Benson R. Wilcox

A strategy to increase the donor pool: use of cadaver lungs for transplantation.

A shortage of suitable donors is a serious obstacle to the widespread application of isolated lung transplantation for end-stage lung disease. We hypothesized that lung tissue likely remains viable for a sufficient period of time to allow for safe postmortem retrieval of lungs for transplantation. Studies were conducted in a nonsurvival model of canine lung allotransplantation. Donor animals were sacrificed, and subsequent lung harvest was delayed for 1 hour, 2 hours, or 4 hours. Pulmonary retrieval was then performed in a standard fashion, flushing the lung block with modified Euro-Collins solution. Lungs were then stored for 4 hours before single allotransplantation. Recipient animals were maintained anesthetized, and followed up for 8 hours. By occlusion of the pulmonary artery and bronchus to the native lung, recipient animals were forced to survive solely on the transplanted lung, with a constant inspired oxygen fraction of 0.40. All 5 recipient animals of 1-hour cadaver lungs survived the 8-hour observation period with excellent hemodynamics and gas exchange. Two of 5 recipients of 2-hour cadaver lungs survived the observation period, whereas a third animal survived for 5 hours with excellent gas exchange. One of 4 animals transplanted with a 4-hour cadaver lung survived the observation period. Retrieval of lungs from cadavers whose hearts are not beating may prove to be a safe and effective method to increase the pulmonary donor pool.

Elective Pulmonary Lobectomy: Factors Associated with Morbidity and Operative Mortality

Periodic review of clinical results is essential to ensure that high-quality patient care is maintained. To that end, we reviewed the morbidity and operative mortality in a consecutive series of 369 pulmonary lobectomies performed between January 1, 1970, and December 31, 1983. There were 251 male and 118 female patients with a mean age of 50.6 years. The thirty-day operative mortality was 2.2% (8/369), with 6 of these deaths related primarily to respiratory insufficiency. Two hundred twenty-four postoperative management problems occurred in 151 patients and included arrhythmia, air leak, pneumothorax, respiratory difficulties, postoperative bleeding, pleural effusion, wound infection, myocardial infarction, pulmonary embolus, empyema, bronchial stump leak, and lobar gangrene. Multiple factors were related to the occurrence of postoperative morbidity and mortality using both chi-square analysis to examine each individual item and discriminant analysis to evaluate their interaction. Chi-square tabulation showed no difference in the occurrence of major postoperative complications (p greater than 0.05) related to the side of operation, an abnormal preoperative electrocardiogram, a forced vital capacity of 2.8 liters or less, a one-second forced expiratory volume (FEV1) of less than 1.7 liters, an oxygen tension of less than 60 mm Hg, or the seniority of the surgeon (resident versus attending). An increased number of complications (p less than 0.05) was found in male patients, in patients operated on for carcinoma, and in patients older than 60 years. Stepwise discriminant analysis included FEV1 as a significant predictor of postoperative complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved results of lung transplantation for patients with cystic fibrosis

Patients with cystic fibrosis pose particular challenges for lung transplant surgeons. Earlier reports from North American centers suggested that patients with cystic fibrosis were at greater risk for heart-lung or isolated lung transplantation than other patients with end-stage pulmonary disease. During a 3 1/2 year period, 44 patients with end-stage lung disease resulting from cystic fibrosis underwent double lung transplantation at this institution. During the same interval, 18 patients with cystic fibrosis died while waiting for lung transplantation. The ages of the recipients ranged from 8 to 45 years, and mean forced expiratory volume in 1 second was 21% predicted. Seven patients had Pseudomonas cepacia bacteria before transplantation. Bilateral sequential implantation with omentopexy was used in all patients. There were no operative deaths, although two patients required urgent retransplantation because of graft failure. Cardiopulmonary bypass was necessary in six procedures in five patients and was associated with an increased blood transfusion requirement, longer postoperative ventilation, and longer hospital stay. Actuarial survival was 85% at 1 year and 67% at 2 years. Infection was the most common cause of death within 6 months of transplantation (Pseudomonas cepacia pneumonia was the cause of death in two patients), and bronchiolitis obliterans was the most common cause of death after 6 months. Actuarial freedom from development of clinically significant bronchiolitis obliterans was 59% at 2 years. Results of pulmonary function tests improved substantially in survivors, with forced expiratory volume in 1 second averaging 78% predicted 2 years after transplantation. Double lung transplantation can be accomplished with acceptable morbidity and mortality in patients with cystic fibrosis.

