Veno-Venous Extracorporeal Membrane Oxygenation in a Mouse

Summary

Here we present a protocol describing the technique of veno-venous extracorporeal membrane oxygenation (ECMO) in a non-intubated, spontaneously breathing mouse. This murine model of ECMO can be effectively implemented in experimental studies of acute and end-stage lung diseases.

Abstract

The use of extracorporeal membrane oxygenation (ECMO) has increased substantially in recent years. ECMO has become a reliable and effective therapy for acute as well as end-stage lung diseases. With the increase in clinical demand and prolonged use of ECMO, procedural optimization and prevention of multi-organ damage are of critical importance. The aim of this protocol is to present a detailed technique of veno-venous ECMO in a non-intubated, spontaneously breathing mouse. This protocol demonstrates the technical design of the ECMO and surgical steps. This murine ECMO model will facilitate the study of pathophysiology related to ECMO (e.g., inflammation,bleeding and thromboembolic events). Due to the abundance of genetically modified mice, the molecular mechanisms involved in ECMO-related complications can also be dissected.

Introduction

Extracorporeal membrane oxygenation (ECMO) is a temporary life support system that takes over functions of the lungs and heart to allow adequate gas exchange and perfusion. Hill et al¹ described the first use of ECMO in patients in 1972; however, it only became widely used after its successful application during the H1N1 influenza pandemic in 2009². Today, ECMO is routinely used as a lifesaving procedure in end-stage heart and lung diseases³. Veno-venous ECMO is increasingly employed as an alternative to invasive mechanical ventilation in awake, non-intubated, spontaneously breathing patients with....

Protocol

Experiments were performed on male C57BL/6 mice, aged 12 weeks. This study was conducted in compliance with guidelines of the German Animal Law under Protocol TSA 16/2250.

1. Materials Preparation

NOTE: All steps are performed under clean, non-sterile conditions. Sterile conditions would be required if animal is to be survived postoperatively.

1. Introduce 3 fenestrations into a 2-Fr polyurethane tube using a surgical blade under a microscope with 16X magnification.
   NOTE: All fenestrations must be located in the distal third of the cannula to ensure optimal blood drainage.
2. Prepare t....

Results

This protocol describes the method of veno-venous ECMO in a mouse. This model is reliable and reproducible, and compared to our previously described model of CPB with respiratory and circulatory arrest^12,13, it is less technically demanding to establish.

ECMO flow in the venous system was maintained between 1.5 and 5 mL/min. The mean arterial pressure was kept between 70.......

Discussion

Previously, we described a successful model of CPB in a mouse^12,13. To implement such a model for acute or end-stage lung disorders we developed an easy-to-use veno-venous ECMO circuit for mice. Different to the CPB model, veno-venous ECMO does not require complicated surgical procedures such as sternotomy and clamping of the aorta, thus reducing the risk of wound bleeding in a fully heparinized animal. To avoid embolization of the oxygenator with blood clots, 2........

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Sterofundin	B.Braun Petzold GmbH	PZN:8609189	in 1:1 with Tetraspan
Tetraspan 6% Solution	B. Braun Melsungen AG	PZN: 05565416	in 1:1 with Sterofundin
Heparin Natrium 25.000	Ratiopharm GmbH	PZN: 3029843	2,5 IU per ml of priming
NaHCO3 8,4% Solution	B. Braun Melsungen AG	PZN: 1579775	3% in priming solution
Carprofen	Zoetis Inc., USA	PZN:00289615	5mg/kg/BW
1 Fr PU Catheter	Instechlabs INC., USA	C10PU-MCA1301	carotide artery
2 Fr PU Catheter	Instechlabs INC., USA	C20PU-MJV1302	jugular vein
8-0 Silk suture braided	Ashaway Line & Twine Co., USA	75290	ligature
Isoflurane	Piramal Critical Care GmbH	PZN:9714675	narcosis
Spring Scissors - 6mm Blades	Fine Science Tools GmbH	15020-15	instruments
Spring Scissors - 2mm Blades	Fine Science Tools GmbH	15000-03	instruments
Halsted-Mosquito Hemostat	Fine Science Tools GmbH	13009-12	instruments
Dumont #55 Forceps	Fine Science Tools GmbH	11295-51	instruments
Castroviejo Micro Needle Holder - 9cm	Fine Science Tools GmbH	12060-02	instruments
Micro Serrefines	Fine Science Tools GmbH	18555-01	instruments
Bulldog Serrefine	Fine Science Tools GmbH	18050-28	instruments
Isoflurane Vaporizer Drager 19.1	Drägerwerk AG & Co. KGaA		anesthesia 1,3 -2,5%
Multichannel Data Aquisition Device with ISOHEART Software	Hugo Sachs Elektronik GmbH, Germany		invasive pressure, ECG, t °C
i-STAT portable device	Abbott Laboratories, Lake Bluff, Illinois, USA		blood gas analysis
i-STAT CG4+ and CG8+ cartridges	Abbott Laboratories, Lake Bluff, Illinois, USA		blood gas analysis
C57Bl/6 mice, male, 30 g, 14 weeks old	Charles River Laboratories		housed 1 week before