Sleep position, autonomic function, and arousal

AIMS: To investigate and compare heart rate variability (HRV) and responses of heart rate and arousal to head-up tilting in infants sleeping prone and supine. METHODS: Thirty seven healthy infants aged 2-4 months were studied. HRV was measured for 500 beats while they were in a horizontal position. Subjects were then tilted 60 degrees head-up, and heart rate recorded over 1 minute and arousal responses observed. Data were collected during both quiet and active sleep for both prone and supine sleep positions. RESULTS: HRV, as assessed by the point dispersion of Poincaré plots, was significantly reduced in the prone position for both sleep states. Sleep position did not influence the changes in heart rate seen during a head-up tilt. Full awakening to the tilt was common in active sleep but significantly less so in the prone position (15% of prone tests vs 54% supine). Full awakening to the tilt rarely occurred during quiet sleep in either sleep position. CONCLUSION: This study provides some evidence that blunted arousal responses and/or altered autonomic function are a feature of the prone sleeping position. Decreased HRV may be a sign of autonomic impairment. It is seen in many disease states and in infants who later die of sudden infant death syndrome (SIDS).     

Sperm cytology in azoospermia

BACKGROUND: To progress the clinical treatment of neonates, especially in the management of respiration, we have to be able to measure their pulmonary function appropriately. Various methods have been developed, but little is known about the pulmonary function of very low birthweight infants (VLBWI) because of the difficulty in taking their measurements with existing equipment. We have developed a very low dead space pneumotachograph to measure lung function in VLBWI. METHODS AND RESULTS: We used our pneumotachograph on 30 infants each weighing less than 1500 g at birth. The infants were intubated with endotracheal tubes of 2.5 or 2.0 mm diameter to measure tidal volume and minute ventilation in the prone and supine position. The tidal volume in the supine position was 6.99 +/- 0.42 mL/kg and 7.58 +/- 0.38 mL/kg in the prone position (mean +/- SE). The tidal volume was significantly larger in the prone than the supine position (P < 0.05). However, no significant difference was observed in minute ventilation and respiratory rates. CONCLUSION: The tidal volume significantly increased in the prone position in VBLWI, confirming the previous observation of larger healthy infants is also applicable to the very low birthweight infants.     

Systems in development: Motor skill acquisition facilitates three-dimensional object completion.

How do infants learn to perceive the backs of objects that they see only from a limited viewpoint? Infants’ 3-dimensional object completion abilities emerge in conjunction with developing motor skills—independent sitting and visual–manual exploration. Infants at 4.5 to 7.5 months of age (n = 28) were habituated to a limited-view object and tested with volumetrically complete and incomplete (hollow) versions of the same object. Parents reported infants’ sitting experience, and infants’ visual–manual exploration of objects was observed in a structured play session. Infants’ self-sitting experience and visual–manual exploratory skills predicted looking at the novel, incomplete object on the habituation task. Further analyses revealed that self-sitting facilitated infants’ visual inspection of objects while they manipulated them. The results are framed within a developmental systems approach, wherein infants’ sitting skill, multimodal object exploration, and object knowledge are linked in developmental time. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of prostaglandin F2 alpha (PGF2 alpha) on oviductal nitric oxide synthase (NOS) activity: possible role of endogenous NO on PGF2 alpha-induced contractions in rat oviduct

The objective was to analyse differences in the epidemiological pattern of sudden death in infancy during two time periods--the Sudden Infant Death Syndrome (SIDS) 'epidemic': 1984-1989, and the period of rapid decline in the SIDS rate 1990-1996. Sex distribution, age, sleeping position, signs of infection, day of the week and place of death were registered and compared for the two time periods studied in all SIDS cases autopsied at the Institute of Forensic Medicine, Oslo. There were significantly more deaths in the age group under four months in the period 1984-89 than in the second period. Prone sleeping position, signs of infection, death outdoors and during the winter were more frequent during the first period than in the second. These features also were more frequent in the age group under four months than in the older babies during the first period. The shift in the epidemiological pattern after 1990, when the risk factor campaign was launched, indicates that prone sleeping position, cold climate, sleeping outdoors and infections seem to be risk factors that are particularly harmful to the youngest infants.     

