The authors have no acknowledgements.

Rules governed by German legislation for animal studies as well as Principles of Laboratory Animal Care (National Institutes of Health publication ed. 8, 2011) were followed. Official permission is granted from the governmental animal care office (Landesamt f&#252;r Natur, Umwelt und Verbraucherschutz Nordrhein-Westfalen, Recklinghausen, Germany).
1. Animals
<ol>
	<li>Use female German landrace pigs (weighing 25-30 kg) housed in open cages.</li>
	<li>Use 5 animals per group (argon and helium...

<ol>
	<li>Link, W. J., Incropera, F. P., Glover, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+plasma+scalpel:+comparison+of+tissue+damage+and+wound+healing+with+electrosurgical+and+steel+scalpels.">A plasma scalpel: comparison of tissue damage and wound healing with electrosurgical and steel scalpels.</a> ArchSurg. 111, 392-397 (1976).</li><li>Kwon, A. H., Inui, H., Kamiyama, Y. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Successful+laparoscopic+haemostasis+using+an+argon+beam+coagulator+for+blunt+traumatic+splenic+injury.">Successful laparoscopic haemostasis using an argon beam coagulator for blunt traumatic splenic injury.</a> EurJSurg. 167, 316-318 (2001).</li><li>Frilling, A., 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=Effectiveness+of+a+new+carrier-bound+fibrin+sealant+versus+argon+beamer+as+haemostatic+agent+during+liver+resection:+a+randomised+prospective+trial.">Effectiveness of a new carrier-bound fibrin sealant versus argon beamer as haemostatic agent during liver resection: a randomised prospective trial.</a> Langenbecks ArchSurg. 390, 114-120 (2005).</li><li>Raiser, J., Zenker, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Argon+plasma+coagulation+for+open+surgical+and+endoscopic+applications:+state+of+the+art.">Argon plasma coagulation for open surgical and endoscopic applications: state of the art.</a> J Phys Appl Phys. 39 (16), 3520-3523 (2006).</li><li>Farin, G., Grund, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Technology+of+argon+plasma+coagulation+with+particular+regard+to+endoscopic+applications.">Technology of argon plasma coagulation with particular regard to endoscopic applications.</a> EndoscSurgAllied Technol. 2, 71-77 (1994).</li><li>Grund, K. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Argon+plasma+coagulation+(APC):+ballyhoo+or+breakthrough?.">Argon plasma coagulation (APC): ballyhoo or breakthrough?.</a> Endoscopy. 29, 196-198 (1997).</li><li>Glowka, T. R., Standop, J., Paschenda, P., Czaplik, M., Kalff, J. C., Tolba, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Argon+and+helium+plasma+coagulation+of+porcine+liver+tissue.">Argon and helium plasma coagulation of porcine liver tissue.</a> J Int Med Res. , (2017).</li><li>Dowling, R. D., Ochoa, J., Yousem, S. A., Peitzman, A., Udekwu, A. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Argon+beam+coagulation+is+superior+to+conventional+techniques+in+repair+of+experimental+splenic+injury.">Argon beam coagulation is superior to conventional techniques in repair of experimental splenic injury.</a> JTrauma. 31, 717-720 (1991).</li><li>Go, P. M., Goodman, G. R., Bruhn, E. W., Hunter, J. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+argon+beam+coagulator+provides+rapid+hemostasis+of+experimental+hepatic+and+splenic+hemorrhage+in+anticoagulated+dogs.">The argon beam coagulator provides rapid hemostasis of experimental hepatic and splenic hemorrhage in anticoagulated dogs.</a> JTrauma. 31, 1294-1300 (1991).</li><li>Brand, C. U., Blum, A., Schlegel, A., Farin, G., Garbe, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Application+of+argon+plasma+coagulation+in+skin+surgery.">Application of argon plasma coagulation in skin surgery.