Biomedical subjects

M Hofbeck

Publications and source records attributed to M Hofbeck.

97 records · Page 6Linked to original sources

PubMedDate not supplied

[Determination of heart time volume using the Fick principle in the early postoperative phase after correction of congenital heart defects. Comparison of the calculation of arterio-mixed venous oxygen differences and pulmonary oxygen uptake with the calculation of arterial-central venous oxygen differences and pulmonary oxygen uptake].

UNLABELLED: Comparison of the calculation by means of the arterio-mixed venous oxygen difference and the oxygen uptake with the calculation by means of the arterio-central venous oxygen difference and the oxygen uptake. OBJECTIVE: How reliable is the measurement of cardiac output on Fick's principle without a pulmonary artery catheter? SETTING: PICU in an University hospital. DESIGN: In the postoperative period following complete repair of congenital heart disease we carried out 91 simultaneous measurements of blood gases in 45 infants and children (mean age 18.6 months, mean body weight 8.9 kg) from a systemic artery, the A. pulmonalis, and the V. cava superior. We also determined the pulmonary oxygen uptake in 24 patients (48 measurements). Cardiac output was calculated on Fick's principle using the arterio-mixed venous oxygen difference and the pulmonary oxygen uptake (HZV a-pa) and compared to the cardiac output derived from the central venous values (HZV a-zv). We differentiated between patients with a left to right shunt of 10% or more postoperatively (group A, n = 18) and all others (group B, n = 27). RESULTS: In both groups the correlation coefficient between HZV a-zv and HZV a-pa was high (group A: r = 0.97, group B: r = 0.94). In group A HZV a-pa (mean: 1958 ml/min) was higher than HZV a-zv (mean: 1340 ml/min), group B showed the opposite situation (mean HZV a-pa: 1136 ml/min, mean HZV a-zv: 1373 ml/min). With the Wilcoxon signet-rank test we found significant differences between the partial pressure of oxygen and the saturation of central venous and mixed venous blood samples in both groups, but HZV a-zv and HZV a-pa were different significantly on a level of p < or = 0.01 only in group A. CONCLUSIONS: In both groups HZV a-pa and HZV a-zv correlated well. Therefore, if a pulmonary artery catheter is not inserted; the course of the cardiac output can be calculated with acceptable reliability from the central venous blood gases. By means of Fick's principle the pulmonary blood flow is determined, which is higher than the systemic blood flow in cases of left to right shunting, because of the recirculation in the pulmonary blood circuit. Interpreting the results this has to be taken into account.

Arteries↗

PubMedDate not supplied

[Interventional treatment of pulmonary atresia with intact ventricular septum by high frequency perforation and balloon dilatation of the pulmonary valve].

Surgical treatment of neonates with pulmonary atresia and intact ventricular septum is associated with a high morbidity and mortality. During the last two years specific radiofrequency-catheters have been developed, which allow the interventional perforation and subsequent balloon dilatation of an atretic pulmonary valve during cardiac catheterization. We report our experience with this new interventional technique in two neonates. In the first case perforation and balloon dilatation of the atretic pulmonary valve was performed without a complication. In the second case the radiofrequency catheter perforated the right ventricular outflow tract. There was no pericardial tamponade and the patient underwent a surgical valvotomy the following day. In our experience radiofrequency-assisted balloon dilatation of the pulmonary valve is a possible alternative in the treatment of neonates with pulmonary atresia, intact ventricular septum and moderate hypoplasia of the right ventricle. Further experience will have to show, whether this new interventional technique can be generally recommended.

Balloon Occlusion↗

PubMedDate not supplied

[Rate of prenatal detection of congenital right heart defects].

Congenital right heart lesions (including tetralogy of Fallot, pulmonary valve stenosis, pulmonary atresia with intact ventricular septum, Ebstein's anomaly and dysplastic tricuspid valve) account for about 19% of congenital cardiac anomalies. We performed a retrospective study in order to assess the percentage of patients with significant right heart lesions (requiring therapy in the first year of life), which is detected prenatally and referred to a centre for perinatal treatment. From 1/1990 until 12/1997 congenital right heart lesions were diagnosed in 21 fetuses and 190 infants (211 patients. The majority of patients had tetralogy of Fallot (64%), less frequently we found critical pulmonary valve stenosis (9%), pulmonary atresia with intact ventricular septum (9%), tricuspid atresia (14%) and Ebstein's anomaly or dysplastic tricuspid valve (4%). Prenatally the cardiac anomaly was diagnosed in all 21 cases who were referred to our center (10%). The highest referral and detection rate was found among fetuses with Ebstein's anomaly or dysplastic tricuspid valve (5/8 patients = 63%) followed by fetuses with pulmonary atresia and intact ventricular septum (5/20 = 25%), critical pulmonary stenosis (4/18 = 22%) or tricuspid atresia (4/29 = 14%). The prenatal referral rate was disappointing in children with tetralogy of Fallot (3/136 = 2.2%). A higher prenatal detection rate of congenital right heart lesions can be achieved only by an improvement of prenatal screening including the 4-chamber view and the origin of the great arteries. A first step would be the inclusion of the fetal 4-chamber view into the routine examination during the 18th-20th week of pregnancy (stage 1 of a multistage concept of prenatal screening) and by assessment of the outflow tracts and the great arteries in pregnancies associated with risk factors or anomalies of the fetus (stage 2 and 3 of a multistage concept).