Arterial to end-tidal carbon dioxide gradient and physiological dead space monitoring during general anaesthesia: effects of patients' position

METHODS: One hundred and five ASA I-II patients, scheduled for elective surgical procedures were studied in order to evaluate the effect of different surgical postures on physiological pulmonary dead space (VDphys/ VT) and arterial to end-tidal carbon dioxide gradient [P(a-Et)CO2]. Patients were divided into four groups according to their position on the operating table: supine position (acting as control group, n = 33), 20 degree Trendelenburg position (n = 24), lateral position (n = 24) and prone position with convex saddle frame (n = 24). Physiologic dead space was measured using Enghoff modification of Bohr equation. Arterial CO2 partial pressure was measured by blood gas analysis and end tidal CO2 was measured by means of an infrared CO2 analyser. All measurements were performed 20 minutes after general anaesthesia induction, with patients mechanically ventilated by a constant inspiratory flow (TV = 8 ml kg-1, RR = 10-14, EIP = 10%) in order to reach a steady state end tidal CO2 ranging between 32 and 36 mmHg; afterwards surgery started. RESULTS: Arterial blood pressure showed a mean decrease of about 5-10% compared to baseline values, but no significant differences in arterial pressure decrease were found between the four groups. A significant VDphys/VT increase in postures other than supine was observed, unless it was statistically significant in lateral and prone position only; while P(a-Et)CO2 was higher in all postures compared to supine. Changes of intrapulmonary gas and blood distribution due to patients' posture are probably responsible for the observed physiologic dead space and CO2 gradient differences. CONCLUSIONS: In conclusion, the clinical practice of predicting PaCO2 from EtCO2 must be tempered by recognition of the potential magnitude of P(a-Et)CO2 gradient, which is higher than normal during general anaesthesia and further increased when positioning the patient other than supine.     

Comparison of two outcome measures for infants with cerebral palsy and infants with motor delays

BACKGROUND AND PURPOSE: The purpose of this study was to compare the Gross Motor Function Measure (GMFM) and the Peabody Developmental Gross Motor Scale (PDMS-GM) as measures of change in infants with cerebr-al palsy (CP) and infants with motor delays. We hypothesized that mean change scores would be greater for the GMFM than for the PDMS-GM. SUBJECTS AND METHODS: Subjects were 42 infants with a mean adjusted age of 13.9 months (SD=6.1, range=4.2-24.2). Twenty-four infants had CP, and 18 infants had motor delays. The GMFM and the PDMS-GM were administered to the infants 3 times over a 6-month period. Raw scores were standardized for data analysis. Data were analyzed using a 3-factor repeated-measures analysis of variance. RESULTS: For the 6-month period, mean PDMS-GM age-equivalent scores increased 3.8 months and mean scaled scores increased 35 points for infants with motor delays compared with increased scores of 1.8 months and 13 points for infants with CP. Mean GMFM scores increased by 12.2% for infants with rmotor delays and by 4.2% for infants with CP. The diagnosis X time interaction was significant. Infants with motor delays had a greater change in motor development compared with the infants with CP. The hypothesis that the GMFM is more responsive to change than the PDMS-GM was not supported. CONCLUSION AND DISCUSSION: The findings suggest that the GMFM and the PDMS-GM are comparable in measuring change in infants with CP or motor delays. Implications for selection and use of either measure are discussed.     

Influence of flupirtine on a G-protein coupled inwardly rectifying potassium current in hippocampal neurones