Cadaver lung donors: Effect of preharvest ventilation on graft function

The pulmonary donor pool would increase substantially if lungs could be safely transplanted after cessation of circulation. To determine whether ventilation of cadaver lungs could improve graft function, canine donors were sacrificed and then ventilated with 100% oxygen (n = 6) or 100% nitrogen (n = 6); 6 served as nonventilated controls. Four hours after death, the lungs were flushed with modified Euro-Collins solution and harvested. Controls were ventilated with 100% oxygen only during flush and harvest. Recipients were rendered dependent on the transplanted lung by occlusion of the right pulmonary artery and bronchus 1 hour after transplantation. Ventilation was maintained at a constant inspired oxygen fraction of 0.4. Four controls died of pulmonary edema shortly after occlusion of the native lung. The mean arterial oxygen tensions in the oxygen-ventilated, nitrogen-ventilated, and control groups at the end of 8 hours were 81 mm Hg (n = 4), 88 mm Hg (n = 3), and 55 mm Hg (n = 2), respectively. Postmortem oxygen ventilation improved early recipient survival and gas exchange. Postmortem nitrogen ventilation improved early gas exchange and delayed recipient death compared with non-ventilated controls. The mechanics of ventilation appears to confer a functional advantage independent of a continued supply of oxygen. Transplantation of lungs harvested from cadavers after cessation of circulation might be feasible.

Anatomically sound, simplified approach to repair of “complete” atrioventricular septal defect

BACKGROUND There are few congenital anomalies of the heart that have benefited more from thorough anatomic analysis than the complex anomaly known as atrioventricular septal defect in the setting of common atrioventricular junction. Recent advances in understanding the anatomy of this lesion have led to alternative methods of repairing these defects. METHODS The medical records of 21 consecutive patients undergoing repair of complete atrioventricular septal defect have been reviewed. Nine of these patients had a standard one- or two-patch repair, and 12 had direct closure of the ventricular element of the defect. RESULTS Direct closure resulted in significantly shorter pump and cross-clamp times. Follow-up for an average of 34 months suggests that when direct closure can be performed, the results are comparable with those of the more standard technique. CONCLUSIONS Our initial success with this approach is encouraging; however, longer follow-up is required to establish whether it will be broadly applicable.

Correlation of Preoperative Pulmonary Function Testing with Clinical Course in Patients after Pneumonectomy

Postoperative morbidity and mortality were correlated with the preoperative results of three widely used tests of pulmonary function in 90 patients who underwent pneumonectomy for carcinoma of the lung. Factors analyzed following operation included thirty-day mortality, the incidence of arrhythmias, the frequency of respiratory complications, and the number of individuals requiring prolonged mechanical ventilation. Fourteen patients had a forced vital capacity (FVC) of 70% or less of predicted normal value. Eleven had a one-second forced expiratory volume (FEV1) of 1.5 liters or less, and 32 had an FEV1 of less than 2 liters. Twenty-six had an FEV1/FVC ratio of 0.6 or less. There were no differences in morbidity or mortality between these individuals and the patients whose test scores exceeded these criteria. As a general rule, decisions regarding operability and extent of resection cannot be made solely on the basis of the three spirometry tests reviewed.

Surgical Management of Left Ventricular–Aortic Discontinuity Complicating Bacterial Endocarditis

Successful hemodynamic repair of left ventricular-aortic discontinuity complicating bacterial endocarditis in 2 patients was achieved using a composite valve-woven Dacron tube graft. The prosthetic valve was sutured without tension into the remaining aortic annulus, ventricular muscle, and base of the aortic leaflet of the mitral valve. Use of the composite graft allows adequate debridement of the abscess, restores ventricular-aortic continuity, excludes the abscess wall from systemic pressure, and does not require saphenous vein coronary bypass. Total exclusion of the aortic root, as described, is a lifesaving alternative repair in the care of desperately ill patients with this condition.

