stafford-Smith, M., Grocott, H. 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P., 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=Factors+that+confound+the+prediction+of+renal+medullary+oxygenation+and+risk+of+acute+kidney+injury+from+measurement+of+bladder+urine+oxygen+tension.">Factors that confound the prediction of renal medullary oxygenation and risk of acute kidney injury from measurement of bladder urine oxygen tension.</a> Acta Physiologica. 227 (1), 13294 (2019).</li><li>Spahn, D. R., 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=The+European+guideline+on+management+of+major+bleeding+and+coagulopathy+following+trauma:+fifth+edition.">The European guideline on management of major bleeding and coagulopathy following trauma: fifth edition.</a> Critical Care. 23 (1), 98 (2019).</li><li>Legrand, M., 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=Fluid+resuscitation+does+not+improve+renal+oxygenation+during+hemorrhagic+shock+in+rats.">Fluid resuscitation does not improve renal oxygenation during hemorrhagic shock in rats.</a> Anesthesiology. 112 (1), 119-127 (2010).</li><li>Badin, J., 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=Relation+between+mean+arterial+pressure+and+renal+function+in+the+early+phase+of+shock:+a+prospective,+explorative+cohort+study.">Relation between mean arterial pressure and renal function in the early phase of shock: a prospective, explorative cohort study.</a> Critical Care. 15 (3), 135 (2011).</li><li>Ribeiro Junio, M. 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N. Silverton, K. Kuck, and L. Lofgren are inventors of a patent and patent application surrounding the noninvasive monitor used in this study. This prototype is under development for commercial consideration by N. Silverton and K. Kuck, but as of yet, no commercial activity has occurred. The other authors declare no competing interests. The interpretation and reporting of these data are the responsibility of the authors alone.

AKI is a common complication in patients with trauma, and currently, there is no validated bedside monitor for kidney tissue oxygenation, which could enable earlier AKI detection and guide potential interventions. This manuscript describes the use and instrumentation of a porcine hemorrhagic shock model to establish noninvasive PuO2 as an early indicator of AKI and a novel resuscitation endpoint in trauma settings.
One of the distinct advantages of this porcine model is the ability ...

