Adult Chest Surgery

Chapter 95. Lung Transplantation Technique 

The decision to perform a single-, double-, or heart-lung transplant depends on numerous factors, including recipient characteristics (e.g., disease, age, and comorbidities), institutional bias, organ availability, and the urgency of the transplant. Single-lung transplantation is a good option for patients with idiopathic pulmonary fibrosis.Selected patients with emphysema, specifically those of shorter stature and older age, also can expect good results with single-lung transplantation. Unilateral transplantation is also acceptable for patients with primary pulmonary hypertension (PPH).However, because these cases are challenging and management can be difficult during the first few postoperative days,some programs prefer the double- or even combined heart-lung transplantation for patients with PPH. Double-lung transplant is mandatory for patients with cystic fibrosis (CF) and bronchiectasis because in both cases the septic native lungs must be excised. When the native disease is accompanied by a preexisting mycetomaor other chronic fungal or mycobacterial infection, double-lung transplantation is also a better option because it minimizes the posttransplant risk of recurrent infection. The heart-lung transplant is reserved for the rare patient with combined end-stage cardiac and pulmonary disease. Most patients requiring heart-lung transplant have Eisenmenger's syndrome with PPH and significant left ventricular dysfunction, perhaps owing to an uncorrected congenital defect. The annual rate of heart-lung transplantation has declined by more than 50% since 1995 not only because single- or double-lung transplant alone is appropriate in the majority of patients but also because no clear survival advantage has been demonstrated in this patient group.5

We prefer the double-lung transplant at our institution irrespective of disease category. Double-lung transplantation has been documented to produce a superior result in patients with obstructive lung disease,and we find that survival is superior and that early postoperative management is far less complicated with the bilateral approach.

GENERAL PRINCIPLES AND PATIENT CHARACTERISTICS

The International Society of Heart and Lung Transplantation registry summarizes the indications for transplantation on a yearly basis (see Fig. 94-3). We have experienced a similar distribution of cases in the more than 800 lung transplants performed at Barnes-Jewish Hospital since inception of its lung transplant program (Fig. 95-1). Most of our patients present with chronic obstructive pulmonary disease or emphysema (42%), CF (18%), 1-antitrypsin deficiency (14%), idiopathic pulmonary fibrosis (12%), or PPH (6%). To be eligible for bilateral lung transplantation, potential transplant recipients should be without significant comorbid disease. Patients with emphysema generally are older than other patient groups (e.g., CF) and thus perhaps are more at risk for cardiovascular or cerebrovascular events. In contrast, CF patients often have occult renal insufficiency secondary to years of antibiotic therapy, particularly with aminoglycosides. Unique infectious concerns are also seen in the CF population because these patients frequently are infected with one or more strains of Pseudomonas aeruginosa and often are colonized with mycobacterial or fungal pathogens. Furthermore, CF patients often have a degree of liver disease, pancreatic insufficiency, or both owing to the multi-organ-system effects of the CF genetic defect. Patients with PPH commonly have residual right-sided heart dysfunction immediately after transplantation and need greater attention to cardiac hemodynamics, often requiring an increase of right-sided filling pressures for hemodynamic stability. Finally, the widespread use of IV prostacyclin (Flolan) has permitted many patients with PPH to delay transplantation. Thus, by the time these patients present for transplant, the degree of right-sided heart failure is often quite severe.

Figure 95-1.

 

Pie chart depicting the most common indications for lung transplantation at the Barnes-Jewish Hospital.

TECHNIQUE

Donor Lung Procurement

If the initial evaluation (i.e., donor history, chest radiograph, bronchoscopy, and manual inspection) reveals no contraindications, we proceed with donor lung procurement. Our technique has been described previously.7After 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 sutures. The inferior vena cava is also encircled unless hemodynamic instability occurs on the attempt to do so. The periadventitial tissue overlying the right pulmonary artery (PA) is dissected. The plane between the artery and the SVC is cleansed. In similar fashion, the right PA is separated from the back 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 the trachea can be encircled with an umbilical tape. After the thoracic dissection is complete, the donor is heparinized (250–300 U/kg). 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. After the cannulas have been placed, a bolus dose of prostaglandin E1 (500 g) is given directly into the PA using a 16-gauge needle.

