Surgical Techniques and Options




TERMINOLOGY





  • Donor



  • Lung preservation



  • Single lung transplantation



  • Sequential bilateral lung transplantation



  • Living donor (lobar) transplantation



  • Heart-lung transplantation





DONOR





  • Twenty percent of otherwise suitable organ donors have lungs that meet standard donor lung criteria ( Table 37-1 ).



    TABLE 37-1 ▪

    STANDARD LUNG DONOR SELECTION CRITERIA



















    Age younger than 55 years
    No history of pulmonary disease
    Normal serial chest radiographs
    Adequate gas exchange (PaO 2 300 mmHg on FiO 2 and PEEP 5 CM [H 2 O])
    Normal bronchoscopic examination
    Negative serologic screening for hepatitis B and human immunodeficiency virus (HIV)
    Recipient matching for ABO blood group
    Size matching

    PEEP, peak end-expiratory pressure.



  • Many brain-dead donors have significant lung parenchymal issues such as contusion, infection, aspiration, or neurogenic pulmonary edema.




    • Size matching between donor and recipient lung volumes is important.



    • Lung volumes are calculated using standard nomograms based on age, sex, and height.




  • In patients with obstructive lung disease, allografts up to 20% larger than the predicted lung volume can be placed due to the increased size of recipient’s pleural space.



  • In patients with restrictive lung disease or pulmonary vascular disease, pleural space is reduced in size; therefore allograft should not be oversized.



  • In sequential bilateral lung transplant, do not oversize.



  • “Marginal” donors refer to organs that are transplanted despite not meeting all of the standard donor selection criteria.



  • “Marginal” donors can provide postoperative function that is nearly equivalent to the standard donors.



  • Other strategies to increase donor pool include living donor lobar transplantation.





LUNG PRESERVATION


Basic Principles





  • Systemic donor heparinization and administration of pulmonary vasodilator prostaglandin E 1 (PGE 1 ) 500 μg into the main pulmonary artery (PA).



  • Pulmonary artery flush in a state of moderate inflation/ventilation with an FiO 2 greater than room air.



  • Extracellular low potassium dextran solution used (Perfadex at temperature of 4° C). Perfadex (Vitrolife, Sweden), a low-potassium Dextran solution has been shown by several groups to produce better results than Euro-Collins solution. This has not been reproduced in all centers. Despite this, most programs have switched to Perfadex as their flush solutions.



  • Ideally, ischemic time should be less than 6 hours.



Donor Extraction





  • Chest x-ray study assessed for infiltrates, and fiberoptic bronchoscopy performed at donor hospital by harvesting team.



  • Final assessment by gross inspection of lungs after median sternotomy.



  • Trachea, vena cavae, and aorta encircled in chest.



  • Donor heparinized, then the cardioplegia cannula is placed in the ascending aorta if the heart is being harvested, and a large-bore pulmonary artery flush cannula is placed in main pulmonary artery (MPA) proximal to bifurcation.



  • PGE 1 may be given into the MPA, producing immediate drop in systemic blood pressure.



  • The superior vena cava is ligated, and inferior vena cava (IVC) is clamped. (Note: IVC drain placed by liver team to drain liver flush.)



  • IVC—right atrial junction is incised to allow cardioplegia to vent from coronary sinus to pericardium.



  • The aorta is cross-clamped, and cardioplegia and PA flush initiated ( Fig. 37-1 ).




    Figure 37-1


    Cardioplegia is administered proximal to an aortic cross clamp and vented through the transsected inferior vena cava ( open arrow ). Pulmonary flush solution is administered through the main pulmonary artery and vented through the amputated tip of the left atrial appendage ( solid arrow ).

    From Sundaresen S, Trachiotis GD, Aoe M, Patterson GA, Cooper JD. Donor lung procurement: Assessment and operative technique. Ann Thorac Surg 1993;56:1409–1413.



  • Left atrial appendage is incised to vent pulmonary artery flush solution.



  • The lungs are ventilated as 3 to 4 L of Perfadex solution are delivered at low pressure (<30 mm Hg).



  • Topical iced slush is applied.




    • Donor heart is removed in situ.



    • After the superior vena cava, aorta, and MPA are divided, the heart is retracted to the right, and the left atrium is opened between the coronary sinus and the inferior pulmonary vein.



    • The left atrial wall is divided leaving a rim of muscle on the pulmonary vein side ( Fig. 37-2 ).




      Figure 37-2


      The ascending aorta is divided. The main pulmonary artery has been transsected at its bifurcation. The heart is retracted upward and to the right to enable safe division of the left atrium leaving suitable cuffs on both cardiac and lung allografts.

      From Sundaresen S, Trachiotis GD, Aoe M, Patterson GA, Cooper JD. Donor lung procurement: Assessment and operative technique. Ann Thorac Surg 1993; 546:1409–1413.




  • Optional retrograde flush of pulmonary veins is performed with balloon tipped catheter.



  • The trachea divided with stapler above the carina with the lungs inflated, then the lungs are removed.



  • If the individual lungs are going to recipients at different hospitals, the donor left main stem bronchus is divided with a cutting stapler, leaving both lungs inflated ( Fig. 37-3 ). Otherwise both lungs should be transported en bloc to be separated at the recipients hospital.




    Figure 37-3


    The pericardium and left atrium are divided, with the left atrium further trimmed ( dotted lines ). The airway is transsected and kept sealed with the use of a gastrointestinal anastomosis stapling device across the proximal left main stem bronchus. The donor airway is further revised for implantation, as shown in the bottom right.

    From Sundaresen S, Trachiotis GD, Aoe M, Patterson GA, Cooper JD. Donor lung procurement: Assessment and operative technique. Ann Thorac Surg 1993; 546:1409–1413.