Zinc deficiency has been associated with growth deficits, reduced dietary intake and appetite, and has been hypothesized to result in reduced activity. This randomized, double-blind, placebo-controlled study examined whether 10 mg of oral zinc as zinc sulfate, given daily for up to 7 mo, affected activity patterns of 85 Guatemalan infants recruited at 6-9 mo of age. Infant activity was assessed by time sampling-observation method at 10-min intervals during a 12-h data collection period, at base line, 3 and 7 mo follow-up. Motor development and the percentage of time infants were observed in various positions (being carried, lying down, sitting, crawling, standing or walking) and engaged in various activities (eating, sleeping, resting, crying/whining or playing) were compared by treatment group. No differences in motor development were observed by treatment group. However, at follow-up 2 (after 7 mo of supplementation), zinc-supplemented infants were significantly more frequently observed sitting up compared with lying down, and were playing during 4.18 +/- 1.95% (P < 0.05) more observations than unsupplemented infants. They were also somewhat less likely to be observed crying or whining (P < 0.10) compared with those receiving the placebo. These effects are independent of other factors including infant age, motor development, sex, maternal education, family socioeconomic status and nutritional status at base line. Further research must be conducted to determine the long-term developmental importance of these differences in activity patterns associated with zinc supplementation in this setting.     

Improved oxygenation utilizing a prone positioner in patients with acute respiratory distress syndrome

OBJECTIVES: (a) To determine whether placing patients with acute respiratory distress syndrome in the prone position by a light-weight portable support frame improves oxygenation, (b) whether one can determine which patients benefit from prone positioning, and (c) to determine an effective technique for prone positioning of patients. DESIGN: Prospective, controlled trial without blinding. SETTING: Medical intensive care units in two urban university-affiliated hospitals. PATIENTS: Fifteen patients meeting a standard definition for acute respiratory distress syndrome were studied prospectively. Each patient acted as his own control for purposes of comparison. INTERVENTION: Patients were assigned randomly to begin in either supine or prone positions. The positioning frame was used to turn patients from one position to the other, and oxygenation, ventilation, respiratory mechanics, and hemodynamics were measured. RESULTS: Significantly better oxygenation was seen in the prone positions than in the supine (P < 0.05). In the overall population there was a decrease in AaDO2 of 21 mmHg when the patients were placed prone. The groups were then divided into responders (n = 9) and nonresponders (n = 6). There were significant differences between the groups (but not between positions) regarding PaO2, baseline, PaCO2, pulmonary artery pressures, and peak inspiratory pressures on the ventilator and in ICU length of stay and time on mechanical ventilatory support. CONCLUSION: Prone positioning improves oxygenation in the majority of patients studied and can be achieved relatively easily.     

Knee-chest vs horizontal side position during induction of spinal anaesthesia in patients undergoing lumbar disc surgery

In the prone knee-chest position the spread of plain 0.5% bupivacaine in the cerebrospinal fluid and associated haemodynamic changes may be different compared with the horizontal position. A randomized comparison was performed in 40 ASA I-II patients, aged 24-61 yr, undergoing lumbar disc surgery. Subarachnoid injection (27-gauge needle) at the L2-3 interspace with 3 ml of 0.5% bupivacaine was performed with the patient in the operative knee-chest position (prone knee-chest group, n = 20) or in the horizontal side position (supine side horizontal group, n = 20). Patients in the supine side horizontal group were turned into the horizontal supine position for 20 min, and subsequently they were placed in the operative knee-chest position. In three patients in the prone knee-chest group, the spinal needle was replaced by a larger needle (25-gauge). The final cephalad extension of sensory analgesia on skin tested by pinprick was T5 (median) in the prone knee-chest group and T6 in the supine side horizontal group. Recovery was also similar, on average 210 min from injection in both groups. The mean decrease in systolic arterial pressure was somewhat greater in the prone knee-chest group (30 mm Hg) than in the supine side horizontal group (13 mm Hg). The need for ephedrine occurred earlier in the supine side horizontal group (three patients, all within 10 min from local anaesthetic injection) than in the prone knee-chest group (six patients, all after 15 min). Four of the latter patients also required administration of an anticholinergic for bradycardia compared with two patients in the supine side horizontal group. Light sedation was given to five patients in the prone knee-chest group and to four in the supine side horizontal group because of numbness and aching in the shoulders. We conclude that spinal block was similar in the two groups but there was a tendency to more frequent episodes of haemodynamic deterioration in the knee-chest position.     

