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The successful resection of an abdominal aortic aneurysm is presented in a patient who had undergone kidney transplantation 4 years previously. Because the transplanted kidney is more sensitive to ischemia than a normal one, a femoro-femoral bypass with a pump oxygenator was used for perfusion of the transplanted kidney during crossclamping. During the clamping time of 40 minutes kidney perfusion was maintained with a perfusion pressure of 60 to 80 mmHg and the flow was 600 to 1000 ml/min. A collagen-seeded Dacron graft (diameter: 18 mm, length: 12 mm) was interposed. The postoperative course was uncomplicated. We believe that performing the femoro-femoral bypass with a pump oxygenator is an effective and simple method for kidney protection in such operations.

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The mechanism of action by which large doses of aprotinin decrease blood loss during cardiac surgery is not completely understood. In a prospective, controlled study, 30 patients undergoing cardiac surgery were given high-dose aprotinin in accordance with a commonly used regimen. Twenty untreated but otherwise comparable patients served as the control group. The effects of aprotinin therapy during cardiopulmonary bypass on coagulation parameters, the kallikrein-kinin system, fibrinolysis, platelet stimulation, and the release of elastase from neutrophils were studied. The fibrinolysis parameters were the only measurements that showed clear and significant differences between the two groups. Aprotinin almost completely inhibited the formation of fibrin and fibrinogen degradation products. It is assumed that inhibition of systemic fibrinolysis and suppression of local fibrinolysis contribute to the hemostatic action of aprotinin. The study did not demonstrate a significant protective effect of aprotinin on platelets. In addition, the dose of aprotinin administered did not affect the kallikrein-kinin system of elastase. Therefore, these data suggest that the previously demonstrated hemostatic effects of aprotinin derive primarily from its antifibrinolytic action.

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Serious complications involving the central nervous system in the course of cardiac surgical procedures have become rare. Nevertheless, CNS dysfunctions still are observed in a considerable number of patients, exceeding by far the number of those at risk from preoperative neurological hazards. The influence of extracorporeal circulation performance and hypothermia on the physiology of cerebral autoregulation, as well as microembolization events seem to be crucial factors in this context. The resulting regional or global posthypoxic changes in brain metabolism may lead to the manifestation of various neurologic and psychiatric disorders in the postoperative course. These often minor disturbances of CNS function can only be detected regularly and diagnosed correctly in a prospective way by consulting specialists in neurology, psychiatry and psychology, as performed at the Department of Thoracic- and Cardiovascular Surgery of the University Hospital in Hamburg since 1974, and currently in use an international multicenter study. We found postoperative neurological abnormalities in more than 50% of our patients. While irreversible brain damage occurred in only 0.5% of cases, about twothird exhibited transient symptoms that were no longer apparent after 8-10 days postoperatively. Obvious psychopathological symptoms were noted in 10% of cases after surgery, and minor, likewise transient, psychiatric disturbances were seen in up to 50% of patients; 20% suffered from long-lasting psychic problems. The subjective complaints in these cases exceeded the results of objective assessments to a remarkable amount. The discussion focuses on a critical valuation of clinical and supplementary examination techniques and on the potential pathophysiologic mechanisms induced by extracorporal circulation.

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Diagnostics and therapy in coagulation disorders are presented. A special emphasis is given to alterations of blood coagulation in cardiac surgery. No major rule can be defined for this particular field. All disturbances of blood coagulation may become clinically overt in highly variable combinations, thus representing no or high risk to patients conditions. This implies that the actual risk has to be estimated individually for every patient and that the risk of the cardiac disorder has to be considered in view of the risk of the operation plus potential disturbances in coagulation. The latter in order to be assessed appropriately, clearly requires a laboratory specialised in diagnostics of coagulation, as well as a highly experienced coagulation physiologist for decision making. Following this policy, we have not been forced to disagree about extracorporeal circulation for cardiac surgery in most instances. Problems have been confined to patients suffering from various hepatic disorders or from impaired platelet functions.

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Seventy-one consecutive patients undergoing coronary artery bypass grafting (CABG) were studied prospectively. New fascicular conduction defects (FCD) were evident in 51 patients (72%) 1 h after cardioplegic cardiac arrest, in 40 patients (56%) after 2 h, in 29 patients (41%) on the first postoperative day, and in 14 patients (20%) on the seventh postoperative day. Right bundle branch block was the most common type of FCD, followed by left anterior hemiblock. FCD were related to longer aortic cross-clamp time, higher age (p less than 0.025), frequency of wall motion abnormalities (p = 0.033), the number of diseased (p = 0.007) and bypassed vessels (p less than 0.0005), a greater intra- (p = 0.018) and postoperative (p = 0.017) demand for catecholamines, a more complicated postoperative course (p = 0.005), and a longer stay in the intensive care unit (p less than 0.01). Ischemic damage to the conduction system during cardioplegic cardiac arrest appears to be the most likely explanation for new FCD after CABG. Severe coronary heart disease contributes to their development. Hence, adequate myocardial preservation is of crucial importance. FCD are associated with increased perioperative morbidity, according to other studies, also with poorer long-term prognosis, especially in case of a left bundle branch block. In this subset a closer follow-up may be indicated.

