Reduced catecholamine excretion at onset of brain death

[Anesthesia and intensive care for heart-lung transplantation]

Since Shumway carried out the first successful heart-lung transplant (HLT) in Stanford in 1981, HLT has become a new therapeutic means for patients with end-stage pulmonary disease or arterial hypertension. However, it is still rarely carried out because of a lack of donors and the complexity of the surgery and postoperative course. This review described the criteria for proper donor and recipient selection, as well as the anaesthetic and postoperative management of HLT patients at Marie Lannelongue Hospital. The lack of suitable organ grafts results, at least in part, from improper donor management. Pulmonary oedema by fluid overloading and excessive haemodilution should be carefully prevented. Low doses of catecholamines and vasopressin maintain circulatory stability and convenient organ function. The indications for HLT (primary pulmonary hypertension, Eisenmenger's complex, and end-stage bronchopulmonary disease) are all characterized by severe pulmonary hypertension, hypoxaemia and cardiac failure. Careful anaesthetic induction is required to avoid circulatory collapse. Cardiopulmonary bypass (CPB) should be started early, so that mediastinal dissection may be carried out in satisfactory haemodynamic conditions. After unclamping the aorta, circulatory support with fluid and catecholamine infusion is often required. High inspired oxygen fraction and end-expiratory positive pressure may be required because of reperfusion pulmonary oedema. Blood transfusion is often needed as there are major blood losses due to dissection of the posterior mediastinum during CPB. Postoperative catecholamine administration is prolonged over several days. Negative fluid balance is often necessary to reduce pulmonary oedema. Improvement in surgical technique, early extubation, and late prescription of steroids have reduced the incidence of tracheal complications. Acute renal failure often occurs as a result of prolonged CPB, hypovolaemia, drug nephrotoxicity and sepsis. Bacterial complications (pneumonia, mediastinitis) are the main causes of early death. After the 15th postoperative day, opportunistic infections and allograft rejection are the main complications. Since 1981, major advances in HLT recipient management resulted in improved survival rates (70-80% at 1 year, and 60-70% at 2 years for the best teams). Despite the complexity of management, and the longterm threat of obliterative bronchiolitis, HLT is, at present time, the only possibility for these young patients to recover a normal quality of life.

[Hemodynamic, coagulation and glycoregulation changes induced by brain death]

Brain death results in various changes in circulation haemostasis, acid-base balance and glycoregulation. This study was carried out between February 1988 and December 1988 in 91 patients with brain death. Age range was between 6 and 58 years. The cause of brain death was brain trauma (71%) and vascular malformations (26%). In all patients a cardio-vascular collapse occurred at the moment of brain death, requiring an intravascular loading (466.3 +/- 240.3 ml.h-1) with crystalloids and albumin. Dopamine was used in 70% of cases at the dose of 3 micrograms.kg.min-1 to improve kidney and splanchnic perfusion. No alterations of acid-base balance were observed in these patients who admitted for organ donation in a short delay (17.1 +/- 6 h). Haemostasis was modified in all patients but the alterations occurred before the brain death and were related to brain injury. Further investigations are required for a better understanding of glycoregulation changes as they could influence pancreatic transplant survival. Hormonal changes have also to be more extensively studied for possible physiopathologic causes of the variations. A better understanding of these alterations will be of benefit for management of patients in brain death and potential organ donors.