Anthropometric indicators of human immunodeficiency virus infection in infants with early and late symptoms in the first months of life

Standardised growth indices (Z-scores of weight-for-age, WA, length-for-age, LA, weight-for-length, WL, according to the reference data of the World Health Organization) have been compared for the first 4 months of life among 119 infants born to mothers affected by the type-1 human immunodeficiency virus (HIV). Infants were subdivided according to their HIV serostatus and the clinical expression of the disease. Uninfected status (n = 92), late (>6 months, n = 18) and early (<3 months, n = 9) onset of symptoms among the HIV infected defined three groups. Infants with early symptoms showed the lowest median WA and LA Z-scores at all times and the LA difference with their uninfected counterparts was already significant at birth. Infants with late symptoms showed early differences in WL and then in WA also compared with the uninfected ones. A < -0.40 LA Z-score at birth gave a 5.9 relative risk (RR) to be an infant with early symptoms (95% CI = 1.2-27.4) while a negative WL Z-score at 2 months of age gave a 4.2 RR for the HIV seropositivity (95% CI = 2.1-8.3). CONCLUSION: Linear growth is the first parameter to be negatively affected among human immunodeficiency virus seropositive infants with early symptoms. In infants with late symptoms the lack of rapid WA and WL increase found among uninfected patients may be viewed as an early anthropometric indicator of HIV status.     

Sleeping position, orientation, and proximity in bedsharing infants and mothers

The impact of mother-infant bedsharing on infant sleeping position, orientation, and proximity to the mother was assessed in 12 breast-feeding Latino mother-infant pairs. Six routinely bedsharing and six routinely solitary-sleeping pairs slept 3 nights in the sleep laboratory. The first night matched the routine home condition, followed by 1 bedsharing night and 1 solitary-sleeping night in random order. During bedsharing infants were never placed prone, regardless of their routine sleeping condition. On the bedsharing night, mothers and infants spent most of the night oriented toward each other; seven of 12 infants remained oriented toward their mothers the entire night. While sleeping in a face-to-face orientation, most pairs slept most of the time less than 30 cm apart with appreciable amounts of time at less than 20 cm. This orientation and proximity should facilitate sensory exchanges between mother and infant which, we hypothesize, influence the infant's sleep physiology and nocturnal behavior. We conclude that bedsharing minimizes the use of the prone infant sleeping position, probably in part to facilitate breast feeding. By promoting nonprone positions, bedsharing may protect some infants from sudden infant death syndrome (SIDS), since prone sleeping is a known risk factor for SIDS. The large percentage of the night that mothers spent oriented toward their infants suggests that a higher degree of maternal vigilance may also result from bedsharing.     

Economic analyses in clinical trials for cooperative groups: operational considerations

The objective of this prospective, cohort study was to compare the nutritional status of full-term infants who were fed human milk (BF, n = 29), formula (FF, n = 30) or evaporated milk formulae (EM, n = 30) for at least 3 months. Infants were seen at enrollment, 3 and 6 months, at which times a blood sample, diet record and anthropometric data were collected. Infants in the EM group received solids earlier (12 +/- 5 weeks) than did FF infants (15 +/- 4 weeks), and both were earlier than BF infants (19 +/- 4 weeks). Only 26% of the EM fed group received iron supplements as ferrous sulphate drops. Seven BF, 12 FF and 20 EM had abnormal ferritin values (< 10 ng ml-1) at 6 months. Copper intake was lower in the EM infants at 3 and 6 months. However, plasma copper and erythrocyte copper zinc superoxide dismutase (ZnCuSOD) levels did not differ between groups. Selenium intake was lower in the EM group (5 +/- 1 and 10 +/- 5 micrograms d-1; 3 and 6 months) than in the FF infants (13 +/- 4 and 19 +/- 7 micrograms d-1; 3 and 6 months). Erythrocyte SeGHSPx levels in EM infants were lower at 6 months (EM, 33.2 +/- 3.4; FF. 35.2 +/- 3.9: BF, 36.1 +/- 3.8 mU mg Hb-1). Thiamin intake (0.99 +/- 0.08 and 1.24 +/- 0.32; 3 and 6 months, mg 1000 kcal-1) was higher in the FF group than in EM infants (0.38 +/- 0.39 and 0.66 +/- 0.38; 3 and 6 months). There were more (13%) abnormal thiamin assays in the EM group at 6 months than in the BF and FF infants (0%). In conclusion, infants fed evaporated milk formula receive adequate copper but may not receive enough thiamin or selenium. Unless supplemented from birth with medicinal iron, intakes of iron will be inadequate.     