An erratum was issued for:&#160;<a href="https://www.jove.com/t/64461">Noninvasive and Invasive Renal Hypoxia Monitoring in a Porcine Model of Hemorrhagic Shock</a>. The Protocol&#160;section was updated.
Step 2.3.1&#160;-&#160;2.3.1.2&#160;of the Protocol was updated from:
<ol>
	<li>Measure PuO2&#160;in the bladder.
	<ol>
		<li>Remove all air from the bladder by slowly squeezing the bladder while ensuring urine does not leak out.</li>
		<li>Place the tip of the luminescence quenching-based PuO2&#160;sensor in the bladder&#160;via&#160;a cystotomy, similar to the catheter.</li>
		<li>Connect the fiber optic cable from the bladder sensor to the data collection device.</li>
	</ol>
	</li>
</ol>
to:
<ol>
	<li>&#160;Measure PuO2 at the outlet of the bladder
	<ol>
		<li>Identify the balloon on the catheter. Just below the balloon make an incision along the long axis of the catheter, ensuring that you do not cut the lumen that connects to the balloon.&#160;</li>
		<li>After making the incision, insert a t-connector that contains the sensing material into the incision.&#160;</li>
		<li>Use tissue glue to secure the t-connector in place.&#160;</li>
		<li>Connect the fiber optic cable from the bladder data collection device to the connector that contains the sensing material.&#160;</li>
	</ol>
	</li>
</ol>
Step 2.3.2.2&#160;-&#160;2.3.2.7&#160;of the Protocol was updated from:
<ol start="2">
	<li>Make a flank incision large enough to expose the kidney (approx. 2-3 in) on the side of the pig at approximately the same location where the kidney was identified.</li>
	<li>With the tips of a retractor together, introduce the retractor into the incision and then spread the tips of the retractor to expose the kidney.</li>
	<li>Use a micro-manipulator or similar tool to hold the oxygen probe steady. If possible, attach this tool to the end of an articulating arm.</li>
	<li>Attach the other end of the articulating arm to the surgical table so that the other end that will hold the oxygen probe is near the opened incision. If the tool that is used to hold the oxygen probe is not connected to an articulating arm, position the tool so the oxygen sensor is near the opened incision and is stable.</li>
	<li>Unlock all articulating joints of the arm. Using ultrasound, place the tip of the oxygen probe in the medulla region of the kidney. Lock all articulating joints on the arm.</li>
	<li>After confirming placement of the tip of the sensor in the medulla with ultrasound, use the micromanipulator to retract the needle housing the luminescence-based oxygen sensor. Connect the other end of the sensor to the data collection device connected to the computer running the data collection software. Start recording.</li>
</ol>
to:
<ol start="2">
	<li>Move the bowel so that you have a clear line of site and access to the entire kidney.&#160;</li>
	<li>Insert the sensor into 2&#34; 18 gauge catheter. Adjust the luer lock connector on the sensor so that the tip of the sensor is exposed. Remove the catheter and place it over an 18 gauge needle.</li>
	<li>Place the 18 gauge needle and 2 in catheter into the renal medulla under ultrasound guidance.</li>
	<li>Remove the needle, keeping the catheter in place. Thread the tissue sensor through the catheter and use the luer lock to connect the sensor to the catheter.&#160;</li>
	<li>Use tissue glue to secure the catheter in place.&#160;</li>
	<li>Connect the tissue sensor to the data collection box.</li>
</ol>
The Table of Materials was updated from:
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>1/8&#34; PVC tubing</td>
			<td>Qosina</td>
			<td>SKU: T4307</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/16&#34; PVC tubing</td>
			<td>Qosina</td>
			<td>SKU: T4310</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/32&#34; (1), 1/8&#34; (1), 5/32&#34; (1) drill bit</td>
			<td>Dewalt</td>
			<td>N/A</td>
			<td>For building noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/8&#34; TPE tubing&#160;</td>
			<td>Qosina</td>
