Simultaneous sudden infant death syndrome (SIDS) in twins is an extremely rare event. Some believe these are natural deaths, whereas others suggest they are unnatural. We report monozygotic twins dying at 12 weeks of age. Extensive investigation concluded that the cause of death was natural. Our case fulfilled the criteria of simultaneous SIDS in twins. However, thermal stress due to excessive thermal insulation, use of a pillow and placing twins in the same cot all represent a potentially unsafe sleeping environment. We recommend the term "simultaneous sudden unexpected death in infancy of twins" to describe such cases.

Aim: It has been hypothesized that the association of pacifier use with reduced risk of sudden infant death is mediated by forward movement of the mandible and tongue that helps open the upper airway. Our aim was to examine whether the mandible is moved forward when an infant is sucking on a pacifier, and if so, whether the mandible remains advanced after the pacifier is removed. Methods: In sixty clinically stable premature infants (corrected gestation age 36.5 +/- 0.3 weeks, mean +/- SEM) the distance from each ear where the pinna met the cheek to the most prominent point of the chin was measured bilaterally, and the average was used as an index of mandibular position. Mandibular position was determined before and after allowing the infants to suck on a pacifier for 10-15 min, and after removing the pacifier. Results: There was a significant forward movement of the mandible when the infants were sucking on the pacifier (59.5 +/- 0.7 vs. 58.6 +/- 0.7 mm, p = 0.001), with no significant change after the pacifier was removed. Conclusions: Pacifier use in preterm infants was associated with a small significant forward displacement of the jaw. These data suggest that pacifier use may help protect the upper airway.

OBJECTIVES: To test prospectively the hypothesis that an infant car seat modification to allow the infant's head to rest in a neutral position on the trunk would prevent narrowing of the upper airway and thus reduce oxygen desaturation in preterm infants who are restrained in car seats. METHODS: Seventeen preterm infants who were approved for discharge were evaluated in a car seat for newborns, with and without a foam insert that provided a slot for the back of the infants' head. Respiration timed inspiratory radiographs for assessment of upper airway dimensions were taken during quiet sleep in each position. Infants were monitored in each position for 30 minutes with continuous polygraphic recording of respiratory, cardiac, and nasal airflow activity and pulse oximetry. RESULTS: Placement of the insert in the car seat was associated with a larger upper airway space (mean +/- standard deviation, 5.2 +/- 1.3 vs 3.6 +/- 1.4 mm). This radiologic improvement was associated with a significant reduction in the frequency of episodes of oxygen desaturation to <85%(1.5 +/- 2.1 vs 3.5 +/- 3.5 episodes/infant), of bradycardia <90 bpm (0.1 +/- 0.3 vs 1 +/- 1.7), and of arousal (median [25th, 75th], 2.5 [1.3, 4.0] vs 5.0 [4.0, 7.0]). CONCLUSIONS: The cause of oxygen desaturation in preterm infants who are restrained in car seats is multifactorial. The present data strongly support the hypothesis that flexion of the head on the body is a significant contributor to these episodes and that the mechanism is posterocephalic displacement of the mandible, leading to narrowing of the upper airway. Critically, this pilot study demonstrates that the frequency of episodes of desaturation in a standard newborn car seat can be substantially reduced by placement of a simple foam insert that allows the infant to maintain the head in a neutral position on the trunk during sleep.

The risk of Sudden Infant Death Syndrome (SIDS) has fallen dramatically in the "Back to Sleep" era; however, half the cases now occur when the infant has been sleeping in bed with another person. Despite the association of SIDS with co-sleeping, parents are receiving mixed messages. It is often presumed that co-sleeping deaths are due to 'overlaying', when the adult rolls on top of the baby, stopping baby from breathing. We examine research that shows that it is not necessary to cover the face, or squash the body of a baby to restrict or prevent breathing and cause oxygen deprivation. At birth, the temporo-mandibular joint is not yet fully formed, and thus the jaw can be easily displaced upwards and backwards pushing the tongue into the upper airway to form a partial or complete block of the airway. Indeed, this can happen with firm flexion of the infant's head so that the chin pushes against its own chest. Further research is needed, but on present evidence, all parents should be advised to sleep their baby in a cot or similar next to their parent's bed, until baby is at least 6 months of age.

