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Biomedical subjects

F Sebening

Publications and source records attributed to F Sebening.

At least 91 records · Page 5Linked to original sources
PubMed1979

The effects of deep hypothermia and circulatory arrest on systemic metabolic state of infants undergoing corrective open heart surgery: a comparison of two methods.

Fortyone of 187 infants undergoing corrective surgery for their congenital cardiac lesions using profound hypothermic circulatory arrest were randomly selected for metabolic studies. Deep hypothermia of 21 to 22 degrees C core temperature was reached by two different techniques: 1. Perfusion cooling by extracorporeal circulation (ECC-C) 2. Surface cooling with ice bags combined with perfusion cooling (SC + ECC-C) After circulatory arrest (34.2 min. ECC-C v.s. 46.7 min. SC + ECC-C) bypass rewarming was used in both groups. The metabolic reaction to these interventions are described. No significant differences in acid base status in oxygen consumption, lactate concentration, serum electrolytes (K+, Na+, Ca++,Cl-) and serum enzyme activity (CPK, alpha-HBDH, LDH, SGOT, SGPT) could be demonstrated between the two groups of patients during the entire course of cooling, circulatory arrest and rewarming. The glucose concentration was significantly lower in the ECC-C group during the entire period of operation. Total cooling time was significantly shorter in the group without surface cooling. (ECC-C: 12 min, v.s. SC + ECC-C: 64 min). Since no favourable effects of the SC + ECC-C method on systemic metabolism could be demonstrated and operative results were similar we now prefer the time-saving ECC-C technique.

Acid-Base Equilibrium↗
PubMed1979

The diagnosis of acute renal failure (ARF) following cardiac surgery with cardio-pulmonary bypass.

The diagnostic value of renal concentrating capacity expressed as free water clearance (CH2O), in comparison with other routine criteria for the early identification of acute renal failure (ARF), was evaluated in 1,203 adult patients undergoing cardiac surgical procedures. On the basis of the appearance of pathologic CH2O values in the range of -20 to 0 ml/hour or more positive, reversible or irreversible ARF was observed in 90 (= 7.5%) of our patients. Mortality in the presence of ARF was 47%; total ARF mortality was 3.5%. CH2O was pathologic for the first time on an average of 1.6 days after operation. In contrast, routine ARF criteria reported in the literature, such as serum urea and creatinine at varying substrate levels or oliguria, allowed diagnosis 1 to 5.5 days later. Moreover, these parameters only partially and less frequently met the criteria for ARF at the different levels. Likewise, the incidence of ARF decreased to a minimum of 1.7% and the total ARF mortality to 1.3%, depending on the severity of the criteria used. Altogether, the occurrence of pathologic CH2O values proved to be the earliest, most frequent and most reliable criterion for the recognition of ARF following cardiac surgery with cardiac-pulmonary bypass.

Acute Kidney Injury↗
PubMed1978

Acute effects of aortocoronary bypass surgery on left ventricular function and regional myocardial mechanics: a clinical study.

The acute effects of myocardial revascularization on overall left ventricular performance and on myocardial segmental wall motion were assessed intraoperatively in 22 patients who had unstable (11 patients) or stable angina pectoris (11 patients). Segmental contraction patterns were evaluated using an ultrasonic transit-time method. In 9 patients with unstable angina pectoris, notable improvement in segmental wall motion was observed as the short-term response to coronary bypass grafting. Hypokinetic patterns were rendered normal after revascularization. Despite marked changes in segmental myocardial function, overall left ventricular performance was not altered notably. In contrast, reperfusion did not lead to acute effects on either segmental wall motion or total left ventricular function in patients with stable angina pectoris. The results indicate that aortocoronary bypass grafting may improve segmental wall motion in patients with unstable angina.

Adult↗
PubMed1978

[Three years experience with biological heart valve prostheses (author's transl)].

Increasing clinical experience has led to a world wide expansion of glutaraldehyde fixed aortic heterografts for valve replacement in patients. The distinct advantage of this valve is a very low rate of thrombembolic complications during the postoperative course. In our hospital 324 such prostheses of the types Hancock and Carpentier have been implanted in 290 patients. In 154 cases follow-up 6 months to 3 years after the operation have been obtained. Thrombembolic complications occured in 1,4%. Other postoperative complications were hepatitis (13,4%), and valvular endocarditis (1,5%). Postoperative control of patients after isolated mitral or aortic valve replacement revealed improved clinical conditions in 90,9%. Dysfunctions of the valve have not been observed. For aortic valve replacement prostheses of a diameter of 27 and 29 mm have been used. In mitral and tricuspid position generally size 31 mm and 33 mm valves were implanted. The decision to use glutaraldehyde fixed biological valves requires the observation of long time results demonstrating reliable mechanical stability of such valves for some decades.

Aortic Valve↗
PubMed1978

[Pacemaker therapy in infants (author's transl)].