</a> Dermatology. 197, 152-157 (1998).</li><li>Carus, T., Rackebrandt, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Collateral+tissue+damage+by+several+types+of+coagulation+(monopolar,+bipolar,+cold+plasma+and+ultrasonic)+in+a+minimally+invasive,+perfused+liver+model.">Collateral tissue damage by several types of coagulation (monopolar, bipolar, cold plasma and ultrasonic) in a minimally invasive, perfused liver model.</a> ISRNSurg. , 518924 (2011).</li><li>Bludau, M., Vallbohmer, D., Gutschow, C., Holscher, A. H., Schroder, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+measurement+of+gastric+mucosal+microcirculation+using+a+combined+laser+Doppler+flowmeter+and+spectrophotometer.">Quantitative measurement of gastric mucosal microcirculation using a combined laser Doppler flowmeter and spectrophotometer.</a> DisEsophagus. , (2008).</li><li>Beckert, S., Witte, M. B., Konigsrainer, A., Coerper, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+impact+of+the+Micro-Lightguide+O2C+for+the+quantification+of+tissue+ischemia+in+diabetic+foot+ulcers.">The impact of the Micro-Lightguide O2C for the quantification of tissue ischemia in diabetic foot ulcers.</a> Diabetes Care. 27, 2863-2867 (2004).</li><li>Erdogan, D., de Graaf, W., van Gulik, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adhesive+strength+of+fibrinogen-coated+collagen+patch+or+liquid+fibrin+sealant+in+an+experimental+liver+resection+model+in+pigs.">Adhesive strength of fibrinogen-coated collagen patch or liquid fibrin sealant in an experimental liver resection model in pigs.</a> Eur Surg Res Eur Chir Forsch Rech Chir Eur. 41 (3), 298-302 (2008).</li><li>Knobloch, K., 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=Microcirculation+of+the+sternum+following+harvesting+of+the+left+internal+mammary+artery.">Microcirculation of the sternum following harvesting of the left internal mammary artery.</a> ThoracCardiovascSurg. 51, 255-259 (2003).</li><li>Kanzler, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recommendation+for+severity+assessment+following+liver+resection+and+liver+transplantation+in+rats:+Part+I.">Recommendation for severity assessment following liver resection and liver transplantation in rats: Part I.</a> Lab Anim. 50 (6), 459-467 (2016).</li><li>Pehb&#246;ck, D., Dietrich, H., Klima, G., Paal, P., Lindner, K. H., Wenzel, V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anesthesia+in+swine+optimizing+a+laboratory+model+to+optimize+translational+research.">Anesthesia in swine optimizing a laboratory model to optimize translational research.</a> Anaesthesist. 64 (1), 65-70 (2015).</li><li>Nykonenko, A., V&#225;vra, P., Zon&#269;a, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Anatomic+Peculiarities+of+Pig+and+Human+Liver.">Anatomic Peculiarities of Pig and Human Liver.</a> Exp Clin Transplant Off J Middle East Soc Organ Transplant. 15 (1), 21-26 (2017).</li><li>Fechner, G., von Pezold, J., Luzar, O., Hauser, S., Tolba, R. H., M&#252;ller, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modified+spectrometry+(O2C+device)+of+intraoperative+microperfusion+predicts+organ+function+after+kidney+transplantation:+a+pilot+study.">Modified spectrometry (O2C device) of intraoperative microperfusion predicts organ function after kidney transplantation: a pilot study.</a> Transplant Proc. 41 (9), 3575-3579 (2009).</li><li>Patterson, E. J., Scudamore, C. H., Owen, D. A., Nagy, A. G., Buczkowski, A. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Radiofrequency+ablation+of+porcine+liver+in+vivo:+effects+of+blood+flow+and+treatment+time+on+lesion+size.">Radiofrequency ablation of porcine liver in vivo: effects of blood flow and treatment time on lesion size.</a> AnnSurg. 227, 559-565 (1998).</li></ol>