In an infant with micrognathia, who was being evaluated after an apparent life-threatening event, respiration timed lateral radiographs showed an increase in the width of the middle airway space during inspiration from 2 mm without the pacifier to 9 mm while sucking on a pacifier. This observation is consistent with the hypothesis that the well-documented association between the pacifier use and reduced risk of sudden infant death syndrome may be at least in part related to changes in airway size.

There is now compelling clinical evidence that prolonged, moderate cerebral hypothermia initiated within a few hours after severe hypoxia-ischemia and continued until resolution of the acute phase of delayed cell death can reduce subsequent neuronal loss and improve behavioral recovery in term infants and adults after cardiac arrest. Perhaps surprisingly, the specific mechanisms of hypothermic neuroprotection remain unclear, at least in part because hypothermia suppresses a broad range of potential injurious factors. In the present review we critically examine proposed mechanisms in relation to the known window of opportunity for effective protection with hypothermia. Better knowledge of the mechanisms of hypothermia is critical to help guide the rational development of future combination treatments to augment neuroprotection with hypothermia, and to identify those most likely to benefit from it.

Fetal exposure to inflammatory mediators is associated with a greater risk of brain injury, and may cause endothelial dysfunction, however, nearly all the evidence is derived from gram-negative bacteria. Intrapleural injections of OK-432, a killed Su-strain of Streptococcus pyogenes, has been used to treat fetal chylothorax. In this study, we evaluated the neural and cardiovascular effects of OK-432 in preterm fetal sheep (104+/-1 days, term 147 days). OK-432 (0.1mg, n=6) or saline vehicle (n=7) was infused into the fetal pleura and fetuses monitored for 7 days. Blood samples were taken routinely for plasma nitrite measurement. Fetal brains were taken for histological assessment at the end of the experiment. Between 3-7 hours post-injection OK-432 administration was associated with transient suppression of fetal body and breathing movements and EEG activity (P<0.05), increased carotid and femoral vascular resistance (P<0.05), but no change in blood pressure. Brain activity and behavior then returned to normal except in one fetus that developed seizures. OK-432 fetuses showed progressive, sustained vasodilatation (P<0.05), with lower blood pressure after 4 days (P<0.05), but normal heart rate. There were no changes in plasma nitrite levels. Histological studies showed bilateral infarction in the dorsal limb of the hippocampus of the fetus that developed seizures, but no injury in other fetuses. We conclude that a single low dose injection of OK-432 can be associated with risk of focal cerebral injury in the preterm fetus, and chronic central and peripheral vasodilatation which does not appear to be mediated by nitric oxide.

Arousal from sleep in healthy adults is associated with a large, transient increase in heart rate (HR). Individuals with Down Syndrome (DS) have attenuated cardiovascular responses to autonomic tests during wakefulness. We tested the hypothesis that the HR response to arousal from sleep is reduced in children with DS compared with healthy children. Twenty children aged 3-17y referred for investigation of sleep disordered breathing (10 DS; 10 obstructive sleep apnea (OSA) controls) matched for age and obstructive apnea/hypopnea index (OAHI) underwent routine overnight polysomnography. In addition 10 non-snoring controls from the general community were studied. Beat-by-beat HR was analysed from 15s pre to 15s post spontaneous arousals and compared between groups using 2-way ANOVA with repeated measures. Data are presented as mean +/- SEM. For both NREM and REM, arousals were associated with a significant increase in HR in all groups (Peak response NREM: DS 118+/-1 % at 3s, OSA controls 124+/-2 % at 4s, Healthy controls 125+/-3 % at 4s. Peak response REM: DS 116+/-2 % at 4s, OSA controls 123+/-3 % at 4s, Healthy controls 125+/-4 at 4s, p<0.001 for all). Posthoc analysis revealed that HR in the DS group was significantly lower than the both control groups at 1-4 s in NREM, and at 4-5 s in REM (p<0.05 for all). In conclusion, the HR response to spontaneous arousal from sleep is reduced in children with DS compared with healthy children. This attenuated cardiovascular response could be due to reduced sympathetic activation or blunted vagal withdrawal and may have implications for the child with DS and OSA.

