Rudolph C. Camishion

Effect of corticosteroid on the acidosis of prolonged cardiopulmonary bypass

Summary Total cardiopulmonary bypass at a flow rate of 50 ml. per kilogram of body weight per minute consistently produced metabolic acidosis in adult mongrel dogs. The acidosis was partially inhibited by pretreatment of the animals with large doses of corticosteroids. The pretreated animals showed a greater survival rate and a better postoperative clinical condition. Possible explanations for the effect of the steroids are discussed.

PROBLEMS IN HEMOSTASIS WITH EXTRACORPOREAL APPARATUS.

When an extracorporeal circulation is employed, the patient’s blood must be rendered incoagulable with heparin. This necessary state of incoagulability may become a serious threat to the life of the patient. Postoperative difficulty with hemostatis when an extracorporeal apparatus has been used is not uncommon. A surgeon performing open-heart operations must, therefore, be prepared to deal with an occasional difficult problem of continued postoperative bleeding. A single simple defect in the coagulation mechanism may be present which can be quickly and easily corrected. On the other hand, there may be multiple defects in the coagulation process, making the task of restoring normal coagulability complex and difficult. Finally, the worst problem of all is when the hematologist has performed every test on the patient’s blood known to his esoteric a r t and reports: “Nothing is the matter with the patient’s blood except that it won’t clot.” We will assume in the following discussion that preoperatively there was no hematologic disorder and no abnormal capillary fragility. We shall also assume that there has been no incompatibility between the blood in the circuit, the blood transfused during the operation, and the patient’s blood. Trauma to the blood is probably the most important factor in the development of a bleeding diathesis af ter employing an extracorporeal blood circuit.11 The concentration of free hemoglobin in the plasma is a rough index of the degree of trauma to the erythrocytes, and hence to other components of the blood. I t is not a quantitative index of the amount of hemolysis, however, as the free hemoglobin in the plasma is continually being removed by the kidneys. However, the greater the observed hemolysis, the greater the chance that a bleeding diathesis will develop. Since the degree of trauma to the blood with any extracorporeal apparatus varies directly with the duration of the perfusion, patients who have had long perfusions are more likely to bleed postoperat‘ively.” Extracorporeal blood circuits should be designed to diminish trauma to the blood caused by excessive turbulence. “Jet effects,” passage of blood at high speed from a narrow conduit into a wide one, a r e particularly injurious to the cellular elements of the blood and should be avoided. Return of blood from the patient to the extracorporeal apparatus by the so-called “coronary-sucker” system may injure erythrocytes, especially if large amounts of a i r are aspirated with the blood.“

Perfluorocarbons as blood substitutes: the early years. Experience with Fluosol DA-20% in the 1980s.

Clinical testing of perfluorocarbons (PFC) as blood substitutes began in the early 1980s in the form of Fluosol DA-20% (FDA), a mixture of perfluorodecalin and perfluorotripropylamine emulsified with Pluronic F68. We have treated 55 patients (Treatment (T) = 40; Control (C) = 15) with intravenous infusions of 30 cc/kg of FDA as part of either a randomized, clinical trial or a humanitarian protocol. All patients were Jehovahs Witnesses who refused blood transfusion and were severely anemic (mean hemoglobin = 4.6 g/d). FDA successfully increased dissolved or plasma oxygen content (P1O2 in ml/dl), but not overall oxygen content (T group: P1O2 baseline = 1.01 +/- .27, P1O2 12hrs = 1.58 +/- .47 [p = < .0001, t-test]; P1O2 12 hrs: T = 1.58 +/- .47, C = 1.00 +/- .31, p = < .0002, t-test). This effect persisted for only 12 hours post infusion, and had no apparent effect on survival. FDA is an ineffective blood substitute because of low concentration and short half-life. Improved emulsion design may resolve these problems, thereby producing a more effective agent. Our discussion will include a review of our data plus a summary of other reports of FDA efficacy as a blood substitute.

Effect of partial and total cardiopulmonary bypass with whole blood or hemodilution priming on pulmonary surfactant activity

Abstract 1. 1. Minimal surface tension of the lungs of dogs was estimated in terms of surfactant activity before, during, and after cardiopulmonary bypass. 2. 2. Surfactant values of normal lungs sampled before the operation ranged from 1.8–11.8 dynes per cm. 2 , averaging 5.1 dynes per cm. 2 3. 3. Animals perfused one or two hours with 50% hemodilution showed little change in surfactant values immediately after the perfusion was completed. However, in those that survived more than fifteen hours the values rose an average of 11.1 dynes per cm. 2 4. 4. 60% of animals perfused with whole blood for one hour had rises in surface tension (average 8.5 dynes/cm. 2 ) both at the completion of bypass and at the time of death. None of these dogs survived more than eight hours. 5. 5. No rise in minimal surface tension was observed in animals placed on controlled ventilation without cardiopulmonary by pass; only one of 6 animals with thoracotomy and heparin showed a persistent rise. 6. 6. Possible explanations for the temporary protection to lung surface afforded by hemodilution as compared to whole blood perfusion are discussed.

Surgical Treatment of Lesions of the Thoracic Aorta in Patients with Multiorgan System Trauma

Thirty-six patients admitted at our Level I Trauma Center with multiorgan system injuries and acute lesions of the thoracic aorta have been studied. Mean Injury Severity Score (ISS) was 27 ± 4. Four patients underwent Emergency Department (ED) resuscitative thoracotomy. One survived and fully recovered. The remaining patients underwent concomitant surgical repair of the aortic lesions and treatment of other multiorgan systems. The overall mortality rate was 17%. ISS for survivors was significantly lower than for nonsurvivors (23 ± 4 vs 35 ± 5, p 0.05). All deaths occurred in the emergent or semiurgent groups. Four patients (two of whom presented with multiple lesions of the thoracic aorta) developed ischemia in distal organs. Two patients developed paralysis and two had lower limb spasticity. All discharged survivors were alive at 12 months follow-up. Sixty-four percent of the patients underwent aortic repair with “clamp/sew” technique. The rest were operated with either heparinized shunts or cardiopulmonary bypass (CPB). The type of surgical repair had no influence on the outcome of patients with single, uncomplicated aortic lesions, however, “clamp/sew” technique did not provide adequate protection when used for repair of multiple aortic tears.