			<td>SKU: T2204</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Biocompatible Glue</td>
			<td>Masterbond</td>
			<td>EP30MED</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Bladder oxygen measurement device</td>
			<td>Presens</td>
			<td>Fibox 4</td>
			<td>Stand-alone fiber optic oxygen meter</td>
		</tr>
		<tr>
			<td>Bladder PuO2 sensor</td>
			<td>Presens</td>
			<td>DP-PSt3</td>
			<td>Oxygen dipping probe</td>
		</tr>
		<tr>
			<td>Chlorhexidine 4% scrub</td>
			<td>Vetone</td>
			<td>N/A</td>
			<td>For scrubbing insertion or puncture sites</td>
		</tr>
		<tr>
			<td>Conical connector with female luer lock</td>
			<td>Qosina</td>
			<td>SKU: 51500</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Cuffed endotracheal tube</td>
			<td>Vetone</td>
			<td>600508</td>
			<td>For sedating the subject and providing respiratory support</td>
		</tr>
		<tr>
			<td>Euthanasia solution (pentobarbital sodium|pheyntoin sodium)</td>
			<td>Vetone</td>
			<td>11168</td>
			<td>For euthanasia after completion of experiment</td>
		</tr>
		<tr>
			<td>General purpose temperature probe, 400 series thermistor</td>
			<td>Novamed</td>
			<td>10-1610-040</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Hemmtop Magic Arm 11 inch</td>
			<td>Amazon</td>
			<td>B08JTZRKYN</td>
			<td>Holding invasive oxygen sensor in place</td>
		</tr>
		<tr>
			<td>HotDog veterinary warming system</td>
			<td>HotDog</td>
			<td>V106</td>
			<td>For controlling subject temperature during experiment</td>
		</tr>
		<tr>
			<td>Invasive tissue oxygen measurement device</td>
			<td>Presens</td>
			<td>Oxy-1 ST&#160;</td>
			<td>Compact oxygen transmitter</td>
		</tr>
		<tr>
			<td>Invasive tissue oxygen sensor</td>
			<td>Presens</td>
			<td>PM-PSt7</td>
			<td>Profiling oxygen microsensor</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Vetone</td>
			<td>501017</td>
			<td>To maintain sedation throughout the experiment</td>
		</tr>
		<tr>
			<td>Isotonic crystalloid solution</td>
			<td>HenrySchein</td>
			<td>1537930 or 1534612</td>
			<td>Used during resuscitation in the critical care period</td>
		</tr>
		<tr>
			<td>Liquid flow sensor</td>
			<td>Sensirion</td>
			<td>LD20-2600B</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Male luer lock to barb connector</td>
			<td>Qosina</td>
			<td>SKU: 11549</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Male to male luer connector</td>
			<td>Qosina</td>
			<td>SKU: 20024</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Noninvasive oxygen measurement device</td>
			<td>Presens</td>
			<td>EOM-O2-mini</td>
			<td>Electro optical module transmitter for contactless oxygen measurements</td>
		</tr>
		<tr>
			<td>Non-vented male luer lock cap</td>
			<td>Qosina</td>
			<td>SKU: 65418</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Norepinephrine</td>
			<td>HenrySchein</td>
			<td>AIN00610</td>
			<td>Infusion during resuscitation</td>
		</tr>
		<tr>
			<td>O2 sensor stick</td>
			<td>Presens</td>
			<td>SST-PSt3-YOP</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>PowerLab data acquisition platform</td>
			<td>AD Instruments</td>
			<td>N/A</td>
			<td>For data collection</td>
		</tr>
		<tr>
			<td>REBOA catheter</td>
			<td>Certus Critical Care</td>
			<td>N/A</td>
			<td>Used in experimental protocol</td>
		</tr>
		<tr>
			<td>Super Sheath arterial catheters (5 Fr, 7 Fr, 9 Fr)</td>
			<td>Boston Scientific</td>
			<td>C1894</td>
			<td>For intravascular access</td>
		</tr>
		<tr>
			<td>Suture</td>
			<td>Ethicon</td>
			<td>C013D</td>
			<td>For securing catheter to skin and closing incisions</td>
		</tr>
		<tr>
			<td>T connector, all female luer locks</td>
			<td>Qosina</td>
			<td>SKU: 88214</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
	</tbody>
</table>
to:
<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Name</td>
			<td>Company</td>
			<td>Catalog Number</td>
			<td>Comments</td>
		</tr>
		<tr>
			<td>1/8&#34; PVC tubing</td>
			<td>Qosina</td>
