Periodic Breathing In Infants Research Articles

Infant periodic breathing and apneic threshold.

A mathematical model was proposed to predict the role played by apneic threshold in periodic breathing in preterm infants. Prior models have mainly applied linear control theory which predicted instability but could not explain sustained periodic breathing. Apneic threshold to CO2 which has been postulated to play a major role in infant periodic breathing is a nonlinear effect and cannot be described by linear theory. Another previously unexplored nonlinear factor affecting instability is brain vascular volume change with CO2 which affects time delay to chemoreceptors. The current model explored the influences of apneic threshold, central and peripheral chemoreceptor gains, cardiac output, lung volume, and circulatory time delay on periodic breathing. Apneic threshold was found to play a major role in ventilatory responses to spontaneous sighs. Sighs led to apneic pauses followed by periods of periodic breathing with peripheral chemoreceptor CO2 gain, cardiac output, and lung volume were at reported normal levels. Apneic threshold when exceeded was observed to cause an asymmetry in the periodic breathing cycling and an increased periodic breathing frequency. Sighs in infants occur frequently enough to lead to repeated stimulation within the epoch duration of periodic breathing for a single sigh. Multiple sighs may then play a major role in promoting continuous periodic breathing in infants. Peripheral chemoreceptor gain estimated using endogenous CO2 led to validated predicted periodic breathing cycle duration as a function of age. Brain vascular volume increase with CO2 contributes to periodic breathing in very young (1-2 day old) preterm infants.

The morphology of periodic breathing in infants and adults

To test the hypothesis that the crescendo–decrescendo type of pattern of periodic breathing is more common in infants than in adulthood, we examined the morphologies of periodic breathing in four groups of subjects: group 1 ( n=10, gestational age 30±1 week), group 2 ( n=10, GA 31±1 week), group 3 ( n=10, GA 38±1 week), and group 4 ( n=10, age 50±4 years). Respiratory pattern and ventilation were measured using a flow-through system. The breathing morphologies were defined according to the respiratory flow. We found (1) a predominant crescendo–decrescendo pattern in preterm infants (groups 1 and 2, >50%) and this changed to a predominant decrescendo breathing in adults (group 4, 50%); (2) total breathing cycle and its phases did not change significantly among the neonatal groups, but they almost doubled in adult subjects; however, the number of breaths per breathing interval remained the same (crescendo–decrescendo) or less (flat and decrescendo) in adults as compared to preterm infants; (3) the duty cycle (breathing interval/cycle duration) remained consistent with age; and (4) at the beginning of each breathing interval, alveolar P co 2 was highest and alveolar P o 2 and O 2 saturation lowest. The findings suggest a change in the strategy of the respiratory control system during periodic breathing between the infant and the adult, perhaps dictated by mechanical and chemoreceptor limitations early in age, with a switch from a crescendo–decrescendo to a predominantly decrescendo pattern.

Optimization of inspiratory work in periodic breathing in infants.

In periodic breathing, there are repeated cycles of bursts of breaths separated by pauses several seconds long. We consider the mechanics of periodic breathing in human infants using calibrated traces of tidal volume and esophageal pressure recorded during the first few days after delivery. Each cycle of periodic breathing was analyzed in terms of the inspiratory time and beginning and end inspiratory volumes for each breath, the number of breaths in the cycle, and the total observed inspiratory work. A simple model was used to characterize the mechanics of the lung during inspiration, and the recordings were used to calculate the parameters of this model. These varied from breath to breath. A theoretical formula is derived for the sum of external work performed during inspiration for each burst. It is shown mathematically that there exists a local minimum in the calculated work as the values of the individual tidal volumes in this formula are allowed to vary, with the constraint that the sum of the ventilation during the cycle is as measured. The measured values of inspiratory timing, the starting volume and pressure, and the mechanical parameters for each inspiration are also used. We show that during each cycle of periodic breathing, the total of the observed external work is highly correlated with this theoretical minimum work. In addition, during the cycle, there is a pattern of overshoot and subsequent undershoot in the work with respect to the theoretical optimum, which suggests a control process operating during the cycle to minimize the work.

Evaluation of periodic breathing in infants

Periodische Atmung im Sauglingsalter ist zunachst als ein physiologisches Phanomen anzusehen. Im Mittel reduziert sich ihr Anteil an der Schlafzeit im Lauf des ersten Lebenshalbjahres deutlich. Wiederholt wurde diese Atmungsform jedoch mit einem erhohten Risiko fur den plotzlichen Kindstod in Verbindung gebracht. Dieses Arbeitsgruppenpapier stellt die Definitionen und physiologischen Grundlagen periodischer Atmung dar, diskutiert pathologische Formen und fuhrt deren Folgen anhand der vorhandenen Literatur auf. Wichtiger Gesichtspunkt fur kunftige Forschungsarbeiten zur periodischen Atmung ist die Differenzierung physiologischer von pathologischen Formen. Hierzu empfiehlt die Arbeitsgruppe die Verwendung einer einheitlichen Definition, die Differenzier der periodischen Atmung nach Auftreten in den verschiedenen Schlafphasen und die Auswertung der begleitenden Blutgasveranderungen.