Since April 1974 until January 1978 permanent pacemakers were implanted in 21 children. The patient age at the time of operation averaged 4.5 years; the youngest patient was 3 months old. Indications for pacemaker implantation were: congenital total a-v block (TAVB) (n = 4), sick syndrom (S-S-S) (n = 4), postoperative TAVB (n = 13). Cardiac failure was present in all patients despite optimal medical treatment. Pacemakers were implanted under general anesthesia and intubation. The stimulation electrodes were positioned by the transvenous route in 16 subjects and by direct fixation upon the ventricle and the atrium in 5 patients. 5 children obtained an atrial triggered, 14 patients R-inhibited demand pacemaker and 2 subjects an asynchronous pacemaker. After a mean observation time of 16.4 months mean pacemaker function is normal in 14 patients. 6 children died 1 to 33 months after implantation despite functioning pacemakers because of congestive heart failure. Pacemaker malfunction was observed in 4 patients. The type of malfunction induced: failure of the impulse generator (n = 2), dislodgement of the electrode (n = 2), threshold increase (n = 1). In 5 children generators were changed 9 to 36 months (m = 23 plus or minus 10) after implantation because of battery depletion. The use of the pacemakers in small children is connected with several specific problems: 1. Application of large generators is hazardous because of impending perforation and secondary infection. 2. Until now miniaturization of pacemakers decreases function time and therefore implies frequent surgical intervention. 3. Stretching and dislodgement of transvenous electrodes may occur due to growth of the child. 4. Threshold increase may limit the life-span of myocardial electrodes. 5. Physiological changes in natural frequency requires changes in stimulation rate. 6. To guarantee normal physical activity demand related adaptation of heart rate is necessary. Because of these reasons a pacemaker system for children should have the following criteria: low weight, small wolume, high energy capacity, atrial or programmable stimulation, a thin elastic perhaps coiled electrode.

Adolescent↗
PubMed1978

[Heart-operations in the first year of life (author's transl)].

During the last 3 years (April 1974 to April 1977) 246 patients in their first year of life underwent surgery because of complex severe congenital heart defects. Corrective surgery was attempted whenever possible, palliative procedures were used only in forms of cardiac malformations not feasible for repair. All corrective operations were done in profound hypothermia (20 to 22 degrees C) with circulatory arrest. 73,6% of all infants survived the operation and were alive 30 days after operation-most of them markedly improved or completely free of symptoms. It is concluded that correction of congenital heart defects with the technique described seems to be a promising improvement of open heart surgery in the first year of life.

Age Factors↗
PubMed1978

[Surgery in newborns and infants with cyanotic cardiac malformations: indication and technique of emergency operations and urgent early surgical interventions (author's transl)].

Between April 1974 and September 1977, 368 infants underwent surgery at the German Heart Center. 287 were less than 1 year of age, and 81 were between the ages of one and two years. In 90 patients (= 24.4%) surgery was necessary because of cyanotic lesions. Within this group corrective procedures were performed in 36 infants during the first year of life, and in 33 during the second year of life, while palliative measures were carried out in these age groups in 15 and 6 infants, respectively. Urgent corrective surgery is indicated as a life-saving measure in neonates with total anomalous pulmonary venous connection (TAPVC) since this lesion is not amenable to either medical nor palliative interventions. Of 10 neonates and young infants who underwent corrective surgery for TAPVC, 3 died during the early post-operative period and 1 subsequently. Balloon atrial septostomy palliatively employed for transposition of the great arteries (TGA) may render only temporary improvement in the clinical status of young infants. In these infants, more favourable results can be achieved through early, functionally-corrective surgery (Mustard-Brom procedure). In 7 infants who underwent correction of TGA during the first year of life there was 1 post-operative death. There was no post-operative mortality in 18 infants whose age at the time of operation was between 1 and 2 years. In the presence of TGA combined with ventricular septal defect there were 3 deaths in 8 infants operated on during the first year of life and none in the 3 who underwent surgery during the second year of life. In the same age groups, early correction of tetralogy of Fallot (TOF) was performed in 11 infants (with 2 deaths) and in 10 infants (with one death), respectively. Thus, in the absence of preclusive, complex anomalies, early surgical correction of congenital cyanotic lesions in young infants consistently yields results superior to that of palliation or two-stage procedures.

Age Factors↗
PubMed1977

[Intraoperative control of revascularisation and indication for reintervention (author's transl)].

Among the procedures of intraoperative control of revascularisation the simple method of probe passage for determination of technical mistakes during anastomoses is very valuable. More informative is the measurement of bypass-flow using an electromagnetic flowmeter. We compared this method with the results of intraoperative angiography, which is performed in our hospital routinely for immediate control of revascularisation. A comparison of 214 veins demonstrated a good statistically significant correlation between run-off and bypass-flow. The quality of the anastomosis can only be judged by intraoperative angiography and does not correlate with a low bypass flow. According to these measurements it was necessary in four cases to perfrom an intraoperative reintervention.