			<td>SKU: T4307</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/16&#34; PVC tubing</td>
			<td>Qosina</td>
			<td>SKU: T4310</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/8&#34; TPE tubing&#160;</td>
			<td>Qosina</td>
			<td>SKU: T2204</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/32&#34; (1), 1/8&#34; (1), 5/32&#34; (1) drill bit</td>
			<td>Dewalt</td>
			<td>N/A</td>
			<td>For building noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Biocompatible Glue</td>
			<td>Masterbond</td>
			<td>EP30MED</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Bladder PuO2 sensor</td>
			<td>Presens</td>
			<td>DP-PSt3</td>
			<td>Oxygen dipping probe</td>
		</tr>
		<tr>
			<td>Bladder oxygen measurement device</td>
			<td>Presens</td>
			<td>Fibox 4</td>
			<td>Stand-alone fiber optic oxygen meter</td>
		</tr>
		<tr>
			<td>Chlorhexidine 4% scrub</td>
			<td>Vetone</td>
			<td>N/A</td>
			<td>For scrubbing insertion or puncture sites</td>
		</tr>
		<tr>
			<td>Conical connector with female luer lock</td>
			<td>Qosina</td>
			<td>SKU: 51500</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Cuffed endotracheal tube</td>
			<td>Vetone</td>
			<td>600508</td>
			<td>For sedating the subject and providing respiratory support</td>
		</tr>
		<tr>
			<td>Euthanasia solution (pentobarbital sodium|pheyntoin sodium)</td>
			<td>Vetone</td>
			<td>11168</td>
			<td>For euthanasia after completion of experiment</td>
		</tr>
		<tr>
			<td>General purpose temperature probe, 400 series thermistor</td>
			<td>Novamed</td>
			<td>10-1610-040</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>HotDog veterinary warming system</td>
			<td>HotDog</td>
			<td>V106</td>
			<td>For controlling subject temperature during experiment</td>
		</tr>
		<tr>
			<td>Invasive tissue oxygen measurement device</td>
			<td>Optronix</td>
			<td>N/A</td>
			<td>OxyLite&#8482; oxygen monitors</td>
		</tr>
		<tr>
			<td>Invasive tissue oxygen sensor</td>
			<td>Optronix</td>
			<td>NX-BF/OT/E</td>
			<td>Oxygen/Temperature bare-fibre sensor</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Vetone</td>
			<td>501017</td>
			<td>To maintain sedation throughout the experiment</td>
		</tr>
		<tr>
			<td>Isotonic crystalloid solution</td>
			<td>HenrySchein</td>
			<td>1537930 or 1534612</td>
			<td>Used during resuscitation in the critical care period</td>
		</tr>
		<tr>
			<td>Liquid flow sensor</td>
			<td>Sensirion</td>
			<td>LD20-2600B</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Male luer lock to barb connector</td>
			<td>Qosina</td>
			<td>SKU: 11549</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Male to male luer connector</td>
			<td>Qosina</td>
			<td>SKU: 20024</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Norepinephrine</td>
			<td>HenrySchein</td>
			<td>AIN00610</td>
			<td>Infusion during resuscitation</td>
		</tr>
		<tr>
			<td>Noninvasive oxygen measurement device</td>
			<td>Presens</td>
			<td>EOM-O2-mini</td>
			<td>Electro optical module transmitter for contactless oxygen measurements</td>
		</tr>
		<tr>
			<td>Non-vented male luer lock cap&#160;</td>
			<td>Qosina</td>
			<td>SKU: 65418</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>O2 sensor stick</td>
			<td>Presens</td>
			<td>SST-PSt3-YOP</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>PowerLab data acquisition platform</td>
			<td>AD Instruments</td>
			<td>N/A</td>
			<td>For data collection</td>
		</tr>
		<tr>
			<td>REBOA catheter</td>
			<td>Certus Critical Care</td>
			<td>N/A</td>
			<td>Used in experimental protocol</td>
		</tr>
		<tr>
			<td>Super Sheath arterial catheters (5 Fr, 7 Fr, 9 Fr)</td>
			<td>Boston Scientific</td>
			<td>C1894</td>
			<td>for intravascular access</td>
		</tr>
		<tr>
			<td>Suture</td>
			<td>Ethicon</td>
			<td>C013D</td>
			<td>For securing catheter to skin and closing incisions</td>
		</tr>
		<tr>
			<td>T connector, all female luer locks</td>
			<td>Qosina</td>
			<td>SKU: 88214</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
	</tbody>
</table>