Rodent models for liver surgery are established for a long time16. Nevertheless, large animal models offer certain advantages: no microsurgical equipment is needed as standard operative equipment for humans can be applied, surgical techniques are comparable to clinical use and standard clinical evaluation methods can be transferred to the experiments. For example, standard clinical blood tests can be carried out without the need for special laboratory test methods (Figure 10</...

Argon plasma coagulation (APC) is a widely used instrument in abdominal surgery for more than three decades1,2. It is a standard technique for the achievement of secondary hemostasis after major hepatectomy by sealing the liver cut surface to prevent later hemorrhages3. Plasma coagulation is a specialized form of radiofrequency electrocautery, which delivers the electrical energy through an arc of ionized gas. Providing monopolar electrothermal hemostasis, this noncontact technique has the advantage of preventing the electrode to stick to the tissue4. The ionized gas beam is automatically directed to the area of the lowest electrical resistance and is turned away when resistance rises due to desiccation to other areas not yet desiccated. This produces a uniform limited depth of coagulation5,6. Factors influencing the coagulation effect are the activation time, the power setting of the coagulation device and the distance from the probe to the tissue. Helium is another carrier gas, which can be used for plasma coagulation7. Recent clinical studies concentrated on clinical outcomes rather than histological and functional findings3,8,9, while experimental studies focused on in vitro investigations10 or experiments on isolated perfused organs11.
The underlying protocol allows the study of the effects of plasma coagulation in a large animal model close to the clinical application using standard human equipment on pigs: Microcirculation is assessed noninvasively by a laser Doppler flowmeter and spectrophotometer, which is a standard clinical tool for this indication12,13. Temperature changes during coagulation are monitored with an infrared thermometer and a thermographic camera. The depth of coagulation is measured on histological hematoxylin/eosin stained sections after harvesting of tissue samples. For the comparison with other means for secondary hemostasis, burst pressure experiments are performed. In contrast to previously described techniques14, these are conducted on explanted organs to exclude blood pressure related effects. In addition to the described investigations on the local effects of plasma coagulation, standard blood tests can also be undertaken in the porcine model.

<table border="0" cellpadding="0" cellspacing="0" width="824">
	<tbody>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Xylazine 20 mg/mL</td>
			<td style="width:184px;">Vetoquinol GmbH</td>
			<td style="width:192px;">Xylapan</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Ketamine 100 mg/mL</td>
			<td style="width:184px;">Ceva GmbH</td>
			<td style="width:192px;">Ceva Ketamine Injection</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Atropine 100 mg / 10 mL</td>
			<td style="width:184px;">Dr. Franz K&#246;hler Chemie GmbH</td>
			<td style="width:192px;">Atropinsulfat K&#246;hler 100mg Amp.</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;">Propofol</td>
			<td style="width:184px;">Fresenius Kabi GmbH</td>
			<td style="width:192px;">Propofol 1% MCT Fresenius</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;">Fentanyl</td>
			<td style="width:184px;">KG Rotexmedica GmbH</td>
			<td style="width:192px;">Fentanyl 0,5mg Rotexmedica</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;">Isoflurane</td>
			<td style="width:184px;">Abbot GmbH</td>
			<td style="width:192px;">Forene 100% (V/V) 250 mL</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;">Ringer&#39;s lactate solution</td>
			<td style="width:184px;">Baxter Deutschland GmbH</td>
			<td style="width:192px;"></td>
			<td style="width:232px;">sodium 131mmol/l, potassium 5 mmol/l, calcium 2 mmol/l, cloride 111 mmol/l, lactate 29 mmol/l</td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Surgical disinfactant</td>
			<td style="width:184px;">Sch&#252;lke &#38; Mayr GmbH</td>
			<td style="width:192px;">Kodan Tinktur forte gef&#228;rbt 1l 104804</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Motorized microscope</td>
			<td style="width:184px;">Nikon Instruments Europe</td>
			<td style="width:192px;">Eclipse TE2000-E</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Microscope camera</td>
			<td style="width:184px;">Nikon Instruments Europe</td>
			<td style="width:192px;">Digitalsight DS-Qi1Mc</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Imaging software</td>
			<td style="width:184px;">Nikon Instruments Europe</td>
			<td style="width:192px;">NIS elements Vers. 4.40</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Plasma coagulator</td>
			<td style="width:184px;">S&#246;ring GmbH</td>
			<td style="width:192px;">CPC-1000</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Argon gas</td>
			<td style="width:184px;">Linde AG</td>
			<td style="width:192px;">Argon 4.8&#160;</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Helium gas</td>
			<td style="width:184px;">Linde AG</td>
			<td style="width:192px;">Helium 4.8</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">O2C</td>
			<td style="width:184px;">LEA Medizintechnik GmbH</td>
			<td style="width:192px;">O2C Version 1212</td>
			<td style="width:232px;">with LF-2 or LF-3 probe</td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;">Infrared thermometer</td>
			<td style="width:184px;">Voltcraft</td>
			<td>VOLTCRAFT IR 260-8S</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Thermographic camera</td>
			<td>InfraTec GmbH</td>
			<td>VarioCAM HD head 820</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Thermographic analysis sofrtware</td>
			<td>InfraTec GmbH</td>
			<td style="width:192px;">IRBIS 3</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Mayer&#39;s Hematoxylin solution</td>
			<td></td>
			<td style="width:192px;">Merck 1.09249</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Eosin solution</td>
			<td style="width:184px;">VWR International GmbH</td>
			<td style="width:192px;">Merck 1.09844</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Rollerpump Masterflex L/S easy Load</td>
			<td style="width:184px;">Cole-Parmer Instrument Company</td>
			<td style="width:192px;">model 7518-10</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Perfusorpump</td>
			<td style="width:184px;">B. Braun Melsungen AG</td>
			<td style="width:192px;">Perfusor secura FT</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Digital pressure meter</td>
			<td style="width:184px;">Greisinger electronic</td>
			<td style="width:192px;">GMH 3161</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Perfusorsyringe, 50 mL</td>
			<td style="width:184px;">B. Braun Melsungen AG</td>
			<td style="width:192px;">REF 8728810 F</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Perfusor line, Type IV Standard, PVC Luer lock</td>
			<td style="width:184px;">B. Braun Melsungen AG</td>
			<td style="width:192px;">REF 8722960</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">3-Way stopcock, Dicofix C35C</td>
			<td style="width:184px;">B. Braun Melsungen AG</td>
			<td style="width:192px;">REF 16494 C</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Silk 2-0. 3 metric</td>
			<td style="width:184px;">Resorba</td>
			<td style="width:192px;">REF H5F</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">Vicryl 4-0 Sutupak</td>
			<td style="width:184px;">Ethicon</td>
			<td>V1224H</td>
			<td style="width:232px;"></td>
		</tr>
		<tr height="47">
			<td height="47" style="height:47px;width:216px;">NaCl 0.9 %</td>
			<td style="width:184px;">B. Braun Melsungen AG</td>
			<td style="width:192px;"></td>
			<td style="width:232px;"></td>
		</tr>
	</tbody>
</table>