Immediately after the prostaglandin E1 infusion, the SVC is ligated, and the inferior vena cava is divided, permitting the right side of the heart to decompress. The aorta is cross-clamped, and cardioplegia is initiated. The left atrial appendage is generously incised, decompressing the left side of the heart. The pulmonary flush consisting of several liters (50–75 mL/kg) of cold (4°C) Perfadex is initiated (Fig. 95-2). 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.

Figure 95-2.

 

Donor heart prepared for explant. Note that the cross-clamp has been placed on the aorta, and two cannulas vent the right and left sides of the heart for delivery of cardioplegic solution. A plane of atria has been developed, and the trachea is encircled with umbilical tape.

 

After the cardioplegia and antegrade pulmonary flush 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 with the cooperation of the heart and lung teams. The heart is retracted to the right, and an incision is made with a no. 11 blade scalpel in the left atrium midway between the coronary sinus and the left pulmonary veins. Scissors then are used to extend the opening superiorly and inferiorly while visualizing the orifices of the left superior and inferior pulmonary veins. The remaining cuff of left atrium can be transected while internally visualizing the right pulmonary veins. 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. 95-3). 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.

Figure 95-3.

 

The donor heart is explanted along with a sufficient cuff of the left atrium. A. The heart is retracted to the right while the cuff is trimmed on the left. B. The heart is flipped over for inspection. Developing the interatrial groove on the right ensures an adequate atrial cuff.

 

After extracting the heart, we use a Foley catheter to deliver a retrograde flush via the pulmonary vein orifices (approximately 300 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 experimentaland clinical researchfound 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. If not already completely encircled, the tracheal dissection is completed 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. 95-4). 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 (see Fig. 95-4). 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.

Figure 95-4.

 

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 has been divided.

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.

If the lungs have been transported en bloc, they are separated as detailed earlier. The PA and left atrial cuffs are freed from any pericardial attachments because these may cause kinking after the anastomosis is completed. The right and left PAs are cleaned back to their first branches and inspected for any injuries or embolic material. The donor bronchus is divided two rings proximal to the upper lobe orifice. Care is taken to minimize dissection of the donor bronchus to preserve collateral flow through the peribronchial nodal tissue.

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.

PREPARATION OF THE RECIPIENT (DOUBLE- AND SINGLE-LUNG TRANSPLANTS)

Before anesthesia is induced, most of our patients have epidural catheters placed. If cardiopulmonary bypass (CPB) is planned, we do not place an epidural because of the requirement for heparinization during CPB. Double-lumen endotracheal intubation is routine. When the indication for transplantation is septic lung disease (e.g., CF or bronchiectasis), the patients are intubated initially with a large single-lumen endotracheal tube to permit vigorous suctioning of purulent secretions through an adult fiberoptic bronchoscope. This step maximizes the effective ventilation during independent lung ventilation and decreases the likelihood that CPB will be required.

Routine monitoring devices include a Swan-Ganz catheter, radial and femoral arterial lines, Foley catheter, and a transesophageal echocardiography probe. For bilateral sequential lung transplants, the patient is positioned supine with all extremities padded and arms tucked in at the sides. A pillow is placed behind the knees to prevent hyperextension and peroneal nerve palsy, which can result from prolonged hyperextension of the knees. A heating blanket is placed up to the midabdomen. If a posterolateral thoracotomy is used for a single-lung transplant recipient, the patient is positioned in the appropriate lateral decubitus position.

