Biomedical subjects

A Mohnhaupt

Publications and source records attributed to A Mohnhaupt.

At least 19 recordsLinked to original sources

PubMed1999

Two types of health care systems and their influence on the introduction of perinatal care: an epidemiological twin model in Berlin from 1950 to 1990.

OBJECTIVES: When perinatal medicine emerged as a new medical discipline in the 1960s, Berlin was as one of the world's leading centers. During that time, the city was separated into two parts, each fostering its own health care system. After the destruction of the Berlin Wall, it was possible to speak with the citizens of East Berlin and to access their database systems. This created the singular opportunity to objectively compare the development of perinatal care in both parts of Berlin. METHODS: Rates of maternal, perinatal, and infant mortality as well as the rate of preterm deliveries were evaluated over time and between East and West Berlin. The timing of introduction of 20 specific perinatal interventions was evaluated across 18 hospitals with more than 500 deliveries (11 in West Berlin and 7 in East Berlin). Interviews were conducted with 100 gynecologists, 100 midwives, and 100 women who had recently delivered their first child from each side of the city regarding their opinions of the importance of these interventions for the quality of perinatal medicine and how they would distribute a budget to improve maternity care. RESULTS: Maternal, perinatal, and infant mortality decreased in both parts of Berlin until 1990 (p < 0.0001), without significant differences between East and West Berlin, though the preterm delivery rate was slightly lower in East Berlin compared with West Berlin (p < 0.06). Some new clinical techniques and treatments--such as cardiotocography, ultrasound, tocolytic therapy, and peridural anesthesia--were introduced earlier in West Berlin. In contrast, certain public health measures--such as maternal transport, screening programs for diabetes, and support of breastfeeding--were introduced much earlier in East Berlin. There were significant differences between the beliefs of gynecologists, midwives, and mothers in East and West Berlin. In general, citizens of East Berlin were more enthusiastic about technological medical advances, whereas citizens of West Berlin were more supportive of public health and alternative methods. In addition, there were significant differences between female and male physicians in their beliefs about how to improve health care, regardless of whether they resided in East or West Berlin. CONCLUSIONS: The results of this study may serve as a basis for reflection on how different social circumstances and health care policies can influence the improvement of maternal and child health care.

Attitude of Health Personnel↗

PubMed1998

Superimposing positive end-expiratory pressure during partial liquid ventilation in experimental lung injury.

This study was undertaken to determine the effects of superimposing incremental levels of positive end-expiratory pressure (PEEP) during partial liquid ventilation (PLV) on gas exchange, respiratory mechanics and morphological changes in experimental acute lung injury (ALI). In a prospective trial, six pigs weighing 30+/-5 kg (mean+/-SD) were tracheotomized, submitted to pressure-controlled mechanical ventilation (pc-CMV) and depleted of surfactant by lung lavage. Animals were then mechanically ventilated with three levels of PEEP: 0.5, 1.0 and 1.5 kPa. PLV was then initiated by intratracheal instillation of 30 mL x kg(-1) perfluorocarbon, followed by pc-CMV with PEEP 0.5, 1.0 and 1.5 kPa. Computed tomography (CT)-based analyses of lung volumes and density were obtained after lung lavage, in PLV and during the combined application of PLV and PEEP. Simultaneously, haemodynamics, gas exchange, dynamic compliance (Cdyn) and dynamic resistance (Rdyn) were determined. Statistical analysis was performed using multivariate analyses of variance for repeated measures (p<0.05). In ALI and before PLV, the application of PEEP significantly reduced cardiac output and intrapulmonary shunt. Arterial oxygen tension (Pa,O2) was increased from 6.9 kPa (52 (42, 54) mmHg) (median, (25th and 75th percentile)) to 8.6 kPa (65 (52, 133) mmHg) (PEEP 1.0 kPa) and 15.6 kPa (117 (90, 195) mmHg) (PEEP 15 kPa) (p<0.05). The lung volume obtained by CT increased, CT density was reduced (p<0.05), Cdyn tended to increase and Rdyn to decrease (nonsignificant). PLV increased arterial carbon dioxide tension and reduced pH (p<0.05). CT lung volume and lung density were increased (p<0.05). Superimposing PEEP on PLV increased Pa,O2 from 9.3 kPa (70 (52,124) mmHg) (PEEP 0.5 kPa) to 12.9 kPa (97 (55, 233) mmHg) (PEEP 1.0 kPa) and 403 kPa (303 (64, 426) mmHg) (PEEP 1.5 kPa) (p<0.05), but had no significant effect on CT lung volume and density. It was concluded that in experimental lung injury, positive end-expiratory pressure provided alveolar recruitment. The combined application of positive end-expiratory pressure and partial liquid ventilation significantly augmented oxygenation and might eventually allow either a reduction in the volumes of perfluorocarbons required, or a reduction in positive end-expiratory pressure necessary to maintain pulmonary gas exchange in acute lung injury.