An erratum was issued for:&#160;<a href="https://www.jove.com/t/64461">Noninvasive and Invasive Renal Hypoxia Monitoring in a Porcine Model of Hemorrhagic Shock</a>. The Protocol and Table of Materials were&#160;updated.

Erratum: Noninvasive and Invasive Renal Hypoxia Monitoring in a Porcine Model of Hemorrhagic Shock

Acute kidney injury (AKI) affects up to 50% of patients with trauma admitted to the intensive care unit1. Patients who develop AKI tend to have longer hospital and intensive care unit lengths of stay and a threefold greater risk of mortality2,3,4. Currently, AKI is most commonly defined by the Kidney Disease Improving Global Outcomes (KDIGO) guidelines, which are based on changes in serum creatinine concentration from baseline or periods of prolonged oliguria5. Baseline creatinine concentration data are unavailable in most patients with trauma, and estimation equations are unreliable and have not been validated in patients with trauma6. In addition, serum creatinine concentration may not change until at least 24 h after the injury, precluding early identification and intervention7. While research suggests that urine output is an earlier indicator of AKI than serum creatinine concentration, the KDIGO criteria require a minimum of 6 h of oliguria, which precludes interventions targeting injury prevention8. The optimal hourly urine output threshold and appropriate duration of oliguria for defining AKI are also debated, which limit its effectiveness as an early marker of the disease9,10. Thus, current diagnostic measures for AKI are not useful in trauma settings, lead to delayed diagnosis of AKI, and do not provide real-time information regarding a patient&#39;s risk status for developing AKI.
While the development of AKI in a trauma setting is complex and likely associated with several causes such as poor renal perfusion due to hypovolemia, reduced renal blood flow due to vasoconstriction, trauma-related inflammation, or ischemia-reperfusion injury, renal hypoxia is a common factor among most forms of AKI11,12. In particular, the medulla region of the kidney is highly susceptible to an imbalance between oxygen demand and supply in the trauma setting due to reduced oxygen delivery and high metabolic activity associated with sodium reabsorption. Thus, if it were possible to measure renal medulla oxygenation, it may be possible to monitor a patient&#39;s risk status for developing AKI. While this is not clinically feasible, urinary partial pressure of oxygen (PuO2) at the outlet of the kidney strongly correlates with medullary tissue oxygenation13,14. Other studies have shown that it is possible to measure bladder PuO2 and that it changes in response to stimuli that alter medullary oxygen and renal pelvis PuO2 levels, such as a decrease in renal blood flow15,16,17. These studies suggest that PuO2 may indicate end-organ perfusion and could be useful for monitoring the impact of interventions in trauma settings on renal function.
To monitor PuO2 noninvasively, a noninvasive PuO2 monitor was developed that can easily connect to the end of a urinary catheter outside the body. The noninvasive PuO2 monitor consists of three main components: a temperature sensor, a luminescence quenching oxygen sensor, and a thermal-based flow sensor. Since each oxygen sensor is optically based and relies on the Stern-Volmer relationship to quantify the relationship between luminescence and oxygen concentration, a temperature sensor is necessary to offset any potential confounding effects of changes in temperature. The flow sensor is important to quantify urine output and to determine the direction and magnitude of urine flow. All three components are connected by a combination of male, female, and t-shaped luer lock connectors and poly-vinyl chloride (PVC) flexible tubing. The end with the conical connector connects to the outlet of the urinary catheter, and the end with tubing over the conical connector connects slides over the connector on the urine collection bag.
Despite measuring distally to the bladder, a recent study showed that low urinary PuO2 during cardiac surgery is associated with an increased risk of developing AKI18,19. Similarly, current animal models have primarily focused on the early detection of AKI during cardiac surgery and sepsis14,20,21,22. Thus, questions remain about the use of this novel device in settings of trauma. The aim of this research is to establish PuO2 as an early marker of AKI and investigate its use as a resuscitative endpoint in patients with trauma. This manuscript describes a porcine model of hemorrhagic shock that includes the placement of the noninvasive PuO2 monitor, a bladder PuO2 sensor, and a tissue oxygen sensor in the renal medulla. Data from the noninvasive monitor will be compared to bladder PuO2 and invasive tissue oxygen measurements. The noninvasive monitor also includes a flow sensor which will be useful