CPB is used routinely for children, for lobar transplants, for patients in whom a double-lumen tube cannot be placed (small adults), whenever intracardiac procedures are indicated, and for most patients with pulmonary hypertension. For most of our patients, however, we do not use CPB (but we prepare to do so should it be emergently required). We also do not routinely use the cell saver because the majority of our transplants are performed with less than 500 mL of blood loss.

BILATERAL SEQUENTIAL LUNG TRANSPLANTS

Incision Considerations

BILATERAL ANTEROLATERAL THORACOTOMY

Our standard exposure is the bilateral anterolateral thoracotomy, which prevents the complication of sternal healing associated with the clamshell incision.10 The skin incision is performed along the inframammary crease at the level of the fourth intercostal space. The skin over the sternum is not divided. The breast tissue and the lower edge of the pectoral muscle are elevated off the chest wall. The chest cavity is entered by dividing the intercostal muscle directly overlying the fifth rib. The internal mammary arteries are identified, isolated, ligated, and divided bilaterally. Alternatively, the internal mammary arteries can be preserved if a 1-cm segment of costal cartilage of the fourth rib is resected at the sternal border, permitting upward mobility of the fourth rib when retracted. More mobility is obtained by dividing the intercostal muscle from within the pleural space to the paraspinal muscles. The serratus anterior muscle and the long thoracic nerve are not divided; rather, they are pulled away from the chest wall to permit access to the posterolateral intercostal space. Optimal exposure then is obtained by appropriate placement of retractors at 90-degree angles from one another (Fig. 95-5). The table is tilted right or left as necessary to maximize exposure during hilar dissection, lung removal, and implantation.

Figure 95-5.

 

Exposure obtained from bilateral anterolateral thoracotomies.

TRANSSTERNAL BILATERAL THORACOTOMY (THORACOSTERNOTOMY) INCISION

This incision provides excellent exposure to the hilar structures as well as the mediastinum and both pleural spaces (Fig. 95-6). Bilateral retractors are used to elevate the chest wall upward. We resort to the full clamshell incision under the following circumstances: (1) a concomitant heart operation is planned, (2) the patient has pulmonary hypertension with secondary cardiomegaly, or (3) the patient has restrictive lung disease and small chest cavities that preclude adequate exposure via bilateral thoracotomies. On occasion, this anterolateral approach does not provide adequate exposure to the left hilum. Usually, this limitation is owing to a small pleural space with shift of the heart to the left. In this circumstance, we have recently used the suction heart-stabilizing device to elevate the heart upward and to the right. This maneuver exposes the left hilum very well and avoids the need for CPB.

Figure 95-6.

 

Enhanced exposure obtained with full clamshell incision.

When an otherwise straightforward transplant requires CPB, we do not usually proceed with the clamshell incision because the ascending aorta and right atrium can be cannulated easily through the medial aspect of the right anterolateral thoracotomy.

If a transverse sternotomy has been performed, our preference is to reapproximate the sternum with a heavy-gauge Steinmann pin and a single figure-of-eight no. 5 sternal wire. Other techniques to reapproximate the sternum have been developed.11

POSTEROLATERAL THORACOTOMY AND ANTEROLATERAL THORACOTOMY

Patients with restrictive lung diseases and small chest cavities and patients with secondary pulmonary hypertension and cardiomegaly may present with their heart filling much of the left anterior hemithorax, making access to the left hilum via the anterior approach quite difficult. In these circumstances, CPB can be avoided by performing the left lung transplant first through a left posterolateral thoracotomy. The patient then is turned supine, and the right lung transplant is performed via a right anterolateral approach.

EXPLANTATION OF RECIPIENT LUNGS

Operative Techniques10,12

To reduce the likelihood of requiring CPB, the least functional lung, as determined by preoperative quantitative ventilation/perfusion imaging, is resected and replaced first. An attempt is made to detach all pleural adhesions and fully mobilize the hila of both lungs before the first lung is explanted. Great care is taken to avoid injuring the phrenic nerve as it passes just anterior to the hilum and the vagus nerve that lies posterior to the hilum. This preliminary dissection shortens the time that the first implanted lung is exposed to the entire cardiac output and thus lessens the likelihood of reperfusion edema in that lung. In this respect, both donor lungs should be prepared for implantation before removing the recipient's lungs, if possible.