ANALYSIS OF INFANTS PRESENTING WITH FEEDING RELATED PROBLEMS AND APPARENT LIFE THREATENING EVENTS: A CLOSER LOOK AT “PSEUDOREFLUX SYNDROME.” 648

A “Pseudoreflux Syndrome” has been described in healthy term neonates who presented with symptoms of gastroesophageal reflux (GER) with and without apnea but were found to have increased periodic breathing (PB). This initial study was limited by a small study population (n=16) and focused on the term neonate. Differentiating GER from PB is important in determining treatment. Object of this study is to analyze 5-channel pneumograms (PCGs) of infants presenting with feeding related problems and/or apparent life threatening events in order to further define and describe the phenomenon of pseudoreflux in infants. The impact of post-conceptional age (PCA) was also examined. 5-channel PCGs of all infants presenting with symptoms of GER and/or apnea to an infant apnea program between 1992 and 1995 were reviewed for sex, race, gestational age (GA), PCA at time of presentation and diagnosis. 166 5-channel PCGs of 161 infants ranging from ages 0.6 to 55 weeks were reviewed[12.1 weeks ±0.9 (SEM)]. Of the infants evaluated, 60% were male, 40% female. 52% were white, 40% African American, 6% Latino and 2% other. 5-channel PCGs of 161 infants studied revealed a diagnosis of GER in 42%, PB in 13%, GER and PB in 25% and absence of either GER and PB in 21%. Average GA was 35 weeks ± 0.4 (SEM). Using analysis of variance (Anova), mean GA was 35 weeks regardless of diagnosis (F-Ratio 0.99, P value 0.40). Average PCA was 47.3 weeks ± 0.8 (SEM). Using Anova, mean PCA was 40 weeks for PB group, 43 weeks for GER/PB group, 51 weeks for GER group and 50 weeks for other group (F-Ratio 8.8, P value 0.00). PB alone was not observed in infants over 48 weeks PCA (0/51). Majority of infants with PB were under 45 weeks PCA(48/60). In conclusion, these results confirm the importance of considering PB in infants presenting with symptoms of GER and/or apnea. Pseudoreflux Syndrome must be distinguished from true GER to institute appropriate therapy. Infants under 45 weeks PCA are at particular risk for PB and should undergo 5-channel PCGs. Pseudoreflux Syndrome is an unlikely consideration in management of infants over 48 weeks PCA.

Airway obstruction during periodic breathing in premature infants.

To characterize changes in pulmonary resistance, timing, and respiratory drive during periodic breathing, we studied 10 healthy preterm infants (body wt 1,340 +/- 240 g, postconceptional age 35 +/- 2 wk). Periodic breathing in these infants was defined by characteristic cycles of ventilation with intervening respiratory pauses greater than or equal to 2 s. Nasal airflow was recorded with a pneumotachometer, and esophageal or pharyngeal pressure was recorded with a fluid-filled catheter. Pulmonary resistance at half-maximal tidal volume, inspiratory time (TI), expiratory time (TE), and mean inspiratory flow (VT/TI) were derived from computer analysis of five cycles of periodic breathing per infant. In 80% of infants periodic breathing was accompanied by completely obstructed breaths at the onset of ventilatory cycles; the site of airway obstruction occurred within the pharynx. The first one-third of the ventilatory phase of each cycle was accompanied by the highest airway resistance of the entire cycle (168 +/- 98 cmH2O.l-1.s). In all infants TI was greatest at the onset of the ventilatory cycle, VT/TI was maximal at the midpoint of the cycle, and TE was longest in the latter two-thirds of each cycle. A characteristic increase and subsequent decrease of 4.5 +/- 1.9 ml in end-expiratory volume also occurred within each cycle. These results demonstrate that partial or complete airway obstruction occurs during periodic breathing. Both apnea and periodic breathing share the element of upper airway instability common to premature infants.

Periodic breathing in infants: a model study.

A model has been adapted to explain periodic breathing in infants during sleep. Using parameter values determined in various studies by others, it is shown that the respiratory control system of certain infants is marginally stable so that a small change in one or more of the parameters can cause periodic breathing with a period of about 14 s.

Postanesthetic apnea and periodic breathing in infants.

Postanesthetic apnea and periodic breathing in infants.