Effect of long-chain polyunsaturated fatty acids in infant formula on problem solving at 10 months of age

BACKGROUND: Long-chain polyunsaturated fatty acids (LCPUFA) are important for normal visual and brain development. Although present in human milk, LCPUFA have until recently been absent from artificial formulas, and infants may have limited ability to synthesise LCPUFA. To determine the clinical significance of this relative deficiency of LCPUFA, we undertook a randomised trial of the relation between LCPUFA supplementation and infant cognitive behaviour. METHODS: 44 term infants had been randomised to a formula supplemented with LCPUFA (21) or not supplemented with LCPUFA (23), which they had taken from birth to age 4 months. Infant cognitive behaviour was assessed at 10 months of age by a means-end problem-solving test--the intentional execution of a sequence of steps to achieve a goal. The problem required three intermediate steps to achieve the final goal, uncovering and retrieving a hidden toy. FINDINGS: Infants who received LCPUFA-supplemented formula had significantly more intentional solutions than infants who received the no-LCPUFA formula (median 2.0 vs 0, p=0.021). Intention scores (median 14.0 vs 11.5 [maximum 18]) were also increased in this group (p=0.035). INTERPRETATION: These findings suggest that term infants may benefit from LCPUFA supplementation, and that the effects persist beyond the period of supplementation. Since higher problem-solving scores in infancy are related to higher childhood IQ scores, supplementation with LCPUFA may be important for the development of childhood intelligence.     

Behavioral reactivity and approach-withdrawal bias in infancy.

Seven hundred seventy-nine infants were screened at 4 months of age for motor and emotional reactivity. At age 9 months, infants who showed extreme patterns of motor and negative (n = 75) or motor and positive (n = 73) reactivity and an unselected control group (n = 86) were administered the Laboratory Temperament Assessment Battery, and baseline electroencephalogram data were collected. Negatively reactive infants showed significantly more avoidance than positively reactive infants and displayed a pattern of right frontal electroencephalogram asymmetry. Positively reactive infants exhibited significantly more approach behavior than controls and exhibited a pattern of left frontal asymmetry. Results support the notion that approach-withdrawal bias underlies reactivity in infancy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biological day-to-day variation and daytime changes of testosterone, follitropin, lutropin and oestradiol-17beta in healthy men

The Alberta Infant Motor Scale (AIMS) is a norm-referenced measure of infant gross motor development. The objectives of this study were: (1) to establish the best cut-off scores on the AIMS for predictive purposes, and (2) to compare the predictive abilities of the AIMS with those of the Movement Assessment of Infants (MAI) and the Peabody Developmental Gross Motor Scale (PDGMS). One hundred and sixty-four infants were assessed at 4 and 8 months adjusted ages on the three measures. A pediatrician assessed each infant's gross motor development at 18 months as normal, suspicious, or abnormal. For the AIMS, two different cut-off points were identified: the 10th centile at 4 months and the 5th centile at 8 months. The MAI provided the best specificity rates at 4 months while the AIMS was superior in specificity at 8 months. Sensitivity rates were comparable between the two tests. The PDGMS in general demonstrated poor predictive abilities.     

Oropharyngeal control of hand-mouth coordination in newborn infants.

This research identifies a coordinative structure of action that integrates hand and mouth activities within hours after birth. Infants in the supine position received 7 presentations of 12% sucrose solution. Differences in hand–mouth coordination relative to preceding and succeeding epochs of nonsucrose presentation were striking: 32% of the sucrose period was spent by infants with hands inside the mouth or in contact with it, and 18%, for the same measures during periods of nonsucrose delivery. In addition the hand was brought to the mouth 50% more often during the sucrose period. These data provide evidence for oropharyngeal control over intergration of gross motor patterns of hand movement as they relate to the mouth. A possible functional significance of these findings is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Haemophilus influenzae type b-specific antibody in infants after maternal immunization