OBJECTIVE: To determine whether moderate hypothermia after hypoxic-ischaemic encephalopathy in neonates improves survival and neurological outcome at 18 months of age. DESIGN: A meta-analysis was performed using a fixed effect model. Risk ratios, risk difference, and number needed to treat, plus 95% confidence intervals, were measured. DATA SOURCES: Studies were identified from the Cochrane central register of controlled trials, the Oxford database of perinatal trials, PubMed, previous reviews, and abstracts. Review methods Reports that compared whole body cooling or selective head cooling with normal care in neonates with hypoxic-ischaemic encephalopathy and that included data on death or disability and on specific neurological outcomes of interest to patients and clinicians were selected. Results We found three trials, encompassing 767 infants, that included information on death and major neurodevelopmental disability after at least 18 months' follow-up. We also identified seven other trials with mortality information but no appropriate neurodevelopmental data. Therapeutic hypothermia significantly reduced the combined rate of death and severe disability in the three trials with 18 month outcomes (risk ratio 0.81, 95% confidence interval 0.71 to 0.93, P=0.002; risk difference -0.11, 95% CI -0.18 to -0.04), with a number needed to treat of nine (95% CI 5 to 25). Hypothermia increased survival with normal neurological function (risk ratio 1.53, 95% CI 1.22 to 1.93, P<0.001; risk difference 0.12, 95% CI 0.06 to 0.18), with a number needed to treat of eight (95% CI 5 to 17), and in survivors reduced the rates of severe disability (P=0.006), cerebral palsy (P=0.004), and mental and the psychomotor developmental index of less than 70 (P=0.01 and P=0.02, respectively). No significant interaction between severity of encephalopathy and treatment effect was detected. Mortality was significantly reduced when we assessed all 10 trials (1320 infants; relative risk 0.78, 95% CI 0.66 to 0.93, P=0.005; risk difference -0.07, 95% CI -0.12 to -0.02), with a number needed to treat of 14 (95% CI 8 to 47). CONCLUSIONS: In infants with hypoxic-ischaemic encephalopathy, moderate hypothermia is associated with a consistent reduction in death and neurological impairment at 18 months.

Activation of the hypothalamic-pituitary-adrenal (HPA) axis is a critical response to perinatal hypoxia. Recent data show that adenosine appears to inhibit baseline levels of fetal cortisol and to restrict the increase in ACTH and cortisol during moderate hypoxia. Since adenosine increases substantially during profound asphyxia, it is possible, but untested, that counter-intuitively it might restrict the HPA response to more severe insults. It is unclear which receptors mediate the effects of adenosine on the HPA axis; however, adenosine A1 receptor activation is important for adaptation to hypoxia. We therefore investigated whether adenosine A1 receptor blockade modulates ACTH and cortisol levels in fetal sheep at 118 to 126 days gestation, randomly allocated to receive an i.v. infusion of either vehicle (vehicle-occlusion, n=7), or 8-Cyclopentyl-1,3-dipropylxanthine (DPCPX, an A1 receptor antagonist, DPCPX-occlusion, n=7), infused 60 min before and during 10 min of umbilical cord occlusion, or infusion of DPCPX for 70 min without occlusion (DPCPX-sham, n=6). Experiments were terminated after 72-h. Fetal ACTH levels increased significantly (p<0.01) during occlusion, but not sham occlusion, and returned to baseline values by 60 min after occlusion. In the vehicle-occlusion group, fetal cortisol and cortisone plasma levels increased significantly (p<0.05) 60 min after the occlusion, and returned to baseline values by 24 h. In contrast, there was a marked increase in both fetal cortisol and cortisone during DPCPX infusion before occlusion, to a level greater even than the maximum rise seen after occlusion alone. This increase was sustained after occlusion, with increased cortisol levels compared to occlusion alone up to 72 h. In conclusion, fetal cortisol concentrations are suppressed by adenosine A1 receptor activity, largely though a direct adrenal mechanism. This suppression can be partially overcome by supraphysiological stimuli such as asphyxia. Key words: cortisol, ACTH, Fetal sheep, adenosine.

