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Biomedical subjects

K Hellberg

Publications and source records attributed to K Hellberg.

At least 37 records · Page 2Linked to original sources
PubMed1981

Stabilization of flail chest by compression osteosynthesis--experimental and clinical results.

It has been demonstrated that the impaired ventilatory parameters can be normalized after early stabilization of flail chest. Most methods for operative fixation, however, have given disappointing results and only plate fixation procedures have been effective. The experimental results of osteosynthesis with dynamic compression plates are presented and demonstrate the superiority of compression osteosynthesis in rib fractures. Compression osteosynthesis resulted in a primary fracture healing with stable fragments after 14 days, whereas conventional plate fixation techniques required a much longer time and showed secondary fracture healing. The benefits of compression osteosynthesis could also be demonstrated in 10 patients with traumatic flail chest. Osteosynthesis resulted in marked pain relief, immediate stabilization of the chest wall, and a shorter time of intubation. Not all fractured ribs need stabilization, dorsal fractures are well fixed by the strong erector muscles, and in the lateral position only ribs III to VII need to be considered. Reasonable stabilization may be achieved with fixation of every second rib. In patients with bilateral rib serial fractures subcutaneous implantation of one or 2 rib struts is recommended--good results were obtained in 12 patients. The indication for operative stabilization of flail chest should be restricted to: 1. Patients with severe ventilatory restriction due to chest wall paradox alone. 2. Flail chest combined with intra-thoracic lesions which require thoracotomy. 3. Flail chest combined with lesions which require a prone position for surgical exploration. 4. Respiratory distress patients when the unstable chest wall interferes with mechanical ventilation or with underlying organs.

Adolescent↗
PubMed1981

Conduit repair for complex congenital heart disease with pulmonary atresia or right ventricular outflow tract obstruction. part I: surgical results.

From 1972 to 1981, 40 valved extracardiac conduits have been implanted to bridge the right ventricular outflow tract (RVOT) in 37 patients for different complex congenital cardiac anomalies. The patients ranged in age from 2 to 23 years (mean 8.5 years). Two Dacron prostheses with incorporated Lillehei-Kaster valves, 1 valveless Dacron conduit, 27 Hancock conduits, and 9 lonescu-Shiley conduits were chosen according to availability and the progress in conduit technology. Thirty-three patients had had up to 4 previous palliative procedure before conduit repair. Although the complication rate appears considerable, the mortality rate seemed to be unaffected by the high percentage of prior surgery. Exchange of the conduit became necessary in 2 children, because of conduit stenosis with calcification of the Hancock valve 5 and 7 years respectively after implantation, and in another patient an outgrown Lillehei-Kaster valve Dacron conduit had to be replaced 9 years after repair. Five children died in the early postoperative course: one in pulmonary failure and kinking of the conduit; one with right heart failure and pulmonary hypertension stage IV; 2 in myocardial failure, and one due to severe bleeding from myocardial failure, and one due to severe bleeding from the prosthesis. Three patients died in the late postoperative course 11 weeks, 4 years and 4 years respectively after conduit repair. Conduit surgery offers new possibilities for repair of complex cyanotic cardiac malformations. At present, however, none of the commercially available conduits is an ideal substitute. Our limited experience with the hemodynamic results of lonescu Shiley conduits is promising although longer observation periods are needed for a definitive judgement. At present, the largest possible conduit should be used whenever possible; problems of compression or kinking can be avoided with proper positioning of the conduit.

Adolescent↗
PubMed1981

Early stenosis and calcification of glutaraldehyde-preserved porcine xenografts in children.

Thirty-four glutaraldehyde-preserved porcine aortic valves have been implanted in children at the Center of Thoracic and Cardiovascular Surgery in Göttingen since 1972. Severe stenosis of the right ventricular outflow tract (RVOT) due to massive calcification of the bioprosthetic valve was detected 15 to 76 months after surgery in 2 of 3 children with hospital-made, and in one of 25 children with commercially available valved conduits. The results with Hancock xenograft valves in mitral position were even more alarming. Five out of 6 children, aged 5 to 15 years (mean 9 years) presented similar massive calcification patterns of the bioprosthesis, necessitating reoperation from 23 to 63 months (mean 38.8 months) after implantation. Focal calcium deposits were found mostly in the central layers of the cusps; severe stenosis and regurgitation were due to immobilization of the leaf-lets which were fixed in a semi-open position. The causes for early valve dysfunction and calcification of glutaraldehyde-fixed porcine aortic bioprostheses in children remain to be further investigated. Degenerative changes have been shown to commence early after implantation, resulting in collagen disruption as early as 2 years later (3, 7, 19). There is evidence that these lesions could be predisposing factors for calcification, leading to accelerated calcification rats in children and patients with a high-calcium-turnover. The use of bioprostheses in children and adolescents must therefore be questioned since they appear to carry a high prospect to early valve deterioration.

Adolescent↗
PubMed1981

Early and long-term results after surgical treatment of abdominal aortic aneurysm.

