Name: Wireless Telemetry Device Implantation in a Fontan Ovine Model for Continuous and Long-Term Hemodynamic Monitoring (Video) | JoVE Journal
Uploaded: 2025-05-02T14:30:00.000+00:00
Duration: 6 min 29 s
Description: Learn wireless telemetry device implantation for continuous hemodynamic monitoring in a Fontan ovine model. This protocol enables long-term collection of cardiovascular data including heart rate, arterial pressure, and vena cava pressures.

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5 minutes

This work was jointly supported by Additional Ventures and The American Heart Association Grant #24AVCSASV1276047 / Christopher Breuer / 2024.&#160; This work was also supported by the Brett Boyer Foundation / Christopher Breuer / 2024. We appreciate the dedicated veterinarian staff at the Animal Research Core. We also wish to express our gratitude to Mary Walker, DVM, MS, for her invaluable expertise and vigilant care throughout the study.

This experimental protocol was approved by the Institutional Animal Care and Use Committee of the Nationwide Children&#39;s Hospital Abigail Wexner Research Institute (AR20-00121). All procedures adhered to the guidelines outlined in the National Institute of Health&#39;s Guide for the Use and Care of Laboratory Animals. This research followed the Animal Research: Reporting of In Vivo Experiments guidelines. Dorset sheep with a weight range of 23-38 kg and an age range of 2-12 months were housed in a specific pathogen-free environment with free access to food and water for at least 1 week before surgery. The equipment and reagents used in the study are listed in the Table of Materials.
1. Animal preparation
<ol>
	<li>Have the sheep undergo evaluation by the veterinary team 1 week prior to surgery to ensure that they can safely undergo anesthesia. Fast healthy sheep and deprive of water for 12 h prior to the surgical procedure.</li>
	<li>Sedate with a combination of ketamine (4 mg/kg) and diazepam (0.5 mg/kg) injected through an internal jugular (IJ) vein.</li>
	<li>Shave sheep according to the planned procedure (detailed below) and over the thigh for electrocautery grounding pad placement. Clean the surgical sites with alcohol.</li>
	<li>Insert an 8-9 mm single-lumen endotracheal tube into the trachea.</li>
	<li>Insert an orogastric tube for decompression of the stomach and rumen.</li>
	<li>Insert a single-lumen venous catheter (16-18 G) into the right jugular vein or a lateral saphenous vein for continuous fluid administration, continuous rate infusion (CRI) of propofol, and drug injection as needed.</li>
	<li>Place an arterial line (22-24 G) in an auricular artery for continuous blood pressure monitoring.</li>
	<li>Place a blood pressure cuff on the right front limb for non-invasive blood pressure measurement, a clip on the ear or tongue to monitor oxygen saturation, and electrocardiogram (ECG) leads on all four limbs.</li>
	<li>During the procedure, maintain anesthesia using inhaled isoflurane 1%-3% with 100% O2 and/or propofol CRI (20-45 mg/kg/h).</li>
	<li>Aseptically clean the surgical sites using a chlorhexidine-based prep and drape in the standard sterile fashion.</li>
	<li>Administer cefazolin (25 mg/kg) for antibiotic prophylaxis before incision and re-dose every 4 h during the operation as needed.</li>
	<li>Administer a subcutaneous injection of local anesthetic, such as bupivacaine 0.25%, at all planned incision sites prior to incision.</li>
</ol>
2. Telemetry device preparation
<ol>
	<li>Open the telemetry software program and turn on the telemetry device using the magnet switch while it is still sealed in its original packaging.</li>
	<li>Within the software program, click on Hardware located at the top bar and select Edit PhysioTel Digital (CLC) Configuration to assign the telemetry unit to a communication link controller (CLC).</li>
	<li>Once a CLC is selected, its CLC Details page will open. Within this page, click on Search for Implants, which will initiate a search for implant devices that are turned on nearby.</li>
	<li>Click Add to add the telemetry unit to the Implants Selected list. The device will now appear under the Configured Implants list on the CLC Details page. Click Save and Exit.</li>
	<li>Start data acquisition by pressing the Play button next to the name of the telemetry unit in the Sampling Control tab. Graph displaying the live data acquisition will automatically open.</li>
	<li>Remove the device from its exterior packaging and transfer it to its sterile interior packaging onto the operating table.</li>