The pulmonary arteries and pulmonary veins are dissected beyond their primary bifurcations to preserve the length of the main trunks. The right PA is usually transected between firings of a vascular stapling device 1 cm beyond the ligated first branch to the right upper lobe. The left PA is transected between staple lines beyond the second branch to the left upper lobe. The pulmonary veins are divided between ties or staple lines, saving maximal length for the future recipient atrial cuff. The bronchus is transected between cartilaginous rings well into the mediastinum at a site suitable for anastomosis. The posterior bundle of lymphatics and bronchial arteries is exposed and divided with electrocautery or ligated and divided.

The lung is removed from the chest, and the operative field is prepared for implantation of the graft. The PA stump is mobilized centrally and then grasped with a clamp and placed on traction anteriorly to afford better access to the bronchus. The pulmonary vein stumps then are grasped and retracted laterally to permit circumferential opening of the pericardium. With the pericardium freed, the vein stumps then are retracted and temporarily fixed anteriorly, providing an excellent view of the bronchus. The left-sided double-lumen endobronchial tube may impair the ability to trim the left bronchus to an appropriately short length, in which case the tube should be backed out a few millimeters. Meticulous hemostasis in the posterior mediastinum is achieved at this point with the knowledge that reaching this portion of the operative field after implantation of the graft lung will be extremely difficult. Finally, a small suction catheter is placed down the appropriate limb of the endotracheal tube to assist in aspiration of blood and iced saline during implantation.

IMPLANTATION

Operative Technique10,12

The donor lung is placed within the recipient's chest cavity covered by a cold lap pad. If space permits, a layer of slush is placed in the empty chest cavity first. We find it simplest to perform the anastomoses from posterior to anterior in the following sequence: bronchus, artery, and atrium. A silk traction suture is placed at the midpoint of the anterior bronchus of the recipient and is used to retract the bronchus out of the mediastinum to help with visibility during the anastomosis. To begin the bronchial anastomosis, donor and recipient posterior peribronchial tissues are approximated. The membranous part of the bronchial anastomosis then is performed with a continuous suture (Fig. 95-7). The cartilaginous airway is performed with interrupted figure-of-eight sutures (Fig. 95-8). Placing two sutures on each side of the previously placed silk suture usually suffices, although on occasion a single interrupted suture is needed in the middle of the anterior wall. The silk suture that marks the middle of the anterior wall is removed, and the airway is irrigated with cold saline. The anterior row sutures then are tied. If the bronchi are of small caliber, which is seen most commonly on the left side, we opt for reapproximating the anterior wall with simple interrupted 3-0 Vicryl sutures to prevent stricturing of the airway. Once the bronchial anastomosis is completed, the suture that was used to reapproximate the posterior peribronchial tissues is continued around, covering the anterior bronchial wall with peribronchial tissue as well. The entire bronchial anastomosis is constructed using 4-0 monofilament absorbable suture material.

Figure 95-7.

 

A running continuous suture is used for the posterior membranous wall of the bronchial anastomosis.

 

Figure 95-8.

 

A. Interrupted figure-of-eight 4-0 PDS suture is used for the anterior wall bronchial anastomosis. B. If the bronchus is small, however, we use interrupted 3-0 Vicryl suture for the anterior wall.

 

Next, the PAs of the donor and recipient are aligned in proper orientation. The recipient's PA then is clamped centrally with a small Satinsky clamp, with care taken to avoid including the Swan-Ganz catheter in the jaws of the clamp. The vascular staple line is resected at a location that matches the size of the donor and recipient arteries. Both donor and recipient PAs are trimmed to prevent excessive length and possible kinking postoperatively. An end-to-end arterial anastomosis is performed with a running continuous 5-0 polypropylene suture (Fig. 95-9). This anastomosis must be made with precise, small suture bites to avoid anastomotic stricture.

