Mean Apnea Duration Research Articles

Preliminary Findings in the Treatment of Obstructive Sleep Apnea with Transtracheal Oxygen

The effects of continuous low flow oxygen via transtracheal oxygen delivery (TTOD) were assessed in four patients with obstructive sleep apnea (OSA) and daytime hypersomnolence who were unable to tolerate continuous positive nasal airway pressure (CPAP). The overall quality of sleep, sleep fragmentation, pattern of respiration, and nocturnal oxygen saturations were evaluated with the patients receiving 2 to 3 L/min of oxygen by TTOD, and the results were compared to polysomnograms with and without nasal cannula oxygen. The mean respiratory disturbance index (apneas plus hypopneas/hour of sleep) was improved by TTOD compared to no therapy or nasal cannula oxygen, and improvement in sleep disturbance was associated with improvement in overall nocturnal oxygen saturation. The mean apnea duration was not increased by TTOD and the duration of the longest apneic spells was decreased by 33 to 85% with this therapy. These improvements in respiratory status were accompanied by symptomatic improvement in daytime sleepiness, and there were no significant side effects. These findings suggest that TTOD may be a safe and effective alternative treatment of OSA for some patients who are unable to tolerate nasal CPAP therapy.

Screeningprogramm zur Erfassung von Kindern mit einem erhöhten SIDS-Risiko (Plötzlicher und unerwarteter Kindstod)

The prospective study presented conducted to prevent SIDS (sudden infant death syndrome). One of the proposed hypotheses on SIDS postulates a brainstem abnormality in the neuroregulation of cardiorespiratory processes. Therefore we characterized cardiorespiratory control mechanisms by examining the neurotransmitter substance P in plasma and polysomnographic investigations. With respect to the probable multifactorial origin of SIDS we selected children firstly anamnestically by means of an epidemiologically evaluated pre-, peri- and postnatal risk score. We reported the results of 208 polysomnographically and biochemically examined children anamnestically selected from a group of 2500 neonates. Examinations were performed on infants aged 2-4 weeks up to 1 year. To characterize respiratory control, length and frequency of apnoeas were separately estimated by means of polysomnography in the sleep states active and quiet sleep. If there were polygraphic risk factors representing a disturbance of respiratory control, the children were prophylactically treated with aminophylline 3 x 3 mg/kg b.w. for 4 weeks. We found a significant age dependence both of the mean apnoea duration in active sleep and the substance P level in plasma in the SIDS-risk group but not in the controls. High mean apnoea duration was correlated with low substance P level in the first months of age in SIDS risk infants selected anamnestically. This may reflect a delayed maturation of respiratory control mechanisms. In this way the polysomnography and the investigation of the neuropeptide substance P may be useful for a screening method indicating wether the respiratory control mechanisms are mature or not.

Influence of lung volume in sleep apnoea.

The influence of a constant increase in functional residual capacity on apnoea characteristics was studied in patients with the sleep apnoea syndrome. Pulmonary inflation was achieved by applying a continuous negative extrathoracic pressure into a Poncho type respirator. Nine patients slept in the Poncho for two consecutive nights, negative extrathoracic pressure being applied during the second night. There was no difference in the total sleep time, its composition within the different sleep stages, the apnoea and apnoea-hypopnoea indices, or the sleep time spent in apnoea between the two nights. The mean (SD) apnoea duration increased with negative extrathoracic pressure from 25.3 (2) to 30.5 (3) seconds (p = 0.003) and time spent in obstructive apnoea (percentage of apnoea time) from 56 (13) to 75 (8) (p = 0.02). The mixed apnoea time (%) decreased from 37 (7) to 21 (7) (p = 0.02). Despite the increase in apnoea duration, less time was spent below each oxygen saturation value during negative extrathoracic pressure. The results were similar for apnoeic episodes during non-REM (non-rapid eye movement) sleep, whereas no significant modifications were seen during REM sleep. It is concluded that the composition of apnoea time and resulting oxygen desaturation are influenced by lung volume.

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.

Sleep Respiratory Instability in Term Neonates under Hyperthermic Conditions: Age, Sex, Type of Feeding, and Rapid Eye Movements

The purpose of this study was to examine the influence of neonatal age, sex, type of feeding, and rapid eye movements on the occurrence of apneic pauses during sleep in a hyperthermic environment. One hundred and twenty fullterm infants (equally divided by sex and type of feeding) were observed during a complete nap within the first and approximately fourth wk of life. Each sleep session was characterized by twenty-one measures including the longest apneic pause, mean apnea duration, relative frequency of apnea, apnea periodicity, respiratory rate, and relative frequency of REM epochs. The relative frequency of REM epochs decreased with age and was greater in formula-fed (versus breast-fed) infants. The longest apneic pauses were greater in the first wk of life and in breast-fed infants. In addition, the average Longest Duration:REM was greater than the average Longest Duration:NREM. Of potential importance was the demonstration that this latter effect was greater in the first wk than in the fourth wk of life. Breast-fed infants and females had larger apnea Mean Duration scores. The relative frequency of apneic pauses (greater than or equal to 2 sec in duration), periodicity, and the relative amount of apnea were greater in the fourth-wk study and in breast-fed infants. The relative frequency of apneic pauses greater than or equal to 6 sec in duration (Apnea6%) and the A6/D% measure were greater in breast-fed infants. Numerous interactions were observed between age, sex, and type of feeding. Respiratory rate decreased with age and was greater during NREM epochs and in formula-fed infants.

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.

Cardiac and ventilatory changes associated with altered salinity inCrangon crangon(L.)

Abstract Heart and scaphognathite activities of C. crangon were monitored during slow (S = 2 %0.day-1) and more rapid (5 = 4 %0 every second hour) dilution of their normal (S = 34 %0) seawater environment. Heart rates were not significantly (P > 0.05) changed by dilution in either experiment and thus contrasted with those of the control group, which showed a significant (P < 0.001) decrease possibly as an acclimatization response - in the slow dilution experiment. Scaphognathite rates increased significantly (P < 0.001) on dilution and mean apnoea duration shortened rapidly at salinities below S = 240/00 and were abolished at S = < 200/00.