  • The lung allografts are immersed in cold flush solution for transport.



  • Before implantation, the pulmonary venous cuffs are trimmed.



  • Hint: The donor pericardium can be used to augment the size of the pulmonary venous cuff.



  • The pulmonary artery is separated from its pericardial attachments out to its upper lobe branch.



  • The main stem bronchus is divided 1 to 2 rings proximal to upper lobe origin.



  • Hint: Minimize dissection at site of bronchus transection to preserve bronchial collateral blood flow to donor bronchus after implantation.



Recipient Anesthesia





  • Full hemodynamic monitoring is performed with a Foley catheter, PA Swan-Ganz catheter, and radial artery catheter.



  • A transesophageal echo probe is useful in patients with pulmonary hypertension to monitor right and left ventricular function.



  • Left-sided double-lumen endotracheal tube for separate ventilation of left and right lung.



  • A single-lumen tube may be necessary in patients with suppurative lung disease such as cystic fibrosis because thick purulent secretions may need to be suctioned frequently from the tube.



Cardiopulmonary Bypass





  • Cardiopulmonary bypass (CPB) is used for patients who do not tolerate single-lung ventilation.



  • For patients of small stature when a single-lumen tube is used



  • For patients with significant pulmonary hypertension who do not tolerate pulmonary artery occlusion



  • For double-lung transplants after implantation of the first lung, to prevent the development of primary graft dysfunction in the first lung due to the entire cardiac output perfusing this lung while implanting the second lung (“first lung syndrome”)



  • For patients who do not tolerate left atrial clamping for construction of the pulmonary venous anastomosis



Technique





  • Right thoracotomy, ascending aortic cannulation for arterial return and right atrium for venous drainage.



  • Left thoracotomy, proximal left pulmonary artery or main pulmonary artery cannulation for venous drainage and descending aorta for arterial return.



  • Median sternotomy, or bilateral thoracosternotomy (clamshell), ascending aorta for arterial return and right atrium for venous drainage. MPA vent catheter.



  • Femoral artery and vein can be used for peripheral cannulation.





SINGLE-LUNG TRANSPLANTATION


Choice of Side





  • Transplant side with least pulmonary function as determined by preoperative quantitative nuclear perfusion scan.



  • Right side preferred if CPB needed as in pulmonary fibrosis patients with associated pulmonary hypertension.



Exposure





  • Posterolateral thoracotomy through fifth interspace is the preferred incision.



  • A median sternotomy can be used for a right-sided single-lung transplant, especially if concomitant coronary bypass surgery or intracardiac repair is performed.





RECIPIENT PNEUMONECTOMY





  • Pleural adhesions are divided.



  • PA and vein are encircled.



  • Care is taken to avoid the phrenic and recurrent laryngeal nerve.



  • Need to use CPB assessed by occluding the pulmonary artery and assessing gas exchange and hemodynamic stability.



  • Intraoperative transesophageal echocardiogram (TEE) useful to assess left and right ventricular function.



  • Upper lobe PA branches are ligated and divided.



  • Distal PA is stapled and divided.



  • Pulmonary vein branches are divided with silk ligatures or stapler.



  • Pericardium around vein stumps is widely opened, and the interatrial groove is dissected.



  • The bronchus is divided proximal to upper lobe origin ( Fig. 37-4 ).




    Figure 37-4


    Excision of the native right lung is depicted. The pulmonary artery is stapled beyond its first upper lobe branch. Pulmonary veins are divided between ligatures, and the bronchus is transsected just proximal to the upper lobe orifice.

    From Shields TW: General Thoracic Surgery. Philadelphia: Lea & Febiger; 1994.





IMPLANTATION





  • Bronchial anastomosis is performed first. The membranous posterior wall is closed with a continuous #4-0 absorbable monofilament suture (PDS or Maxon). The anterior cartilaginous airway is reapproximated with interrupted simple or figure-of-eight absorbable suture (Vicryl, PDS, or Maxon) ( Fig. 37-5 ).




    Figure 37-5


    A bronchial anastomosis is depicted. The membranous wall is approximated ( A and C ). If the airways are large, a figure-eight cartilaginous suture technique can be seen ( A ). Smaller airways require simple, interrupted sutures ( C ). Peribronchial mediastinal tissue covers the anastomosis ( B and D ).

    From Meyers BF, Patterson GA. Bilateral lung transplantation. Op Tech Thorac Cardiovasc Surg 1999;4:169.



  • No attempt is made to intussuscept the smaller bronchus to avoid future bronchial stenosis.



  • The pulmonary artery anastomosis is similarly fashioned with a vascular clamp placed proximally to control the recipient branch pulmonary artery. Excess length is trimmed from the donor and recipient branch PAs before creating an anastomosis with #5-0 polypropylene suture ( Fig. 37-6 ).




    Figure 37-6


    A central pulmonary artery clamp is placed, the staple line is excised, and an end-to-end anastomosis is constructed with 5-0 polypropylene.

    From Meyers BF: Technical aspects of adult lung transplantation. Semin Thorac Cardiovasc Surg 1998;10:213.



  • After an atrial clamp is placed controlling the pulmonary vein stumps and part of the recipient left atrial wall, the pulmonary vein stumps are amputated and the bridge of tissue is divided to create a left atrial cuff.



  • The pulmonary veins are anastomosed with a #5-0 monofilament suture ( Fig. 37-7 ).




    Figure 37-7


    A central left atrial clamp is in place while the vein stumps are amputated and the bridge of atrial muscle is divided. The 4-0 polypropylene suture is used to complete the anastomosis.

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Jun 24, 2019 | Posted by in CARDIAC SURGERY | Comments Off on Surgical Techniques and Options
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