assessment of plasma coagulation on liver tissue in a large animal model in vivo

Plasma coagulation as a form of electrocautery is used in liver surgery for decades to seal the large liver cut surface after major hepatectomy to prevent hemorrhages at a later stage. The exact effects of plasma coagulation on liver tissue are only poorly examined. In our porcine model, the coagulation effects can be examined close to the clinical application. A combined laser Doppler flowmeter and spectrophotometer documents microcirculation changes during coagulation at 8 mm tissue depth noninvasively, providing quantifiable information about hemostasis beyond the subjective clinical impression. The temperature at coagulation site is assessed with an infrared thermometer prior and post coagulation and with a thermographic camera during coagulation, a measurement of the gas beam temperature is not possible due to the upper threshold of the devices. The depth of coagulation is measured microscopically on hematoxylin/eosin stained sections after calibration with an object micrometer and gives an exact information about the power setting-coagulation depth-relation. The sealing effect is examined on the bile ducts as it is not possible for a plasma coagulator to seal larger blood vessels. Burst pressure experiments are carried out on explanted organs to rule out blood pressure related effects.

Microcirculation: Utilizing the diagnostic device for hemostasis following plasma coagulation can be demonstrated by microcirculation changes. Capillary blood flow (displayed as arbitrary units (AU)) decreases from a baseline value of 142.7 &#177; 76.08 AU to 57.78 &#177; 49.57 AU at 25 W device output power, to 48.5 &#177; 7.26 AU at 50 W and to 5.04 &#177; 1.31 AU at 100 W (Figure 4).
<p class="jove_content" fo:keep-together.within-page...

Watch this Scientific Journal Video about Assessment of Plasma Coagulation on Liver Tissue in a Large Animal Model In Vivo at JoVE.com

Assessment of Plasma Coagulation on Liver Tissue in a Large Animal Model In Vivo

Here we present a protocol to experimentally assess plasma coagulation in liver tissue in vivo. In a porcine model, microcirculation is examined by laser Doppler, coagulation depth is measured histologically, temperature at coagulation site by infrared thermometer and thermographic camera, and duct sealing effect is documented by burst pressure experiments.

Assessment of Plasma Coagulation on Liver Tissue in a Large Animal Model In Vivo

Plasma coagulation as a form of electrocautery is used in liver surgery for decades to seal the large liver cut surface after major hepatectomy to prevent ...