Echocardiography↗

PubMedDate not supplied

Color Doppler imaging of modified Blalock-Taussig shunts during infancy.

To assess the role of color Doppler echocardiography in the early postoperative evaluation of patients with a Blalock-Taussig shunt we examined 13 consecutive infants who underwent insertion of either a modified right (6 patients) or a modified left (7 patients) Blalock-Taussig shunt (age range 7 days to 6 months, mean age 8 weeks). Examination of the patients in a high parasternal right or left long axis was able to determine patency of the shunt in 12 patients. In the remaining patient, who did not show flow in the shunt, complete occlusion of the shunt was confirmed by angiography. From subcostal views we were able to demonstrate patency of the shunt in 75% of the infants and in all patients younger than 4 weeks of age. In our experience color Doppler echocardiography is a highly reliable method for early postoperative evaluation of infants with a Blalock-Taussig shunt.

Anastomosis, Surgical↗

PubMedDate not supplied

Color Doppler imaging of modified Blalock-Taussig shunts during infancy.

Anastomosis, Surgical↗

PubMedDate not supplied

[Screening for fetal heart defects in the four chamber view with evaluation of larger arteries: possibilities and limits].

The four-chamber view and the visualization of the root of the left and right ventricular outflow tracts has been proposed as a screening method for the detection of congenital heart disease in the fetus. In order to study the diagnostical value of the method we investigated 1600 fetuses between the 17th and 40th gestational week without anamnestic risk for congenital heart disease with this screening method in a two years' period. We found 33 fetuses to have an abnormality either in the four-chamber view or in the ventricular outflow tracts. The sensitivity of the method in the detection of congenital heart disease was found to be 81%, the specificity 99% and the positive predictive value 88%. Women at high risk for congenital heart disease in the fetus should still undergo a more detailed echocardiographic examination to maximize the sensitivity in the detection of structural heart defects. Nevertheless, the described screening procedure is an effective and feasible method to detect fetuses with severe congenital heart disease, whose prognosis may be improved by the delivery in a perinatological center.

Aorta, Thoracic↗

PubMedDate not supplied

[Perinatal management of children with prenatal diagnosis of congenital heart defects].

During the recent years an increasing number of patients with congenital heart disease has been diagnosed prenatally by fetal echocardiography. The purpose of this study was to answer the question, which consequences will result from this prenatal information concerning the timing and mode of delivery as well as the neonatal treatment in these patients. From 12/1990 until 10/1994 21 neonates were treated in our center who had prenatal diagnosis of congenital cardiac malformation. In none of these patients we decided to change the timing or mode of delivery based on the hemodynamic findings of the cardiac malformation. Postnatally there was no evidence that this mode of delivery had a negative impact on the outcome in one of these neonates. All children, however, were delivered in a perinatal centre providing optimal perinatal care and early involvement of a pediatric cardiologist in the postnatal treatment. The perinatal treatment of patients with isolated ventricular or atrioventricular septal defects did not require specific intensive care measurements. On the other hand the majority of neonates with left heart, right heart or complex cardiac malformations required early intubation (81%), mechanical ventilation and intravenous administration of prostaglandin E1 (69%). Due to the prenatal diagnosis these measures were started before the adverse effects of ductal closure could lead to a hemodynamic deterioration in these patients. Despite this treatment 11/21 patients (52%) died in the neonatal period or in early infancy. Based on our experience we do not propose a change in the mode of delivery in the majority of children with prenatal diagnosis of congenital cardiac malformations. For further improvement in the perinatal treatment of children with congenital heart disease a close cooperation of gynecologists, neonatologists and pediatric cardiologists as well as concentration of those patients to perinatal centres will be necessary.

Echocardiography↗