	<li>Zero the device while it remains in its interior packaging. Wait until measurements from the device have been stable for 30 s and use the stabilized non-pulsatile mean (NPMN) pressure values as the offset.</li>
	<li>Within Subject Setup, select the settings icon next to the parameter that is being zeroed and open the Offsets tab. Enter the offset value obtained from the NPMN measurements into the text box.</li>
	<li>After inputting the offset, check if the NPMN readings are 0 &#177; 0.1 mmHg. If not, repeat step 2.7 until values are within the desired range.</li>
	<li>Perform steps 2.7-2.9 for both pressure channels.</li>
	<li>Before inserting the pressure-sensing catheters into a blood vessel, tap the tip to identify its corresponding channel. Taps will become apparent in the waveform output.</li>
	<li>Use the catheter corresponding to the left ventricular pressure (LVP) channel for arterial pressure measurement and the blood pressure (BP) channel for venous pressure measurement.</li>
	<li>Within the Standard Attributes tab of the Blood Pressure Analysis Attributes dialog box, set the minimum pulse height to 1 mmHg for the BP channel.</li>
</ol>
3. Method 1: Femoral artery and vein cannulation
<ol>
	<li>Shave the sheep in a wide perimeter around the right groin and over the abdomen and chest.</li>
	<li>Position the sheep supine on the operating table with their front limbs secured in flexion using a flexible cloth belt and hind limbs secured in extension using a slipknot tie to allow for access to the groin (Figure 1A).</li>
	<li>Make a 5-cm transverse incision in the right inguinal region centered over the palpable femoral artery, approximately 1 cm below the inguinal crease.</li>
	<li>Using a combination of electrocautery and blunt dissection, dissect through the subcutaneous tissue to the femoral triangle. Locate the femoral vessels by palpating for the arterial pulse.</li>
	<li>Divide between the sartorius and adductor longus muscle along the direction of the muscle fibers to expose the femoral vessels (Figure 1B).</li>
	<li>Using a combination of blunt and sharp dissection, clear the connective tissue from the femoral vessels circumferentially.</li>
	<li>Pass a double-looped 2-0 silk tie around both vessels proximal and distal to the cannulation site for temporary vessel ligation.</li>
	<li>Make a 6-cm transverse incision through the skin in the right lower abdomen, approximately 3 cm above the inguinal crease.</li>
	<li>Using a combination of electrocautery and blunt dissection, dissect through the subcutaneous fat and connective tissue to create a 6 cm x 4 cm pocket superficial to the external oblique.</li>
	<li>Insert the telemetry device into the subcutaneous pocket and secure it in place using a 2-0 silk suture (Figure 1C).</li>
	<li>Tunnel the telemetry device antenna under the subcutaneous tissue and secure it in place using a 2-0 silk suture.</li>
	<li>For placement of the biopotential (ECG) leads, make 1-cm counter incisions in the skin over the mid and lower abdomen, as well as the lower and upper chest. Tunnel subcutaneously to connect these incisions to the device body pocket and guide the ECG leads to their desired location.</li>
	<li>Place the positive electrode in the subcutaneous tissue to the left of the lower sternum. Ensure that the silicone tubing is removed to reveal the tip of the steel wire underneath.</li>
	<li>Place the negative electrode in the subcutaneous tissue to the right of the upper sternum.</li>
	<li>Excess wiring for both leads can be coiled and secured in the subcutaneous location using a 2-0 silk suture.</li>
	<li>Create a subcutaneous tunnel from the lower abdominal device pocket to the inguinal incision and thread the two pressure catheters through.</li>
	<li>Place a purse-string stitch using a 6-0 polypropylene suture around the cannulation site of both the femoral artery and vein, which can be secured using a plastic tourniquet.</li>
	<li>Fill the catheter gel tips with non-compressible, high-viscosity gel to prevent coagulation inside the catheter tips, ensuring no air bubbles.</li>
	<li>Administer a dose of intravenous heparin (100 units/kg) 3 min before cannulation.</li>
	<li>Tighten the proximal and distal 2-0 silk tourniquets around the femoral artery. Carefully incise into the vessel at the center of the purse-string stitch using a #11 blade scalpel and dilate slightly with the tip of a curved hemostat.</li>
	<li>Insert the pressure catheter corresponding to the LVP channel and advance it into the abdominal aorta, loosening the proximal silk tourniquet to allow for passage of the catheter. Tighten the purse-string suture and tie it around the catheter.</li>