From 1959 to July 1981, 121 patients underwent surgery for abdominal aortic aneurysm. One hundred-nine patients were male and 12 female. Ninety-one patients had an elective operation, 30 patients were operated on an emergency basis. Among the electively treated there were 32 asymptomatic patients. Early mortality of electively operated patients was 13.2% in period I (1959 to 1974), and 8.8% in period II (1975 to 1981). The early death rate of asymptomatic patients decreased from 9.4% to 4.8%. The prognosis of emergency patients remained unchanged: 50% died in both periods. Cardiac complications were the major cause of early death. The late complication rate related to the aneurysmectomy was 18.1%. Four patients died of rupture of the proximal anastomosis. Aneurysm-related reoperations were necessary in 19.1% of the patients. The mortality rate for patients under 65 years was 6.1% in period II, and 16.7% in patients over 70 years. Another severe risk factor is coronary artery disease (16.0% mortality in period II), especially in combination with advanced age (21.4% mortality in period II). The results indicate that the abdominal aortic aneurysm should be treated electively; however, poor risk patients should not undergo surgery if the aneurysm is asymptomatic. In younger patients with coronary artery disease, coronary artery bypass surgery should be considered prior to aneurysmectomy.

Adult↗
PubMed1981

Hemodynamics and energy balance of the left ventricle during low flow venoarterial bypass and venoarterial counterpulsation with an oxygenator in experimental animals.

The effects of partial venoarterial continuous flow and counterpulsating bypass with an oxygenator on the hemodynamics and energy balance of the left ventricle were studied in 8 anesthetized closed-chest dogs. A mean blood flow of 35%, and 48% of the animals's cardiac output was pumped via an extracorporeal circuit. 1. with continuous flow by means of a roller pump, and 2. with ECG-synchronized counterpulsation by means of a one-chambered electropneumatically driven ventricle pump. Central venous shunt blood was oxygenated with a double oxygenator and returned into the descending aorta. A bypass of 48% of cardiac output both with continuous and counter-pulsating flow resulted in a significant decrease of the maximal rise in left ventricular pressure (dp/dt max, 32% and 30% respectively) and of the calculated myocardial oxygen requirement (10% and 16% respectively). The improved myocardial energy balance during diastolic counterpulsation was due to a significant decrease in systolic aortic pressure (11%). During bypass of 35% of cardiac output with continuous flow the hemodynamics and energy balance of the left ventricle remained essentially unchanged. However, during bypass with counterpulsating flow a significant decrease in systolic pressure (7%) dp/dt max. (19%), and myocardial requirement oxidend (9%) was obtained. The results indicate that, if combined with counterpulsation, partial venoarterial bypass of only 35% of cardiac output can be an effective method of supporting the failing heart. Low flow venoarterial counterpulsation may therefore be of value for transitory use up to 72 hours in postoperative low-output syndrome or myocardial infarction whenever intraaortic balloon pumping alone is not sufficient or combined right and left heart failure is present.

Animals↗
PubMed1980

[Severe cardiogenic hemolytic anemia with decreased flexibility of erythrocytes following surgical correction of mitral valve stenosis (author's transl)].

After surgical correction of a common atrium and closure of a mitral cleft, a mitral stenosis developed in a 5 year old girl. Postoperatively a pronounced hemolysis developed necessitating multiple blood transfusions. Rheologic measurements showed that hemolysis was due to a loss of erythrocyte deformability after mechanical damage. On the basis of these measurements it was concluded that the mitral stenosis was most likely responsible for this mechanical damage. Following another surgical correction of the mitral valve there was no hemolysis anymore.

Anemia, Hemolytic↗
PubMed1977

[Supporting the pumpfunction of the right atrium. A new therapeutic concept after physiological repair of tricuspid atresia (author's transl)].

A new indication for the External Conterpulsation (ECP) is demonstrated. Due to the venous augmentation a "pulse wave" is created in the V. cava inferior and in the right atrium and the ECP acts as a "peripheral pumpventricle", thus increasing pulmonary blood flow and left ventricular enddiastolic pressure. This new application of ECP is of valve in cases with low output syndrome after physiological repair of tricuspid atresia as demonstreated in a case report.

Adolescent↗
PubMed1976

[Haemodynamics, oxygen demand and oxygen uptake of the heart during isovolaemic haemodilution (author's transl)].

1. In experiments on 5 closed chest dogs an isovolaemic haemodilution with 6% dextran resulted in a drop of haemoglobin content to 6,4g%. Except for a small decrease of arterial pO2 and O2-saturation the body oxygen supply remained undisturbed. -- 2. According to only very small haemodynamic alterations (except compensatory cardiac output increase) myocardial O2-demand increased very little and mainly is caused by moderate augmentation of ventricular wall tension. The decrease of arterial O2 content was fully compensated by an increase of myocardial blood flow. O2 supply to the myocardium was not critically changed. -- 3. In accordance with other investigators it is concluded that in case of coronary insufficiency or increased myocardial O2 demand intentional hemodilution should be avoided. Patients with myocardial insufficiency considered for therapeutic hemodilution should be digitalized preoperatively.

