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Biomedical subjects

G Schmalisch

Publications and source records attributed to G Schmalisch.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Percentile curves of functional residual capacity of newborn infants].

BACKGROUND: Helium dilution or nitrogen washout techniques are commonly used to measure the functional residual capacity (FRC) in newborn babies. For both techniques equipment is available. Its clinical application, however, was difficult since there were no FRC reference ranges for the different weight groups of newborn infants; reference studies are very time consuming and cause several technical and ethical problems. METHODS: Statistical methods were used to evaluate several results from the literature and to exclude significantly differing data of some authors. Measured values of FRC were related to body weight, and the percentiles of FRC/kg were estimated by the smoothed cumulative distribution function of the pooled data. RESULTS: No significant differences were found between the results of helium dilution and nitrogen washout techniques. The distribution of 178 results showed a significant skewedness (x5% = 18.3 ml/kg; x50% = 27.5 ml/kg x95% = 42.8 ml/kg), which could also be seen in the percentile curves calculated approximately, assuming a linear development of functional residual capacity with body weight. CONCLUSION: Percentile curves describe best the development and interindividual variability of FRC in newborn babies as our evaluation could show. We conclude that the nonparametric estimation of percentiles is more adequate for the description than the use of simple regression models.

Birth Weight↗
PubMed1992

Randomized double blind trial of Ambroxol for the treatment of respiratory distress syndrome.

In order to test the ability of Ambroxol to improve the clinical course of respiratory distress syndrome and to reduce the incidence of complications a multicentre, randomized, placebo-controlled double-blind trial was conducted. Entry was limited to infants with a birth weight below 1500 g. A total of 179 neonates were enrolled, but 31 were later excluded because they had other diseases. Of the remaining 148 babies, 74 received Ambroxol (birth weight 1190 +/- 216 g; gestational age 29.1 +/- 1.9 weeks) and 74 placebo (birth weight 1168 +/- 216 g; gestational age 28.9 +/- 1.9 weeks). In the Ambroxol group 23 (31%) and in the placebo group 27 (37%) infants died during the first 5 months of life. In 28 day-survivors Ambroxol was able to significantly improve the PaO2/FiO2 ratio, mean airway pressure, phospholipid profile of tracheal effluent and pulmonary mechanics of spontaneously breathing infants. In addition, the incidences of bronchopulmonary dysplasia (29% vs 54%), intraventricular haemorrhage (25% vs 44%) and postnatally acquired pneumonia (15% vs 36%) were significantly reduced in the Ambroxol group as compared to the control group. No adverse events attributed to the Ambroxol treatment were reported.

Ambroxol↗
PubMed1991

[Measuring equipment for bedside diagnosis of respiratory function in spontaneously breathing newborn infants].

Equipment was developed for bedside lung function testing in the newborn using the simultaneous measurement of air flow rate, tidal volume, and esophageal pressure changes as a measure of transpulmonary pressure. The equipment has a number of advantages for the investigation of very low birthweight infants. A flow-through technique was used to eliminate the dead space of the face mask and a very thin micro-tipped catheter permits ready measurement of esophageal pressure. With this equipment, long-term measurements are also possible in oxygen-dependent newborns and the air-tightness of the mask can be monitored continuously. Long-time measurements in neonates are a prerequisite for standardizing the measuring conditions and adapting the duration of the measurement to the variability of the signals, especially in newborn with an irregular pattern of breathing.

Computer Systems↗
PubMed1991

[Assessment of respiratory physiology signals in very low-weight newborn infant with respiratory deficiency].

1. Lung function tests in newborn babies breathing spontaneously were performed commonly using a pneumotachometer to measure the tidal volume and an esophageal catheter to measure the transpulmonary pressure changes. 2. The quality of the measured signals depends on the breath-to-breath variability of the signals as well as on the frequency of different artifacts and disturbances due to physiological interferences. 3. The evaluation of the signals in very low birth weight infants with respiratory distress is often difficult due to the irregular pattern of respiration, the reduced signal-noise-ratio and the high number of artifacts. 4. The subjective assessment of the quality of 115 records of respiratory signals has shown that 54% of all records can be evaluated easily, in 40.8% the evaluation was difficult and in 5.2% an evaluation was not possible. 5. The qualitative analysis of respiratory signals shows that in this age group the computer-aided signal evaluation requires a new view in the detection and elimination of artifacts as well as in the calculation of characteristic results from a sufficient number of evaluated breathing cycles.

Humans↗
PubMed1990

[The fundamental pulmonary mechanics processes in pressure-limited artificial ventilation of neonates].

