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Biomedical subjects

L H Andersen

Publications and source records attributed to L H Andersen.

34 records · Page 2Linked to original sources
PubMed1979

Measurements of cardiac stroke volume in various body positions in pregnancy and during Caesarean section: a comparison between thermodilution and impedance cardiography.

A total of 220 simultaneous pairs of measurements of cardiac stroke volume were made in twelve women before and during Caesarean section in order to compare impedance cardiography with the thermodilution method. A significantly higher coefficient of correlation was found before (r = 0.77) than during anaesthesia (r = 0.55). Further, there was a significant difference in the slope of the regression lines: before anaesthesia the slope was 1.07 and during anaesthesia with thiopentone, nitrous oxide, oxygen and suxamethonium it was 0.45. Significant changes in the intercept on the Y-axis were found before (-13.9 ml) and during anaesthesia (33.4 ml). When the uterus was displaced upwards and to the left from the 15 degrees tilt position the stroke volume and the cardiac output were increased when measured by both methods to nearly the same values as in the left lateral position. It is concluded that the impedance method is reliable for measuring cardiac stroke volume in late pregnancy under physiological conditions in the conscious patient, but that it cannot replace the thermodilution method in pharmacological studies.

Adult↗
PubMed1978

Pulmonary abnormalities in mitral valve disease. Comparison between pulmonary wedge pressure, regional pulmonary blood flow and chest films.

Chest films, right sided heart catheterization, and measurement of the regional lung perfusion, using 133Xe, were carried out 31 times on patients with mitral valve disease. A relationship was found between the radiologic evaluation in 3 grades, and the values of pulmonary wedge pressure and the apical and basal perfusion. Changes in flow distribution as reflected in altered appearance of the vessels and the presence of interstitial edema were found to be the most sensitive factors in the evaluation of pulmonary wedge pressure. Chest radiography was thus found suitable for the evaluation of pulmonary wedge pressure in mitral valve disease.

Adult↗
PubMed1978

Effect of a single graded dose of terbutaline tablets in patients with chronic bronchitis and bronchoconstriction. A double-blind, placebo, cross-over study.

Terbutaline, a selective beta2-adrenergic receptor stimulator was given to 10 patients with chronic bronchitis. The effects of the drug were tested by measurements of forced expiratory volume in 1 sec (FEV1), peak expiratory flow rate (PEFR), heart rate, blood pressure and blood gas analysis. The measurements were performed before and 1, 2, 4, 5, and 6 h after oral administration of placebo, 2.5 mg, or 5.0 mg terbutaline. Terbutaline caused a significant dose-related increase in FEV1 and PEFR as compared with placebo. The maximal effects were found at the 4-h measurement and were still present at the measurements performed at 6 h. Heart rate, blood pressure and arterial oxygen tension (PaO2) were not significantly affected. Four patients experienced side effects as tremor and/or heart palpitations. It is concluded that orally administered terbutaline may be an important therapeutical agent in the treatment of chronic bronchitis.

Aged↗
PubMed1977

Changes in the pattern of regional pulmonary blood flow after PGF2alpha infusion in pregnant women.

The central haemodynamics and regional lung function were measured in the sitting position before and after infusion of prostaglandin F2alpha (PGF2alpha) in seven healthy women in the first trimester of pregnancy. The dosage level of PGF2alpha was: 100mug/min for 10 minutes followed by 300mug/min for 5 minutes. The pulmonary arterial pressure, wedge pressure, and cardiac output were measured by means of a flow direct Swan-Ganz catheter introduced through an antecubital vein. The regional perfusion of the lungs was determined, in the sitting position, by external counting over the chest following intravenous injection of Xe133. The thoracic impedance was measured with the Minnesota Impedance Cardiograph Model 304A and the impedance was considered as an expression of the thoracic fluid volume. A significant redistribution of the pulmonary blood flow after PGF2alpha administration was found, ie an increase in the apical blood flow and a reduction in the basal blood flow. Further, the point of maximal blood flow moved in direction of the apex. A significant increase in both arterial [1.92-2.76 kPa (14.4-20.7 mmHg)] and wedge pressures [0.56-0.83 kPa (4.2-6.2 mmHg)] was found at the highest dosage level, whereas no changes were seen in the cardiac output and thoracic impedance. The findings indicate vasoconstriction of the arterial and possibly on the venous side of the pulmonary vascular bed during PGF2alpha infusion.