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Neurological and psychological reactions to open-heart surgery are widely underestimated phenomena and occur in a much higher incidence than one might expect. When analyzed retrospectively, up to 3.8% of patients who underwent cardiac surgery at the Hamburg University Hospital exhibited these reactions, whereas 35%-50% presented with symptoms and signs of perioperative CNS dysfunctions in prospective studies at our department. About the same percentages are detected in prospective studies of the patients' perioperative psychopathology, stating that a great number of cardiac patients exceed the normal range of anxious, tense, and depressive moods in this setting. The consequences of these findings for the patients' quality of life and the impact for the perioperative management of patients undergoing open-heart surgery are discussed. The current prospective studies, preliminary results of which are presented here, are part of an international interdisciplinary study, initiated to bring more light into the complicated relations between ECC-assisted cardiac surgery, anaesthesiology, neurology and psychology.

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The influence of anesthesia on plasma cortisol has most often been studied in connection with routine operations. To investigate the specific effects of modern inhalation anesthetics more accurately, we examined the specific effects of four inhalation anesthetics on human plasma cortisol during volunteer studies on the influence of anesthetics on the electroencephalogramm. METHODS. A group of 17 (10 m, 7 f) young healthy volunteers who had not received any premedication and were not intubated were studied after informed consent had been obtained. In the first series of experiments the concentration of halothane, enflurane, isoflurane or N2O was increased to MAC (minimal alveolar concentration) 0.5 for a 15-min steady-state period. Blood samples were taken 5 min prior to induction (I), 35 min after induction, on steady-state MAC 0.5 (II), and 15 (III) and 35 (IV) min after the end of anesthesia. In a second series, with 5 subjects, the concentration of halothane, enflurane or isoflurane was first increased to a steady state of MAC 1.0. After reduction to MAC 0.5 steady-state, anesthesia was supplemented with 53% N2O to give a steady state of MAC 1.0 again. Blood samples were taken 5 min prior to induction (I), after the attainment of steady-state MAC 1.0 (II), 35 min later at MAC 0.5 (III), 40 min later at MAC 1.0 with volatile anesthetic/N2O (IV), and 15 (V) and 35 (VI) min after the end of anesthesia. RESULTS. MAC 0.5 N2O produced a marked rise in mean plasma cortisol, from 64.2 micrograms/l to 164.5 micrograms/l.(ABSTRACT TRUNCATED AT 250 WORDS)

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The whole-body arterial and venous dilating properties of nitroglycerin (NTG) and sodium nitroprusside (SNP) were investigated during extracorporeal circulation and normal circulation in patients undergoing coronary bypass surgery. SNP was found to lower preload and afterload for the time of drug administration. During extracorporeal circulation and normal circulation, an average volume of 340 ml was stored in the capacitance vessels when the mean arterial pressure was lowered for 20 mm Hg. When the reduction in preload was compensated by a volume load (blood transfusions), this resulted in a pure impedance reduction by SNP. NTG showed more complex effects. Even with the continuous infusion of NTG only a short-termed, self-limiting afterload reduction occurred during extracorporeal circulation. During normal circulation, the reduction in preload was more extensive with NTG than with SNP, an average volume of 600 ml was stored in the capacitance vessels when the mean arterial pressure was lowered for 20 mm Hg by NTG. While the volume storage by SNP was reversible after termination of the infusion, this was not the case with NTG, where the volume was stored for 1-2 hours. The volume storage by NTG became smaller with an increased filling of the capacitance system. Additionally, the venous resistance of the cardiopulmonary bypass showed different effects on the volume storage by SNP and NTG. In conclusion, the different effects of NTG and SNP cannot be explained by a single, homogenous compartment model of the peripheral circulation but by affecting two different compartments of the capacitance system.