During the past years the incidence of artificial ventilation in newborn and premature babies increased continuously. The optimization of the respirator therapy requires the knowledge of the fundamental lung mechanic processes during the artificial ventilation. Using the simple model RC V(t) + V(t) = CP(t) the relationships between the flow, volume and pressure signals were demonstrated. This model was also used to explain the development of the inadvertent PEEP as well as to determine lung mechanic parameters from the measured signals. In the future the monitoring of tidal volume will be an integrated part of the respirator. Therefore, the influence of the lung mechanics and the parameter-settings of the respirator on the ventilation has been investigated in detail.

Humans↗
PubMed1989

Ambroxol for prevention and treatment of hyaline membrane disease.

To estimate the efficacy of ambroxol for clinical use in prenatal prevention and postnatal therapy of hyaline membrane disease (HMD) all available experimental and clinical data were reviewed. The administration of ambroxol in animals has a certain promoting influence on lung maturation, a high specificity to lung tissue and a favourable relationship between intended action and negative adverse effects. In clinical studies concerning the prevention of HMD, ambroxol increases the values of amniotic fluid parameters used for estimation of lung maturity and reduces the incidence of HMD at least as effectively as corticosteroids. The number of infants at less than 33 gestational weeks in these reports is small, and further studies will have to confirm the results. Ambroxol applied postnatally has beneficial effects on the course of severe HMD by increasing survival rate, by decreasing duration of oxygen need and artificial ventilation and by improving compliance. Pharmacological studies in preterm HMD-infants showed no influence of ambroxol on blood pressure and heart rate. In 3 of 8 newborns a transient increase of transcutaneous oxygen tension was seen during infusion of ambroxol. Ambroxol is quickly bound to tissue receptors which release it continuously indicating that repeated applications are as effective as continuous infusion.

Adrenal Cortex Hormones↗
PubMed1987

Creatine and density of red blood cells in perinatal hypoxia.

Signs of stimulated erythropoiesis, such as increased creatine and decreased density of red cells are good indicators of hypoxemia in adults and older children. The sensitivity of both tests in perinatal hypoxia was found to be reduced. The causes for this reduction were investigated.

Animals↗
PubMed1986

Behaviour of cell physiological and biochemical indicators of maturation and aging of red blood cells in density fractionated red blood cells during a bleeding anaemia of the rabbit.

Changes of the density, MCV, MCHC, RNA-concentration and the activities of the enzyme G6PD and ASAT due to maturation and aging of rbc were investigated by repeated density gradient separation of these cells during a bleeding anaemia of the rabbit. The mean density of reticulocytes and erythrocytes decreases during the course of the anaemia by 14 and 10 g/l respectively. The difference between the density of both cell types increases from 3 to 6 to 12 g/l during the anaemia. Maturation and aging of rbc are characterized by an increase of the MCHC from 200 to 350 g/l cells and the decrease of MCV by 10-25%. The RNA concentration and the ASAT activity show an almost parallel behaviour in cells of different densities during the anaemia. Remarkable differences are observed between the ASAT activity and the G6PD activity: The G6PD activity decreases mainly during the aging process and almost not during the maturation, while the ASAT activity falls constantly during maturation and aging. As observed in former studies we could distinguish and isolate 4 characteristic populations of reticulocytes in certain density fractions during the anaemia: Normal young reticulocytes, line 2 reticulocytes, megaloreticulocytes and reticulocytes of high density.

Anemia↗
PubMed1986

[Peculiarities of respiratory mechanical studies in spontaneously breathing newborn infants. 3: Practical experiences with respiratory mechanical studies in premature and newborn infants].

The experiences with three different measuring devices for the analysis of respiratory physiology in spontaneously breathing newborns are reported, the construction and the properties of the measuring devices are described, the preparations and the performance of the analysis are explained. Finally, the suitability of each of the measuring devices for the routine application is valuated. The equipments are suitable for the bed-side long-term measurement of mechanics of breathing under spontaneous and CPAP-respiration in order to use the advantages of the analysis of the respiratory physiology for the prophylaxis, therapy and metaphylaxis especially in the neonatology.

Airway Resistance↗
PubMed1984

[Peculiarities of respiratory mechanical studies in spontaneously breathing newborn infants. 2: Evaluation technics, parameter distribution and diagnostic validity].