Figure 95-9.

 

A running continuous suture is used for the PA anastomosis.

 

Both vein stumps then are retracted laterally, and a Satinsky clamp is placed centrally on the recipient's left atrium. Once the clamp is placed, an umbilical tape is used to tie the clamp in closed position to minimize the likelihood of dislodgement during subsequent lateral retraction of the clamp. The vein stumps then are amputated, and the bridge of atrium between vein stumps is divided to create the atrial cuff (Fig. 95-10). Gentle lateral traction on the Satinsky clamp can bring this anastomosis to a more accessible location. Alternatively, a retraction suture placed in the pericardium 2–3 cm above the inferior pulmonary vein, with care taken to avoid injury to the phrenic nerve, can be used to partially suspend the heart, providing better exposure to the left atrial anastomosis. The anastomosis is performed with continuous 4-0 polypropylene suture. Sutures are placed using a mattress technique, which achieves good intima-to-intima apposition and excludes all atrial muscle. This limits the thrombogenicity of this suture line. The suture line is left open on its anterior aspect. The lung is partially inflated, and the pulmonary artery clamp is loosened momentarily. The lung is flushed with the atrial clamp still in place so as to flush out residual pulmonary perfusate solution. The left atrial clamp then is opened momentarily to completely deair the atrium. The atrial suture line is secured, and the clamps are removed completely. All suture lines, as well as the cut edges of pericardium, then are checked for hemostasis as ventilation and perfusion are restored.

Figure 95-10.

 

The pulmonary vein stumps are individually amputated, and the bridge of tissue in between is divided to permit preservation of cuff length.

The contralateral transplant is conducted in the same fashion. Traditionally, we have drained the pleural space with two large-caliber chest tubes, one angled and one straight. More recently, if hemostasis during the procedure is excellent, we use two no. 19 Blake drains (Ethicon, Somerville, NJ) in each pleural space, one placed apically and one placed along the diaphragm. The ribs are reapproximated with interrupted figure-of-eight monofilament nonabsorbable suture. The pectoralis muscle and fascia are reapproximated with standard suture material, as is the subcutaneous layer. If a major submammary dissection has been necessary, we drain the submammary space. Staples or a running subcuticular suture is used for the skin, and then sterile dry dressings are applied. Before leaving the OR, bronchoscopy is performed to inspect the bronchial anastomosis and clear away any secretions. The patient is taken while still intubated to the thoracic ICU for postoperative monitoring.

SINGLE-LUNG TRANSPLANTATION

Choice of Side

The choice of side of transplant is based on several factors. Usually, the side with the poorest function determined by preoperative ventilation/perfusion scanning is transplanted. If need for CPB is anticipated, the right side is preferred because cannulation of the ascending aorta and right atrial appendage can be performed easily through the anterior aspect of the thoracotomy. Cannulation of the descending aorta and main PA can be accomplished through the left chest but is somewhat more tedious. We avoid groin cannulation whenever possible. For patients with Eisenmenger's syndrome, we prefer the right side to facilitate closure of the coexisting atrial or ventricular septal defects. A patent ductus arteriosus can be repaired in association with a transplant on either side.

Exposure

The standard incision is a generous posterolateral thoracotomy through the fifth interspace. Some groups have recommended the anterior axillary muscle-sparing thoracotomy for emphysema patients.13 Alternatively, an anterolateral fourth interspace thoracotomy provides excellent exposure, particularly on the right side. This is especially useful if a need for CPB is anticipated.

Pneumonectomy and Implantation

The techniques of pneumonectomy and implantation are identical to those just described for double-lung transplantation.

