This article details the surgical procedure for harvesting a cardiopulmonary block from an anesthetized rabbit. The method involves careful dissection and ligation to ensure the integrity of the heart and lungs for further assays.
To harvest the cardiopulmonary block - a complex containing heart and lungs, place an anesthetized rabbit in the supine position on a dissection board. Now, incise the skin and muscle layers in the neck region to expose the trachea. Using a small opening, insert a cannula through the trachea and suture in its place.
Connect the cannula to a respiration pump. Mechanically, apply positive-pressure ventilation through the cannula to prevent lung collapse during the subsequent surgical procedure. Next, dissect the thoracic cavity to expose the heart.
Identify the right ventricle of the heart and inject heparin to prevent blood clotting. Immediately following the injection, ligate the superior and inferior vena cava - veins carrying deoxygenated blood from the body to the heart. Ligation of these veins ceases the blood flow to the lungs. Subsequently, perform exsanguination by draining a large volume of blood from the cardiopulmonary block for the ease of harvest.
Upon completion of exsanguination, sever all the underlying connections to separate the cardiopulmonary complex from the thoracic cavity. Finally, resect the trachea above the cannula and remove the entire cardiopulmonary block from the rabbit's body. The functional cardiopulmonary block is ready for further assays.
Connect the respiration pump to the tracheal cannula. Set the tidal volume at 10 milliliters per kilogram, and initiate the ventilation quickly after the tracheotomy and before the thorax is opened, to maintain positive pressure in the lungs for preventing lung collapse during the surgery.
To access the thoracic cavity, use a scalpel or scissors to open the thorax wall and perform a medial sternotomy up to the upper third of the thorax. Hold the thorax halves open with two retractors. Localize the superior and inferior vena cava and tag them with threads.
Before the exsanguination of the animal, identify the right ventricle, and inject 1000 UI/kg of heparin. Immediately after the injection, ligate the superior and inferior vena cava with the pre-looped thread.
Cut through the manubrium sterni to extend the medial sternotomy towards the tracheal cannula, releasing the trachea on both sides from connecting tissue. Now, resect the trachea above the tracheal cannula and gently pull up the cannula in a craniocaudal axis.
After exsanguination, for harvesting the cardiopulmonary block, use direct digital dissection or spring scissors to separate the connective tissue, and remove the lungs from the thorax. Next, dissect the vasculature and esophagus.
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