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R Haidmayer

Publications and source records attributed to R Haidmayer.

33 records · Page 2Linked to original sources
PubMed1982

Physiological and clinical aspects of respiration control in infants with relation to the sudden infant death syndrome.

We have examined the behavior of several variables which are related to respiratory control in 114 infants (up to 6 months of age) in order to assess the risk for the sudden infant death syndrome (SIDS), 23 of the infants had already had demonstratable serious or life threatening apneas or respiratory problems during surgical anesthesia. These infants were assigned as a risk group, and the rest of the investigated babies was taken as a control group. We found that practically all infants of the risk group had apneas during sleep, which lasted longer than 8 s each. Only 22% of the infants of the control group had apneas of such a duration. As a statistical parameter, calculated from at least 1 hour recording of respiration, we defined the mean apnea duration (MA-value) as average value of apnea duration time in seconds per minute of recording. The MA-value proved to be significantly elevated in the infants of the risk group. The trend to hypoxia in the infants of the risk group was also indicated by the observation of lower transcutaneous PO2-values (tc-PO2) during sleep, when compared with control infants. In agreement with this observation is the increase of the 2,3-DPG concentration and the decrease of the density of erythrocytes of the infants of the risk group. Breathing hypoxic gas mixtures tended to depress respiration in all infants tested, and, especially in the risk group, to elicit irregular respiratory patterns. On the other hand, we observed that inhalation of pure oxygen markedly stimulated respiration in all infants investigated. We conclude from these observations that a risk for SIDS may be related to a particular response pattern of the respiratory center during the early postnatal life. We are able to distinguish infants with a higher risk for SIDS from other children by determination of the MA-value during sleep.

Aminophylline↗
PubMed1981

Influence of ambient temperature on calorigenic action of thyroid hormones in young mice.

In 5- and 7-day-old HAICR mice the calorigenic action of thyroxine (T4) and triiodothyronine (T3) was investigated at different ambient temperatures. After treating animals with 5 microgram T4 or 1 microgram T3 per g body weight and day, their oxygen consumption was compared with that of litter mate controls at 23 degree, 27 degree, 31 degree and 35 degree C. The hormone action was highly dependent on ambient temperature, 1 microgram T3 being most effective. A thyroid hormone effect could never be observed at 31 degree C, the animals' nest temperature. By application of propranolol, which almost selectively blocks nonshivering thermogenesis (NST), we could show that T3 increases minimal oxygen consumption (MOC) as well as the capacity for NST. In addition, it could be shown that also oxygen consumption of liver tissue of 5-day-old mice is elevated by preceding treatment with thyroid hormones. The ambient temperature effects are discussed in relation to the thermoregulatory situation of the mice during the early postnatal period.

Animals↗
PubMed1980

[Paradoxical ventilatory response of babies to pure oxygen (author's transl)].

In order to determine indicators for the risk of SIDS (sudden infant death syndrome) the respiratory responses of babies (age 1 to 5 months) during sleep to various gas mixtures was examined. Using a face mask combined with a pneumotachograph in all cases a marked increase of the ventilation was found, when the babies were exposed to pure oxygen. Furthermore, the response of the babies to the exposure to mild hypoxia was tested. In 24 out of 36 babies a ventilatory depression was observed which sometimes was coupled with periodic or arrhythmic ventilation. These paradox reactions--depression by mild hypoxia and stimulation by hyperoxia--might be related to a possible circulus vitiosus in the pathogenesis of SIDS.

Carbon Dioxide↗
PubMed1980

[Erythrocyte density distribution disorders in infants with respiratory regulation disorders].

The frequency distribution of the density of erythrocytes was investigated in 22 babies by using the method of Danon and Marikovsky. This investigation seems to be a very suitable method for identifying minimal alterations in the oxygen transport system. In all 22 babies typical S-like density distribution curves were observed similar to those of adults. Eight of the babies with clinically demonstrable disorders in respiration control (ARS) were taken as one group. In comparison with the control group (14 babies) it could be shown that the erythrocytes of the ARS-babies had a lower density than the erythrocytes of normal babies. This difference proved to be statistically significant. No difference between control group and ARS-group could be shown with respect to the distribution of size of the erythrocytes, the mean cell hemoglobin concentration (MCHC), and the mean cell volume (MCV). We assume that the deviation in density distribution of erythrocytes from normal in the ARS-group may be attributed to biochemical changes provoked by the chronical hypoxia. It can be stated that, independent of the interpretation of this phenomenon, a new additional factor could be found for the identification of risks for ARS and possibly for the sudden infant death syndrome (SIDS).

Apnea↗
PubMedDate not supplied

[The Graz SIDS Risk Questionnaire: I. Development and validation].

Based on the results from semistructured interviews with parents of fifty SIDS victims and of fifty matched controls we developed a SIDS risk questionnaire, the so-called SRFB Graz. In a retrospective study this questionnaire was applied to 65 SIDS victims and 195 comparable controls. By statistical analysis a cut point was computed, which discriminates SIDS cases from controls with a sensitivity of 86% and a specificity of 95%.