	<li>Repeat steps 3.20 and 3.21 for femoral vein cannulation using the pressure catheter corresponding to the BP channel and advance it into the abdominal IVC (Figure 1D).</li>
	<li>Confirm that the catheter tips are located appropriately in the IVC and aorta using fluoroscopy.</li>
	<li>Reapproximate the sartorius muscle using a 2-0 absorbable suture.</li>
	<li>Close the skin with deep dermal and subcuticular sutures using 3-0 and 4-0 absorbable sutures, respectively.</li>
</ol>
4. Method 2: Carotid artery and internal jugular vein cannulation
<ol>
	<li>Shave the sheep in a wide perimeter around the left neck and down over the chest.</li>
	<li>Position the sheep in right lateral decubitus on the operating table with the left front limb secured in flexion using a slipknot tie to expose the chest (Figure 2A).</li>
	<li>Make a 5-cm longitudinal skin incision above the left carotid artery and IJ vein, approximately 7 cm cranial to the thoracic inlet.</li>
	<li>Using electrocautery, dissect through the subcutaneous fat, connective tissue, and platysma to expose the neck vessels (Figure 2B).</li>
	<li>Using a combination of blunt and sharp dissection, clear the connective tissue from the left carotid artery and IJ vein circumferentially.</li>
	<li>Pass a double-looped 2-0 silk tie around both vessels proximal and distal to the cannulation site for temporary vessel ligation.</li>
	<li>Make a 6-cm longitudinal incision at the base of the left neck between the scapula and cervical spine.</li>
	<li>Using a combination of electrocautery and blunt dissection, dissect through the subcutaneous fat and connective tissue to create a 6 cm x 4 cm pocket extending toward the spine.</li>
	<li>Insert the telemetry device into the subcutaneous pocket and secure it in place using a 2-0 silk suture.</li>
	<li>Tunnel the telemetry device antenna under the subcutaneous tissue and secure it in place using a 2-0 silk suture.</li>
	<li>Make 1-cm counter skin incisions at the base of the neck, as well as the lower left and upper right chest, for placement of the ECG leads. Tunnel subcutaneously to connect these incisions to the device body pocket and guide the ECG leads to their desired location (Figure 2C).</li>
	<li>Place the ECG leads similarly to the steps described above for the femoral implant procedure (section 3).</li>
	<li>Create a subcutaneous tunnel from the lateral device pocket to the medial neck incision and thread the two pressure catheters through. Prep these pressure catheters using gel prior to cannulation, as detailed in the femoral implant procedure.</li>
	<li>Using a 6-0 polypropylene suture, place a purse-string stitch around the site of cannulation on both vessels and secure with a plastic tourniquet.</li>
	<li>Administer a dose of intravenous heparin (100 units/kg) 3 min before cannulation.</li>
	<li>Tighten the proximal and distal 2-0 silk tourniquets around the carotid artery. Carefully incise into the vessel at the center of the purse-string stitch using a #11 blade scalpel and dilate slightly with the tip of a curved hemostat.</li>
	<li>Insert the pressure catheter corresponding to the LVP channel and advance it into the thoracic ascending aorta, loosening the proximal silk tourniquet to allow for passage of the catheter. Tighten the purse-string suture and tie it around the catheter.</li>
	<li>Repeat steps 4.16 and 4.17 for cannulation of the left IJ vein using the pressure catheter corresponding to the BP channel and advance it into the thoracic SVC.</li>
	<li>Confirm the appropriate location of the catheter tips in the thoracic SVC and ascending aorta using fluoroscopy (Figure 2D).</li>
	<li>Reapproximate the platysma muscle using a 2-0 absorbable suture.</li>
	<li>Close the skin with deep dermal and subcuticular sutures using 3-0 and 4-0 absorbable sutures, respectively.</li>
</ol>
5. Recovery
<ol>
	<li>Discontinue anesthetics. Remove the orogastric tube and extubate when the sheep is breathing without assistance from the ventilator. This typically occurs after the sheep shows signs of arousal (movement, blinking, response to painful stimuli, jaw tone, chewing).</li>
	<li>Remove the arterial line. 
	NOTE: Continuous blood pressure monitoring can be provided by the telemetry device if one of its pressure catheters has been placed into the aorta.</li>
	<li>Transfer the sheep to an isolated housing unit for recovery. Assist the sheep with staying in sternal recumbency and then eventually with standing.</li>
	<li>Administer intravenous banamine (2.2 mg/kg) and subcutaneous buprenorphine&#160;(0.03 mg/kg) for postoperative pain (follow vetrenarian recommendations at institution).</li>
</ol>