Manual evaluation techniques are commonly used until now for the evaluation of recordings. They will be replaced by a computer-aided evaluation of the measuring signals which has several advantages, e.g. reduction of manual expense, processing of high quantities of data, application of powerful algorithms for computation. Both methods are discussed shortly. Hitherto a lot of reference values for the breathing mechanics in newborns have been set up but the various parameters show a wide scatter. This reduces the diagnostical value of breathing mechanical investigations and the clinical interpretation of the measuring results is rendered more difficult. Possibilities for the reduction of the scatter of parameters consist in standardizations of the measurement technique, the investigative conditions and the evaluation techniques as well as in the evaluation of a higher number of breaths in order to get characteristical values for the actual clinical state. The judgment of the diagnostical value of breathing mechanical investigations is commonly based on the subjective assessment by the investigator. Until now systematic investigations for the quantification of the diagnostic value (sensitivity, specifity, predictive value, ...) are not known, because the computation needs a high quantity of data from healthy newborns and such with respiratory distress. The number of cases in the different publications is often too small for these computations. The missing standardization makes it for some purposes impossible to combine the results of the different working groups.

Birth Weight↗
PubMed1983

A simple method for the approximation of the behaviour of marker constituents in density-fractionated red blood cells by means of normalized cumulative distribution functions.

The present paper proposes a mathematical approach for the approximation of the relation between the concentration (or activity) of a cell constituent and the cumulative red cell distribution after density gradient centrifugation by means of normalized cumulative distribution functions (NCDF). With only one parameter (easily obtained on a programmable pocket calculator) and the mean concentration of the substance in the total red cell population this functional relation can be described in good approximation. The goodness of fit expressed by v2 (= square of correlation coefficient) to the experimentally obtained data is demonstrated for the cell constituents creatine (v2 = 0.85-0.97), RNA (v2 = 0.82-0.87) and G-6PD (v2 = 0.60-0.95). The method of NCDF is shown to be superior to an exponential function. It permits the estimation of a concentration (or activity) of a cell constituent for any chosen density-fractionated cell portion and thus gives information on the ratio of standardized portions of young: old cells.

Cell Separation↗
PubMed1983

[Peculiarities of respiration mechanics in spontaneously breathing newborn infants. 1. Principles of the measurement technics].

Disturbances of breathing mechanics may involve disturbances of ventilation as one cause of hypoxaemia. The qualitative and quantitative analysis of breathing mechanics has several diagnostical and therapeutical advantages, but their application in newborns, under conditions of spontaneous ventilation, is rendered more difficult by the missing co-operation of the newborns and by the missing of suitable measurement devices for a bedside measurement. The determination of parameters of breathing mechanics is based on the measurement of breathing flow rate (V), tidal volume (VT) and esophageal pressure (Pe). Bodyplethysmographs, face masks and nasal prongs can be used for the measurement of V and VT, however, face masks have the most methodological and technical advantages for the bedside application, moreover, they guarantee a very low injury of newborns. Until now the fluid-filled open catheter is used most frequently for the measurement of esophageal pressure, however, it will be replaced in future by the microtip pressure transducer (Tip-catheter), which offers fundamental advantages. In addition to these technical problems the complete clinical application of breathing mechanical investigations is rendered more difficult, because the standardization of the investigative conditions, the parameters and the proposals on evaluation techniques are absent until now.

Airway Resistance↗
PubMed1982

The antenatal use of ambroxol (bromhexine metabolite VIII) to prevent hyaline membrane disease: a controlled double-blind study.

A prospective double-blind clinical trial was carried out to determine whether ambroxol (bromhexine metabolite VIII) treatment (1000 mg/day for a period of 5 days) reduces the risk of hyaline membrane disease (HMD) in potentially premature infants. Amniocentesis was performed before the first and 24 h after the last application of ambroxol or placebo to assess the development of the total phospholipid phosphorus content, the L/S ratio, the P/S ratio, and the properties of the surface tension of the amniotic fluid after ambroxol or placebo. There were 246 infants born to 224 mothers. Of the 116 infants with less than or equal to 36 completed weeks' gestation, 56 were in the ambroxol and 60 in the placebo group. No differences between groups occurred in risk factors for HMD (diabetes, asphyxia, male sex, cesarean section). Statistically significant differences in favor of the infants in the ambroxol group were found in the HMD incidence: 23.2% in the ambroxol group compared with 41.7% in the placebo group (p less than 0.05). There was no reduction of the HMD incidence in the less than or equal to 32-week gestational age category in the ambroxol group compared with the placebo group inspite of the fact that all the examined parameters for determining lung maturity reflected a stimulatory effect of ambroxol compared with the results of the placebo group, particularly before the 33rd week of gestation. Prolonged rupture of the membranes played no protective role against HMD.

Ambroxol↗