Effect of a free radical scavenger on cadaver lung transplantation

The pulmonary donor pool would increase substantially if lungs could be safely transplanted after cessation of circulation. To determine whether the addition of the free radical scavenger dimethylthiourea to the perfusate of cadaver lungs could improve graft function, canine donors were sacrificed, and lungs retrieved 2 hours after death. In a blinded fashion, dimethylthiourea was added to the modified Euro-Collins solution and infused into recipients (n = 9) perioperatively; a placebo was included in the perfusate of control animals (n = 9). Donor animals were ventilated with 100% oxygen only during flush and harvest. Recipients were rendered dependent upon the single left transplanted lung by occlusion of the right pulmonary artery and bronchus 1 hour after transplantation. Ventilation was maintained at a constant inspiratory oxygen fraction of 0.4. Recipients were followed up for 8 hours or until death. Three of 9 control animals survived the 8-hour observation period, whereas 6 of 9 recipients of cadaver lungs harvested with dimethylthiourea survived the observation period. Two deaths in the dimethylthiourea group occurred after 7 hours, implying that the effects of the ischemia and reperfusion injury were ameliorated by the use of this agent in this model. This study supports the notion that perfusate modification may improve the yield of cadaver lung retrieval and may allow for transplantation of lungs harvested from cadavers after cessation of circulation.

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.

Optimal timing of administration of a free radical scavenger in lung preservation

The optimal timing of administration of free radical scavengers in lung preservation has yet to be determined. In previous studies, the oxygen free radical scavenger dimethylthiourea (DMTU) has improved pulmonary function when added to Eurocollins flush solution at the time of lung harvest and infused at the time of lung reimplantation. To determine when DMTU must be administered in order to preserve lung function most effectively, 16 dogs underwent lung allotransplantation. Donor lungs were flushed with modified Eurocollins solution (50 ml/kg) and stored for 12 hr at 4 degrees C. DMTU was either added to the flush solution (5 g) or infused (20 g over 2 hr) at the time of reimplantation. Investigators were blinded to the time of DMTU administration. The contralateral pulmonary artery was ligated after a 1-hr stabilization period. Measurements were recorded for 8 hr while keeping FiO2 constant at 40%. The flush group demonstrated significantly improved survival and oxygenation compared with the infusion group. The mortality rate was 50% in the infusion treatment group, while no deaths occurred in the flush animals. Lung function is adequately preserved after 12-hr storage when DMTU is administered in the flush solution at the time of harvest. It would appear that oxygen free radical scavengers must be present in lung tissue during storage in order to be effective.

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)

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.

Enhanced pulmonary function using dimethylthiourea for twelve-hour lung preservation

Current preservation techniques for lung transplantation limit ischemic time to 6 hours. The purpose of this study was to evaluate the ability of dimethylthiourea, a low molecular weight free radical scavenger, to prolong this interval. An in vivo canine transplantation model was used to assess lung function. At harvest and after circulatory arrest, the donor lung was flushed with modified Euro-Collins solution (50 mL/kg). In a blinded fashion, dimethylthiourea (5 g) or saline solution was added to the flush solution at harvest and also infused (20 g over 2 hours) at reimplantation. Harvested lungs were stored for 12 hours at 4 degrees C. Allotransplantation was performed in recipient dogs ventilated with 40% O2. After 1 hour, the contralateral pulmonary artery was ligated, forcing the dog to be dependent on the transplanted lung. Twelve dogs were studied, with 6 randomly assigned to each treatment group in a blinded fashion. Measurements were recorded for 8 hours, keeping the inspired oxygen fraction constant at 0.40. All dimethylthiourea-treated dogs survived the observation period, whereas one third of the dogs that received saline solution died. Dimethylthiourea-treated dogs had significantly greater arterial oxygen tension and significantly less pulmonary vascular resistance compared with control animals. These results suggest that treatment of the lung with a free radical scavenger (dimethylthiourea) improves pulmonary function after reimplantation in a canine model after 12-hour hypothermic storage.

Splenic artery aneurysm. A rare cause of upper gastrointestinal bleeding

Most splenic artery aneurysms (SAAs) are asymptomatic at the time of discovery, being found incidentally during laparotomy or angiography. SAAs are most likely to be found in multiparous women. Complications of SAAs include free intraperitoneal rupture and erosion into abdominal viscera or vessels, with resultant high mortality. Surgery is indicated for symptomatic, enlarging, or large (greater than or equal to 2.5 cm) SAAs as well as any SAA found in women of childbearing age. Treatment of such aneurysms depends on the location and includes excision, ligation, and splenectomy. The present report presents the first known case, to our knowledge, of SAA presenting with massive upper gastrointestinal bleeding from erosion into the stomach in a nulliparous woman. Prompt surgical intervention resulted in correct diagnosis and patient survival.

Major hepatic resections: a 10-year experience with emphasis on special problems

From 1976-1985, 32 patients underwent major hepatic resection at the University of Mississippi Medical Center. This experience was reviewed to determine the relationship of blood loss, postoperative hyperbilirubinemia, and the performance of concomitant surgical procedures to operative mortality, local tumor recurrence, and long-term survival. There were no deaths among 16 elective resections. Of 16 patients undergoing emergency resections, seven died (43.8%). The mortality rate correlated strongly with intraoperative transfusion of more than 10 units of blood and with postoperative hyperbilirubinemia. Performance of additional procedures increased mortality significantly after emergency, but not elective, hepatic resection. Median survival was 53.4 months in patients resected for hepatoma and 33.5 months in those patients resected for metastatic colon lesions. Local recurrence in a patient with hepatoma was managed by resection at 13 months, with no evidence of further recurrence at 69 months.

The treatment of postperfusion bleeding using epsilon-aminocaproic acid, cryoprecipitate, fresh-frozen plasma, and protamine sulfate

The evaluation of excessive hemorrhage was carried out in 774 patients after cardiopulmonary bypass. Excessive hemorrhage was defined in any adult patient as chest tube drainage of more than 600 ml within the first eight hours after operation. Using the prothrombin time, partial thromboplastin time, fibrinogen level, and tri-F titer tests, it was possible to differentiate medical from surgical bleeding. Hyperfibrinolytic bleeding was the most frequently identifiable coagulation disorder and occurred in 159 patients (20%). All these patients were successfully treated with Amicar (epsilon-aminocaproic acid) alone, or with Amicar supplemented with cryoprecipitate or fresh-frozen plasma. Three patients (0.4%) were noted to have residual heparin and required additional protamine sulfate. Five patients (0.6%) had normal coagulation studies and required immediate reexploration. The overall blood consumption per patient was 2.1 units of packed cells. Whole blood and platelets were not used.