Normothermic Negative Pressure Ventilation Ex Situ Lung Perfusion: Evaluation of Lung Function and Metabolism

Summary

This paper describes a porcine model of negative pressure ventilation ex situ lung perfusion, including procurement, attachment, and management on the custom-made platform. Focus is made on anesthetic and surgical techniques, as well as troubleshooting.

Abstract

Lung transplantation (LTx) remains the standard of care for end-stage lung disease. A shortage of suitable donor organs and concerns over donor organ quality exacerbated by excessive geographic transportation distance and stringent donor organ acceptance criteria pose limitations to current LTx efforts. Ex situ lung perfusion (ESLP) is an innovative technology that has shown promise in attenuating these limitations. The physiologic ventilation and perfusion of the lungs outside of the inflammatory milieu of the donor body affords ESLP several advantages over traditional cold static preservation (CSP). There is evidence that negative pressure ventilation (NPV) ESLP is superior to positive pressure ventilation (PPV) ESLP, with PPV inducing more significant ventilator-induced lung injury, pro-inflammatory cytokine production, pulmonary edema, and bullae formation. The NPV advantage is perhaps due to the homogenous distribution of intrathoracic pressure across the entire lung surface. The clinical safety and feasibility of a custom NPV-ESLP device have been demonstrated in a recent clinical trial involving extender criteria donor (ECD) human lungs. Herein, the use of this custom device is described in a juvenile porcine model of normothermic NPV-ESLP over a 12 h duration, paying particular attention to management techniques. Pre-surgical preparation, including ESLP software initialization, priming, and de-airing of the ESLP circuit, and the addition of anti-thrombotic, anti-microbial, and anti-inflammatory agents, is specified. The intraoperative techniques of central line insertion, lung biopsy, exsanguination, blood collection, cardiectomy, and pneumonectomy are described. Furthermore, particular focus is paid to anesthetic considerations, with anesthesia induction, maintenance, and dynamic modifications outlined. The protocol also specifies the custom device's initialization, maintenance, and termination of perfusion and ventilation. Dynamic organ management techniques, including alterations in ventilation and metabolic parameters to optimize organ function, are thoroughly described. Finally, the physiological and metabolic assessment of lung function is characterized and depicted in the representative results.

Introduction

Lung transplantation (LTx) remains the standard of care for end-stage lung disease¹; however, LTx has significant limitations including inadequate donor organ utilization² and a waitlist mortality of 40%³, which is higher than any other solid organ transplant^4,5. Donor organ utilization rates are low (20-30%) due to organ quality concerns. Excessive geographic transportation distance compounded by stringent donor organ acceptance criteria exacerbates these quality concerns. LTx also trails other solid organ transplants in terms of long-ter....

Protocol

The procedures performed in this manuscript comply with the guidelines of the Canadian Council on Animal Care and the guide for the care and use of laboratory animals. The institutional animal care committee of the University of Alberta approved the protocols. Female juvenile Yorkshire pigs between 35-50 kg were used exclusively. Proper biosafety training was required by all individuals involved in ESLP procedures. A schematic overview of the entire NPV-ESLP experiment is represented in Figure 1

Discussion

There are several critical surgical steps along with troubleshooting needed to ensure a successful ESLP run. Juvenile porcine lungs are extremely delicate compared to adult human lungs, so the procuring surgeon must be cautious when handling porcine lungs. It is critical to attempt a "no-touch" technique to avoid causing trauma and atelectasis when dissecting out the lungs. "No-touch" means using the bare minimum amount of manual manipulation of the lungs during procurement. Recruitment maneuvers while on.......

Materials

Name	Company	Catalog Number	Comments
0 ETHIBOND Green 1 x 36" Endo Loop 0	ETHICON	D8573
2-0 SILK Black 12" x 18" Strands	ETHICON	SA77G
ABL 800 FLEX Blood Gas Analyzer	Radiometer	989-963
Adult-Pediatric Electrostatic Filter HME - Small	Covidien	352/5877
Arterial Filter	SORIN GROUP	01706/03
Backhaus Towel Clamp	Pilling	454300
Biomedicus Pump	Maquet	BPX-80
Cable Ties – White 12”	HUASU International	HS4830001
Calcium Chloride	Fisher Scientific	C69-500G
Cooley Sternal Retractor	Pilling	341162
CUSHING Gutschdressing Forceps	Pilling	466200
D-glucose	Sigma-Aldrich	G5767-500G
Deep Deaver Retractor	Pilling	481826
Debakey Straight Vascular Tissue Forceps	Pilling	351808
Debakey-Metzenbaum Dissecting	Pilling	342202
Scissors	Pilling	342202
Endotracheal Tube 9.0mm CUFD	Mallinckrodt	9590E	Cuff removed for ESLP apparatus
Flow Transducer	BIO-PROBE	TX 40
Human Albumin Serum	Grifols Therapeutics	2223708
Infusion Pump	Baxter	AS50
Inspire 7 M Hollow Fiber Membrane Oxygenator	SORIN GROUP	K190690
Intercept Tubing 1/4" x 1/16" x 8'	Medtronic	3108
Intercept Tubing 3/8" x 3/32" x 6'	Medtronic	3506
Intercept Tubing Connector 3/8" x 1/2"	Medtronic	6013
MAYO Dissecting Scissors	Pilling	460420
Medical Carbon Dioxide Tank	Praxair	5823115
Medical Nitrogen Tank	Praxair	NI M-K
Medical Oxygen Tank	Praxair	2014408
Organ Chamber	Tevosol
PlasmaLyte A	Baxter	TB2544
Poole Suction Tube	Pilling	162212
Potassium Phosphate	Fischer Scientific	P285-500G
Scale	TANITA	KD4063611
Silicon Support Membrane	Tevosol
Sodium Bicarbonate	Sigma-Aldrich	792519-1KG
Sodium Chloride 0.9%	Baxter	JB1324
Sorin XTRA Cell Saver	SORIN GROUP	75221
Sternal Saw	Stryker	6207
Surgical Electrocautery Device	Kls Martin	ME411
Temperature Sensor probe	Omniacell Tertia Srl	1777288F
THAM Buffer	Thermo Fisher Scientific	15504020	made from UltraPureTM Tris
TruWave Pressure Transducer	Edwards	VSYPX272
Two-Lumen Central Venous Catheter 7fr	Arrowg+ard	CS-12702-E
Vorse Tubing Clamp	Pilling	351377
Willauer-Deaver Retractor	Pilling	341720
Yankauer Suction Tube	Pilling	162300