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

Summary

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

Abstract

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

Introduction

Hemorrhage continues to be the dominant cause of preventable deaths in patients undergoing traumatic events, accounting for 90% of trauma-related deaths in the military setting and 40% of post-traumatic deaths in the civilian population^1,2. Although direct pressure can treat compressible hemorrhage, non-compressible torso hemorrhage remains difficult to treat and can be lethal without prompt hemostatic control. The historical approach of resuscitative thoracotomy or laparotomy with aortic cross-clamping has proved to be extremely invasive^3,4. This inte....

Protocol

In conducting research using animals, the investigators adhered to the Animal Welfare Act Regulations and other Federal statutes relating to animals and experiments involving animals and the principles set forth in the current version of the Guide for Care and Use of Laboratory Animals of the National Research Council. This study protocol was approved by the University of Michigan Institutional Animal Care and Use Committee (IACUC). The experiments were conducted in compliance with all regulations and guidelines regardin.......

Discussion

In this protocol, we highlighted a hemorrhagic shock model in swine. This model has been shown to be both reliable and reproducible^16,17,18,19. Models similar to this have been employed in several scientific studies investigating the effects of hemorrhagic shock on animal physiology^16,20. Furthermore, this model has also been used for t.......

Materials

Name	Company	Catalog Number	Comments
Yorkshire-Landrace Swine	Michigan State University Veterinary Farm
Anesthesia: Telazol	Pfizer		Dose: 2-8 mg/kg; IM
Anti-cholinergic: Atropine	Pfizer		Dose: 1mg, IM
Anesthesia: Isoflurane	Baxter		Dose: 1-5%, INH
Betadine	Humco
Alcohol 70%	Humco	NDC 0395-4202-28
Datex-Aespire Anesthesia Machine	GE Healthcare	7900
Endotracheal tube	DEE Veterinary	20170518	Appropriate size for animal (6.5 or 7.0F)
Laryngoscope	Miller	85-0045
Stylet	Hudson RCI	5-151--1
Jelco 20G IV Catheter	Smiths Medical	4054
Operating Room Monitor (Vital Signs Monitor)	SurgiVet Advisor	V9201	May require at least 2
Surgical Gowns	Kimberly Clark	90142	Use appropriate size for surgeon.
Sterile surgical gloves	Cardinal Health (Allegiance)	22537-570	Use appropriate size for surgeon.
Cautery Pencil	Medline	ESPB 2000
Suction tubing	Medline	DYND50251
Sunction tip: Yankauer	Medline	DYND50130
Bovie Aaron 1250 Electrocautery Unit	Bovie Medical Co. FL	BOV-A1250U
Salpel Blade - Size #10	Cardinal Health (Allegiance)	32295-010
Scalpel Handle	Martin	10-295-11
Debakey Forceps	Roboz	RS-7562
Weitlander Retractor	Roboz	RS-8612
Mayo Scissors	Roboz	RS-76870SC
Army-navy Retractor	Teleflex	164715
Mixter Right-angle Forceps	Teleflex	175073
5F (1.7 mm) 11 cm Insertion Sheath with 0.35" Guidewire	Boston Scientific	16035-05B
8F (2.7 mm) 11 cm Insertion Sheath with 0.35'' Guidewire	Boston Scientific	16035-08B
20G angled Introducer Needle	Arrow	AK-09903-S
14F (4.78 mm) 13 cm Insertion Sheath with 10F dilator	Cook Medical	G08024
2-0 Silk 18'' 45 cm	Ethicon	A185H
3-0 Vicryl 36'' 90 cm	Ethicon	J344H
3-0 Nylon 18'' 45 cm	Ethicon	663G
4-0 Prolene 30'' 75 cm	Ethicon	8831H
20 ml syringe	Metronic/Covidien	8881512878
3 mL syringe	Metronic/Covidien	1180300555
6 mL syringe	Metronic/Covidien	1180600777
1000ml 0.9% Saline	Baxter	2B1324X
Foley Catheter (18F 30 cc)	Bard	0166V18S
Urinary Drainage Bag	Bard	154002
9F 10 cm Insertion Sheath	Arrow	AK-09903-S
Swan-Ganz pulmonary artery catheter (8F)	Edwards Lifesciences co. CA	746F8
Carotid Flow Probe System	Transonic, Ithaca, NY		3, 4, or 6 mm probes
SABOT catheter	Hayes Inc.
CODA balloon catheter	Cook Medical	8379144
Ultrasound, M-Turbo	SonoSite
Amplatz Stiff Guidewire (0.035 inch, 260 cm)	Cook Medical	G03460
Arterial Blood Gas Syringes	Smiths Medical	4041-2
Arterial Blood Gas Analyzer	Nova Biochemical	ABL800
Masterflex Pump	Cole Palmer	HV-77921-75
Blood Collection Bags	Terumo	1BBD606A
Macro IV drip set	Hospira	12672-28
Pentobarbital	Pfizer		Dose: 100 mg/kg; IV
Eppendorf Tubes	Sorenson	11590
50 cc conical tubes	Falcon	352097
Formalin	Fisherbrand	431121
Bair Hugger Normothermia System	Arizant Healthcare, Inc.