for understanding the relationship between urine flow rate and oxygen ingress, which reduces the ability to infer renal medullar tissue oxygenation from noninvasive PuO2 as urine traverses the urinary tract. Additionally, data from the three oxygen sensors will be compared to systemic vital signs, such as mean arterial pressure. The central hypothesis is that noninvasive PuO2 data will strongly correlate with invasive medullary oxygen content and will reflect medullary hypoxia during resuscitation. Noninvasive PuO2 monitoring has the potential to improve trauma-related outcomes by identifying AKI earlier and serving as a novel resuscitative endpoint after hemorrhage that is indicative of end-organ rather than systemic oxygenation.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1/8&#34; PVC tubing</td>
			<td>Qosina</td>
			<td>SKU: T4307</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/16&#34; PVC tubing</td>
			<td>Qosina</td>
			<td>SKU: T4310</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/8&#34; TPE tubing&#160;</td>
			<td>Qosina</td>
			<td>SKU: T2204</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>3/32&#34; (1), 1/8&#34; (1), 5/32&#34; (1) drill bit</td>
			<td>Dewalt</td>
			<td>N/A</td>
			<td>For building noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Biocompatible Glue</td>
			<td>Masterbond</td>
			<td>EP30MED</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Bladder PuO2 sensor</td>
			<td>Presens</td>
			<td>DP-PSt3</td>
			<td>Oxygen dipping probe</td>
		</tr>
		<tr>
			<td>Bladder oxygen measurement device</td>
			<td>Presens</td>
			<td>Fibox 4</td>
			<td>Stand-alone fiber optic oxygen meter</td>
		</tr>
		<tr>
			<td>Chlorhexidine 4% scrub</td>
			<td>Vetone</td>
			<td>N/A</td>
			<td>For scrubbing insertion or puncture sites</td>
		</tr>
		<tr>
			<td>Conical connector with female luer lock</td>
			<td>Qosina</td>
			<td>SKU: 51500</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Cuffed endotracheal tube</td>
			<td>Vetone</td>
			<td>600508</td>
			<td>For sedating the subject and providing respiratory support</td>
		</tr>
		<tr>
			<td>Euthanasia solution (pentobarbital sodium|pheyntoin sodium)</td>
			<td>Vetone</td>
			<td>11168</td>
			<td>For euthanasia after completion of experiment</td>
		</tr>
		<tr>
			<td>General purpose temperature probe, 400 series thermistor</td>
			<td>Novamed</td>
			<td>10-1610-040</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>HotDog veterinary warming system</td>
			<td>HotDog</td>
			<td>V106</td>
			<td>For controlling subject temperature during experiment</td>
		</tr>
		<tr>
			<td>Invasive tissue oxygen measurement device</td>
			<td>Optronix</td>
			<td>N/A</td>
			<td>OxyLite&#8482; oxygen monitors</td>
		</tr>
		<tr>
			<td>Invasive tissue oxygen sensor</td>
			<td>Optronix</td>
			<td>NX-BF/OT/E</td>
			<td>Oxygen/Temperature bare-fibre sensor</td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Vetone</td>
			<td>501017</td>
			<td>To maintain sedation throughout the experiment</td>
		</tr>
		<tr>
			<td>Isotonic crystalloid solution</td>
			<td>HenrySchein</td>
			<td>1537930 or 1534612</td>
			<td>Used during resuscitation in the critical care period</td>
		</tr>
		<tr>
			<td>Liquid flow sensor</td>
			<td>Sensirion</td>
			<td>LD20-2600B</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Male luer lock to barb connector</td>
			<td>Qosina</td>
			<td>SKU: 11549</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Male to male luer connector</td>
			<td>Qosina</td>
			<td>SKU: 20024</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>Norepinephrine</td>
			<td>HenrySchein</td>
			<td>AIN00610</td>
			<td>Infusion during resuscitation</td>
		</tr>
		<tr>
			<td>Noninvasive oxygen measurement device</td>
			<td>Presens</td>
			<td>EOM-O2-mini</td>
			<td>Electro optical module transmitter for contactless oxygen measurements</td>
		</tr>
		<tr>
			<td>Non-vented male luer lock cap&#160;</td>
			<td>Qosina</td>
			<td>SKU: 65418</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>O2 sensor stick</td>
			<td>Presens</td>
			<td>SST-PSt3-YOP</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
		<tr>
			<td>PowerLab data acquisition platform</td>
			<td>AD Instruments</td>
			<td>N/A</td>
			<td>For data collection</td>
		</tr>
		<tr>
			<td>REBOA catheter</td>
			<td>Certus Critical Care</td>
			<td>N/A</td>
			<td>Used in experimental protocol</td>
		</tr>
		<tr>
			<td>Super Sheath arterial catheters (5 Fr, 7 Fr, 9 Fr)</td>
			<td>Boston Scientific</td>
			<td>C1894</td>
			<td>for intravascular access</td>
		</tr>
		<tr>
			<td>Suture</td>
			<td>Ethicon</td>
			<td>C013D</td>
			<td>For securing catheter to skin and closing incisions</td>
		</tr>
		<tr>
			<td>T connector, all female luer locks</td>
			<td>Qosina</td>
			<td>SKU: 88214</td>
			<td>Part of noninvasive PuO2 monitor</td>
		</tr>
	</tbody>
</table>