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<li>Mazza, G. A., Gribaudo, E., Agnoletti, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((The+pathophysiology+and+complications+of+Fontan+circulation%5BTitle%5D)+AND+%22Acta+Biomed%22%5BJournal%5D)">The pathophysiology and complications of Fontan circulation.</a> Acta Biomed. 92 (5), e2021260(2021).</li>
<li>Schwartz, I., Mccracken, C. E., Petit, C. J., Sachdeva, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Late+outcomes+after+the+Fontan+procedure+in+patients+with+single+ventricle%3A+A+meta-analysis%5BTitle%5D)+AND+%22Heart%22%5BJournal%5D)">Late outcomes after the Fontan procedure in patients with single ventricle: A meta-analysis.</a> Heart. 104 (18), 1508-1514 (2018).</li>
<li>Zafar, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Long-term+kidney+function+after+the+Fontan+operation%3A+Jacc+review+topic+of+the+week%5BTitle%5D)+AND+%22J+Am+Coll+Cardiol%22%5BJournal%5D)">Long-term kidney function after the Fontan operation: Jacc review topic of the week.</a> J Am Coll Cardiol. 76 (3), 334-341 (2020).</li>
<li>Van Puyvelde, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Creation+of+the+Fontan+circulation+in+sheep%3A+A+survival+model%5BTitle%5D)+AND+%22Interact+Cardiovasc+Thorac+Surg%22%5BJournal%5D)">Creation of the Fontan circulation in sheep: A survival model.</a> Interact Cardiovasc Thorac Surg. 29 (1), 15-21 (2019).</li>
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<li>Cysyk, J. P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Miniaturized+Fontan+circulation+assist+device%3A+Chronic+in+vivo+evaluation%5BTitle%5D)+AND+%22ASAIO+J%22%5BJournal%5D)">Miniaturized Fontan circulation assist device: Chronic in vivo evaluation.</a> ASAIO J. 67 (11), 1240-1249 (2021).</li>
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<li>Wei, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Mechanical+circulatory+support+of+a+univentricular+Fontan+circulation+with+a+continuous+axial-flow+pump+in+a+piglet+model%5BTitle%5D)+AND+%22ASAIO+J%22%5BJournal%5D)">Mechanical circulatory support of a univentricular Fontan circulation with a continuous axial-flow pump in a piglet model.</a> ASAIO J. 61 (2), 196-201 (2015).</li>
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<li>Physiotel digital l series. , At
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</ol>