Austria↗
PubMedDate not supplied

[The 1-hour oxycardiorespirography as routine study in the diagnosis of cardiorespiratory dysregulation in infancy--an attempt at establishing normal values].

Because of the growing demand to evaluate cardiorespiratory dysfunctions the short-time oxycardiorespirography becomes a more and more important and powerful tool in the daily clinical routine. Therefore, from about one hour lasting records we studied the distribution of MA-values (mean apnea duration), duration of the longest apnea, percentage of periodic breathing time, lowest heart rate values, lowest transcutaneous PO2 values and highest transcutaneous PCO2 values in an obstetrical optimal low-risk group of 90 infants and a obstetrical non-optimal group of 152 infants between four and ten weeks of age. Percentiles of each variable were calculated, and we suggest the 90th percentiles as new threshold values to judge these short-time recordings. In comparison to relevant data from the literature we could demonstrate that deviating threshold values have to be applied to short-time recordings in comparison to long-time recordings. In addition, the respiratory behaviour of the optimal group is compared to that of the non-optimal group of the same age. Interestingly enough, no difference in the respiratory behaviour between these groups could be demonstrated.

Blood Gas Analysis↗
PubMedDate not supplied

[Acoustically evoked brain stem potentials in infants at risk for SIDS with and without aminophylline therapy].

We investigated brainstem auditory evoked potentials (BAEP) in 20 infants at risk of SIDS (age 5 days to 4 months) and in 7 control infants (age 5 days to 4 months). 19 infants were diagnosed as having sleep apnea syndrome (SAS), which we consider to be a possible risk factor for SIDS. The diagnosis of SAS was made in general in the presence of clinical symptoms such as apneas, cyanosis during sleep, poorly coordinated sucking, swallowing and respiration and gastro-oesophageal reflux in combination with an abnormal pneumogramm in a one hour oxycardiorespirography. One infant had the history of a near miss event but a normal pneumogramm, 2 infants, both with SAS, were siblings of SIDS infants. We applied BAEP on 12 infants at risk of SIDS with and on 12 infants at risk of SIDS without aminophyllin treatment. 3 infants at risk of SIDS had two BAEP studies, one before and one during aminophyllin treatment. The time interval between these two studies was 1 week to 16 days. Aminophyllin, given only to infants with SAS was administered orally (therapeutic range 4-10 micrograms/ml). All infants at risk of SIDS and all control infants had normal I-V-IPL (below 2 x SD). There was a tendency to longer I-V IPL in infants at risk of SIDS. When infants at risk of SIDS with and without aminophyllin treatment were compared as a group the I-V-IPL was shorter in the infants with aminophyllin. BAEP can be useful in studying disturbances of the autonomic function of brainstem centers but do not allow the prediction of an individual SIDS risk.

Aminophylline↗
PubMedDate not supplied

[Control of breathing in the central alveolar hypoventilation syndrome with and without a phrenic pacemaker].

Primary central alveolar hypoventilation (CAHV) is a rare disorder described in newborns, children, and adults. We report a 2 9/12 year old child with CAHV of unknown etiology. The evaluation of her ventilatory control system showed abnormalities awake and in the different sleep states. Hypoventilation was found to be more severe during non-REM sleep than during REM sleep and awake state. She had central apnea, an irregular respiratory rhythm in the non-REM sleep too, and diminished ventilatory response to inhaled 5%-6% CO2 in both REM and non-REM sleep. Her ventilation decreased when she was breathing 50% and 100% oxygen. During breathing 15% oxygen she did not arouse in spite a transcutaneous pO2 of 10 mmHg. She was first treated with mechanical ventilation during sleep and has now received bilateral simultaneous phrenic pacemaker support during quiet sleep for about one year. With the phrenic pacemaker she has normal minute volume and transcutaneous blood gases during sleep. During a respiratory infection she needed again mechanical ventilation via her tracheostoma 24 hours a day for one week. This case of a CAHV demonstrates a dysfunction of the central and partially also of the peripheral chemoreceptors. The abnormalities of the ventilation were demonstrable not only in the non-REM sleep but also in the REM sleep and awake state.

Child, Preschool↗
PubMedDate not supplied

[Early diagnosis of central respiratory disorders in infants to avoid postoperative complications].

Infants with a higher incidence of frequent and prolonged apneas during sleep (sleep apnea syndrome) as a consequence of a delayed maturation of respiratory control, have an increased risk for respiratory problems after anesthesia. In 12 babies (one to five months old) showing visible apneas with cyanosis up to 12 hours after herniotomies, the respiratory pattern was examined by impedance pneumography during spontaneous sleep. The mean apnea duration (M.A. value) amounted to 8,6 +/- 5,96 sec/min, whereas the M.A. value of a comparable control group was significantly lower (2,97 +/- 2,13 sec/min) Aminophylline prophylaxis of risk infants diminished significantly the frequency of postoperative respiratory complications.

Aminophylline↗