BACKGROUND: Grasping at birth is well-known as a reflex in response to a stimulation of the palm of the hand. Recent studies revealed that this grasping was not only a pure reflex because human newborns are able to detect and to remember differences in shape features. The manual perception of shapes has not been investigated in preterm human infants. The aim of the present study was to investigate manual perception by preterm infants. METHODOLOGY/PRINCIPAL FINDINGS: We used a habituation/reaction to novelty procedure in twenty-four human preterm infants from 33 to 34+6 post-conceptional age. After habituation to an object (prism or cylinder) in one hand (left or right) in a habituation phase, babies were given either the same object or the other (novel) object in the same hand in a test phase. We observed that after successive presentations of the same object, a decrease of the holding time is observed for each preterm infant. Moreover, a significant increase of the holding time is obtained with the presentation of the novel object. Finally, the comparison between the current performance of preterm infants and those of full-term newborns showed that preterm babies only had a faster tactile habituation to a shape. CONCLUSION/SIGNIFICANCE: For the first time, the results reveal that preterm infants from 33 to 34+6 GW can detect the specific features that differentiate prism and cylinder shapes by touch, and remember them. The results suggest that there is no qualitative, but only quantitative, difference between the perceptual abilities of preterm babies and those of full-term babies in perceiving shape manually.

Objective: The purpose of this work was to compare the incidence of apnea, hypopnea, bradycardia, or oxygen desaturation in healthy term newborns placed in hospital cribs, infant car safety beds, or infant car safety seats. Methods: A consecutive series of 200 newborns was recruited on the second day of life. Each subject was studied while placed in the hospital crib (30 minutes), car bed (60 minutes), and car seat (60 minutes). Physiologic data, including oxygen saturation, frequency, and type of apnea, hypopnea, and bradycardia were obtained and analyzed in a blinded manner. Results: The mean oxygen saturation level was significantly different among all of the positions (97.9% for the hospital crib, 96.3% for the car bed, and 95.7% for the car seat; P <.001). The mean minimal oxygen saturation level was lower while in both safety devices (83.7% for the car bed and 83.6% for the car seat) compared with in the hospital crib (87.4%)(P <.001). The mean total time spent with an oxygen saturation level of <95% was significantly higher (P =.003) in both safety devices (car seat: 23.9%; car bed: 17.2%) when compared with the hospital crib (6.5%). A second study of 50 subjects in which each infant was placed in each position for 120 minutes yielded similar results. Conclusions: In healthy term newborns, significant desaturations were observed in both car beds and car seats as compared with hospital cribs. This study was limited by lack of documentation of sleep stage. Therefore, these safety devices should only be used for protection during travel and not as replacements for cribs.

Background: Prenatal exposure to tobacco can have significant effects on infants. The objective was to investigate whether maternal smoking affects the size of the thymus.<br /> Material/Methods: A group of 50 pregnant women who smoked throughout pregnancy and a control group of 92 non-smoking pregnant women were studied. The full-term newborn babies' length, weight, and head circumference were measured. The size of the thymus was assessed by sonography during the first six hours of life in both the study group and the control group newborns.<br /> Results: The results of the anthropometric measurements in respect of length (50.36+/-2.27, 50.15+/-1.40 cm, p=0.51), weight (3.43+/-5.13, 3.57+/-4.38 kg, p=0.07), head circumference (34.47+/-1.22, 34.57+/-0.93 cm, p=0.62), and head circumference/weight ratio ((9.94+/-1.40, 9.79+/-1.16 cm/kg, p=0.50) were not significantly different between the patient and control groups, respectively. The thymic index (Ti) and thymic index/weight ratio (Ti/w) of the newborns of the smoking group were lower than in the controls (8.70+/-5.80 vs. 13.26+/-5.46, p<0.001 and 2.47+/-1.55 vs. 3.69+/-1.43, p<0.001, respectively). Moreover, the birth weight, head circumference/weight ratio, Ti, and Ti/w of the newborns of those smoking more than 10 cigarettes per day were significantly lower than those smoking less than 10 (3.08+/-0.55 vs. 3.58+/-0.45, p<0.001; 10.65+/-1.84 vs. 9.67+/-1.11, p=0.03; 5.95+/-4 vs. 10.25+/-6.12, p=0.01; and 1.82+/-1.08 vs. 2.84+/-1.66, p=0.02, respectively).<br /> Conclusions: These results show that smoking while pregnant has a significant effect on the general involution of the newborn and size of the thymus, which plays an important role in the immune system.<br />