Special analysis of the emg and diaphragmatic muscle fatigue during periodic breathing in infants

Pediatric PulmonologyVolume 1, Issue 5 p. 287-288 Selected Abstract Special analysis of the emg and diaphragmatic muscle fatigue during periodic breathing in infants Nugent St, Nugent St J Appl Physiol 1985; 58:830–833Search for more papers by this authorFinley Jp, Finley Jp J Appl Physiol 1985; 58:830–833Search for more papers by this author Nugent St, Nugent St J Appl Physiol 1985; 58:830–833Search for more papers by this authorFinley Jp, Finley Jp J Appl Physiol 1985; 58:830–833Search for more papers by this author First published: September/October 1985 https://doi.org/10.1002/ppul.1950010523AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume1, Issue5September/October 1985Pages 287-288 RelatedInformation

Respiratory EMG findings in relation to periodic breathing in infants

Intercostal and diaphragm EMG activity was analysed in periodically breathing infants. The aim was to investigate relationships between changes in tonic activity in the respiratory muscles and switches in spontaneous breathing pattern from periodic to continuous and vice versa. A heterogeneous group of 13 normal and neurologically suspect infants was studied. They had all previously undergone polygraphic investigation and were selected because their polygraphic records showed at least three minutes uninterrupted periodic breathing (PB). PB appeared to represent an oscillation with a length of about 16 seconds superimposed on the basic state related irregular and regular breathing patterns. The development of a normal level of tonic activity in the respiratory muscles at the transition from state 2 to state 1 coincided with the switching from periodic to continuous breathing. Continuation of PB throughout a state 1 epoch in the presence of tonic respiratory muscle activity was exceptional. Sighs alone or sighs together with brief movements during state 1 were followed on occasion by a drop in tonic activity and a switch from continuous to periodic breathing. If the tonic activity rose again, PB either stopped or became less pronounced. TcPO 2 level measured in four infants rose when tonic activity rose and was lower during PB than during continuous breathing. The observations made in this study suggest that mechanical or chemical changes caused by changes in tonic activity level may affect the stability of respiratory control in infancy.

Spectral analysis of the EMG and diaphragmatic muscle fatigue during periodic breathing in infants.

Periodic breathing occurs commonly in full-term and preterm infants. The mechanisms which switch breathing on and off within a cycle of periodic breathing are not certain. Since immature infants may experience diaphragmatic muscle fatigue, one potential switching mechanism is fatigue. Power spectra of the electromyogram, uncontaminated by the electrocardiograph artifact, were studied for evidence of diaphragmatic muscle fatigue during spontaneous periodic breathing in infants. A fall in the high-frequency (103-600 Hz) power and an increase in the low-frequency (23-47 Hz) power during periodic as compared with normal breathing would indicate fatigue. This effect was not observed in any of the infants studied. Hence, there is no evidence that periodic breathing is the result of diaphragmatic muscle fatigue. This finding suggests that the effect of drugs such as theophylline in eliminating periodic breathing may be unrelated to the fact that they also reduce fatigue.

Periodic breathing in infants with histories of prolonged apnea.

Periodic breathing (PB) during sleep was investigated in two groups of full-term infants with histories of apnea that were terminated by resuscitation. One group of infants had been reported to be asleep whereas the other group had been reported to be awake when apnea was noted. Electrophysiologic sleep recordings were made after the apneic incident. The infants with histories of prolonged apnea while asleep exhibited more PB during recorded sleep than infants with histories of apnea while awake. Increased PB during sleep in full-term infants, therefore, may not be associated with all prolonged apneic episodes in infants but may be specifically associated with those episodes that occur during sleep.

Periodic Breathing in Infants With Near-Miss Sudden Infant Death Syndrome

Twelve-hour nocturnal home recordings of respiration and heart rates were obtained during sleep in 32 infants with near-miss sudden infant death syndrome (SIDS) and in 32 control infants, and the recordings were analyzed for periodic breathing. An episode of periodic breathing was defined as three or more apneic pauses of three or more seconds. The duration of respirations interrupting the pauses was 20 seconds or less. Analysis revealed a statistically significant difference (P less than .001) between the two groups, using criteria of percent of periodic breathing episodes, number of periodic breathing episodes/100 min of recorded sleep time, average duration of all episodes, and duration of the longest episode of periodic breathing. It is concluded that periodic breathing is present in excessive amounts during sleep in infants with near-miss sudden infant death syndrome.

THE EFFECTS OF HYPOXIA ON THE RESPIRATION OF NEWBORN INFANTS

The effects of administering atmospheres containing 10 and 12% oxygen to healthy newborn infants of different ages have been studied. Infants under 24 hours of age tended to hypoventilate throughout the period of hypoxia. Infants six to 11 days of age hyperventilated for the first two or three minutes and then showed a decrease, although not so marked as observed in the infants under 24 hours of age. Infants 16 to 48 days of age showed the most marked increase in ventilation, but even in these infants it was poorly maintained as compared to responses seen in adults. Hypoxia produced a slowing of the respiratory rate in all infants except the very oldest. Tidal air was increased at first and then decreased. The increases in tidal air accounted for most of the increase in minute volume seen in the older infants. Hypoxia increased the incidence of periodic breathing in the two older groups of infants, but had very little effect on infants under 24 hours of age. Respiratory patterns did not appear to be altered by the hypoxic conditions employed in this study. It has been postulated that the comparatively weak response to hypoxia made by infants immediately after birth possibly is dependent on relatively poor chemoreceptor reflexes and that the latter increase in strength during the first weeks of postnatal life. It has also been suggested that the relative inability to induce periodic breathing in infants under 24 hours of age as compared to those several weeks old is further evidence indicating that metabolism of the medullary respiratory centers is to a larger extent anerobic than at the later periods of postnatal life.