This project was funded by the Additional Ventures Cures Collaborative, Palo Alto, California.

We have developed two surgical methods for the implantation of a wireless telemetry device into an ovine model. The device was successfully implanted in 5 sheep to achieve continuous, long-term monitoring and recording of several cardiovascular parameters, including heart rate, arterial blood pressure, and localized venous pressures from the abdominal IVC and thoracic SVC. All sheep survived the surgery for device implantation without any major complications and went on to undergo a single-stage Fontan operation one mont...

The development of the Fontan procedure in 1971 led to significant improvements in outcomes for patients with single ventricle1. The purpose of this operation is to separate systemic and pulmonary venous return to the heart, thereby increasing systemic oxygenation and relieving volume load on the systemic ventricle. Since its introduction, numerous modifications have been made to the surgical approach. Currently, total bypass of the right heart is most often achieved through staged reconstruction2,3. Typically, the first stage is performed during the first week of life4. Patients then undergo a second stage, which consists of either the Glenn procedure or hemi-Fontan, to redirect blood flow from the superior vena cava (SVC) to the pulmonary artery (PA)5. This is followed by the Fontan procedure, which involves the creation of an extracardiac conduit or lateral tunnel between the inferior vena cava (IVC) and PA6. Surgical advancements such as those made throughout the history of the Fontan procedure could not have been achieved without the use of animal models7.
While the Fontan procedure drastically improves life expectancy for single ventricle patients, it is well recognized that the resulting circulation, which operates without a subpulmonic pump, causes significant disease burden in the long term as a consequence of chronically elevated central venous pressures (CVP) and decreased cardiac output8,9,10,11,12. Chronic Fontan animal models are a valuable asset to studying the late physiological outcomes associated with this operation13. Active data collection of cardiovascular parameters, such as CVP, heart rate, and other vital signs, to capture the postoperative hemodynamic changes is essential for a comprehensive evaluation of developing pathophysiology. Furthermore, animal models are a necessary tool for testing the capability of novel ventricular assist devices designed to alleviate the hemodynamic shortcomings of the Fontan circulation in vivo14,15,16,17,18,19.
However, effective data collection poses a significant challenge. Invasive catheter-based techniques are limited by their transient nature, associated procedural risks, and the inability to monitor the animal&#39;s condition over extended periods. Moreover, previous attempts to create a large animal Fontan model have been hindered by poor survival rates, presumably due to the failure of normal hearts to adapt to the acute establishment of the Fontan circulation7,20. To this end, the use of wireless telemetry systems provides a novel solution for real-time, long-term collection of cardiovascular data in freely moving animals21,22. These devices may also enable close postoperative monitoring, which could lead to improved animal welfare and survival.
Here, we describe the methodology for the successful implantation and use of a wireless telemetry system23 in a chronic Fontan ovine model. This technique provided a robust and reliable means of continuous hemodynamic data collection, enabling the study of venous pressures and other key physiological parameters. Implementation of this technology in preclinical models is critical for advancing our understanding of Fontan physiology and the development of new therapeutic strategies aimed at improving the long-term outcomes of Fontan patients.

