Breathing patterns, oxygen and carbon dioxide levels in sleeping healthy infants during the first nine months after birth

Data on arterial oxygen saturation (SaO2), transcutaneous PO2, pCO2 (tcpO2, tcpCO2) and breathing patterns in sleeping healthy term infants were obtained during the first 9 mo after birth. Forty-four healthy infants, mean GA at birth 40 +/- 1.0 wk, mean BW 3520 +/- 562 g were examined between 2 wk and 9 mo postnatally in a cross-sectional study. SaO2, tcpO2, tcpCO2, heart rate (HR), rib cage and abdominal respiratory movements were recorded during natural nocturnal sleep, stratified for sleep states (active sleep (AS), indeterminate sleep (IS), quiet sleep (QS)). The data on AS and IS were pooled as in previous studies. The variables were analysed with respect to age. SaO2 in AS + IS and QS was 96.1 +/- 1.3%, 96.6 +/- 1.4%, respectively. TcpO2 in AS + IS was 10.6 +/- 1.1 kPa and 10.7 +/- 1.3 kPa in QS, while tcpCO2 in AS + IS was 5.4 +/- 0.3 kPa and 5.4 +/- 0.4 kPa in QS. Neither SaO2 nor tcpO2 was influenced by age. TcpCO2 decreased significantly postnatally. Five infants (11.3%) experienced episodes of hypoxaemia with a mean decrease in SaO2 to 86 +/- 1.5%. In four infants these hypoxaemic episodes were linked to upper airway obstructions. Episodes of SaO2 < 90% in conjunction with a decrease in HR to < 100 bpm were detected in one infant only. Periodic breathing (PB) was observed in 38.6% of infants. Conclusion: Oxygenation and carbon dioxide levels in sleeping healthy term infants were comparable to those reported in older children. Hypoxaemic episodes, if present, are associated with upper airway obstruction. PB, often assumed to be a pathological feature, is a normal breathing pattern in this age group.     

Oxygen saturation and breathing patterns in preterm infants with cyanotic episodes

The pathophysiology of cyanotic/apnoeic episodes in preterm infants was investigated using overnight tape recordings of beat-to-beat arterial oxygen saturation (SaO2), plethysmographic waveforms from the oximeter, breathing movements and nasal airflow. Recordings were made in 16 preterm infants with recurrent cyanotic episodes of unknown cause that had received stimulation or resuscitation, and 15 preterm controls, matched for birth weight, post-conceptional and postnatal age. The recordings were analysed for baseline SaO2, the number of hypoxaemic episodes (SaO2 < or = 80% for > or = 4 s) and the breathing patterns associated with each episode. There was a significant difference in the total number of hypoxaemic episodes between patients and controls (520 versus 100; p < 0.01), but no difference was found for mean baseline SaO2 (98.6 versus 99.0%; p > 0.05). The mean duration of each hypoxaemic episode in the patients was 9.5 s compared with 5.8 s in the controls (p < 0.01). Although most hypoxaemic episodes (62 and 76%) were associated with pauses in breathing movements, a proportion (8 and 18%, respectively) occurred despite continuous airflow and breathing movements in both patients (6 of 16) and preterm controls (2 of 15). The rate of decrease in SaO2 was significantly more rapid during these latter hypoxaemic episodes than during episodes associated with isolated apnoeic pauses (8.5 versus 3.2% per second, p = 0.02). Preterm infants with cyanotic episodes have increased numbers of clinically unapparent hypoxaemic episodes, some of which have continued ventilation and rapid desaturation. The pathogenesis of these episodes warrants further investigation.     

Increased inspiratory effort in infants with a history of apparent life-threatening event

