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Biomedical subjects

J Kugelberg

Publications and source records attributed to J Kugelberg.

At least 19 recordsLinked to original sources
PubMed1992

Venoarterial extracorporeal membrane oxygenation--how safe is it? Evaluation with a new experimental model.

This study was undertaken to find out if about 25% right cardiac output is sufficient for preservation of lung function during prolonged periods of venoarterial extracorporeal membrane oxygenation. Six healthy pigs weighing 57 kg were subjected to 18-hour venoarterial extracorporeal membrane oxygenation. During this period 1200 ml/min venous blood was delivered to the lungs through the pulmonary artery with the help of a separate roller pump and with use of the animal's own right ventricle to generate the pulse. Animals were observed for 6 hours after weaning from the venoarterial extracorporeal membrane oxygenation. At the sixth hour after extracorporeal membrane oxygenation, arterial oxygen tension, venous oxygen tension, lung compliance, and cardiac output had decreased significantly. Pulmonary vascular resistance and pulmonary clearance of technetium 99m-diethylenetriamine pentaacetic acid increased significantly also. The systemic arterial and venous carbon dioxide tensions, pH, and the base excess remained unchanged, as did the blood pressure and the systemic vascular resistance. Histopathology of the lung specimens revealed focal alveolar wall thickening and alveolar capillary congestion. The major portion of the pulmonary parenchyma looked normal. Alterations in pulmonary parameters cited were, to a major extent, explained on the basis of the experimental protocol followed and were believed to be reversible. This study suggests that about 25% of the systemic cardiac output should be diverted into the pulmonary artery for prevention of irreversible physiologic and histopathologic changes in the lungs during 18-hour normothermic venoarterial extracorporeal membrane oxygenation in healthy juvenile pigs.

Animals↗
PubMed1991

Pulmonary sequelae of prolonged total venoarterial bypass: evaluation with a new experimental model.

Total normothermic venoarterial bypass was established in 6 healthy pigs over a period of 18 hours. A heparin-coated closed extracorporeal system was used and no heparin was administered systemically. During the bypass period the main pulmonary artery was occluded and the heart was maintained in a beating state. All the animals maintained stable hemodynamics and normal blood gases during the entire period of bypass. In the postbypass period, the central hemodynamics continued to be stable while the arterial oxygen tension (inspired oxygen fraction = 0.21) decreased significantly (p less than or equal to 0.05). The total body oxygen uptake, on the other hand, remained unaltered. All the animals died within 4 hours after weaning off the venoarterial bypass circuit on account of pulmonary edema in 2 and cardiac arrest in 4. Death was preceded by progressive pulmonary hypertension and lactacidosis in all the animals. Histological examination of the lungs showed pulmonary parenchymal damage ranging from interstitial edema to intraalveolar hemorrhage and parenchymal necrosis involving more than 80% of the pulmonary parenchyma. A normothermic total venoarterial bypass of 18 hours duration or more produces pulmonary edema of varying severity, pulmonary hypertension, pulmonary parenchymal necrosis, and lactacidosis in healthy juvenile pigs, resulting uniformly in their death. Despite these sequelae the systemic arterial hypoxemia may only be mild to moderate.

Acidosis↗
PubMed1991

Veno-right ventricular bypass as total extracorporeal lung assistance. An experimental study.

Efficacy of veno-right ventricular bypass as a total extracorporeal lung assistance was studied for a period of 24 hours in six healthy pigs with a mean weight of 60 kg. A covalently bonded heparin-coated extracorporeal membrane oxygenation system and a roller pump were used for the bypass. No local or systemic heparin was administered. The bypass was established with an open chest with two 28F venous cannulas and one 24F arterial cannula. The arterial cannula was placed in the right ventricle across the tricuspid valve. With the lung function totally disabled, this extracorporeal lung assistance maintained normal systemic arterial and mixed venous blood gases during the entire 24-hour period in all the animals. No significant tricuspid insufficiency was observed, and the animals maintained normal central hemodynamics. There was no hemolysis, and the platelet counts remained essentially unaltered. Multiple foci of clot formation were observed in all the oxygenators, but no macroscopic thrombosis or embolization was seen either in the heart or in the lungs. A veno-right ventricular bypass offers total extracorporeal lung assistance in 60 kg juvenile pigs for a period of 24 hours. Tricuspid valve competence is an important prerequisite for the success of this procedure.

