[Experience of parents in home monitoring of apnea for prevention of sudden infant death (SIDS)]. / Erfahrungen der Eltern mit dem Apnoe-Heimmonitoring zur Prävention des plötzlichen Kindstodes (SIDS).

89 of 119 parents of infants with apnea home monitoring answered to a standard questionnaire concerning different aspects of home monitoring. In almost all cases the home monitoring was finished at the begin of the study, lasting from six months to 12 months. The indications for an apnea monitor were: apparent life threatening event (n = 8), SIDS-sibling (n = 24), sleep apnea syndrome (n = 40) and parents pressing request (n = 17). 90% of parents felt to have got enough information about the function of the apnea monitor (mostly Graseby MR-10 monitor) and what they have to do when there is an apnea alarm. 6% of parents changed the monitor because of technical problems. Most of the alarms were registrated by almost all parents between 24 h and 6 h. 35% of parents stimulated their infants in case of an apnea alarm gently to vigorously, one infant had a mouth to mouth resuscitation. Questions concerning the psychological and social impact of home monitoring on parents demonstrated that there was some stress like anxiety, sleep disturbances mainly in the mothers. We conclude from parents experience with apnea home monitoring the need for an adequate medical, technical and psychological support.

[The Graz SIDS Risk Questionnaire: I. Development and validation]. / Der SIDS-Risikofragebogen Graz (SRFB): I. Entwicklung und Validierung.

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%.

[The 1-hour oxycardiorespirography as routine study in the diagnosis of cardiorespiratory dysregulation in infancy--an attempt at establishing normal values]. / Die einstündige Oxycardiorespirographie als Routineuntersuchung zur Diagnose kardiorespiratorischer Dysregulationen im Säuglingsalter--Ein Versuch zur Aufstellung von "Normalwerten".

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.

Neurological status, sleep apnea frequency and blood oxygenation in six weeks old infants.

A study was carried out to investigate the correlation between sleep apnea frequency, blood oxygenation and neurological condition in 21 infants at six weeks of age with inconspicuous medical history. Polygraphic recordings of respiratory behaviour and transcutaneous blood gas monitoring lasted for at least five hours. To quantify the results of the neurological examination we established a neurological optimality score (NOS). We found statistically significant correlations between several indexes of apneas and indexes of blood oxygenation and NOS. Thus, a reduced NOS was strongly correlated with higher apnea frequencies and with pronounced drops of transcutaneous PO2-values. In addition all but one infant who were diagnosed as having a sleep apnea syndrome showed a greater than ten percent reduction of NOS. Some pathophysiological considerations to explain our findings are put forward and the possible role of the neuromodulator adenosine is emphasized.

[Air pollution and sudden infant death in Graz 1982 to 1987]. / Luftverschmutzung und plötzlicher Säuglingstod in Graz im Zeitraum von 1982 bis 1987.

We correlated the incidence of the sudden infant death syndrome (SIDS) and the degree of air pollution in each district of Graz over a time period of five years. The degree of air pollution was derived from a mapping of epiphytical lichen vegetation by Grill et al. (1988). We found an increased incidence of SIDS in districts with poor air quality. Although this result is not statistically significant a possible increase in SIDS risk because of air pollution cannot be excluded. Some pathophysiological explanations are discussed.

Factors involved in the pathogenesis of unexpected near miss events of infants (ALTE).

Near miss events or apparent life threatening events (ALTE) are considered preliminary stages of sudden infant death syndrome (SIDS). The current definition of near miss SIDS postulates that such an event happens unexpectedly and that no life threatening cause of disease can be detected. However in 32 of 34 observations of ALTE pathological changes actually could be identified by through investigations: 11 central nervous diseases, 10 respiratory tract disturbances, 5 metabolic abnormalities, 5 disturbances of the digestive tract and 1 cardiac disease. There were 22 morphologically manifested causes as opposed to 10 functional failures mainly respiratory control and oesophageal disturbances. Irrespective of the main diagnosis sleep apnea syndrome (SAS) could be detected in 17 of 28 infants combined with bradycardia in 5 cases, and oesophageal disturbances in 16 of 17 infants. Four babies later died, two of them suffered from carnitine deficiency and one from organic acidopathy. It is our conclusion that numerous, even banal causes of disease are able to trigger ALTE if there is a coincidence with phases of increased instability of vital regulatory mechanisms of autonomous centres in infants.

Computer-based sleep monitoring in SIDS-risk infants--preliminary results.

A computerized, PC-based system is introduced for sleep monitoring in infants. The system is capable of digitizing and storing 22 physiological variables over a whole-night sleep period. The preprocessed data can be displayed on a single page; further processing can be done on the digitally stored data.

[Acoustically evoked brain stem potentials in infants at risk for SIDS with and without aminophylline therapy]. / Akustisch evozierte Hirnstammpotentiale beim SIDS-Risiko-Säugling mit und ohne Aminophyllintherapie.

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.

[Control of breathing in the central alveolar hypoventilation syndrome with and without a phrenic pacemaker]. / Untersuchungen der Atemregulation bei zentralem alveolärem Hypoventilations-Syndrom ohne und mit Zwerchfellschrittmacher.

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.

[Effect of aminophylline therapy in mature infants with sleep apnea syndrome]. / Effekt einer Aminophyllintherapie beim reifgeborenen Säugling mit Schlafapnoesyndrom.