The objective of this study was to compare the results of polysomnography between infants with a history of apparent life-threatening event (ALTE) and controls. In this case-control study, 40 full-term ALTE infants, aged 2-36 wk at the time of the event, were compared with 40 age- and sex-matched randomly selected controls. SaO2, tcpO2, tcpCO2, heart rate (HR), vector of rib cage and abdominal respiratory movements (phase angle, as an index of inspiratory effort) were recorded during natural nocturnal active and quiet sleep (AS, QS). SaO2, tcpO2, tcpCO2 were similar in ALTE and controls in both sleep states. Phase angle was increased in ALTE infants in both AS (59+/-46 vs 26+/-17 degrees) and QS (53+/-46 vs 18+/-14, p < 0.001). Eleven ALTE infants (27.5%) experienced SaO2 < 90%, with a mean decrease in SaO2 to 86+/-1.6% (mean +/- SD), compared with 10% for controls (p=0.003). In eight ALTE infants, SaO2 values <90% were linked to thoracoabdominal asynchrony. SaO2 < 90% in conjunction with HR <100 bpm were detected in three ALTE infants and one control. Periodic breathing was observed in 45% of ALTE infants and 40% of controls. CONCLUSION: The mean values of oxygen saturation, tcpO2 and carbon dioxide levels in ALTE infants are comparable with those of healthy controls but the ALTE infants exhibit more hypoxaemic episodes and increased inspiratory effort during sleep.     

Arterial oxygen saturation in preterm infants at discharge from the hospital and six weeks later.

To obtain normal data on arterial oxygen saturation (SaO2) in preterm infants and to study early developmental changes in SaO2, we obtained overnight tape recordings of SaO2 and breathing movements in 160 preterm infants at their discharge from three special care baby units (mean gestational age at birth 33 weeks; at time of study, 37 weeks). One hundred ten infants (69%) underwent a second recording 6 weeks later. Median baseline SaO2 during regular breathing was 99.5% (range 88.7% to 100%) at discharge, and 100% (range 95.3% to 100%) at follow-up (p less than 0.001). The number of episodes of desaturation, defined as a fall in SaO2 to less than or equal to 80% for at least 4 seconds, corrected to the mean duration of recording (12.2 hours), decreased from a median of 3 (0 to 355) to 0 (0 to 17) (p less than 0.001). The median duration of each episode of desaturation remained unchanged (5.2 (4.0 to 22.7) vs 5.5 (4.2 to 24.0) seconds). At discharge, a small minority of infants had a clinically unrecognized low baseline SaO2 (lowest, 88.7%; 5th percentile, 95.7%) or a high number of desaturation episodes (the highest was six times the 95th percentile value). At follow-up, all outlying values had normalized. Follow-up recordings made between 42 and 47 weeks of gestational age (n = 53) were compared with similar recordings from 67 term infants at the same gestational age. The preterm infants had a significantly higher baseline SaO2 and no more desaturation than the infants born at term. Knowledge of normal ranges of oxygenation and their changes with age may be of value in identifying clinically undetected hypoxemia in preterm infants at discharge from the hospital. The potential influence of such hypoxemia on clinical outcome remains to be determined.     

Patterns of oxygenation during periodic breathing in preterm infants

The characteristics of the arterial oxygen saturation (SaO2) signal during episodes of hypoxaemia (SaO2 less than or equal to 80% for greater than or equal to 4 s) associated with periodic and non-periodic apnoeic pauses were studied in 16 preterm infants with cyanotic episodes (patients). and 15 asymptomatic preterm infants (controls), matched on birthweight and gestational age. The patients showed a significantly higher percentage of apnoeic pauses followed by a hypoxaemic episode (25 vs. 6%, P less than 0.01), and a two-fold increase in the slope of the desaturation curve (8.4 vs. 4.3% per s, P less than 0.005) in periodic compared with non-periodic breathing. All other characteristic of oxygenation (baseline SaO2 before episodes of hypoxaemia, delay between onset of apnoeic pause and onset of desaturation, lowest SaO2 during episodes of hypoxaemia) were similar for periodic and non-periodic breathing patterns. Similar, but not significant, differences between isolated and periodic apnoeic pauses were also present in the controls. An analysis of episodes of bradycardia (less than or equal to 100 beats per minute (bpm] showed that out of 121 episodes in the patients 118 were accompanied by a fall in SaO2 to less than or equal to 80%, and in the remaining three SaO2 fell to 82%, 85% and 86%, respectively. Thus all episodes of bradycardia (less than or equal to 100 bpm) were associated with a fall in SaO2 detected by beat-to-beat pulse oximetry. Examination of hypoxaemic episodes and their relationship with bradycardia and with apnoeic pauses, periodic and non-periodic, may help the further understanding of the control of arterial oxygenation in preterm infants with cyanotic episodes.     

Oxygen saturation and breathing patterns in infancy. 2: Preterm infants at discharge from special care.