Controlled Reperfusion

We routinely slowly release the PA clamp over several minutes to allow for a slightly less rapid reperfusion of the newly transplanted lung. Other groups, on the basis of experimental evidence, have begun to use controlled reperfusion in combination with leukocyte depletion.14–17 Lick and colleagues16 described this technique in human lung transplants. They reported a small nonrandomized series using a technique modified from experimental study and reported no reperfusion injury. Before performing the controlled reperfusion, 1500 mL of blood from the recipient is collected in a reservoir and mixed with a nutrient-rich solution to make the modified perfusate. A cannula is placed through the untied PA anastomosis while the Satinsky clamp remains in place. The left atrial anastomosis remains untied and is loosened to permit egress of the modified perfusate. The Satinsky clamp also remains in place on the recipient's left atrium. At the time of reperfusion, the leukocyte-filtered, modified perfusate is pumped at a controlled rate (200 mL/min) and pressure (<120 mm Hg) for 10 minutes through the transplanted lung. As it drains from the left atrial anastomosis, the perfusate is re-collected through the use of a cell saver attached to the circuit. After the controlled reperfusion period, the salvaged and washed red blood cells can be reinfused. The lung is ventilated with 50% inspired oxygen concentration during the period. Drawbacks to this technique include increased blood requirements and hypotension thought to be secondary to hypovolemia.16

Use of CPB

When CPB is planned, we routinely use aprotinin. We prefer to do the majority of the dissection before administration of heparin and cannulation. A two-stage venous cannula is placed in the atrium, and an aortic perfusion cannula is placed in the ascending aorta. We also routinely place a pulmonary artery vent. After cannulation, the bypass pump is instituted at full flow, and both lungs are excised. After the first lung is implanted, the left atrium is deaired and the left atrial clamp removed. The PA clamp is left in place. If the left atrial clamp is also left in place, there is often not enough atrium available for clamp placement on the opposite side. The lung is packed in iced saline and slush while the second lung is implanted.

Postoperative Care

Immediately after the surgery, patients are transported intubated to the ICU for constant monitoring. Once stabilized, a standard ventilator pressure-support weaning protocol is initiated. We favor pressure-control ventilation to limit peak airway pressures and prevent barotrauma to the bronchial anastomosis. Plateau pressures should be limited to no more than 35 mm Hg. Fifty percent of lung transplant recipients at our institution are weaned from mechanical ventilation and extubated within 48 hours of transplantation. Patients typically leave the OR on high FIO2. However, if the initial postoperative arterial blood gas demonstrates a PaO2 of more than 70 mm Hg and/or saturations greater than 90%, then the FIO2 is weaned, and repeat measurements of arterial oxygenation are made after each change to minimize the risk of oxygen toxicity. In most patients without significant reperfusion edema, the FIO2 can be weaned successfully to 30% or less within the first 24 hours of transplantation. Postoperatively, a quantitative lung perfusion scan is usually performed to assess for adequate patency and graft flow. If a lobar or greater perfusion defect is appreciated, the cause should be further interrogated by angiography or operative exploration.

In single-lung transplant patients with chronic obstructive pulmonary disease, zero or minimal positive end-expiratory pressure is used, along with an adequate expiratory phase of ventilation, to prevent air trapping in the native lung. An expiratory hold maneuver may be useful to detect air trapping in these patients. Careful fluid management is necessary to avoid substantial transplant lung edema, and usually negative fluid balance is attempted within the first 48 hours. Adequate urine output is carefully maintained with combinations of blood, colloid, and diuretics. Recent evidence suggests that lung injury caused by transplantation significantly reduces the ability of the lungs to clear edema fluid.18 Although often employed in renal doses to facilitate diuresis, the role of low-dose dopamine at 2–3 g/kg/min remains controversial. Overly aggressive diuresis can result in renal insufficiency, which may be exacerbated by high postoperative cyclosporine or tacrolimus levels, and careful monitoring of immunosuppressive medication levels and renal function is essential in the immediate postoperative period.