Surgical Management of Symptomatic Pulmonary Aspergilloma

Pulmonary aspergilloma is a potentially life-threatening disease resulting from the colonization of lung cavities by the ubiquitous fungus Aspergillus fumigatus. Complex aspergilloma, characterized by thick-walled cavities with surrounding parenchymal inflammation, is a risk factor for increased morbidity and mortality. Fifteen patients with symptomatic aspergilloma underwent major thoracic procedures at North Carolina Memorial Hospital between January 1, 1972, and December 31, 1983. Twelve of the patients had hemoptysis; in 7 it was recurrent and in 5, life threatening. Tuberculosis and sarcoidosis were the most common underlying causes of lung disease, and more than half of the patients had other coexistent serious medical illness. Eleven of the 15 patients were seen with complex aspergilloma; all of the 4 major complications and the 2 deaths occurred in these patients. Bronchopleural fistula with persistent air space was the most common serious complication, and required thoracoplasty in 3 patients. Nine patients, including 5 with complex aspergilloma, had no postoperative complications, and there were no recurrent symptoms in any of the 13 operative survivors over a mean follow-up of five years. It is concluded that aggressive pulmonary resection can provide effective long-term palliation in critically ill patients with symptomatic pulmonary aspergilloma.

Isolated lung transplantation for end-stage lung disease: A viable therapy

Since January 1990, we have performed 29 isolated lung transplantations in 28 patients with end-stage lung disease (12 single, 16 bilateral). Recipient diagnoses were: cystic fibrosis (11), chronic obstructive pulmonary disease (6), pulmonary fibrosis (6), eosinophilic granulomatosis (1), postinfectious lung disease (1), adult respiratory distress syndrome (1), and primary pulmonary hypertension (2). There have been four deaths, two in patients with pulmonary fibrosis and two in patients with primary pulmonary hypertension. Four patients have undergone transplantation while on ventilatory support for respiratory failure (2 with cystic fibrosis, 1 having redo lung transplantation with cystic fibrosis, and 1 with adult respiratory distress syndrome); all of these have survived. Six patients required cardiopulmonary bypass, which was associated with increased transfusion requirement. All patients 2 months after discharge have returned to an active life-style, except for 2 patients who currently await retransplantation. Preoperative pulmonary rehabilitation has resulted in significant improvement in exercise performance in all patients. Immunosuppression consists of cyclosporine, azathioprine, and antilymphoblast globulin (University of Minnesota), withholding systemic steroids in the early postoperative period. We have employed bronchial omentopexy in all but four transplants; there has been one partial bronchial dehiscence, two instances of bronchomalacia requiring internal stenting, and one airway stenosis. Cytomegalovirus disease has been seen frequently (15 cases), but has responded well to treatment with ganciclovir. Other complication shave included one drug-related prolonged postoperative ventilation, thrombosis of a left lung after bilateral lung transplantation requiring retransplantation, five episodes of unilateral phrenic nerve palsy after bilateral lung transplantation (4 resolved), and the requirement of massive transfusion (greater than 10 units) in 5 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of time domain algorithms for estimating aortic characteristic impedance in humans

Using data obtained intraoperatively from 134 patients (262 data sets), ten algorithms for estimating aortic characteristic impedance from the relative slopes of the aortic pressure and flow (electromagnetic flow probe) waveforms during early systole were compared to the estimate obtained by averaging input impedance modulus values for frequencies between 2 and 16 Hz (Zc). Results clearly confirmed the relationship between these slopes and Zc:r>or=0.80, y intercepts approximately=0.0 and slopes approximately=1.0 for all algorithms tested. However, four algorithms yielded estimates with r >or=0.95. The common trait of these four algorithms was their dependence on portions of the pressure and flow waveforms independently centered around peak derivatives. Results imply that Zc can be estimated successfully in real time, which would be advantageous in critical postoperative periods. Furthermore, cumbersome computational procedures can be eliminated whenever Zc is the only spectral-related parameter to be calculated.<<ETX>>