Overnight 12 hour tape recordings of arterial oxygen saturation (SaO2, pulse oximeter in the beat to beat mode), breathing movements, and airflow were made on 66 preterm infants (median gestational age 34 weeks, range 25-36) who had reached term (37 weeks) and were ready for discharge from the special care baby unit. No infant was given additional inspired oxygen during the study. The median baseline SaO2 was 99.4% (range 88.9-100%). Eight infants had baseline SaO2 values below 97%, the lowest value observed in a study on full term infants. All but one infant had short-lived falls in SaO2 to less than or equal to 80% (desaturations), which were more frequent (5.4 compared with 0.9/hour) and longer (mean duration 1.5 compared with 1.2 seconds) than in full term infants. There was no evidence that gestational age at birth influenced the frequency or duration of desaturations among the preterm infants. The frequency of relatively prolonged episodes of desaturation (SaO2 less than or equal to 80% for greater than or equal to 4 seconds), however, decreased significantly with increasing gestational age (0.5, 0.4, 0.2, and 0.1 episodes/hour in infants at less than or equal to 32, 33-34, 35, and 36 weeks'' gestational age, respectively). Analysis of the respiratory patterns associated with such episodes showed that 5% occurred despite both continued breathing movements and continuous airflow. Five infants had outlying recordings: three had baseline SaO2 values of less than 95% (88.9, 92.7, and 93.8%), and two had many prolonged desaturations (14 and 92/hour; median for total group 0.2, 95th centile 2.3). None of these five infants had been considered clinically to have dis order of oxygenation. Although these data are insufficient to provide information about outcome, we conclude that reference data on arterial oxygenation in preterm infants are important to enable the identification of otherwise unrecognized hypoxaemia.     

Oxygen desaturation during sleep in infants and young children with congenital heart disease.

Oxygen saturation (SaO2) during sleep and pulmonary functions were evaluated in 19 infants with congenital heart disease, aged 6 +/- 4 months, and in 11 normal infants, aged 8 +/- 5 months, to determine whether infants with congenital heart disease have more frequent oxygen desaturation during sleep and, if so, its relationship to underlying pulmonary function. Infants with congenital heart disease were classified as acyanotic (n = 11) or cyanotic (n = 8) on the basis of their aortic SaO2 at the time of cardiac catheterization (greater or less than 90% SaO2). Pulmonary function tests included respiratory rate, functional residual capacity, total respiratory system compliance, and maximal flows at functional residual capacity. Significant differences were found in the values for the lowest SaO2 of each 5-minute epoch (SaO2L) averaged during the entire sleep time (normal 94% +/- 2%, acyanotic 90% +/- 3%, and cyanotic 74% +/- 4%; p less than 0.01). The three groups also differed significantly in frequency distributions of percentage of total sleep time with SaO2L less than 90% (SaO2%T) (normal 10% +/- 17%, acyanotic 36% +/- 34%, and cyanotic 97% +/- 4%; p less than 0.05). Compared with the control group, the acyanotic group had a higher respiratory rate (66 +/- 19 breaths/min vs 35 +/- 6 breaths/min; p less than 0.01), a lower tidal volume (65% +/- 29% predicted vs 105% +/- 18% predicted; p less than 0.01), and a lower total respiratory compliance (59% +/- 18% predicted vs 106% +/- 30% predicted; p less than 0.01). A negative correlation existed between SaO2%T and aortic SaO2 (R2 = 0.64; p less than 0.01). We conclude that oxygen desaturation occurs during sleep in infants with congenital heart disease; the presence of desaturation appears to be related to the initial degree of hypoxemia and the presence of abnormal pulmonary function.     

Blood pressure in sleep disordered breathing.