Animals↗
PubMed1990

Reversal of lethal citrate intoxication by intravenous infusion of calcium. An experimental study in pigs.

Intravenous infusions of 750 and 1000 ml 2.2% sodium citrate were given over a 60 min period to 17 pigs to study its effect on aortic pressure, electrocardiogram, ionised calcium, and citrate clearance. In group 1 (seven pigs) the animals did not receive calcium and the median survival time was 30 min (range 20-70 min). In groups 2 and 3 (five in each group) the pigs were treated with calcium chloride infusions (1 ml 10% calcium chloride to 10 ml citrate) and they all survived. In group 1 the ionised calcium concentrations in blood fell to values below 0.4 mmol/l, after which the blood pressure dropped abruptly. In the animals treated with calcium the mean ionised calcium concentration fell to 0.6 mmol/l, whereas total calcium increased to more than 7 mmol/l. The aortic pressure was consistently within normal values in the groups treated with calcium, but in the group that was not treated the blood pressure fell dramatically. There was no correlation between electrocardiographic changes and ionised calcium concentrations. In summary, calcium was an effective antidote to lethal citrate intoxication, and the only reliable method of determining the necessary dose of calcium was monitoring of ionised calcium concentrations.

Animals↗
PubMed1989

Cerebral vasoreactivity to carbon dioxide during cardiopulmonary perfusion at normothermia and hypothermia.

With the pH-stat acid-base regulation strategy during hypothermic cardiopulmonary bypass (CPB), carbon dioxide (CO2) is generally administered to maintain the partial pressure of arterial CO2 at a higher level than with the alpha-stat method. With preserved CO2 vasoreactivity during CPB, this induction of "respiratory acidosis" can lead to a much higher cerebral blood flow level than is motivated metabolically. To evaluate CO2 vasoreactivity, cerebral blood flow was measured using a xenon 133 washout technique before, during, and after CPB at different CO2 levels in patients who were undergoing coronary artery bypass grafting with perfusion at either hypothermia or normothermia. The overall CO2 reactivity was 1.2 mL/100 g/min/mm Hg. There was no difference between the groups. The CO2 reactivity was not affected by temperature or CPB. The induced hemodilution resulted in higher cerebral blood flow levels during CPB, although this was counteracted by the temperature-dependent decrease in the hypothermia group. After CPB, a transient increase in cerebral blood flow was noted in the hypothermia group, the reason for which remains unclear. The study shows that manipulation of the CO2 level at different temperatures results in similar changes in cerebral blood flow irrespective of the estimated metabolic demand. This finding further elucidates the question of whether alpha-stat or pH-stat is the most physiological way to regulate the acid-base balance during hypothermic CPB.

Acid-Base Equilibrium↗
PubMed1989

Myxofibrosarcoma in the left atrium originally presented as a cardiac myxoma with chondroid differentiation. A clinico-pathological report.

Malignant cardiac tumours located on heart valves are very rare. We report on a myxofibrosarcoma originally presented as a cardiac myxoma (CM), partly with chondroid differentiation, located on the posterior leaflet of the mitral valve. The tumor recurred twice, the first time disguised as a CM with only minor components of myxofibrosarcoma, and finally metastazised as a myxofibrosarcoma. Patient survival (40 months from first surgery) was surprisingly long and this may well reflect both the effectiveness of the combined radiation and cytostatic treatment and the histopathological features of the tumor.

Adult↗
PubMed1988

Hemoconcentration by ultrafiltration during open-heart surgery.