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There is an increase in endotracheal tube-cuff volume and pressure due to nitrous oxide diffusion into the cuff during anaesthesia. A rise of the cuff pressure up to 100 mm Hg (high volume-low pressure cuffs!) within only two hours is nothing out of the ordinary. The inspiratory nitrous oxide concentration influences the cuff pressure rises. The rate of pressure rise depends on the diffusion constant of the cuff material for nitrous oxide, on the cuff wall thickness, and on the difference of nitrous oxide concentration between cuff and trachea or tracheal tissue. An innovation of the blocking system--we call it the Rediffusion System--reduces the nitrous oxide-induced rise of cuff pressure even during long lasting endotracheal anaesthesia with a high FIN2O. The principle of the Rediffusion System is the enlargement of the pilot balloon in order to improve its diffusion capacity for nitrous oxide. In this way a rediffusion into the air is enabled for that nitrous oxide that diffused into the blocking system through the cuff wall. In endotracheal tubes with a Rediffusion System, cuff pressure never exceeds capillary perfusion pressure of the tracheal mucosa. In our in vitro-experiments we found an increase of cuff pressure from 14.2 +/- 0.5 mm Hg to only 27.3 +/- 1.9 mm Hg within six hours (FIN2O = 0.66). Within 150 minutes of endotracheal anaesthesia (FIN2O = 0.66) cuff pressure rose from 14.6 +/- 0.5 mm Hg to only 21.5 +/- 3.6 mm Hg.(ABSTRACT TRUNCATED AT 250 WORDS)

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Endotracheal anaesthesia with the help of orotracheal intubation is 100 years old. In 1880, William Macewen was the first to describe and to perform that technique. In his paper entitled "clinical observations on the introduction of tracheal tubes by the mouth instead of performing tracheotomy or laryngotomy' he describes in addition two cases of endotracheal intubation lasting at least 36 h. He can, therefore, be said also to have performed the first long-time intubation.

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Bleeding through the pores of thoracic vascular grafts sealed with bioadhesive has been eliminated without inducing additional defects in the coagulation system. This has been true regardless of whether additional valve replacement or aorto-coronary bypass procedures were performed. The operative risk and the need for blood transfusions has been lowered significantly thus reducing the cost of these procedures. Bioadhesive has been also applied successfully in a variety of perioperative bleeding complications.

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The mechanisms of nitrous oxide-diffusion through the endotracheal tube-cuff wall are still unknown in detail. In 30 patients we observed the pressure in low and high pressure-cuffs during operations with extracorporeal circulation (ECC). Under the chosen circumstances we found in low pressure-cuffs an increase of the initial pressure of 15.15 mm Hg up to 74,7 mm Hg until the beginning of ECC. During the ECC cuff pressure decreased to 32.25 mm Hg and was dependent on the body-temperature of the patients. After ECC the cuff pressure increased again up to 79.05 mm Hg until the operation was finished. The pressure changes in high pressure-cuffs were similar at different pressure-levels. These results show that in vivo the whole cuff-wall is diffusion-area for nitrous oxide. The main part of gas diffusion occurs through the contact area of the cuff with the tracheal wall.

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On 10 patients and 5 probands we used topical ultrasonic aerosol inhalation anaesthesia for endotracheal intubation during spontaneously breathing and local anaesthesia. 6 ml lignocaine 10% was inhaled for 4 minutes. There were no complications during or after inhalation. We injected a hypnotic just before intubation in most cases.

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The main cause for the rise in cuff-pressure during anesthesia is the diffusion of nitrous oxide into the tube cuff. Gas-diffusion induced pressure changes in low pressure-high volume cuffs are registered continuously. Exposure of an air-filled cuff into an anaesthetic gas atmosphere in vitro shows, that there is an increase in cuff-pressure up to 150 mm Hg within 8 hours. This pressure-plateau remains for several hours. In intubated patients cuff-pressure increases even more. During anesthesia lasting 4--5 hours we recorded pressures up to 150 mm Hg, too. To prevent these high pressures we recommend the reducing of cuff-volume within defined times of anesthesia or, alternatively, the use of the anesthetic gas mixture as cuff inflating gas.

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Out of more than 1000 patients operated upon by means of cardioplegia in profound myocardial hypothermia (15 degrees - 20 degrees C) aortic crossclamping time exceeded 150 min in 26 cases. The average clamping time in this group of patients was 169 +/- 22 min (150 to 227 min). The average duration of the cardioplegic coronary perfusion was 35 +/- 21 min (14 to 99 min). The following procedures were performed. Aneurysmectomy of the ascending thoracic aorta combined with valve replacement (n = 7); valve replacement combined with aorto-coronary bypass procedures (n = 9); multiple valve replacement (n = 3); multiple coronary grafting (n = 6) and one complicated reoperation. Three patients (11.5%) died, none intraoperatively and none as the result of a heart failure connected with the operation.

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In cardiac surgery hemofiltration can be used: 1. to balance fluids during ECC, especially in long-term perfusion; 2. to carry out open heart procedures in patients with terminal renal insufficiency; 3. to treat acute hyperkalemia. The model of the 12.5 by 4.5 cm DIAFILTER TM and the model of operation are described. The compounds of the ultrafiltrate (UF) are identical with that of plasma water. Particles with a molecular weight of less than 50,000 can pass freely across the filtration membrane. The filtration capacity is 100 cc/min UF (Q blood: 300 cc/min, pressure across the membrane 600 mm Hg and hematokrit (Hkt) 25%). The technical details of operation are explained. Its general use as well as its simplicity is demonstrated in 10 patients.

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