Angiography↗
PubMed1977

[Surgical repair of Ebstein's disease (author's transl)].

In 1976 4 patients with Ebstein's disease underwent surgical repair. In one patient (22 yrs.) the tricuspid valve leaflets were suitable for reconstructive surgery using Hardys method in addition to De Vegas annuloplasty. In the other three cases (17, 29, 51 yrs. old) excision of the malformed tricuspid valve was necessary, and porcine heterografts of greatest possible diameter were implanted. Three patients improved considerably 9 months postoperatively. The fourth patient, a 51 years old woman, died 2 days postoperatively on cardiac failure. From our own results and based upon reports from the literature we conclude that reconstructive surgery of the tricuspid valve should be preferred to replacement. If valve replacement is necessary, bioprostheses ought to be used. At the age of 15 to 40 years, surgical repair seems to have the best prognosis in patients with Ebstein's malformation.

Adolescent↗
PubMed1976

[Open-heart surgery during deep hypothermia in infancy].

A total of 47 infants (2,7 to 9,6 kg in weight, 3 days to 21 months of age, 89% under one year) underwent early total correction of severe congenital heart defects in profound hypothermia of about 22degreesC and circulatory arrest (11 to 64 minutes). 8 patients were operated upon without extracorporeal circulation (ECC) (mortality 63%). 37 infants were additionally cooled and rewarmed with ECC (mortality 22%). The most common diagnosis were: Total atrioventricular canal (11), aortic stenosis with and without combined lesions (8), tetralogy of Fallot (7), ventricular septum defect (7) and transposition of the great arteries (4).

Aortic Valve Stenosis↗
PubMed1976

[Hemodynamic studies after the implantation of Hancock-heart valves (author's transl)].

Velocity profile, pressure gradient across the valve and blood flow have been measured in 10 patients after the implantation of bioprostheses of the sizes 27 and 29 millimeters in aortic position. According to these hemodynamic measurements the use of bioprostheses for the aortic valve replacement is recommendable. The low flow velocities in the area of the muscle containing valve cusp did not effect a detectable stenosis intraoperatively under the conditions of rest. The hemodynamic data showed no differences between the Hancock-Zuhdi and the Edwards-Carpentier bioprostheses. Despite of good hemodynamic conditions and a low risk of thromboembolic complications after the aortic valve replacement with bioprostheses reservation is recommended to its clinical use until the long term mechanical stability (more than 6 years) of the biological heart valve prosthesis has been secured.

Adolescent↗
PubMed1976

A new type of fluorocarbon liquid oxygenator.

A new oxygenator based on gas transfer across liquid-liquid interfaces (liquid oxygenator) is introduced. Perfluorinated chemicals are used as gas carriers. This liquid oxygenator differs from others in its concept basing on the dispersion of the blood droplets in an inert liquid by means of shear forces. This method allows high efficiency both with respect to saturation and to required blood flow. The results of gas transfer experiments in vitro and in vivo are satisfactory.

Animals↗
PubMed1976

[Direct measurement of papillary muscle dynamics in the intact canine left ventricle during acute coronary occlusion (author's transl)].

UNLABELLED: The functions of the normal and ischemic papillary muscle in the intact canine heart were studied using an ultrasonic transit time method. Miniaturized piezoelectric crystals (1.5-2 mm 0) were implanted during extracorporeal circulation into the root and tip of the anterior and posterior papillary muscle of the left ventricle. RESULTS: 1. Phasic changes of left ventricular geometry during the heart cycle determine the dynamic pattern of papillary muscle movements. 2. The amplitude and velocity of papillary muscle length is directly related to those of myocardial wall segments. 3. Experimental ischemia induces total dysfunction of the papillary muscle within seconds. 4. Despite total muscle dysfunction no mitral insufficiency occured.

Animals↗
PubMed1975

[Instantaneous blood flow velocity profiles before and after aortic valve replacement (author's transl)].

In 17 patients the instantaneous velocity profile was recorded before and after aortic valve replacement (Starr-Edwards, Björk-Shiley, Lillehei-Kaster). A single gated pulsed Doppler Ultrasonic flownmeter was used for analysis. Distal of these valves a flat flow profile was recorded showing high velocity gradients near the walls. As a main cause of this, numerous eddies and turbulent flow have been suggested. Downstream of a Starr valve a flat profile appears with a slowing down of forward flow just behind the ball. The disk valves Lillehei-Kaster and Björk-Shiley demonstrated a higher flow velocity in direction to the larger opening. The "in vivo" studies have been supported by "in vitro" measurements. The highest flow velocities were above 100 cm/sec and thus, according to Reynolds definition, in the turbulent range. The turbulent flow produces a washing effect, which is emphasized during the cardiac cycle. The importance of these data can be discussed by clinical results only.

Aorta↗