noninvasive and invasive renal hypoxia monitoring in a porcine model of hemorrhagic shock

Up to 50% of patients with trauma develop acute kidney injury (AKI), in part due to poor renal perfusion after severe blood loss. AKI is currently diagnosed based on a change in serum creatinine concentration from baseline or prolonged periods of decreased urine output. Unfortunately, baseline serum creatinine concentration data is unavailable in most patients with trauma, and current estimation methods are inaccurate. In addition, serum creatinine concentration may not change until 24-48 h after the injury. Lastly, oliguria must persist for a minimum of 6 h to diagnose AKI, making it impractical for early diagnosis. AKI diagnostic approaches available today are not useful for predicting risk during the resuscitation of patients with trauma. Studies suggest that urinary partial pressure of oxygen (PuO2) may be useful for assessing renal hypoxia. A monitor that connects the urinary catheter and the urine collection bag was developed to measure PuO2 noninvasively. The device incorporates an optical oxygen sensor that estimates PuO2 based on luminescence quenching principles. In addition, the device measures urinary flow and temperature, the latter to adjust for confounding effects of temperature changes. Urinary flow is measured to compensate for the effects of oxygen ingress during periods of low urine flow. This article describes a porcine model of hemorrhagic shock to study the relationship between noninvasive PuO2, renal hypoxia, and AKI development. A key element of the model is the ultrasound-guided surgical placement in the renal medulla of an oxygen probe, which is based on an unsheathed optical microfiber. PuO2 will also be measured in the bladder and compared to the kidney and noninvasive PuO2 measurements. This model can be used to test PuO2 as an early marker of AKI and assess PuO2 as a resuscitative endpoint after hemorrhage that is indicative of end-organ rather than systemic oxygenation.

Figure 1 shows an image of the noninvasive PuO2 monitor described in this manuscript. Figure 2 shows a plot of MAP and noninvasive PuO2 measurements in a single subject during an experiment similar to the described porcine hemorrhage model. At the start of the experiment, as hemorrhage was initiated, there was a drop in MAP and PuO2. Following the initial decline in PuO2 it gradually increased until after the REBOA bal...

Watch this Scientific Journal Video about Noninvasive and Invasive Renal Hypoxia Monitoring in a Porcine Model of Hemorrhagic Shock at JoVE.com

Noninvasive and Invasive Renal Hypoxia Monitoring in a Porcine Model of Hemorrhagic Shock

Presented here is a protocol to measure renal oxygenation in the medulla and noninvasive urine oxygen partial pressure in a hemorrhagic shock porcine model to establish urine oxygen partial pressure as an early indicator of acute kidney injury (AKI) and a novel resuscitative endpoint.

Up to 50% of patients with trauma develop acute kidney injury (AKI), in part due to poor renal perfusion after severe blood loss. AKI is currently ...