AIMS: To investigate blood pressure (BP) in children with sleep disordered breathing (SDB). METHODS: BP was measured during single night polysomnography in 23 suspected SDB child patients with adenotonsillar hypertrophy, but without respiratory or heart failure, or coma. The age related changes of the observed BP were normalised to the BP index. The BP indices were examined in relation to SDB measures, such as the desaturation time (percentage of time with oxygen saturation (SaO2) <90% against the total sleep time), SaO2 nadir, apnoea-hypopnoea index (AHI), and arousal index, in addition to age and body mass index (BMI). RESULTS: The systolic BP index during rapid eye movement sleep (REMS) tended to correlate with AHI, while the diastolic index during REM sleep showed a significant correlation with AHI. The BP indices during non-REMS and wakefulness showed no correlation with the parameters obtained. Patients with an AHI of 10 or more (n = 7, AHIhigh) had significantly higher systolic and diastolic BP indices during both wakefulness and REMS, compared with those with an AHI of less than 10 (n = 16, AHIlow). Two patients in AHIhigh showed no sleep related dip of diastolic BP, and three patients in AHIlow lacked the sleep related dip in systolic BP. By means of multiple regression analysis, age, BMI, and AHI were found to be significant predictor variables of the systolic BP index during REMS. CONCLUSIONS: BP in paediatric SDB patients is positively correlated with the degree of SDB.     

Association between gastroesophageal reflux and dips in the oxygen transcutaneous saturation of the hemoglobin in infants with chronic obstructive ventilatory disease

OBJECTIVE: To verify the association between oxygen desaturation episodes and the dips in pH in infants with chronic obstructive respiratory symptoms. METHOD: Cross-sectional study with children 24 months old or younger hospitalized for investigation of chronic obstructive respiratory symptoms from 1997 to 1999. The patients underwent esophageal pH monitoring associated with transcutaneous oxygen saturation during the night. The patients were included in the study according to their need to be hospitalized and availability of equipment. The indices used to measure this association were reflux index, total number of refluxes, number of refluxes longer than 5 minutes, Euler index, ZMD index, 24-hour mean pH, and mean pH of desaturation. RESULTS: We studied 44 children. The mean age was 7.5 months, and 20% had desaturation below 93% during pH monitoring. We used the t test to compare the occurrence of desaturation with the pH monitoring parameters. We found higher significance with the reflux index (RI), number of episodes longer than 5 minutes, ZMD index, 24-hour mean pH, and mean pH of desaturation. The bivariate analysis, taking into account possible confounding factors and RI, showed PR equal to 6.61 (IC 95% 1.67 - 26.12) for an RI higher than 4%. CONCLUSION: Oxygen saturation monitoring associated with pH monitoring may be a useful tool to establish an association between GER and respiratory problems in patients with chronic or recurrent wheeze.     

Asynchronous breathing during sleep.

BACKGROUND: Children rarely complain of symptoms associated with sleep disordered breathing (SDB). Paradoxical inward rib cage movement (PIRCM) during sleep might prove useful for detecting SDB. AIMS: (1) To determine the correlation between the degree of PIRCM and other measures of disordered breathing during sleep. PIRCM occurs physiologically throughout rapid eye movement sleep in neonates, while no PIRCM has been reported during sleep in adolescents. (2) To determine the chronological changes in the degree of PIRCM. METHODS: PIRCM was quantified by means of the laboured breathing index (LBI). LBI was determined by respiratory inductive plethysmography; PIRCM accompanies a high LBI. Sleep recordings obtained for 101 subjects for various reasons (aged from 3.5 months to 19 years) were analysed. RESULTS: In 22 records, the minimum SaO2 value was 90% or more and no obstructive apnoea of more than 10 seconds was observed. In these 22 records, LBI during rapid eye movement sleep decreased significantly with age, reaching the mature low level at 3.3 years of age. In the other 79 records, LBI correlated well with measures of obstructed breathing during sleep. CONCLUSIONS: By paying more attention to PIRCM, more obstructed breathing during sleep might be found among children aged 3 years or more.     

Oxygen saturation and breathing patterns in infancy. 1: Full term infants in the second month of life.

Overnight 12 hour tape recordings were made of arterial oxygen saturation (SaO2, pulse oximeter in the beat to beat mode) and abdominal wall breathing movement on 67 healthy, full term infants between the ages of 29 and 54 (median 39) days. The median baseline SaO2 during regular breathing was 99.8% (range 97.0-100%). Fifty four infants (81%) had shortlived episodes during which SaO2 fell to 80% or less (desaturation); the median rate was 0.9 desaturations/hour, and the median duration of each desaturation was 1.2 seconds. The 97th centile value for the duration of all episodes in which SaO2 fell to less than or equal to 80% was 4.0 seconds. The frequency of desaturations was significantly higher, and their duration significantly longer, when the breathing pattern was non-regular rather than regular. The percentage of apnoeic pauses (greater than or equal to 4 seconds in duration) followed by a desaturation was higher during non-regular than regular breathing; it was particularly high during periodic breathing. A knowledge of normal variability of baseline measurements of oxygenation and of the relationship between oxygenation and breathing patterns in infants is essential to the use of pulse oximetry in clinical practice.     