<table><tbody><tr><td>0.9% Sodium Chloride solution</td><td>Baxter Healthcare Corporation</td><td>Pharmacy</td><td>Intraoperative fluid resuscitation and wound rinse</td></tr><tr><td>16 G intravenous catheter</td><td>BD</td><td>382259</td><td>For fluid and drug administration</td></tr><tr><td>22 G intravascular catheter</td><td>BD</td><td>381423</td><td>For arterial&amp;nbsp; blood pressure monitoring</td></tr><tr><td>70% isopropyl alcohol</td><td>Aspen Vet</td><td>11795782</td><td>Topical cleaning solution</td></tr><tr><td>ACT cartridge</td><td>Abbot Diagnostics</td><td>03P86-25</td><td>Activated clotting time</td></tr><tr><td>Backhaus towel clamp</td><td>Medline</td><td>MDS1411111</td><td>To affix sterile drape&amp;nbsp;</td></tr><tr><td>Banamine</td><td>Hospira Pharmaceuticals</td><td>Pharmacy</td><td>Postoperative pain control: concentration 50 mg/mL, dose 2.2 mg/kg</td></tr><tr><td>Blood pressure cuff</td><td>Royal Philips</td><td>9.89803E+11</td><td>Non-invasive blood pressure monitoring</td></tr><tr><td>Bupivacaine hydrochloride</td><td>Hospira Pharmaceuticals</td><td>Pharmacy</td><td>Local anesthetic: concentration 2.5 mg/mL, dose 2.5 mg/kg</td></tr><tr><td>Buprenorphine</td><td>Hospira Pharmaceuticals</td><td>Pharmacy</td><td>Postoperative pain control: concentration 0.3 mg/mL, dose 0.03 mg/kg</td></tr><tr><td>Castroviejo needle holder</td><td>Medline</td><td>MDS0750386</td><td>Needle holder when suturing blood vessels</td></tr><tr><td>Cautery cleaner pad</td><td>Cardinal Health</td><td>300-2SS</td><td>To clean cautery pencil tip</td></tr><tr><td>Cautery pencil</td><td>Medline</td><td>ESRK3002L</td><td>For dissection using electrocautery</td></tr><tr><td>Cefazolin</td><td>Hospira Pharmaceuticals</td><td>Pharmacy</td><td>Antibiotic prophylaxis</td></tr><tr><td>Cetacaine</td><td>Cetylite</td><td>220</td><td>Topical anesthetic spray for intubation</td></tr><tr><td>Chloraprep</td><td>BD</td><td>930825</td><td>Topical antiseptic</td></tr><tr><td>Debakey atraumatic forceps</td><td>Medline</td><td>MDS1130630F</td><td>For tissue handling</td></tr><tr><td>Diazepam</td><td>Hospira Pharmaceuticals</td><td>Pharmacy</td><td>Sedative: concentration 5 mg/mL, dose 0.5 mg/kg</td></tr><tr><td>ECG leads</td><td>3M</td><td>2570</td><td>ECG monitoring</td></tr><tr><td>Endotracheal tube, size 8-9</td><td>Covidien</td><td>86452, 86114, or 86454</td><td>To secure airway</td></tr><tr><td>Hartmann hemostatic forceps</td><td>Medline</td><td>MDS1221109</td><td>To clamp blood vessels and hold small sutures</td></tr><tr><td>Heparin</td><td>Hospira Pharmaceuticals</td><td>Pharmacy</td><td>Anticoagulant: 1,000 USP units/mL</td></tr><tr><td>Pressure transducer kit</td><td>Edwards Lifesciences</td><td>VSYPX12N</td><td>For arterial&amp;nbsp; blood pressure monitoring</td></tr><tr><td>Pulse oximeter lingual clip</td><td>Nellcor</td><td>PO736</td><td>For pulse oximetry</td></tr><tr><td>Isoflurane</td><td>Baxter Healthcare Corporation</td><td>Pharmacy</td><td>Anesthetic: dose 1-3%</td></tr><tr><td>Kantrowitz forcep (right angle)</td><td>Medline</td><td>MDS1243528</td><td>For blunt dissection around blood vessels</td></tr><tr><td>Ketamine</td><td>Hospira Pharmaceuticals</td><td>Pharmacy</td><td>Sedative: concentration 100 mg/mL, dose 4 mg/kg</td></tr><tr><td>Laparotomy drape</td><td>Medline</td><td>DYNJP3008</td><td>Sterile drape</td></tr><tr><td>Lubricating jelly</td><td>Medline</td><td>MDS0322273Z</td><td>Endotracheal tube lubricant</td></tr><tr><td>Mayo Hegar needle holder</td><td>Medline</td><td>MDS2418420F</td><td>Needle holder when suturing soft tissue</td></tr><tr><td>Mayo scissors</td><td>Medline</td><td>MDS0816121</td><td>To cut suture</td></tr><tr><td>Metzenbaum curved scissors</td><td>Medline</td><td>MDS3223226</td><td>For sharp dissection</td></tr><tr><td>Needles and syringes</td><td>Cardinal Health</td><td>309604</td><td>For intravenous and subcutaneous drug administration&amp;nbsp;</td></tr><tr><td>Optixcare</td><td>Aventix</td><td>OPX-4252</td><td>Corneal lubricant</td></tr><tr><td>Perma-Hand silk suture</td><td>Ethicon</td><td>C016D</td><td>For blood vessel ligation and attachment of the telemetry device subcutaneously</td></tr><tr><td>PhysioTel Digital wireless telemetry device</td><td>Data Sciences International</td><td>L21 model</td><td>Wireless telemetry device implant</td></tr><tr><td>Pierce microforceps</td><td>Medline</td><td>MDG384908</td><td>Small needle handling&amp;nbsp;</td></tr><tr><td>Plastic tourniquet and suture snare</td><td>Medtronic&amp;nbsp;</td><td>79013</td><td>To facilitate hemostasis during vessel cannulation</td></tr><tr><td>Pressure bag</td><td>Carefusion</td><td>64-10029</td><td>For arterial blood pressure monitoring</td></tr><tr><td>Prolene 6-0 suture</td><td>Ethicon</td><td>8307H</td><td>Purse string stitch for vessel cannulation</td></tr><tr><td>Propofol</td><td>Fresenius Kabi</td><td>Pharmacy</td><td>Anesthetic: concentration 10 mg/mL, dose 20-45 mg/kg/h</td></tr><tr><td>Scalpel #10 blade</td><td>Medline</td><td>MDS15310</td><td>For skin incisions</td></tr><tr><td>Scalpel #11 blade</td><td>Medline</td><td>CISION11CS</td><td>For incision into blood vessels</td></tr><tr><td>Schnidt tonsil forceps</td><td>Medline</td><td>MDS5018719</td><td>For blunt dissection through subcutaneous tissue</td></tr><tr><td>SoftCarry stretcher</td><td>Four Flags Over Aspen</td><td>SSTR-4</td><td>For animal transportation</td></tr><tr><td>Sterile disposable OR towel</td><td>Medline</td><td>MDT2168201</td><td>Sterile drape</td></tr><tr><td>Sterile bowl</td><td>LSL Industries</td><td>5232</td><td>To hold saline solution</td></tr><tr><td>Sterile cotton X-ray detectable gauze sponge</td><td>Medline</td><td>NON21430LF</td><td>Fluid absorption</td></tr><tr><td>Orogastric tube</td><td>Jorgensen Lab, Inc.</td><td>J0348R</td><td>For stomach and rumen decompression</td></tr><tr><td>T-port</td><td>Medline</td><td>DYNDTN0001</td><td>Intravenous catheter tubing connector</td></tr><tr><td>Urine drainage bag</td><td>Covidien</td><td>3512</td><td>Connects to orogastric tube to collect gastric fluids</td></tr><tr><td>Veterinary trocar with stylet</td><td>Braintree Scientific, Inc.</td><td>TRO-STY 7B-12</td><td>To guide telemetry wires through subcutaneous tissue</td></tr><tr><td>Vicryl 2-0 suture</td><td>Ethicon</td><td>VCPB269H</td><td>Closure of subcutaneous soft tissue</td></tr><tr><td>Vicryl 3-0 suture</td><td>Ethicon</td><td>VCPB416H</td><td>Closure of deep dermal layer</td></tr><tr><td>Vicryl 4-0 suture</td><td>Ethicon</td><td>J494H</td><td>Closer of subcuticular layer</td></tr><tr><td>Warming blanket</td><td>Jorgensen Lab, Inc.</td><td>J1034B</td><td>To maintain animal&#039;s body temperature</td></tr><tr><td>Weitlander retractor</td><td>Teleflex Medical</td><td>165358</td><td>For wound retraction</td></tr><tr><td>Yankauer bulb tip suction</td><td>Medline</td><td>DYND50138</td><td>Sterile waste management</td></tr></tbody></table>

