If the initial evaluation (i.e., donor history, chest radiograph, bronchoscopy) reveals no contraindications, we proceed with donor lung procurement. Our technique has been described previously.8,9 A T-shaped incision centered on the sternal angle is performed over the sternum. After median sternotomy and opening of the pleural spaces, the pericardium is opened, and stay sutures are placed, permitting exposure of the great vessels. The superior vena cava (SVC) is encircled caudal to the azygos vein with silk ties. Alternatively, if heart is also being procured, the azygos vein can be carefully ligated. Usually it is not necessary to encircle the inferior vena cava. The periadventitial tissue overlying the right pulmonary artery (PA) is dissected. The plane between the artery and the SVC is dissected. In similar fashion, the right PA is separated from the posterior aspect of the ascending aorta.
The aorta-pulmonary artery window is dissected in preparation for the aortic cross-clamp. The SVC and aorta are gently retracted laterally, and the posterior pericardium is incised above the right PA, permitting access to the trachea. The plane of the trachea is developed manually and two-thirds of the trachea dissected. We do not encircle the trachea completely at this point to avoid bleeding and inadvertent injury to membranous trachea. Instead of amputating the left atrial appendage, we routinely vent the left heart through the interatrial groove, especially when both heart and lungs are being harvested. This avoids the need of suturing the left atrial appendage after cardiac implantation. In order to do this, the interatrial groove is dissected. After the thoracic dissection is complete, the donor is heparinized with 30,000 units of heparin. The ascending aorta is cannulated with a routine cardioplegia cannula for cardiac preservation. At the bifurcation of the main PA, a Sarns (Ann Arbor, MI) 6.5-mm curved metal cannula is placed and secured with a purse-string suture. If the cannula is placed close to the PA bifurcation, as is in case of heart procurement, the tip of the cannula should face the pulmonic valve to prevent preferential perfusion of any one main PA (Fig. 109-2). After the cannulas have been placed, a bolus dose of prostaglandin E1 (500 μg) is given directly into the PA using a 16-gauge needle.
Donor heart prepared for explant. Note that the cross-clamp has been placed on the aorta. Venting of the left heart can either be done through left atrial appendage or by incising the interatrial groove (preferred method). A plane of atria is developed if the latter method is used.
Immediately after the prostaglandin E1 infusion, the SVC is ligated, the interatrial groove is incised and the inferior vena cava is divided, permitting the right and left side of the heart to decompress. The aorta is cross-clamped, and cardioplegia is initiated. The pulmonary flush consisting of several liters (50–75 mL/kg) of cold (4°C) Perfadex® is initiated. The chest cavity is cooled with ice-slush normal saline. Gentle ventilation is continued throughout to prevent hyperinflation or atelectasis and to enhance distribution of the flush solution.
After the cardioplegia and antegrade pulmonary flushes are completed, the cannulas are removed. The heart then is extracted. The inferior vena cava is freed posteriorly and dissected up to the level of the right atrium. Division of the left atrium proceeds from the venting incision in the interatrial groove with the cooperation of the heart and lung teams. The orifices of the superior and inferior pulmonary veins are visualized to leave adequate cuff for lung implantation. The surgeon on the left side of the table can visualize the right vein orifices best and should divide the left atrial cuff over the right pulmonary veins. An appropriate residual atrial cuff should have a rim of left atrial muscle around each of the pulmonary vein orifices. An adequate cuff can be ensured if the interatrial groove is developed on the right (Fig. 109-3). The SVC is transected between ties, followed by both division of the aorta proximal to the cross-clamp and the PA at its bifurcation. The heart then is passed off the field. The appearance of the surgical anatomy after passing off the heart is shown in Figure 109-4.
The donor heart is explanted along with a sufficient cuff of the left atrium. We prefer to start the incision of the left atrium through the interatrial groove on the right side so that the pulmonary veins are visualized. The incision is continued circumferentially to the left side carefully avoiding the left pulmonary veins on the lung side and the circumflex artery on the heart side.
Appearance of chest cavity after the donor heart has been removed but before the double-lung bloc has been resected. Esophagectomy has been performed (not shown), and the trachea is being divided.
After extracting the heart, we use a Foley catheter to deliver a retrograde flush via the pulmonary vein orifices (approximately 250 mL of cold Perfadex® in each orifice). During retrograde flushing, residual blood and small clots are often flushed out of the opened PA bifurcation. Alternatively, this retrograde flush can be done on the back table before departing from the donor site. We incorporated this retrograde flushing procedure into our donor procurements after experimental10 and clinical research11 found it to be superior to the antegrade flush, with less pulmonary edema, lower airway resistance, and better oxygenation during the first several hours after transplantation.
We then proceed with en bloc removal of the contents of the thoracic cavity. Removal of the lungs by this technique prevents injury to the membranous trachea, pulmonary arteries, and pulmonary veins. The tracheal dissection is completed at least two to three rings above the carina. The endotracheal tube is opened to atmosphere, and the lungs are permitted to deflate to approximate end-tidal volume while the endotracheal tube is backed into the proximal trachea. The trachea is sealed with a linear stapler and divided at least two rings above the carina (Fig. 109-4). Immediately posteriorly, the esophagus is encircled, stapled, and divided using a linear stapler. While retracting both lungs, heavy scissors are used to divide all the mediastinal tissue down to the spine. Staying directly on the spine, the posterior mediastinal tissue is divided. At this point, the pericardium near the diaphragm is transected. The inferior pulmonary ligaments are sharply divided. The lower esophagus is encircled and divided with the linear stapler. Posterior mediastinal tissue is sharply divided to connect with the superior aspect of the dissection. The lungs then are removed en bloc along with the thoracic esophagus and aorta.
If the lungs are returning to the same institution, they are tripled-bagged together with cold preservation solution and transported on ice. Alternatively, if the lungs are to be used at separate institutions, they are divided on the back table. While the lung bloc is kept in an ice-slush bath, the donor esophagus and aorta are removed, and the pericardium is excised. The lungs are separated by dividing the posterior pericardium, the left atrium between the pulmonary veins, the main PA at the bifurcation, and the left bronchus above the takeoff of the upper lobe bronchus. The left bronchus is divided between staples to maintain the inflation of each lung.
Donor Heart–lung Procurement
The donor harvest procedure for a heart–lung bloc is similar to the separate harvests for heart and lungs, with the exception that the heart and lungs are removed en bloc. After the pulmonary flush and cardioplegia are completed, the SVC is transected between ties, followed by division of the aorta proximal to the cross-clamp. The trachea is completely encircled, doubly stapled, and transected, again permitting the lungs to deflate to approximate end-tidal volume. En bloc removal of the contents of the thoracic cavity proceeds as in the lung procurement technique.