Following the pneumonectomy access to the heart is more difficult as heart not only shifts towards the side of pneumonectomy but also posteriorly due to loss of it's anchor to pulmonary veins. Following right pneumonectomy, left to right displacement of the mediastinum occurs mostly by transfer with subsequent dextroposition of the heart and arrangement of the aortic arch in a frontal plane. On the contrary, after left pneumonectomy right to left shift occurs mostly through rotation with the aortic arch arranged in the sagital plane [10
]. Severe distortion of mediastinal anatomy following pneumonectomy has been reported in the literature. [11
While performing the operation care has to be taken during sternotomy to avoid injury to the hyperinflated lung that often lies in close contact with posterior surface of the sternum. We encountered intrapericardial adhesions on the posterior surface of the heart in our first patient this, we believe, occurred due to intrapericardial technique used while performing pneumonectomy on this patient.
Following right pneumonectomy the shift of the heart in the right hemithorax can make access to right atrium for establishing cardiopulmonary bypass (CPB) difficult. In their case report, Berrizbeitia et al report difficulty they encountered during cannulation of inferior venacava (IVC) in a patient who had undergone right pneumonectomy [6
]. The fixity of IVC at it's hiatus in diaphragm prevents it from moving rightward resulting in acute angulation between right atrium and the IVC. The venous cannulation to establish CPB may be achieved with more ease if operator stands on left side of the patient. Another factor that needs to be considered in a patient who had previous right pneumonectomy is that, right superior pulmonary vein is not available for venting therefore, alternative sites may have to be used.
Following left pneumonectomy access to arteries in the circumflex region becomes difficult due to shift of heart to the left side, this difficulty has also been reported by Medalion et al [7
]. We did not come across any report of off pump coronary artery bypass graft surgery (OPCAB) being performed on patients with previous pneumonectomy, but we estimate that following left pneumonectomy, exposure of posterior surface of heart to graft circumflex coronary artery territory during an OPCAB procedure would be technically challenging.
We would like to highlight certain important points that need to be considered while choosing internal thoracic artery (ITA) as a conduit while performing CABG in these patients. The chest wall on the side of pneumonectomy becomes rigid, hence spreading of sternal retractor leads to uneven spreading. ITA from the side of pneumonectomy is difficult to harvest. Pedicled ITA may not reach its targeted vessel due to displacement of heart moreover; the ITA graft may become kinked by the hyper-inflated lung. Various studies have shown that increased pain associated with ITA harvesting may be responsible for decreased postoperative pulmonary function [14
]. This becomes more relevant in patients who already have compromised pulmonary function. Demirtas et al have reported use of left ITA to graft LAD in a patient who had left pneumonectomy in the past [16
]. Their patient developed acute left heart failure on arrival to postoperative intensive care unit and required internal cardiac massage. Berrizbeitia et al used SVG to graft LAD[6
]. We did not use the ITA in our patient who had undergone left pneumonectomy.
There are important considerations for the anaesthesiologist too, internal jugular vein cannulation can be difficult following pneumonectomy due to shift of the mediastinum. Care has to be taken to protect the single lung and sudden fluid overload can lead to pulmonary oedema [11
]. Early extubation is desirable to avoid risk of prolonged ventilation; external warming at the cessation of CPB and on arrival to intensive care unit could facilitate early extubation. Use of thoracic epidural analgesia improves pain control and facilitates easy expectoration and avoids many of the post-operative pulmonary complications [17
]. Similarly, intensive chest physiotherapy and early mobilization becomes more important in these patients to avoid atelactasis and risk of deep vein thrombosis. We utilised benefits of epidural analgesia and stressed on early mobilisation and chest physiotherapy in both our patients.