Determination of Cardiac Output in a Porcine Model for Ex Vivo Pulmonary Perfusion

Podsumowanie

This protocol describes the surgical technique used for the placement of a thermodilution catheter through the jugular vein in pigs to estimate cardiac output and ensure adequate lung perfusion during ex vivo lung perfusion (EVLP).

Streszczenie

Due to their physiological similarities to humans, pigs are used as experimental models for ex vivo lung perfusion (EVLP). EVLP is a technique that perfuses lungs that are not suitable for transplantation via an extracorporeal circulation pump to improve their function and increase their viability. Existing EVLP protocols are differentiated by the type of perfusion solution and perfusion flow, which varies from 40%-100% of the estimated cardiac output (CO) according to the body surface area (BSA). Devices for measuring CO use simple physical principles and other mathematical models. Thermodilution in animal models continues to be the reference standard for estimating CO because of its simplicity and ease of reproduction. Therefore, the objective of this study was to reproduce the measurement of CO by thermodilution in pigs and compare its precision and accuracy with those obtained by the BSA, weight, and Fick's method, to establish perfusion flow during EVLP. In 23 pigs, a thermodilution catheter was placed in the right jugular vein, and the carotid artery on the same side was cannulated. Blood samples were obtained for gasometry, and CO was estimated by thermodilution, adjusted body surface area, Fick's principle, and per body weight. The CO obtained by the BSA was greater (p = 0.0001, ANOVA, Tukey) than that obtained by the other methods. We conclude that although the methods used in this study to estimate CO are reliable, there are significant differences between them; therefore, each method must be evaluated by the investigator to determine which meets the needs of the protocol.

Wprowadzenie

In lung transplantation centers, ex vivo lung perfusion (EVLP) is a tool that helps increase the potential for donation of lungs that do not meet the standard criteria for transplantation¹. This is achieved by preserving and improving the lung functionality of donors with brain death or cardiac arrest, as well as by evaluating lung performance before transplantation^2,3,4. In EVLP, an extracorporeal circulation pump allows perfusion of the lung to be transplanted through a membrane gas exchanger and a leukocyte trapping filter^....

Protokół

The protocol (B09-17) was approved by the bioethics committee of the INER (Instituto Nacional de Enfermedades Respiratorias "Ismael Cosio Villegas"). Twenty-three clinically healthy Landrace pigs of either sex, weighing between 20-25 kg, were used for this study. The animals were handled according to the technical specifications for the Care and Use of Laboratory Animals of the Official Mexican Standard¹⁷ and the Guide for the Care and Use of Laboratory Animals of the USA¹⁸. All animals were obtained from the Instituto Nacional de Enfermedades Respiratorias Ismael Cosio Villegas and were housed in individual cage....

Dyskusje

EVLP in pigs has a direct translation to human clinical practice, given the comparability in the size, physiology, and genomic sequence of the two species²². According to the EVLP protocol selected by the researcher, the measurement of CO is essential for determining the flow required to perfuse the lungs. Moreover, depending on the resources and knowledge available, the appropriate method can be chosen. However, no study has compared the methods for evaluating CO simultaneously against a referenc.......

Materiały

Name	Company	Catalog Number	Comments
Anesthesia machine	General Electric	Carescape 620
Atropine	Amixteria, Stern Pharma GmbH
Catheter Insyte Autoguard 20 GA	Becton Dickinson	381434
Electrocautery pencil	BBraun Aesculap	GN211
Endotracheal tube with a 7 Fr balloon	Rush	MG 027770 002
Fentanyl	Janssen-Cilag
Iodopovidone	Degasa	NDC6732635208
Laryngoscope	Riester
Lidocaine Spray	Pisa
Pressure transducers	Edwards Lifesciences	PX260
Propofol	Pisa
Sevofluorane	Pisa
Silk sutures 2-0	Covidien	GS833
Sodium pentobarbital	Pfizer
straight blade of laryngoscope #3	Miller; Riester
Swan-Ganz 5Fr thermodilution catheter	Arrow Thermodilution Ballon Catheter	Ref AI-07165
Tiletamine-zolazepam	Virbac
Vecuronium bromide	Pisa