Animals↗
PubMed1976

[Haemodynamics and tolerance to hypoxia of the myocardium under 6%-oxygen ventilation following acute isovolaemic haemodilution in experimental animals (author's transl)].

1. In experiments on closed chest dogs in a control group and a group of previous isovolaemic haemodiluted dogs a cardiovascular stress was produced by means of reduction of inspiratory O2 content to 6% O2--2. Under haemodilution only small changes of the heart rate, aortic pressure and dp/dtmax occurred, pointing to a decreased sympathoadrenergic response. Augmentation of LVEDP and pulmonary artery pressure is considered to be related to left ventricular insufficiency.--3. According to haemodynamic changes myocardial O2 demand in the control group during hypoxia is increasedby 120% and in contrast remains unchanged after previous haemodilution.--4. Despite the reduced oxygen content under haemodilution severe arterial hypoxemia affects mean survival time of the animals (18.5 min and 21.5 min respectively) only little. However, there is a greater variation from 11 to 26 min in the haemodiluted animals.

Animals↗
PubMed1975

[Diangosis and treatment of pulmonary arteriovenous fistula in infancy (author's transl)].

Pulmonary arteriovenous fistulas are seldom diagnosed in infancy because of few signs and symptoms in early life. The clinical picture is due to the right-to-left shunt and includes dyspnea, cyanosis, polycythemia, clubbing, and murmur over the fistula. The diagnosis can be suspected by demonstration of a typical density on chest X-ray. It can be established by angiocardiography. Because of the life-threatening complications resectional treatment is recommended already in infancy. A case is reported, diagnosed on the second day of life by angiocardiography and treated 3 months later by lobectomy.

Adolescent↗
PubMed1975

[Coronary circulation and myocardial oxygen cosumption after cardioplegic arrest (author's transl)].

Coronary blood flow, myocardial oxygen consumption, and cardiac hemodynamics was measured before and after cardiopulmonary bypass in two group of patients (7 and 4) with minor congenital heart disease where cardiac arrest was induced by means of "cardioplegin" or "external surface cooling" (Shumway). Only myocardial oxygen consumption was reduced 20% after bypass in the "cardioplegin" group; all other measured parameters remained essentially constant.

Acid-Base Equilibrium↗
PubMed1975

[Improvement of myocardial blood flow and cardiac hemodynamic by means of intraaortic balloon pumping IABP during experimental heart failure (author's transl)].

The influence of the intraaortic balloon pumping (IABP) on the hemodynamic and coronary blood flow under control conditions and after experimental heart failure induced by coronary artery ligature was proved on eight dogs. By timely use of IABP (systolic pressure over 60-70 mmHg), the cardiac hemodynamics can be improved by means of reducing myocardial oxygen demands, and on the other hand by raising the coronary perfusion and oxygen supply.

Animals↗
PubMed1975

[Diagnostic and therapy of postoperative cardiac low-output-syndrome by means of intraaortic balloon pumping (IABP) or external counterpulsation (ECP)--a comparison (author's transl)].

A beneficial influence on the myocardial energy imbalance of the hypoxaemically damaged heart can be reached with either intraaortic balloon pumping (IABP) or external counterpulsation (ECP). In the realm of our acquired clinical experience with two groups of patients, the technical demands of these cardiac assist devices are discussed and distinguished from one another in relation to different indications.

Adult↗
PubMed1975

[Drug induced acute renal failure after heart surgery (author's transl)].

The incidence of acute renal failure following cardiac surgery was markedly increased during the last years in our medical center. There was no correlation to known etiologic factors such as preexisting disease, hemolysis, low perfusion rates, post-operative low output syndrome etc. Post-operative renal failure was mainly seen in children between 2 and 10 years and was noted after 3-4 days of normal renal function. Peritoneal dialysis was carried out in 39% of out patients and the overall mortality was 10.7%. Careful analysis of our cases exhibited a correlation of the post operative acute renal failure to the intravenous application of Aescin. After abandoning this drug from our post-operative therapy we did not observe a similar case since almost one year.

Acute Kidney Injury↗
PubMed1975

Effects of thiopental (Trapanal) on coronary blood flow and myocardial metabolism in man.

The influence of thiopental (Trapanal) on coronary blood flow (MPF), myocardial oxygen consumption (MVO2), and general haemodynamics was investigated in seven patients without heart disease. Besides measurement of MBF, the amount of substrates (glucose, lactate, pyruvate and free fatty acids (FFA) was also determined in arterial and coronary sinus blood samples. Thiopental was given intravenously in a mean dose of 4 mg/kg b,w, MBF was measured by means of the argon method. After injection of thiopental, all seven patients showed a significant increase of MBF and MVO2, a fact which can essentially be explained by the increase of heart rate. The effects of thiopental on arterial concentrations, arterior-coronary substrate differences, myocardial uptake, and O2-extraction ratio of the different substrates are discussed.

Adult↗