This method can help answer key questions in the field of clinical liver surgery about the energy setting depth relation of argon and helium plasma coagulation and the plasma coagulation process itself. The main advantages of this technique are that the large animal model is similar to the clinical application and that no special equipment is needed. Infrared thermography can be used to monitor temperature distribution and temperature decay but also to monitor breathing rate and pies.Furthermore, inflammation processes can be monitored by infrared thermography. Demonstrating the procedure will be Pascal Paschenda, a technician from our group. At least one hour before beginning the procedure, switch on the thermographic camera notebook and infrared thermometer.When the equipment is ready, place an anesthetized 25 to 30 kilogram female German Landrace pig in the supine position on a standard surgical table and use a standard surgical swab to disinfect the surgical area three times with a standard surgical disinfectant. Then use a scalpel to make a wide midline laparotomy from the xiphoid process to the pubis and install surgical retractors to expose the liver tissue. To obtain baseline microcirculation measurements, switch on the laser doppler flow meter and spectrophotometer and use a flat probe to measure the flow and velocity.Next, switch on the plasma coagulation device, open the appropriate carrier gas bottle, and adjust the gas flow to three liters per minute. Select the appropriate coagulation device output power and use a titanium mold with a square aperture of one by one square centimeter to standardize the coagulation zone. Then use a one centimeter probe distance to coagulate the region for five seconds.To measure the post coagulation microcirculation, place the flat probe on each coagulation site to measure the flow and velocity of each site. To measure the temperature at each site, adjust the focus of the thermographic camera and set the frame over the first coagulation site so that the region of coagulation and the surrounding tissue affected by the heat transfer are located in the middle of the field of view. Record the coagulation process with the plasma coagulator on the liver surface with a thermographic camera over a two minute period.Then analyze the image sequences with the appropriate thermography analysis software. To measure the burst pressure, first switch on the automatic pumps and pressure meter. Next, divide all of the ligamentous connections to the liver and divide the hepatic pedicle above the superior duodenal flexure, leaving long portions of portal vein and common bile duct intact.Then divide the caval vein above and below the liver to allow retrieval of the organ. Using sharp scissors, resect half of the left medial liver lobe and plasma coagulate the cut surface. Isolate the portal vein, common hepatic artery, and bile duct in the hepatic pedicle.Using overhold forceps, clamp the portal vein. Then use a monofil suture 4.0 to ligate the vessel. Clamp the common hepatic artery with a second pair of overhold forceps and ligate the artery with another monofil suture 4.0.Insert a French 16 catheter into the common bile duct, ligating the duct with 2.0 silk suture. And connect the catheter to the automatic pumps. Install a three-way stopcock with a pressure meter and fill a profusion syringe with saline.Start the automatic pumps with a delivery rate of 99 milliliters per hour. Then monitor the liver cut surface and pressure meter for leakage and record the burst pressure. In this representative experiment, the capillary blood flow decreased about 60%from baseline at 25 watts of device output power, 66%at 50 watts, and nearly 100%at 100 watts.No change in temperature was observed during or after plasma coagulation. Plasma coagulation creates a superficial zone of necrosis that can be easily distinguished from the normal liver parenchyma. Following helium plasma coagulation, the coagulation depth increases significantly in direct correlation to the applied plasma device output power.Note that burst pressure measurements carried out on the cut surface of the explanted left medial liver lobe demonstrate no difference after helium or argon plasma coagulation. Using these techniques, the last to quantify the local coagulatory effect and to estimate the bile duct sealing effect of plasma coagulation. These techniques can also be used to compare different means of bilio and hemostasis in a surgical setting similar to that in human patients.Further, the hemo and biliostatic effects of plasma coagulation can be applied after major hepatectomies in the same model. After watching this video, you should have a good understanding of how to assess the major effects of argon and helium plasma coagulation in a large animal model.

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JoVE Journal

Medicine

8.7K visualizações.  University of Bonn. This method can help answer key questions in the field of clinical liver surgery about the energy setting depth relation of argon and helium plasma coagulation and the plasma coagulation process itself. The main advantages of this technique are that the large animal model is similar to the clinical application and that no special equipment is needed. Infrared thermography can be used to monitor temperature distribution and temperature decay but also to monitor breathing rate and pies.F...