This protocol is significant because it will establish urine oxygen partial pressure as an early indicator of acute kidney injury, and potentially reduce the incidence in patients with traumatic hemorrhagic shock. As this is a porcine model, it is highly translatable to humans. This technique involves measuring oxygen concentration directly in the renal medulla which cannot be done in humans.To begin, prepare all puncture sites by scrubbing the skin of Yorkshire swine with three alternating scrubs of chlorhexidine, followed by alcohol. After the last scrub, apply chlorhexidine and allow it to dry completely. Then, drape the surgical site in a sterile fashion.Locally infiltrate all puncture and incision sites with 2%lidocaine for local pain relief. Using ultrasound guidance and the seldinger technique, place a nine French catheter in the right external jugular vein for medication infusion and central venous pressure monitoring. Next, to monitor pressure distal to the balloon of the resuscitative endovascular occlusion of the aorta or reboa catheter via the left femoral artery sheath.Connect a disposable pressure transducer to the arterial catheter, distal to the reboa balloon. Perform a midline laparotomy by making an incision along the midline of the abdomen, starting at the inferior part of the sternum and ending at the pubis. To measure PuO2 at the outlet of the bladder, identify the balloon on the catheter.Then, just below the balloon make an incision along the long axis of the catheter, ensuring not to cut the lumen that connects the balloon. After making an incision, insert a T-connector containing sensing material into the incision and secure the connector in place using tissue glue. With the abdomen open, identify the bladder and perform a cystotomy or make a small incision to insert the tip of a 20 French urinary catheter in the bladder.Close the cystotomy with the urinary catheter in place using a purse string suture. Then, secure the catheter to the skin with sutures. Before connecting the outlet of the catheter to the urinary collection bag, insert the cone-shaped end of the non-invasive urinary partial pressure of oxygen or PuO2 monitor into the outlet of the catheter.Place the open tubing at the end of the novel PuO2 monitor over the cone-shaped connector on the tubing connected to the urine collection bag. Next, locate the spleen and identify the hilum of the spleen or the site where the splenic artery and vein enter the spleen. Ligate each vessel using modified miller knots using 2-0 sutures.Then, clamp and transect each vessel. Connect the fiber optic cable from the bladder data collection device to the connector that contains the sensing material. To measure medullary renal tissue oxygenation, identify the location of the kidney internally and move the bowel to have a clear line of sight and access to the entire kidney.Under ultrasound guidance, place an 18 gauge needle and the two inch catheter into the renal medulla by inserting the needle into the kidney at a 45 degree angle relative to the surface of the kidney, such that the lure lock end of the needle is positioned towards the feet. Remove the needle while maintaining the catheter in place. Thread the tissue sensor through the catheter and connect the sensor to the catheter using the lure lock.Secure the catheter using tissue glue and connect the tissue sensor to the data collection box. To induce hemorrhagic shock, remove 25%of the animal's estimated blood volume through the right brachial artery sheath over 30 minutes into a gently agitated citrated blood collection bag. Mark the beginning of blood removal as time zero minute.Store the removed blood in a water bath at 37 degrees Celsius. Next, insert a seven French reboa catheter in the right femoral artery sheath. Place the balloon of the catheter immediately superior to the diaphragm, and confirm the location using fluoroscopy.At 30 minutes, inflate the reboa balloon and completely occlude the aorta for 45 minutes. Next, infuse intravenous calcium over 10 minutes to prevent citrate induced hypocalcemia. Then initiate resuscitation and administer critical care.At 70 minutes, transfuse pig with shed blood over 15 minutes. At 105 minutes, deflate the reboa balloon for 10 minutes. Then, resuscitate the pig until 360 minutes with norepinephrine and fluids to maintain a mean arterial pressure, or MAP, higher than 65 millimeters of mercury.A plot of MAP and non-invasive PuO2 measurements during the described hemorrhagic shock porcine model is shown here. At the start of the experiment, as hemorrhage was initiated, there was a drop in MAP and PuO2. Following the initial decline in PuO2, it gradually increased until after the reboa balloon was deflated.During the critical care phase, there was a significant drop off in PuO2. The MAP appears to remain constant during the critical care period, and PuO2 reaches a maximum at around 180 minutes followed by a decrease until 240 minutes, which is followed by a gradual increase until the end of the experiment. Based on this study, urine oxygen partial pressure monitoring may lead to earlier detection of acute kidney injury and guide future potential interventions to improve outcomes in patients with trauma.

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Research

JoVE Journal

Bioengineering

1.1K visualizações.  University of Utah. Esse protocolo é significativo, pois estabelecerá a pressão parcial de oxigênio na urina como um indicador precoce de lesão renal aguda e, potencialmente, reduzirá a incidência em pacientes com choque hemorrágico traumático. Por se tratar de um modelo suíno, é altamente traduzível para humanos. Esta técnica envolve a medição da concentração de oxigênio diretamente na medula renal, o que não pode ser feito em humanos.Para começar, prepare todos os locais de punção ...