wireless telemetry device implantation in a fontan ovine model for continuous and long-term hemodynamic monitoring

Wireless Telemetry Device Implantation in a Fontan Ovine Model for Continuous and Long-Term Hemodynamic Monitoring

While the Fontan procedure drastically improves life expectancy for patients with single ventricle, it is well recognized that the resulting circulation causes significant disease burden long term as a consequence of chronically elevated central venous pressures and decreased cardiac output. Chronic Fontan animal models are a valuable asset to studying the late physiological outcomes associated with this operation and a necessary tool in the evaluation of future devices designed to alleviate Fontan failure. However, previous attempts at the creation of chronic Fontan models have been hindered by poor survival rates. Additionally, effective hemodynamic data collection poses a significant challenge in freely moving animals. To this end, the use of wireless implantable telemetry systems provides a novel solution for real-time and long-term monitoring of cardiovascular data. This protocol describes the methodology for surgical implantation of a wireless telemetry device in a Fontan survival ovine model, facilitating the continuous and ongoing recording of several hemodynamic parameters, including heart rate, arterial blood pressure, and localized pressures in the inferior (IVC) and superior vena cava (SVC). Telemetry devices were implanted with cannulation of either the carotid artery and internal jugular vein or femoral artery and vein, for placement of pressure-sensing catheters in the ascending aorta and SVC or abdominal aorta and IVC, respectively. The use of the wireless telemetry systems enabled close postoperative monitoring following a single-stage Fontan operation, which contributed to improved animal welfare and survival.

Surgical outcomes 
A total of 13 sheep underwent single-stage Fontan surgery involving total cavopulmonary connection with detachment of both the SVC and IVC from the right atrium, direct end-to-side anastomosis of the SVC to PA, and placement of an extracardiac conduit between the IVC and PA. Sheep underwent this procedure at a mean age of 13.3 ± 7.6 months. Of these, 3 sheep underwent wireless telemetry device implantation with placement of pressure-sensing catheters into the abdominal aorta and IVC...

This protocol describes the surgical methodology for implanting a large animal wireless telemetry device to enable continuous and long-term collection of hemodynamic data, including heart rate, arterial blood pressure, inferior and superior vena cava pressures, and cardiac rhythm.

While the Fontan procedure drastically improves life expectancy for patients with single ventricle, it is well recognized that the resulting circulation ...