Animals↗

PubMed1997

[Factors modifying postoperative astigmatism after no-stitch cataract surgery].

BACKGROUND: One of the main advantages of the no-stitch technique in cataract surgery is that induced astigmatism occurs less frequently than with any other procedure and stabilizes within a very short time postoperatively. The resultant high wound strength enabled us to alter the incision parameters in an attempt to identify those which influenced postoperative astigmatism, the ultimate goal being to improve the prognosis of the expected astigmatism. Since the influence of tunnel width and incision length and shape were well known, we investigated the influence of incision depth and site and that of various parameters in a prospective randomized and controlled clinical trial. METHODS: The study included 256 eyes with a 7-mm tunnel incision as examined in 256 patients. The following subgroups of 27 eyes each were investigated: primary incision depth of 300 microns versus 500 microns, limbal incision versus scleral incision, scleral incision in the 12 o'clock position versus temporal scleral incision, and limbal incision in the 12 o'clock position versus temporal limbal incision. In another group the influence of age, IOP, axial length of the globe, preoperative astigmatism, corneal diameter, and postoperative astigmatism as measured by the keratometer were all assessed using Spearman's correlation coefficient. RESULTS: Temporal incisions made 2 mm posterior to the limbus resulted in induced astigmatism of 0.64 +/- 0.22 D 6 months postoperatively, which was less than after incisions in the 12 o'clock position (0.98 +/- 0.40 D). Induced astigmatism was highest after limbal incisions in the 12 o'clock position (1.31 +/- 0.60 D), yet was less if a temporal limbal incision was made (0.84 +/- 0.52 D). Incision depth did not have significant influence on induced astigmatism. Of the parameters, age (Spearman's correlation coefficient after 4 weeks 0.34; P = 0.002; after 6 months 0.28; P = 0.01), and preoperative astigmatism (Spearman's correlation coefficient after 4 weeks 0.28; P = 0.01; after 6 months 0.27; P = 0.01) had a significant influence on postoperative astigmatism. CONCLUSIONS: These findings indicate that induced astigmatism was highest after limbal incisions in the 12 o'clock position and lowest after scleral incisions in the temporal position. Age and preoperative astigmatism were also found to influence induced astigmatism significantly. All of these factors have to taken into account to minimize postoperative astigmatism.

Adult↗

PubMed1996

Seroprevalence of Lyme borreliosis in forestry workers from Brandenburg, Germany.

In 1992 blood samples were taken from 630 forestry workers in the state of Brandenburg, Germany, and an inquiry about tick bites and possible symptoms of Lyme borreliosis carried out in order to determine the seroprevalence of the disease. To estimate the rate of seroconversion within six months, 406 of the individuals were investigated a second time. IgG and IgM antibodies against Borrelia burgdorferi were detected in serum using an indirect immunofluorescence assay (IFA) and an immunoblot assay (IBA). Fifty-three percent of the forestry workers reported suffering a tick bite, 8% of whom recalled an erythema after the bite. Positive results were found more frequently in the forestry workers than in a control group of 200 healthy blood donors in both the IgG-IFA (8% vs. 4%, p < 0.05) and the IgG-IBA (18% vs. 5%, p < 0.05). The detection of IgG antibodies correlated with a tick bite and erythema history. There was a tendency of lower seropositivity by the IgG-IBA in individuals who treated the ticks before removal with chemicals or other agents compared to those without such treatment (16.8% vs. 23.9%, 0.05 > p < 0.1). Likewise, there was a tendency of lower seropositivity by the IgG-IFA in individuals being treated with antibiotics for other reasons compared to untreated individuals (3.15% vs. 8.9%, p < 0.05), although the two groups did not differ in the IgG-IBA (13.8% vs. 18.5%, p > 0.1). The rate of seroconversion within six months ranged from 5 to 7%. It is concluded that forestry workers in Brandenburg, Germany, are at risk for infection with Borrelia burgdorferi, but clinical signs of infection are rare.

Adolescent↗

PubMed1996

The onset of inter-human contacts: longitudinal ultrasound observations in early twin pregnancies.