Pneumograms of 33 fullterm infants (age 1-16 weeks) with idiopathic sleep apnea syndrome (SAS), treated with aminophyllin administered orally, were compared with pneumograms of 12 age-matched infants without aminophyllin treatment. In a one hour oxycardiorespirography (OCRG) all infants had pneumogram abnormalities defined as apneas greater than or equal to 15 s, greater than or equal to 3 apneas lasting 10 s, MA-value (mean duration of all apneas during sleep time) greater than or equal to 7 s/min, and greater than or equal to 3 episodes of periodic breathing. The diagnosis of an SAS, discussed as a possible risk factor of SIDS, was made in general in the presence of clinical symptoms such as apneas, cyanosis during sleep, poorly coordinated sucking, swallowing and respiration, and gastro-esophageal reflux (GER) in combination with an abnormal pneumogram. Of the 33 infants 12 with a history of an SIDS sibling were clinically asymptomatic. We found that after one week of aminophyllin treatment in 88% the pneumograms were normal. The mean plasma concentration of aminophyllin at this time was 8.3 micrograms/ml (range 4-19 micrograms/ml). All abnormalities showed a statistically significant reduction. In the infants without aminophyllin the pneumogram was still abnormal and no abnormality was significantly reduced. After at least 6 weeks we discontinued aminophyllin and one week later we monitored the OCRG. In 83% of the infants we found a normal pneumogram and compared to the initial pneumogram there was again a statistically significant difference.(ABSTRACT TRUNCATED AT 250 WORDS)

Physiological approaches to respiratory control mechanisms in infants. Assessing the risk for SIDS.

We have examined in a group of normal infants and in an "at-risk" group with clinical sleep apnea syndrome the duration and frequency distribution of apneas during sleep. In order to improve the estimation of an apnea factor, we introduced a weighting function which is based on the expected frequency distribution of apnea durations of normal infants. We were able to observe a good agreement between clinical rating, based on anamnestic symptoms, and numerical scoring. All infants of the at-risk group were treated with aminophylline, and the respiratory state improved significantly in nearly all cases. Breathing hypoxic gas mixtures tended to depress respiration, especially in the at-risk group, with a pronounced drop of pO2-values. Investigations on the coordination of respiration, sucking, and swallowing during nutritive sucking demonstrated a correspondence between disturbed coordination ability and the sleep apnea syndrome (SAS). This relationship is interpreted to be a result of an immaturity of the autonomic nervous system. In order to evaluate possible hereditary components in conjunction with respiratory disorders and, possibly, SIDS, we studied siblings of SIDS victims, of near-miss infants, and of infants with SAS. Only siblings of SAS and near-miss infants showed clinical signs of respiratory disorders with a rather high prevalence, whereas most of the siblings of SIDS victims were completely lacking conspicuous respiratory symptoms. Our results suggest that not all infants with sleep apnea syndrome are necessarily at increased risk for SIDS.

Effects of naloxone on apnoea duration during sleep in infants at risk for SIDS.

The effects of intravenous injections of the opiate antagonist naloxone (0.005-0.4 mg/kg body weight) on respiratory pattern, apnoea duration and frequency were investigated in six infants with severe sleep apnoea syndrome. Since several authors found elevated plasma- and CSF-levels of endogenous opioids (endorphines) in infants with sleep apnoea syndrome, we wanted to determine whether the impairment of the control mechanisms of respiration during sleep is due to an effect of endogenous opioids. Independent of the dose, naloxone did not exert any effect on respiratory pattern and occurrence of periodic apnoea. We were unable to prove that endorphines play a major role in pathogenesis of sleep apnoea syndrome in infancy and possibly in sudden infant death syndrome (SIDS). We speculate that elevated levels of endorphines reported by some investigators rather seem to be a consequence of hypoxic stress than a cause for sleep apnoeas.

[Sleep apnea in infants and the risk of SIDS]. / Schlafapnoen beim Säugling und SIDS-Risiko.

The examination of the respiratory function in 184 sleeping infants gave evidence of a significant difference in several parameters between the so-called SIDS risk group and the control group. The risk group (97 babies) consists of 60 infants with frequent prolonged apneas, 30 infants with postnarcotic apneas and 7 near miss infants. Polygraphic registration during sleep showed significantly more apneas in the risk group. These apneas often appeared more frequently during certain periods. The average respiratory deficit expressed as the MA-value (MA = average apnea duration) in the risk group was significantly higher than in control infants. Besides that we were able to prove a more frequent pathological gastroesophageal reflux in the risk infants than in control infants.

Combined disturbance of respiratory regulation and esophageal function in early infancy.

An evident coincidence exists between increased and extended apneas during sleep and frequent gastroesophageal reflux as well as disturbances of propulsive esophageal peristalsis. The tendency to develop apnea and disturbed esophageal function are related to the degree of the maturity of the patient. This indicates that in some infants, a combined regulatory immaturity of the autonomic centers persists. Moreover, the gastroesophageal reflux fosters the clinical manifestation of sleep apneas. The risk of a reflex apnea accompanied by gastroesophageal reflux increases in proportion to the disturbance in the central respiratory regulation present at the same time. This pathomechanism can be considered one of the causes of the sudden infant death syndrome. The possibility of effective prophylaxis consists in treating the apneic tendency with aminophylline and the treatment of reflux by elevating the upper body and thickening the nourishment given.