Results of composite graft replacement for aortic root aneurysms.

From 1972 to 1980, 41 patients (aged 19 to 79) with aortic root problems have been managed surgically with a composite graft. Forty patients (97.5%) are long-term survivors who to date have had no complications related to the aortic root. This series of patients included 10 with acute dissection of the aortic root and ascending aorta. Thirty-one patients undergoing elective operations for aortic root aneurysms included three with chronic ascending aortic dissection with aortic regurgitation, three with previous operations on the aortic root, and six patients who had associated coronary artery bypass or mitral valve replacement. Follow-up to 8 years shows that patients with composite graft replacement have exhibited no early or late complications of this procedure. Two late deaths at 1 1/2 and 5 1/2 years were unrelated to the aortic root procedure. Experience seems to indicate that composite graft management of aortic root aneurysms is a most reliable and durable operation for the majority of patients with this disease.

Cardiac operation and end-stage renal disease.

From 1972-1979, 22 patients with end-stage renal disease underwent 23 cardiac operations involving the pump oxygenator. Fourteen patients had coronary artery bypasss, 2 had aortic valve replacement, 2 had mitral valve replacement (MVR), 2 had MVR with coronary artery bypass, and 2 had ascending aortic root replacement with a composite graft. One patient underwent successful reoperation for a false aneurysm of the left ventricle after MVR. There were 2 postoperative deaths, for a mortality of 9.1%. The patients undergoing coronary artery bypass had an average of 2.7 grafts and an average Functional Class improvement from New York Heart Association Class III or IV to Class I to II. Eighteen patients required preoperative and postoperative dialysis to control blood volume, potassium, and uremia. Four patients had functioning renal transplants, and 4 patients underwent subsequent successful renal transplantation. We conclude that: (1) patients who have transplants and require dialysis can be successfully managed for cardiac operation in spite of their complex associated medical problems; (2) functional and symptomatic improvement simplifies continued management of the patient needing dialysis; and (3) improvement of a cardiac disability can allow favorable renal transplantation in selected patients.

Accidental hypothermia: core rewarming with partial bypass.

Three patients with profound hypothermia were treated by rewarming on partial bypass. Two surivived and have normal mental and metabolic functions. The resuscitation of the hypothermic patient should be approached with enthusiasm since the outcome is often much better than expected from initial vital signs and neurologic examination. To avoid ventricular fibrillation the patient should be handled gently and an effort should be made to keep the patient well oxygenated and the pH normal. Blood gases should be measured often and corrected for temperature. The potassium concentration and hydration status of the patient should also be monitored closely. The rewarming of profoundly hypothermic patients can readily be accomplished with a pump oxygenator and heat exchanger. The indications for this method are not established from our small experience and the few cases reported in the literature. Certainly ventricular fibrillation is a compelling indication. Patients with frozen extremities might also benefit from this method since theoretically tissue salvage would be increased. Finally, those patients who do not respond rapidly to external rewarming may be at less risk of ventricular fibrillation if rewarmed on bypass.

Hyperbaric oxygenation and erythrocyte antioxidant enzymes in multiple sclerosis patients.

Erythrocyte glutathione peroxidase, catalase, and superoxide dismutase activities were measured in 18 patients with clinically definite MS, and results compared with those from neurological controls. These studies indicated that glutathione peroxidase activity in erythrocytes of MS patients was not different from that of the neurological controls. However, superoxide dismutase was lower in the MS patients compared to neurological controls. The effect of hyperbaric oxygenation on these erythrocyte enzymes in MS patient's was also investigated. Exposure of MS patients to 2 ata with either 10% O2 or 100% O2 had no effect on glutathione peroxidase activity. Comparison of each individual MS patient's pre- and post-treatment superoxide dismutase values indicated a significant increase after 100% O2. Similar examination of each individual's catalase activity indicated an increase after exposure to both 10% O2 and 100% O2 at 2 ata. These data suggest that erythrocyte enzyme response to oxygen stress does not involve changes in activity of all the antioxidant enzymes. Instead, only specific enzymes appear to be affected by HBO.

Light microscopic and ultrastructural study of the adverse effects of oxygen therapy on the neonate lung.

Alterations of lung tissues were evaluated in 74 infants with respiratory distress who received respirator therapy and high concentrations of oxygen for varying durations. Infant survival ranged from 3 hours to 135 days. Sequential pathologic changes were revealed to be an exudative reaction superimposed upon the early stages of typical hyaline membrane disease. This merged with and was eventually replaced by a reparative fibroproliferative response that was most pronounced in those infants who survived for the longest period of time. This response appeared causally related to the development of pulmonary complications of interstitial fibrosis, emphysema, obliterative bronchiolitis and cystic bronchiolectasis. Correlative ultrastructural studies disclosed generalized capillary endothelial damage in early stages of oxygen therapy, interstitial edema and alteration of alveolar cells attributed to the toxic effects of oxygen. Proliferation of type 2 alveolar cells with incorporation of hyaline membranes into septal walls was a notable feature of the reparative reaction and appeared significant in the subsequent development of interstitial fibrosis.