**6.2 Heart Lung en Bloc**

'Heart-Lung en Bloc' transplantation surgery has become less frequent over the years (Lund LH, Khush KK, Cherikh WS, Goldfarb S, Kucheryavaya AY, Levvey BJ, et al. The Registry of the International Society for Heart and Lung Transplantation: Thirty-fourth Adult Heart Transplantation Report-2017; Focus Theme: Allograft ischemic time. J Heart Lung Transplant. 2017;36(10):1037-46). However, there are still select indications for it, and one should be aware of how it is performed. The procurement surgeon performs the assessments for both heart and double lungs (as discussed in the earlier section) and oversees physiological and anatomical assessments both for the heart and lungs. The heart assessment is made in standard fashion- the coronaries are palpated, the aorta is inspected, the right atrium and pulmonary artery are assessed, and any palpable thrills are ruled out. Look thoroughly for contusions and note any evidence of trauma. Injuries which could impact implantation should be thoroughly discussed with the rest of the team. Once the assessment is complete and the heart is deemed good for transplant, we proceed to assess the lungs in standard fashion. Our assessment includes bronchoscopy, ventilatory mechanics, compliance and gentle recruitment followed by selective pulmonary vein blood gasses done on a vent setting of 100% fiO2 and PEEP of 5 cmH2O.

Administer heparin to do the donor as soon as all the teams are ready. The aorta is then canulated, and the PA cannulation follows shortly after (as described earlier, the bevel should be turned towards the pulmonary valve). It is important that the pulmoplegia (Perfadex) be kept no higher than 30 cm off the table thereby letting it run by gravity.

Once all the teams are ready for cross clamp, prostaglandin is injected into the PA. The heart is vented through the left atrial appendage. A major notable difference from the double lung procurement is that there is no retrograde flush; only an anterograde flush is done. The SVC (superior vena cava) is snared above the level of the azygos vein; the azygos vein would have been ligated earlier. The IVC is partially transected at a point of agreement with the liver team.

It is prudent to patiently wait for the heart to empty, and then cross clamp the ascending aorta right below the innominate artery. We suggest not clamping the aorta when the heart is still ejecting. After this, start the cardioplegia infusion, while also measuring the aortic root pressure and wait for the heart to arrest prior to starting pulmoplegia (Griffith BP, Magliato KE. Heart-lung transplantation. Operative Techniques in Thoracic and Cardiovascular Surgery. 1999;4(2):124-41). As soon as the flush is started, we cover the heart, lungs, and entire pleural cavity with ice slush. All the while be aware that the heart is not distending, that the aortic root is firm, the LV is soft and of course that the LA appendage is adequately draining. Look at lung surfaces to see that they're evenly blanched.

Request the Anesthesia team to decrease the FiO2 to 50% and ventilate the lungs for proper distribution of pulmoplegia to all the lobes. Again, it is important to keep an eye on the LV to make sure it is not distending. Avoid lifting the heart so as not to cause aortic insufficiency! Ensure there is a backup cardioplegia bag in case of a hypertrophied LV. Avoid pulmoplegia going into the coronaries! Either keep the root distended with additional cardioplegia or transect the aorta and place a yonkaeur sucker till the pulmoplegia is done.

Once the cardioplegia and the pulmoplegia are done, the pulmoplegia cannula is removed and the purse-string suture is secured. Similarly, the cardioplegia cannula is removed and the suture secured depending upon institution preference. We then complete the inferior vena cava (IVC) transection and then transect the ascending aorta as high as possible. We then divide the inferior pulmonary ligaments on both sides and complete the division of the posterior pericardium. It is important to keep the nasogastric tube so that we can palpate and tell where the esophagus is to not contaminate the mediastinum. Be sure to dissect anterior to the esophagus and go up to the level of the azygos vein and then divide the azygos vein.

Now for the final steps. Loop the trachea as high as possible. After a few recruitment breaths, the endotracheal tube is withdrawn, and trachea is stapled at 60% of the tidal volume. Then we divide the SVC as high as possible near junction of innominate vein, taking care to avoid retaining a piece of central line while transecting the SVC. Now we have IVC, SVC, Aorta and trachea all divided. Important not to have more than 60% of the tidal volume to avoid barotrauma. The heart lung bloc is delivered onto back table. Quick inspection is made for iatrogenic injuries. The heart lung bloc is then packed in the heart solution. Have adequate solution enough to immerse the entire bloc. The inner bag contains only the preservative solution, while the second and third bag have ice slush. The heart-lung is then labeled accordingly and packed in the cooler for transportation. It is important to communicate to the implanting surgeon the conduct of the harvest and update him about any iatrogenic injuries and need for repairing the left atrial appendage venting site.