Before extubation, patients undergo bronchoscopy to ensure adequate clearance of secretions and viability of the donor bronchi. After extubation, the apical chest tubes are removed in the absence of an air leak, commonly within 48 hours postoperatively. Because of the frequent occurrence and recurrence of pleural effusions postoperatively, especially in bilateral lung transplant recipients, the basal chest tubes remain for several days and usually are removed on postoperative days 5–7 (chest tube drainage <150 mL/24 hours).

Vigorous chest physiotherapy, postural drainage, inhaled bronchodilators, and frequent clearance of pulmonary secretions is required in the postoperative care of these patients. Early and constant involvement of the physical therapy team ensures that transplant recipients are out of bed to chair, ambulatory with assistance, and using the treadmill or exercise bikes as soon as possible, even if they remain intubated. In patients with early allograft dysfunction requiring prolonged intubation, early tracheostomy permits easier mobility and better patient comfort, oral hygiene, and clearance of pulmonary secretions.

Adequate pain control is a necessity to prevent atelectasis owing to poor chest movement and inadequate coughing effort secondary to postthoracotomy incisional pain. An epidural catheter provides an excellent means of achieving pain control with minimal systemic effects. In one study after lung transplantation, use of an epidural catheter was associated with faster extubation and decreased ICU days compared with IV morphine.19 Patients often require at least some oral narcotics in the first few weeks after transplantation for pain management. Use of oral narcotics or acetaminophen is preferred to nonsteroidal anti-inflammatory drugs that can exacerbate renal insufficiency in these patients already on cyclosporine or other potentially nephrotoxic drugs. Procedure-specific and postoperative complications are reviewed in Chapter 98.

HEART-LUNG TRANSPLANTATION

Preparation of the Recipient

The recipient is brought to the OR and anesthetized. Surgical exposure is improved if the recipient is able to tolerate single-lung ventilation and a double-lumen endotracheal tube can be used. Routine monitoring devices are the same as detailed for a lung transplantation.

The type of incision performed is based on surgeon preference with either a median sternotomy or an antero-transsternal (clamshell) thoracotomy, each of which provides excellent exposure. We routinely use aprotinin. For CPB, the ascending aorta is cannulated, and bicaval cannulation provides venous return. Both pleural spaces are opened, and adhesions are divided. The recipient is cooled to between 28°C and 32°C, and mechanical ventilation is ceased to permit better exposure. The pericardium around the level of the hilum is excised, and the PA and veins are mobilized in the intrapericardial space. The right atrium is excised adjacent to the atrioventricular groove anteriorly, and the excision is extended circumferentially along the atrial septum. The aorta is divided above the aortic valve and retracted superiorly. The remaining PAs, left atrium, and ventricular structures are dissected free from surrounding mediastinal tissue, and the patient's heart is removed (Fig. 95-11).

Figure 95-11.

 

Recipient operation for heart-lung transplantation showing removal of the anterior pericardium and dissection of the ascending aorta and both venae cavae. The phrenic nerves are separated on pedicles, providing a space for insertion of the lung grafts. The cannulas for CPB are shown, as are the lines for removal of heart and lungs.

 

The bronchi on each side are mobilized, stapled proximally, and divided. The bronchi are divided beyond the staple line, and both lungs are removed separately. It is important to identify and preserve both phrenic nerves (Fig. 95-12).

Figure 95-12.

 

Recipient operation for heart-lung transplantation showing the heart removed and the division of the bronchi to allow for individual lung removal.

 

The bronchial stumps and tracheal carina are mobilized, and the recipient trachea is divided immediately above the carina (Fig. 95-13). Care must be taken to ensure that bronchial vessels in the subcarinal space are controlled and that hemostasis is ensured before the graft is placed and anastomoses are completed. Exposure to the posterior mediastinum to establish hemostasis after heart-lung implantation is difficult and hazardous. Before the graft is placed, the pericardial openings are extended inferiorly and superiorly to create bilateral openings through which each donor lung can be introduced into its respective pleural space.