OBJECTIVE: To study the kinetics of Haemophilus influenzae type b (Hib)-specific antibody in infants born to mothers immunized with an Hib polysaccharide or one of two Hib conjugate vaccines. STUDY DESIGN: Serum antibody to the polyribosylribitol (PRP) moiety of Hib was measured by radioimmunoassay and enzyme-linked immunosorbent assay at birth and at 2 and 6 months of age in infants born to women immunized with Hib polysaccharide or conjugate vaccine (PRP-D and HbOC). A subset of infants > or = 6 months of age was immunized with Hib conjugate vaccine after licensure of this vaccine for infants. A comparison group of 18 infants born to unimmunized women received the same Hib conjugate vaccine on a similar schedule. RESULTS: Total PRP antibody concentrations were 1.50, 14.4 and 20.4 microg/ml in 2-month-old infants born to mothers immunized with polysaccharide, PRP-D and HbOC vaccines, respectively, and 2.54, 1.35 and 2.46 microg/ml in 6-month-old infants. Infants born to mothers immunized with polysaccharide vaccine had significantly less PRP antibody at 2 months of age but similar antibody concentrations at 6 months of age. Persistence or increases in total PRP antibody during 6 months were noted in 21 of 47 (44.6%) study infants. A subset of study and comparison infants was immunized with a mean of 2.6 doses of Hib vaccines between 6 months and 2 years of age, and all infants had total PRP antibody concentrations > or = 0.15 microg/ml. CONCLUSION: Conjugate Hib vaccines administered during the last trimester of pregnancy resulted in significantly higher PRP antibody titers in infants at birth and 2 months of age than did polysaccharide vaccine. A subset of infants born to immunized mothers was subsequently immunized with Hib conjugate vaccine and had antibody concentrations similar to those in infants born to nonimmunized women.     

Feeding practices and growth among low-income Peruvian infants: a comparison of internationally-recommended definitions

BACKGROUND: Data from a longitudinal study of 153 low-income Peruvian infants were used to assess the relationship between internationally-recommended definitions of feeding practices and infants' monthly weight gain and weight status at 12 months. METHODS: Infants were classified into feeding categories using monthly reported data. Analysis of variance was used to assess the relationship between reported usual feeding practices and growth. Reported breastfeeding practices were compared to observed breastfeeding practices and to weighted breast milk intakes to determine the validity of recommended breastfeeding definitions. RESULTS: Breastfed infants who consumed non-human milks during the first month of life gained less weight during that month (P < 0.002) than exclusively and predominantly breastfed infants. Reported daily nursing frequency was associated with observed nursing frequency and breast milk energy intake (P < 0.05) for infants < 9 months old. Patterns of growth varied according to early diets. Infants who consumed breast milk and non-human milks and those who were fully weaned by 4 months were more likely to be underweight at 12 months than other infants. Infants classified as token breastfeeders ( < or = 3 times/24 hours) from 0 to 120 days had monthly gains that were similar to those of fully weaned infants. CONCLUSIONS: Infants feeding definitions should 1) continue to differentiate exclusively breastfed infants from other infants who are almost exclusively or predominantly breastfed; 2) distinguish partially breastfed infants who consume only non-breastfeeding frequency or the % of their total daily energy that comes from breast milk.     

Infant arousal in an en-face exchange with a new partner: effects of prematurity and perinatal biological risk

Very low birth weight (VLBW) infants of higher (n = 18) and lower (n = 29) perinatal biological risk were contrasted at 4 months adjusted age with healthy full-term infants (n = 32) in their arousal during a standardized peekaboo game with an examiner. VLBW infants showed less positive arousal, more negative arousal, and 3 mixtures of behavioral cues across the peekaboo game seldom seen for full-term infants-strong cues of both positive and negative arousal, strong cues of negative arousal alone, and no strong cues of either positive or negative arousal. Contrary to expectations, perinatal biological risk did not strongly predict variations in arousal within the VLBW group. Possible changes in how internal and external sources of arousal are integrated provide one explanation for the presence of strong relationships between perinatal biological risk and social responsiveness near term age and their disappearance by 4 months of age.