Hypoelectrolytemia and metabolic alkalosis in infants with cystic fibrosis.

The records of all children in the Tucson area diagnosed as having cystic fibrosis (CF) before the age of 12 months were reviewed to ascertain the prevalence of metabolic alkalosis as a major presenting manifestation of CF. Five of eleven infants (46%) in whom CF had been diagnosed between 1 and 12 months of age initially were seen with hypokalemia, hypochloremia, and metabolic alkalosis unassociated with marked dehydration, hyperpyrexia, or major pulmonary and/or gastrointestinal symptoms. Two infants had repeated episodes of metabolic alkalosis; for one of these infants, both episodes of metabolic alkalosis occurred before the diagnosis of CF. It is postulated that chronic loss of sweat electrolytes together with mild gastrointestinal or respiratory illness may predispose the infant with cystic fibrosis to a severe electrolyte and acid-base disturbance. The lack of shock and hyperpyrexia together with the apparent chronicity of electrolyte losses differentiates metabolic alkalosis from the heat prostration syndrome, a more acute complication of cystic fibrosis. Quantitative sweat testing should be part of the evaluation of any infant with unexplained metabolic alkalosis. Serum electrolytes should be assessed regularly in infants with cystic fibrosis during hot weather months.     

The effects of swaddling on oxygen saturation and respiratory rate of healthy infants in Mongolia

BACKGROUND: Infant swaddling is common practice in some developing countries where infant respiratory morbidity is also prevalent. Little is known about the effect of swaddling on respiratory variables in healthy infants. Such information could have important implications for respiratory diseases. AIMS: To compare respiratory rates (RR) and arterial oxygen saturations (SaO2) of healthy swaddled infants and non-swaddled infants during different conditions of sleep and arousal. SETTING: Community based, nested case control study in Ulaanbaatar, Mongolia. SUBJECTS AND METHODS: Habitually swaddled and non-swaddled infants aged 9-10 weeks taking part in a randomised controlled trial of swaddling. Respiratory rate and SaO2 were measured during quiet wakefulness, feeding, quiet and active sleep. Habitually swaddled infants were studied in swaddled and non-swaddled conditions. Habitually non-swaddled infants were studied only in the non-swaddled state. RESULTS: SaO2 was higher during awake states compared with sleep states in all groups of infants. Habitually swaddled infants had lower mean SaO2 in the swaddled compared with non-swaddled condition (96.5% vs. 96.9%, p < 0.01) but these were not significantly different from the mean SaO2 of non-swaddled infants (96.9%, minimum p = 0.22). Habitually swaddled infants in the swaddled and non-swaddled states had similar respiratory rates, but these were, in both cases, significantly lower than in habitually non-swaddled infants. CONCLUSION: Swaddling has little or no clinical effect on SaO2 or respiratory rates in healthy 9-10-week-old infants in Mongolia.     

Changes in nocturnal oximetry after treatment of exacerbations in cystic fibrosis

Sleep related arterial oxygen desaturation has been described in clinically stable young adults with cystic fibrosis. The incidence and severity of nocturnal oxygen desaturation in children during infective exacerbations and the changes that occur with treatment were examined. Forty five children with proved cystic fibrosis, median age 8.9 years, admitted to the Regional Cystic Fibrosis Unit underwent clinical evaluation, spirometry, and measurement of peak flow and nocturnal oxygen saturation on admission and after 10 days' treatment. There was a significant improvement in all the above measurements, with the averaged overnight saturation changing from a mean (SD) 92.7 (2.7)% to 94.3 (2.0)%, mean (SE) difference 1.58 (0.37). The time spent with a saturation 4% or more below their clinic value showed a marked improvement from 122 (152) minutes on the first night to 21 (30.7) on the second, mean (SE) difference 101 (22.4). Eight young children could not perform pulmonary function tests, all desaturated on the admission night. Nocturnal hypoxaemia is a common finding in young cystic fibrosis patients during infective exacerbations but improves with treatment. Overnight oximetry is simple to perform, well tolerated, and identifies patients with marked nocturnal desaturation.     