Figure 95-13.

 

After the heart and lungs are removed from the chest, the trachea is divided immediately above the carina to prepare for the tracheal anastomosis.

 

The donor heart-lung block is brought into the operative field, and each lung is passed through the opening in the pericardium into the pleural cavities posterior to the phrenic nerve-pericardial pedicles. Lick and colleagues20have reported a modified technique in which the lungs are placed anterior to the phrenic nerves into each hemithorax. Placing the hila in front of the phrenic nerves minimizes dissection around and traction on the phrenic nerves and additionally permits the heart-lung block to be rotated anteriorly and medially to inspect for hemostasis in the posterior mediastinum after implantation.20

The tracheal anastomosis is performed first. We use a running 4-0 monofilament absorbable suture (Fig. 95-14). After the tracheal anastomosis, the right atrial anastomosis is performed either by the bicaval technique or by the right cuff technique described by Shumway and Lower.

Figure 95-14.

 

The heart-lung graft is brought into the field, and the right lung is passed underneath the right phrenic nerve pedicle. The same is done with the left lung. The tracheal anastomosis is performed first using a continuous 4-0 polypropylene suture.

 

The aortic anastomosis is performed last while the patient is being rewarmed. Attention to deairing the heart and aorta is imperative. Transesophageal echocardiography is extremely useful for assessing residual air. After achieving stable hemodynamics and gas exchange, the patient is weaned from CPB, and the cannulas are removed. Temporary pacing wires are placed on the donor right atrium and ventricle (Fig. 95-15). Right-angled chest tubes are placed in the pleural spaces along the diaphragm, and a straight chest tube is placed in the mediastinum.

Figure 95-15.

 

Completion of the heart-lung implantation showing the right atrial cuff anastomotic technique (alternatively, bicaval anastomoses can be performed) and the completed aortic anastomosis. The cannulas are removed, and temporary pacing wires are placed.

Postoperative Care

While much of the postoperative care for heart-lung graft recipients is similar to that detailed earlier for lung transplant recipients, there are some important points to keep in mind. Between 10% and 20% of heart-lung recipients experience a short period (usually less than 1 week) of transient sinus node dysfunction that perioperatively often presents as sinus bradycardia. Recipients routinely have atrial and ventricular pacing wires placed at the time of the operation, and maintenance of a paced heart rate between 90 and 110 beats/min may be necessary for adequate cardiac output given the dependency of the denervated heart on rate. Alternatively, isoproterenol (0.005–0.01 g/kg/min) may be used for the first few days postoperatively to maintain heart rate. Persistence of sinus node dysfunction, although rare, may require a permanent pacemaker. Other dysrhythmias are seen commonly as well and need to be treated appropriately.

Right-sided heart dysfunction can occur in the immediate postoperative period and has several potential causes, for example, ischemia and inadequate preservation. It can be exacerbated by ischemia-reperfusion injury in the transplanted lungs with the increased pulmonary vascular resistance. Early identification and treatment are necessary. In addition to pulmonary vasodilators, right-sided heart failure usually is treated successfully with inotropic support. Global depressed myocardial performance also can occur and usually is treated successfully with inotropic support. Contributing causes such as hypovolemia, sepsis, cardiac tamponade, and bradycardia should be considered and treated when found.21 Inotropic support is weaned gradually over the first several postoperative days.

EDITOR'S COMMENT

A major barrier in the early years of lung transplantation was anastomotic failure secondary to poor healing. In retrospect, many of the early donor airways were too long. Since the antegrade bronchial circulation was divided when the organ was procured, anastomotic healing was dependent upon retrograde pulmonary blood flow. A major development in lung transplantation was the recognition that a short donor bronchus was more likely to be adequately perfused and less likely to dehisce. This principle of retrograde bronchial perfusion also applies to sleeve reconstructions.

–SJM

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