OBJECTIVES: To determine the frequency and severity of clinically significant events of spitting up in normal newborns during the first 24 hours of life and to correlate the events with sleeping position. DESIGN: Prospective observational study. SETTING: Children born between August 2003 and October 2004 in newborn nurseries at 2 hospitals. PARTICIPANTS: Healthy full-term newborns (n = 3240)(>/=37 weeks estimated gestational age) during the first 24 hours of life. OUTCOME MEASURES: Frequency of, and intervention required for, spitting up in supine, side-lying, and prone positions while asleep and awake. RESULTS: Of the 3240 infants, 96.6% did not spit up during sleep. A total of 142 episodes of spitting up were documented in 111 newborns during sleep. While the newborns were supine and asleep, there were 130 episodes of spitting up. Of these episodes, 55% did not require any intervention, 37% only required brief suctioning with a bulb syringe, 6% required gentle stimulation, and 2% required wall suction. Both nurseries had a policy that newborns should sleep supine; therefore, only 6 newborns were noted to have spitting up episodes while lying on the side, with 66.7% requiring no intervention and 33.3% requiring bulb syringe. No episodes of apnea, cyanosis, documented aspirations, neonatal intensive care unit admissions, or deaths from spitting up were noted. CONCLUSIONS: We conclude that clinically significant spitting up occurs infrequently in hospital newborn nurseries while the newborns are asleep. Fewer than 4% of newborns spit up while sleeping in the supine position in the first 24 hours of life, and none required significant intervention or experienced serious sequelae.

STUDY OBJECTIVE:s: Polysomnography is important in the evaluation of children and adolescents with sleep-disordered breathing. Adult criteria for obstructive sleep apnea have been shown to be inapplicable to children. Nevertheless, very little data are available regarding normal respiratory parameters during sleep in healthy children and adolescents. The purpose of the study was to characterize normal polysomnography values in healthy children and adolescents and to establish respiratory reference values for pediatric polysomnography. Design, setting and participants: Seventy healthy, normal children and adolescents were studied. Age ranged from 1 to 15 years (mean +/- SD, 8.02 +/- 4.57 years). All children underwent overnight polysomnography including EEG, electromyography, electrooculography, ECG, pulse oximetry arterial oxygen saturation (SpO(2)), chest wall and abdomen motion, oral and nasal airflow, and end-tidal PCO(2)(PETCO(2)). RESULTS: Three children (4%) had a mean of 0.37 obstructive apneas (OAs) per hour of sleep (1 to 5 OAs per child per study), with mean apnea duration of 10.3 +/- 2.1 s. This was not accompanied with oxygen desaturation. Twenty-six children had one to seven central apneas (CAs) per child, resulting in a mean of 0.4 CAs per hour of sleep (median, 0.33; 97.5 percentile, 0.9). Eleven of the 58 events of CA in six children coincided with oxygen desaturation to a minimum of 88%(nadir apnea desaturation range, 88 to 93%). The mean SpO(2) was 97.2 +/- 0.8% with SpO(2) nadir of 94.6 +/- 2.2%. PETCO(2)> 45 mm Hg occurred for 1.6 +/- 3.8% of total sleep time (TST) in 21 of 70 children (30%), with a distribution of 1.3 +/- 3.03% in the range of 46 to 47 mm Hg;< 0.7% were within the range of 48 to 50 mm Hg; and in 0.29 +/- 0.24% of TST, PETCO(2) values were > 50 mm Hg. CONCLUSIONS: Based on these data, the recommended limits for normal values are as follows: OA index, 1; CA index, 0.9; oxygen desaturation, 89%; baseline saturation, 92%; and PETCO(2)> 45 mm Hg for < 10% of TST.