Blood Pressure↗
PubMed1976

Pattern of total and regional lung function in subjects with bronchoconstriction induced by 15-me PGF2 alpha.

Closing volume (single breath nitrogen test), regional ventilation and perfusion (using intravenous xenon-133), and total lung function (TLC, VC, and FEV) were measured before and after intramuscular administration of 250 mug 15-methyl prostaglandin F2alpha (15-me PGF2alpha) in 10 healthy women. The cardiac output was measured with the Minnesota impedance cardiograph model 304A and the transthoracic impedance was used as an expression of the thoracic fluid volume. The slope of the alveolar plateau on the closing volume tracing showed a 271% increase 20 minutes after the prostaglandin administration, at which time the closing volume per cent (CV%) had decreased (P less than 0-01) and the closing capacity (CC%) had increased (P less than 0-05). Vital capacity (VC) decreased (P less than 0-01), residual volume (RV) increased (P less than 0-01), and the total lung capacity (TLC) remained unchanged. The maximal decrease (9%) in FEV1 was seen after 20 minutes. All these measurements except the slope of the alveolar plateau returned to control levels after 60 minutes. The redistribution of regional ventilation was more pronounced than that of the regional pulmonary blood flow. No change was observed in cardiac output and transthoracic impedance. None of the patients experienced any dyspnoea. Our results are consistent with a more pronounced effect of prostaglandin F2alpha on the small airways (the alveolar plateau) than on the larger airways (FEV1). In cases where an increase in the slope of the alveolar plateau is observed, the closing volume per cent should not be used as a measurement of the lung disease. It is concluded that the single breath nitrogen test (N2 closing volume) is more sensitive than the conventional tests.

Bronchi↗
PubMed1976

Added apparatus dead space in the N2-closing volume test: - a refinement or a bias.

14 subjects without symptoms of cardiopulmonary disease underwent paired closing volume determinations by the modified single breath nitrogen test. Measurements were performed with an apparatus dead space of approximately 40 ml and approximately 350 ml. A rise in closing volume percent for all subjects was found in measurements with dead space of 350 ml. This Difference was statistically significant at the 0.001 level for the group as a whole. No change in the accuracy of the method, expressed as the standard deviation of each subjects values with and without added dead space cojld be demonstrated. Linear regression analysis of the closing volume percent values measured with added dead space as a function of closing volume percent values measured without added dead space showed the expected highly significant positive correlation. However the regression line was not parallel to line of identity, indicating that the higher the initial value of closing volume percent the higher rise after addition of apparatus dead space. With reference to characterizing a person as normal or abnormal this could be considered a refinement of the method.

Adult↗
PubMed1976

Epidemiological limitations of the nitrogen closing volume test.

Closing volume was measured in 216 men aged 46-68 years. They were divided in 5 age groups and classified as either symptomatic or asymptomatic according to answer to standardized interviews. In 3 of 5 age groups mean value for closing volume percent (CV%) for symptomatic persons was lower than the mean value for asymptomatic persons. CV% is not considered useful as the dependent variable in a multiple regression analysis. In all 5 age groups the mean value of slope of alveolar plateau was higher for symptomatic than for asymptomatic persons. Slope af alveolar plateau is considered useful as dependent variable in a multiple regression analysis. One of the reasons for the false negative CV%-values is believed to be influence of increased uneven and sequential ventilation of the lungs, expressed in the slope of alveolar plateau.

Aged↗
PubMed1976

Displacement of endocardial pacemaker electrodes. A comparison between Elema 588 B and Chardack 5818.

The implantation of a permanent pacemaker has been carried out on 159 patients suffering from Adams-Stokes seizures. Elema 588 B electrodes were implanted in 119 patients and Chardack 5818 electrodes in 40 patients. The two types of electrodes differ with regard to both the implantation technique and weight and thickness. No difference was found in the incidence of electrode displacement or survival between the two groups, similarly the experience of the physician with regard to implantation had no influence on the frequency of displacement. Displacement on the other hand occurred significantly more frequently in those patients suffering from heart disease demonstrable by x-ray examination.

Adams-Stokes Syndrome↗