So our lab conducts clinical translational research focused on congenital heart disease, and we have developed several large animal models to evaluate the performance of tissue-engineered vascular grafts, as well as study the late physiological changes associated with the fontan circulation. Freely moving large animals, close post-operative hemodynamic monitoring, as well as long-term data collection, unlike humans, can pose significant challenges. With our protocol, we are able to obtain long-term and realtime hemodynamic data, which allows us to study the late term physiological changes, as well as initiate goal-directed therapies in our animals, ultimately improving their survival.[Narrator] Position the sheep in the right lateral decubitus on the operating table and secure the left front limb inflection using a slip knot tie to expose the chest. Make a five centimeter longitudinal skin incision above the left carotid artery and internal jugular vein, approximately seven centimeters cranial to the thoracic inlet. Using electrocautery, dissect through the subcutaneous fat, connective tissue, and platysma muscle to expose the neck vessels. Using a combination of blunt and sharp dissection, clear the connective tissue circumferentially from the left carotid artery and internal jugular vein. Now, pass a double looped 2-O silk tie around both vessels, proximal and distal to the cannulation site for temporary vessel ligation. Then make a six centimeter longitudinal incision at the base of the left neck between the scapula and cervical spine. Using a combination of electrocautery and blunt dissection, dissect through the subcutaneous fat and connective tissue to create a six by four centimeter pocket extending toward the spine. Then insert the telemetry device into the subcutaneous pocket, and secure it in place using a 2-0 silk suture. Tunnel the telemetry device antenna under the subcutaneous tissue, and secure it in place using a 2-0 silk suture. Now ,make one centimeter counter skin incisions at the base of the neck, lower left chest, and upper right chest, for placement of the electrocardiogram leads. Tunnel subcutaneously to connect these incisions to the device body pocket, and guide the leads to their intended positions. Place the positive electrocardiogram electrode in the subcutaneous tissue to the left of the lower sternum, removing the silicone tubing, encasing the tip of the steel wire underneath. Place the negative electrode in the subcutaneous tissue to the right of the upper sternum. Prepare the pressure catheters using gel before cannulation. Create a subcutaneous tunnel from the lateral device pocket to the medial neck incision and thread the two pressure catheters through using a 6-O polypropylene suture, place a purse string stitch around the cannulation site on both vessels, and secure it with a plastic tourniquet. Then, tighten the proximal and distal 2-O silk tourniquets around the carotid artery, carefully incise into the vessel at the center of the purse string stitch using a number 11 blade scalpel, and slightly dilate with the tip of a curved hemostat. Insert the pressure catheter for the left ventricular pressure channel into the thoracic ascending aorta. Loosen the proximal silk tourniquet to allow catheter passage, then tighten the purse string suture around the catheter. Repeat the previous steps to cannulate the left internal jugular vein using the pressure catheter for the blood pressure channel, and advance it into the thoracic superior vena cava. Confirm the position of catheter tips in the thoracic superior vena cava and descending aorta using fluoroscopy. Finally, reapproximate the platysma muscle using a 2-O absorbable suture. Close the skin with deep dermal sutures using 3-O absorbable sutures, and subcuticular region with 4-O absorbable sutures. Wireless telemetry device implantation allowed for continuous monitoring of several cardiovascular parameters, including heart rate, arterial pressure and inferior vena cava or superior vena cava pressure. For instance, hemodynamic trends in one sheep following the fontan procedure showed a peak in heart rate around day three, while inferior vena cava pressure exhibited a mild but sustained elevation in pressure from the time of surgery until post-operative day 21. Variations in venous pressures were observed minute to minute, though overall trends appeared to show an acute increase in both abdominal inferior vena cava and thoracic superior vena cava pressures following the establishment of the fontan circulation. Invasive pressure measurements of the thoracic superior vena cava showed mean values fluctuating between two and four millimeters of mercury, corresponding closely with the telemetry device readings, which averaged around 1.1 millimeters of mercury. Abdominal inferior vena cava pressure was consistently higher during recumbent, and dropped significantly whenever the sheep transitioned to a standing position.

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Learn wireless telemetry device implantation for continuous hemodynamic monitoring in a Fontan ovine model. This protocol enables long-term collection of cardiovascular data including heart rate, arterial pressure, and vena cava pressures.

Wireless Telemetry Device Implantation in a Fontan Ovine Model for Continuous and Long-Term Hemodynamic Monitoring

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