OBJECTIVES: To test prospectively the hypothesis that an infant car seat modification to allow the infant's head to rest in a neutral position on the trunk would prevent narrowing of the upper airway and thus reduce oxygen desaturation in preterm infants who are restrained in car seats. METHODS: Seventeen preterm infants who were approved for discharge were evaluated in a car seat for newborns, with and without a foam insert that provided a slot for the back of the infants' head. Respiration timed inspiratory radiographs for assessment of upper airway dimensions were taken during quiet sleep in each position. Infants were monitored in each position for 30 minutes with continuous polygraphic recording of respiratory, cardiac, and nasal airflow activity and pulse oximetry. RESULTS: Placement of the insert in the car seat was associated with a larger upper airway space (mean +/- standard deviation, 5.2 +/- 1.3 vs 3.6 +/- 1.4 mm). This radiologic improvement was associated with a significant reduction in the frequency of episodes of oxygen desaturation to <85%(1.5 +/- 2.1 vs 3.5 +/- 3.5 episodes/infant), of bradycardia <90 bpm (0.1 +/- 0.3 vs 1 +/- 1.7), and of arousal (median [25th, 75th], 2.5 [1.3, 4.0] vs 5.0 [4.0, 7.0]). CONCLUSIONS: The cause of oxygen desaturation in preterm infants who are restrained in car seats is multifactorial. The present data strongly support the hypothesis that flexion of the head on the body is a significant contributor to these episodes and that the mechanism is posterocephalic displacement of the mandible, leading to narrowing of the upper airway. Critically, this pilot study demonstrates that the frequency of episodes of desaturation in a standard newborn car seat can be substantially reduced by placement of a simple foam insert that allows the infant to maintain the head in a neutral position on the trunk during sleep.

OBJECTIVE: Recently it has been shown that the adult sleep EEG is mostly determined by high-dimensional, linear dynamics with the exception of the A phase of the cyclic alternating pattern which displays more synchronized nonlinear dynamics. It is not known how these two different types of brain dynamics develop in early life; for this reason the aim of this study was that to extend the nonlinear analysis to the EEG during sleep recorded in premature and full-term newborns. METHODS: EEG epochs were chosen from a total of 24 polygraphic recordings from 14 babies (9 males and 5 females) aged between 33 weeks 3 days and 4 months conceptional age. All subjects were neurologically normal and showed normal psychomotor development at follow-up. A total of 243 artifact-free epochs was chosen during active sleep (AS, 74 total epochs), quiet sleep (QS, 76 total epochs) and indeterminate sleep (IS, 93 total epochs). The dynamic properties of the EEG were assessed by means of the nonlinear cross prediction test which uses 3 different 'model' time series in order to predict nonlinearly the original data set (Pred, Ama, and Tir). Pred is a measure of the predictability of the time series, and Ama and Tir are measures of asymmetry, indicating nonlinear structure. RESULTS: Our results show that the structure of sleep EEG in newborns is significantly different from that of adults, it cannot be distinguished from that of high-dimensional noise in the majority of epochs, and shows a tendency to become nonlinear in nature, mostly during QS, in a small percentage of the epochs analyzed. CONCLUSIONS: These findings can be interpreted as the effect of immature synaptic interconnections between neurons in the newborn brain.

Swallowing is a powerful inhibitor of respiratory rhythm in infants. The present study was aimed at investigating the influence of states of alertness on non-nutritive swallowing (NNS) frequency, on NNS and respiration coordination, and on bursts of NNS frequency in newborn lambs. Six full term newborn lambs were instrumented for electroencephalogram, eye movement, diaphragm and thyroarytenoid muscle electromyogram, nasal flow and electrocardiogram. Polysomnographic recordings were performed in non-sedated lambs, using radiotelemetry. NNS frequency was significantly higher during quiet wakefulness (W) and active sleep (AS) than during quiet sleep (QS). NNS mainly interrupted inspiration and the transition phases between expiration and inspiration, especially in W and AS. Bursts of NNS occurred significantly more often during AS. This study highlights the relevance of the ovine model to study ontogeny of NNS during sleep, and documents the influence of sleep on NNS and respiration coordination.

We prospectively tested the hypothesis that prevention of lateral movement of the head, using a specially designed head support apparatus, would prevent oxygen desaturation in preterm infants restrained in car seats. Preterm infants reaching 34 to 35 weeks' gestation were studied at the week of discharge in 3 different conditions for 20 minutes each time: supine decubitus, sitting position in a newborn car seat, and sitting position in the car seat equipped with an apparatus that supports the head, while monitored by pulse oxymetry. Data are expressed as percent of time over each period during which the oxygen saturation was below 90, 92, 94, or 96%. Statistical analysis was by analysis of variance (ANOVA) followed by paired Student t-test for differences of means. There were no significant differences among groups in percent of time with oxygen saturation below 96, 94, 92, or 90%. Oxygenation is not improved in relatively healthy preterm infants placed in a car seat when their head is supported to prevent lateral movements by a special apparatus.

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.