Twin pregnancies provide us with the opportunity to observe first reactions towards touch in utero, and this study illustrates the onset and development of these contacts. Forty women with twin pregnancies volunteered to take part in this study, 25 of whom (five monochorionic, 20 dichorionic pairs) fulfilled the inclusion criteria. Between 8 and 12 weeks' gestation, ultrasound examinations were performed transvaginally, and from 13 weeks onwards transabdominally, at weekly intervals. Ultrasound findings were recorded on videotapes and were analyzed retrospectively. The first contacts producing reactions in the co-twin were defined as primary contacts, which could be slow or fast arm/leg/head/body contacts. Primary contacts followed an action-reaction model, and usually lasted < 3 s. These contacts were initially slow and then became fast. The first reactions of the co-twin towards touch were observed at 65 postmenstrual days. Contacts of longer duration between both bodies including extremities, or contacts initiated by sucking movements towards the co-twin were defined as complex contacts and were observed from 85 and 92 post-menstrual days, respectively. Nearly all contacts occurred significantly earlier in monochorionic compared to dichorionic twins. Female/female pairs seemed to develop complex body contacts earlier than male/male pairs, but for the onset of other contacts we have not yet found significant differences between gender combinations.

Age of Onset↗

PubMed1995

From biochemical to biophysical placental function tests in fetal surveillance.

Radioimmunoassays of human placental lactogen and estriol levels in the maternal plasma, ultrasound biometry of the abdominal diameter (AD), pulsed Doppler measurements of uteroplacental arteries, the common carotid artery (CCA), and the umbilical artery (UA) and fetal heart rate monitoring were simultaneously performed in 219 risk pregnancies from 26 weeks' onward at regular intervals. The prognostic value of all tests to predict small for gestational age infants (SGA) and fetal distress was evaluated simultaneously. Receiver operator characteristic allowed the simultaneous comparison of all methods: The AD was most predictive for early detection of SGA, even more than uteroplacental blood flow. Fetal blood flow redistribution expressed as a ratio of the resistance index of CCA/UA was the most significant test for detection of fetal distress later in pregnancy, even more than antenatal cardiotocography. Considering cutoff levels used in clinical routine, the sensitivity and specificity of the fetal AD in detecting intrauterine growth retardation more than 28 days before birth, were 71 and 81%, respectively. Pulsed Doppler measurements of CCA/UA less than 7 days before the delivery had a sensitivity and specificity of 83 and 90%, respectively. Our results demonstrate the historical change in fetal surveillance within one study group: If accurate routine ultrasound is available, the use of biochemical placental function tests is not justified, a procedure that is already accepted in nearly all perinatal centers. Fetal cerebral versus umbilical blood flow measurements should be applied as a tool to measure fetal blood flow redistribution in small fetuses to predict most precisely the risk for poor outcome and perinatal hypoxia.

Estriol↗

PubMed1995

Hepatic venous catheterization in patients undergoing positive end-expiratory pressure ventilation after OLT: technique and clinical impact.

The objective of this study was to determine the feasibility and clinical impact of hepatic venous oxygenation monitoring in patients undergoing positive end-expiratory pressure (PEEP) ventilation after OLT. The design comprised a prospective study using repeated-measures design, within an intensive-care unit for liver-transplanted patients in a university hospital. Sixteen consecutive adult patients undergoing orthotopic liver transplantation were enrolled. Postoperatively, a fiber-optic pulmonary artery catheter was inserted into the right hepatic vein. Patients were submitted to controlled ventilation with three different levels of end-expiratory pressure (PEEP): 0, 5 and 10 mbar. Hemodynamics, hepatic venous pressure, mixed venous (SvO2) and hepatic venous oxygenation (SvhO2) were measured. The average time required for hepatic venous catheterization was 2.9 +/- 1.2 min; serious complications were not observed. PEEP 5 mbar did not alter hemodynamics and SvhO2; PEEP 10 mbar significantly reduced cardiac index, SvO2 and widened arteriovenous content difference (p < 0.05). The mean difference between SvO2 and SvhO2 was 6.3 +/- 6.0% and did not change during PEEP ventilation. A significantly positive relationship was observed between SvO2 and SvhO2 (r = 0.91, p < 0.05). Hepatic venous catheterization appeared to be practical and could be utilized to evaluate the effects of therapeutic interventions on the transplanted liver. However, the small number of patients studied will not allow the assessment of any risk-benefit ratio of the technique investigated. Low levels of PEEP provided hemodynamic stability and did not alter hepatic oxygen supply-demand ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1993

Evaluation of the fetal assessment score in pregnancies at risk for intrauterine hypoxia.