Ultrafiltration was used during extracorporeal circulation (ECC) with heart-lung machine in 17 critically ill cardiac patients. In ultrafiltration (hemofiltration), water and small molecules (e.g. urea, creatinine and electrolytes), are separated from the blood by hydrostatic pressure generated on the blood side of a semipermeable membrane. The patients had severe water overload for three reasons, viz. congestive heart failure (10), renal failure (6) or iatrogenic extreme hemodilution (1). On average 2090 (800-5700) ml water was filtered off, increasing the hematocrit from 25 to 33%. Three indications for ultrafiltration during ECC and two modes of such treatment are exemplified in three case reports. No negative effect of the treatment was observed. Ultrafiltration during ECC thus may help to improve the postoperative course in patients with severe water overload due to congestive heart failure, renal failure or iatrogenic extreme hemodilution.

Aged↗
PubMed1986

Late cardiac tamponade following open-heart surgery. Diagnosis and treatment.

Late cardiac tamponade is a rare but serious complication following open-heart surgery. It occurred in 9 (0.8%) of 1 094 consecutive patients 6 to 13 (median 8) days after operation. Six patients had undergone valve replacement and three coronary bypass surgery. All were on anticoagulant medication postoperatively (median TT index 7%). Early symptoms of cardiac tamponade were nausea and general malaise (present in all 9 cases), whereas classical signs of tamponade such as arterial hypotension and distended neck veins appeared late. The cardiac silhouette was radiographically enlarged in all cases, but this finding was seldom diagnostic. Computed tomography gave the surest diagnosis and permitted quantitative assessment of the fluid in the pericardium. Pericardial needle puncture was effective in temporarily relieving the tamponade, but insertion of a tube by the subxiphoid approach gave definitive drainage.

Aged↗
PubMed1983

Acute immobilization of the disc in the Björk-Shiley aortic tilting disc valve prosthesis. A report of 3 cases.

Acute non-thrombotic immobilization of the disc in the Björk-Shiley aortic valve prosthesis occurred as a result of extrinsic factors in three patients. Unravelled suture or long suture ends were the cause in two cases. Tissue detached from the aortic intima migrated into the valve and locked the disc in closed position in one case. The mechanisms of extrinsic disc immobilization and its prevention and treatment are discussed.

Acute Disease↗
PubMed1983

Multicentre investigation of myocardial protection with cold cardioplegia.

In order to analyze factors of importance for the efficiency of myocardial protection during open-heart surgery, a study was made of 144 patients undergoing isolated aortic valve replacement with various cardioplegic techniques. The cardioplegia was of Bretschneider type in 54 cases, St Thomas in 31 and Ringer-potassium type in 11 cases. Single or multi-dose blood cardioplegia was used in 11 cases and continuous blood cardioplegia in 30 cases. Local cardiac hypothermia was additionally employed in all patients. The efficiency of myocardial protection was assessed mainly from the incidence of postoperative conduction disturbances, myocardial enzyme release and need for inotropic support. All patients survived the operation. In 20% surgery was followed by transient or persistent disturbance of conduction, in 9% by abnormally increased CK-MB release and in 5% by requirement for inotropic support. Preoperative risk factors such as high age or severe left ventricular (LV) hypertrophy or dysfunction had little influence on the results. Patients in whom aortic stenosis (AS) was dominant in the complex with aortic insufficiency (AS + AI) showed 20-hour postoperative CK-MB enzyme activity twice as high as those with pure aortic insufficiency. The most important factors in myocardial protection were the duration of aortic occlusion and the myocardial temperature during cardioplegia. When the aortic occlusion lasted more than 80 min there was a 32% incidence of conduction disturbances and 20-hour CK-MB activity thrice as high as after shorter occlusion. Patients with mean myocardial temperature below 18 degrees C during cardioplegia invariably had low enzyme activities, which indicated good myocardial protection. The best overall results were obtained in patients operated on during hypothermia at 25-27 degrees C, with single or multi-dose blood cardioplegia and with efficient local cooling of the heart.