Changes in nocturnal oximetry after treatment of exacerbations in cystic fibrosis.

Sleep related arterial oxygen desaturation has been described in clinically stable young adults with cystic fibrosis. The incidence and severity of nocturnal oxygen desaturation in children during infective exacerbations and the changes that occur with treatment were examined. Forty five children with proved cystic fibrosis, median age 8.9 years, admitted to the Regional Cystic Fibrosis Unit underwent clinical evaluation, spirometry, and measurement of peak flow and nocturnal oxygen saturation on admission and after 10 days' treatment. There was a significant improvement in all the above measurements, with the averaged overnight saturation changing from a mean (SD) 92.7 (2.7)% to 94.3 (2.0)%, mean (SE) difference 1.58 (0.37). The time spent with a saturation 4% or more below their clinic value showed a marked improvement from 122 (152) minutes on the first night to 21 (30.7) on the second, mean (SE) difference 101 (22.4). Eight young children could not perform pulmonary function tests, all desaturated on the admission night. Nocturnal hypoxaemia is a common finding in young cystic fibrosis patients during infective exacerbations but improves with treatment. Overnight oximetry is simple to perform, well tolerated, and identifies patients with marked nocturnal desaturation.     

Children and nocturnal snoring: Evaluation of the effects of sleep related respiratory resistive load and daytime functioning

Twenty-five children, age range 2 to 14 years (mean age=7), were referred to the Stanford University Sleep Disorders Clinic for various clinical symptoms, including excessive daytime somnolence, heavy nocturnal snoring, and abnormal daytime behavior. All children (10 girls and 15 boys) were polygraphically monitored during sleep. No sleep apnea syndrome or oxygen desaturation was revealed. However, each child presented significant respiratory resistive load during sleep associated with electrocardiographic R-R interval and endoesophageal pressure swings. The most laborious breathing occurred during REM sleep. Second degree atrioventricular blocks were also noted. Tonsillectomy and/or adenoidectomy was performed in every case and resulted in a complete disappearance or substantial amelioration of the reported symptoms. Objective evaluation by Multiple Sleep Latency Test and Wilkinson Addition Test confirmed the beneficial effect of surgery.     

Down综合征患儿睡眠特征多导睡眠图的回顾性研究

目的 探讨Down综合征患儿的睡眠结构和基本睡眠参数的特点。方法 选取10例Down综合征患儿为Down组，采用染色体核型检查进行Down综合征的诊断，其中男7例，女3例，年龄中位数8岁2个月；选取声带小结患儿14例及突发性耳聋6例患儿为对照组，其中男12例，女8例，年龄中位数8岁9个月。两组患儿均接受整夜多导睡眠图监测，按中华医学会耳鼻咽喉科学分会制定的儿童阻塞性睡眠呼吸暂停低通气综合征（OSAHS）诊疗指南（草案）中的标准进行呼吸事件的定义和OSAHS的诊断，阻塞性呼吸暂停指数（OAI）每小时≤1次或呼吸暂停低通气指数(AHI) 每小时≤5次，最低血氧饱和度(LSaO2)≥0.92可以排除OSAHS。应用Mann-Whitney U和精确概率检验，比较Down组和对照组的睡眠结构，并进行睡眠期LSaO2、OAI、AHI、脑电醒觉反应指数及睡眠期肢体运动事件指数的比较。结果 ①两组间在年龄、性别和体重指数等差异无统计学意义（P＞0.05）；②Down组和对照组比较，快动眼睡眠比例减少，且差异有显著统计学意义（Z=-2.6，P= 0.009）；③睡眠期LSaO2较对照组显著下降（P＜0.05），OAI、AHI及睡眠期肢体运动事件指数Down组较对照组显著升高（P＜0.05）；④10例Down综合征患儿中有6例符合OSAHS诊断，6例中有5例为男性。结论 Down综合征患儿存在睡眠呼吸紊乱，应使用多导睡眠检测的方法尽早发现睡眠呼吸紊乱的问题。     