OBJECTIVE: Our purpose was to define the diagnostic value of a new fetal assessment score that is based on each of the components of the Apgar score. STUDY DESIGN: A fetal assessment score was established to study the main fetal vital functions: (1) cardiovascular (heart rate, color of the skin in the Apgar score), now based on fetal heart rate patterns and Doppler assessment of fetal blood flow redistribution, (2) fetal respiratory (quality of breathing in the Apgar score), now based on Doppler assessment of uteroplacental perfusion, and (3) neuromuscular function (tone and reflexes in the Apgar score), now based on fetal tone and response to external stimuli. The fetal assessment score was used in the study of 110 postdate pregnancies and 103 small-for-gestational-age infants and was compared with the traditional biophysical profile score in the prediction of perinatal outcome. RESULTS: There were significant associations between both the fetal assessment score and the biophysical profile score with fetal distress that necessitated operative delivery, low Apgar scores, and low umbilical cord arterial blood pH. However, receiver-operator characteristic plots demonstrated that the fetal assessment score was superior to the biophysical profile score in predicting fetal distress and low Apgar values particularly in the small-for-gestational-age infants. The best single parameters in predicting fetal distress were the amniotic fluid volume in the biophysical profile score and fetal heart rate patterns and pulsed Doppler measurements in the new score. CONCLUSION: A fetal Apgar score in which respiration is assessed by placental perfusion rather than chest movements and in which skin color is assessed by centralization of fetal blood flow may be better than the traditional biophysical profile score in predicting fetal hypoxic compromise.

Apgar Score↗

PubMed1992

Comparison of the prognostic value of pulsed Doppler blood flow parameters to predict SGA and fetal distress.

A total of 219 women with complicated pregnancies had Doppler assessment of uteroplacental arteries, the umbilical artery, the fetal common carotid artery and the descending thoracic aorta to determine the prognostic value of Doppler examinations to predict the birth of a small-for-gestational-age (SGA) infant with or without fetal distress. Preliminary reproducibility studies showed that the resistance index, pulsatility index and intensity weighted flow velocity had the lowest coefficients of variation. Data on the systolic/diastolic ratio and mean blood flow volume were, therefore, not considered for further evaluation. Measurements were classified according to the time interval of the examination to the delivery of the baby according to the following groupings: 0-14 days, 15-28 days and 29-42 days. For evaluation of the SGA fetus complicated by fetal distress, only measurements within 2 weeks of delivery were analyzed. Significant differences were calculated by considering the area below the receiver operator characteristic (ROC) curves. Only Doppler studies of the uteroplacental arteries (mainly resistance index) were predictive of the later development of the SGA fetus. All fetal parameters showed an increasing improvement in the predictive capacity for an SGA infant, the closer the measurements were made to the time of delivery. This improvement was not observed for uteroplacental vessels. The resistance index of the uteroplacental vessels was significantly higher in SGA pregnancies complicated by fetal distress compared to SGA pregnancies alone. However, ROC analysis revealed that fetal Doppler velocimetry was more strongly related to fetal distress than SGA only. The single best fetal parameter was the mean velocity in the fetal descending thoracic aorta but the velocity ratio of the fetal common carotid artery over the fetal descending thoracic aorta had the highest predictive capacity for the SGA pregnancy complicated by fetal distress.

Journal Article↗

PubMed1991

The geriatric patient in surgery. Experience with patients over the age of 85 years.

Between 1982 and 1989 hospitalized treatment was applied to 615 patients aged between 85 and 101 years. The average age was 88.8 years. Operations were performed on 406 of them (66.1%). The surgical lethality amounted 16.5%. The lethality in conjunction with emergency operation was as high as 30.8% or as low as 10.7% in the context of elective operations. X-ray findings recorded from heart and lung as well as ECG provided reliable criteria for assessment of the surgical risk.

Age Factors↗

PubMed1988

[The elderly surgical patient. Experiences with patients over 85].

Hospitalised treatment was applied to 326 patients aged between 85 and 101 years, between 1982 and 1987. Operations were performed on 215 of them. The surgical lethality amounted to 16.3 per cent, though lethality in conjunction with emergency operations was as high as 23.9 per cent or as low as 11.8 per cent in the context of elective operations. X-ray findings recorded from heart and lung as well as ECG provided reliable criteria for assessment of the surgical risk.

Aged↗

PubMed1987

Design of a new pulse duplicator system for prosthetic heart valves.

This paper discusses results of a computer simulation for designing a new pulse duplicator system for mechanical heart valves. The design objective of the system is to obtain a compact, efficient pulse duplicator system capable of accurately measuring the volume flow rate across a valve. The volume flow rate is determined as the derivative of the volume displacement of an actuator piston which directly drives the fluid. The system does not need any circulatory loop, since the piston is controlled on-line to follow command signals representing an aortic impedance. The results of the computer simulation show: the designed PI-controllers of the actuator can precisely control valve motion to follow given command signals, the eigenvalues of the controllers have to be carefully chosen to prevent unstable behaviors of a valve in diastole, and the dimensions of the actuator is optimized by minimizing a cost function of the total efficiency of the system.

Biomechanical Phenomena↗

PubMed1983