Adult↗
PubMed1983

Surgical intervention in staphylococcal endocarditis.

Uncomplicated endocarditis is cured by medical treatment at a rate of 80% (75% 5-year survival rate). If incompensated, only 12% has shown to be curable without surgery. With valve replacement, on the other hand, the rate of success will be 80%. Of those surgically treated cases, less than 10% will develop recrudescent infection. Left heart vegetations predict the risk of congestive heart failure and/or embolism. It is assumed that 7-10 days of efficient antibiotic therapy without effect should lead to surgery. We have made valve replacement in six cases during recent years in staphylococcal endocarditis. The main indication for operation was congestive heart failure, and the valve used was the Björk-Shiley tilting disc. All patients had vegetations on the leaflets. One patient had a mitral insufficiency, and the other five had aortic insufficiency. Two cases were lost within four months after surgery. In general, indications for valve replacement are heart incompensation or vegetations on leaflets.

Adult↗
PubMed1980

Computed tomography in preoperative staging of bronchogenic carcinoma.

Thirty-five patients with non-oat-cell primary bronchogenic carcinoma were studied with computed tomography (CT) and retrospectively analyzed to evaluate the usefulness of CT in the preoperative staging. All patients underwent mediastinoscopy, and those with a negative exploration were referred for thoracotomy. Computed tomography demonstrated lymph nodes in 31 patients, 17 of them having nodes larger than 1 cm. Malignant involvement of lymph nodes was present in only 2 of these 17 patients. However, nodal involvement was present in five of the patients with lymph nodes less than 1 cm in diameter. Nine out of 10 patients who proved unresectable at thoracotomy were correctly evaluated at CT. Five additional patients were incorrectly presumed to be unresectable. The use of CT for staging of primary lung tumors, therefore, needs further investigation.

Adult↗
PubMed1979

The circulatory response to specific ventilatory patterns using a tidal volume ventilator.

The circulatory response to different ventilatory patterns during artificial ventilation was examined in 17 sternotomized piglets. A constant CO2-tension level was maintained in all investigations by reference to analyses of the end-tidal infra-red CO2 fraction and arterial CO2-tension. The greatest variation in mean values for end-tidal CO2-tension was 0.2 kPa. Total compliance and lung compliance were lower at a ventilator volume/pressure quotient of 20 compared to those at 80 ml/kPa, and at f = 30 compared to f = 11 cycles/min. Higher cardiac output, lower pulmonary vascular resistance and systemic vascular resistance were measured at f = 11 (inspiration 20%) than at f = 30 (inspiration 50%). An increase in inspiration time by about 100% at the lower ventilatory frequency (f = 11) resulted in a significant but uncompensated decrease in cardiac output and stroke volume. These results demonstrate the value of a rapid insufflation in order to give longer expiration time per minute for the benefit of the venous return and cardiac output.

Animals↗
PubMed1979

Myocardial protection during heart surgery. An experimental evaluation of normothermic and hypothermic cardioplegia.

Heart surgery with hypothermic cardioplegia during normothermic bypass is sometimes complicated by rewarming of the myocardium caused by collateral flow of arterial blood. This problem is particularly evident in surgery of congenital malformations. The present work is a comparative study in dogs on 3 methods of avoiding the rewarming problem. In the first group, the heart was kept cold and the warm blood was drained off from the left atrium. In the second group, total body hypothermia to the level desired was used and in the third group, normothermic cardioplegia was induced (Cardioplegin) in normothermic animals. In the two latter groups, the undesired temperature gradient between heart and body was eliminated. Evaluation of the differences was made by means of ventricular function determinations. Local, hypothermic cardioplegia showed the best postoperative function (69%) followed by the total body cooling which was fully acceptable (41%). Normothermic cardioplegia after the same duration of arrest showed a too low myocardial performance (20%).

Anesthesia↗