Asynchronous breathing during sleep

BACKGROUND—Children rarely complain of symptoms associated with sleep disordered breathing (SDB). Paradoxical inward rib cage movement (PIRCM) during sleep might prove useful for detecting SDB.
AIMS—(1) To determine the correlation between the degree of PIRCM and other measures of disordered breathing during sleep. PIRCM occurs physiologically throughout rapid eye movement sleep in neonates, while no PIRCM has been reported during sleep in adolescents. (2) To determine the chronological changes in the degree of PIRCM.
METHODS—PIRCM was quantified by means of the laboured breathing index (LBI). LBI was determined by respiratory inductive plethysmography; PIRCM accompanies a high LBI. Sleep recordings obtained for 101subjects for various reasons (aged from 3.5 months to 19 years) were analysed.
RESULTS—In 22 records, the minimum SaO2 value was 90% or more and no obstructive apnoea of more than 10 seconds was observed. In these 22 records, LBI during rapid eye movement sleep decreased significantly with age, reaching the mature low level at 3.3 years of age. In the other 79 records, LBI correlated well with measures of obstructed breathing during sleep.
CONCLUSIONS—By paying more attention to PIRCM, more obstructed breathing during sleep might be found among children aged 3 years or more.

     

Sleep architecture in children with adenoidal hypertrophy

AIM: Adenoidal hypertrophy (AH) in children is associated with obstructive manifestations like mouth breathing, snoring. Unfortunately, little is known regarding sleep architecture of AH in children. The purpose of this study was therefore undertaken to investigate the polysomnographic variables in children with AH. METHOD: 47 children with AH and 11 controls underwent nocturnal polysomnography. Sleep was scored manually according to the standard set by Rechtschaffen. RESULTS: In AH, stage 1 sleep percentage and rapid eye movement (REM) latency were increased significantly, while the sleep percentage of stage 2 and REM was decreased remarkably compared with that of controls. Arousal index in AH was much more higher than that in controls. Arousal index in REM sleep was higher than that in non-rapid eye movement (NREM) sleep in AH, but the number of arousals in REM sleep was lower than that in NREM sleep. Hypopnea events were the most common type of respiratory events, followed by obstructive events in AH and controls. Apnea/hypopnea index in AH was higher in comparison to controls. No significant difference was found between the children with AH and controls in SaO(2) nadir (%) and base mean SaO(2) (%). Apnea/hypopnea index was related to hypopnea arousal in REM sleep and hypoxemia arousal in NREM sleep. CONCLUSION: AH is predominantly characterised by a hypopnea with little obstruction in children. Our results clearly and for the first time demonstrated that sleep architecture was abnormal in children with AH. We therefore speculate that hypopnea arousal in REM sleep and hypoxemia arousal in NREM sleep may play an important role in the course of respiratory disturbance.     

Effects of child seats on the cardiorespiratory function of newborns

BACKGROUND: This study aims to determine the effect of differently positioned infant car seats on cardio-respiratory parameters in healthy full-term newborns. METHODS: We examined 15 healthy term newborns for respiratory compromise due to normal restraint in a recommended infant car seat. There are currently two types of car seats available in Japan: a chair-shaped car seat and a bed-shaped car seat. Using a sleep apnea recorder, we simultaneously monitored heart rate, percutaneous oxygen saturation, chest impedance and nasal airflow in infants placed in each of the car seats and also placed in the supine position on a nursery cot. Episodes of oxygen desaturation below 95% and longer than 10 s (mild desaturation) and below 90% longer and than 10 s (moderate desaturation) were evaluated over 30 min observation period. RESULTS: The amount of time infants spent in a sleep state was significantly longer in the car seats than it was on the cot (P = 0.0015 for bed-shaped, P = 0.0012 for chair-shaped) and there was no difference in this measure between the two types of car safety seats. Mean of oxygen saturation with the chair-shaped car seat (95.8%) was significantly lower than that with the bed-shaped car seat (98.8%) (P = 0.0008). Newborn infants laid on the cot showed no episodes of desaturation. Newborn infants placed in the chair-shaped car seat had significantly more episodes of mild desaturation (mean, 7.33 times in nine of 15 infants), whereas in the bed-shaped seat observed only once each in two infants (P = 0.008). Moderate desaturation was observed in four of 15 infants in the chair-shaped car seat, whereas not observed in the bed-shaped car seat (P = 0.068). CONCLUSION: The results suggest that prior to discharge the degree of oxygen desaturation that occurs when an infant is placed in a chair-style car seat should be checked.