Caffeine decreases intermittent hypoxia in preterm infants nearing term-equivalent age.

OBJECTIVE: To determine whether intermittent hypoxia (IH) persisting after 36 weeks postmenstrual age (PMA) can be attenuated using caffeine doses sufficient to maintain caffeine concentrations >20 µg ml-1. STUDY DESIGN: Twenty-seven infants born <32 weeks were started on caffeine citrate at 10 mg kg-1 day-1 when clinical caffeine was discontinued. At 36 weeks PMA, the dose was increased to 14 or 20 mg kg-1 day-1 divided twice a day (BID) to compensate for progressively increasing caffeine metabolism. Caffeine concentrations were measured weekly. The extent of IH derived from continuous pulse oximetry was compared to data from 53 control infants. RESULT: The mean (s.d.) gestational age of enrolled infants was 27.9±2 weeks. Median caffeine levels were >20 µg ml-1 on study caffeine doses. IH was significantly attenuated through 38 weeks PMA compared with the control group. CONCLUSION: Caffeine doses of 14 to 20 mg kg-1 day-1 were sufficient to maintain caffeine concentrations >20 µg ml-1 and reduce IH in preterm infants at 36 to 38 weeks PMA.

Infant cry: a clue to diagnosis.

It has been postulated that the infant cry is a reflection of complex neurophysiologic functions and that analysis of the infant cry can be utilized to assess the infant's status. To test this hypothesis a model of cry production was developed utilizing a computer-based signal processing system that enabled the observer to relate closely the acoustic properties of the cry to the anatomic and physiologic characteristics of the infant producing the cry. The cries of 87 infants were analyzed following a standardized pain stimulus. Cry features were grouped into eight evaluative tests. Only seven of 55 apparently normal term infants had the abnormality "glottal instability" whereas 11 of 12 infants with bilirubin values in the 10 to 20 mg/100 ml range displayed the glottal instability pattern. An additional group of 17 infants with a variety of problems was studied; 14 of 17 displayed two or more abnormalities, and ten of 12 infants with respiratory disease had a unique pattern. Of particular interest was the finding of acoustical features suggestive of a constriction in the vocal tract in three infants; two of these infants were studied prospectively and subsequently were victims of sudden infant death syndrome and the third had a sibling with recurrent apnea. These results suggest that the analysis of the infant cry holds promise for detecting a number of abnormalities and may prove valuable as screening test to detect infants at risk for sudden infant death syndrome.

Parents and procedures: a randomized controlled trial.

INTRODUCTION: Previous work has shown that parents prefer to be present when their children undergo common invasive procedures, although physicians are ambivalent about parental presence. PURPOSE: To determine the effect of a parent-focused intervention on the pain and performance of the procedure, anxiety of parents and clinicians, and parental satisfaction with care. POPULATION: Children younger than 3 years old undergoing venipuncture, intravenous cannulation, or uretheral catheterization. SETTING: Pediatric emergency department of Boston City Hospital. DESIGN: Randomized controlled trial with three groups; parents present and given instructions on how to help their children; parents present, but no instructions given; and parents not present. INTERVENTION: The parents were instructed to touch, talk to, and maintain eye contact during the procedure. RESULTS: A total of 431 parents was randomized to the intervention (N = 153), present (N = 147), and not present (N = 131) groups. The groups were equivalent with respect to measured sociodemographic variables and parents' previous experience in the pediatric emergency department. No differences emerged with respect to pain (3-point scale measured by parent and clinician, and analysis of cry); performance of the procedure (number of attempts, completion of procedure by first clinician, time); clinician anxiety; or parental satisfaction with care. Parents who were present were more likely to rate the pain of the children as extreme/severe (52%) in comparison to clinicians (15%, kappa .07, poor agreement) and were significantly less anxious than parents who were not present. CONCLUSION: Overall, the intervention was not effective in reducing the pain of routine procedures. Parental presence did not negatively affect performance of the procedure or increase clinician anxiety. Parents who were present were less anxious than those who were not present. CLINICAL IMPLICATION: In general, parents have indicated that they want to be present when their children undergo procedures. The results of this study challenge the traditional belief that parental presence negatively affects our ability to successfully complete procedures. We should encourage parents who want to be present to stay during procedures.

Effects of in utero cocaine exposure on newborn acoustical cry characteristics.

As part of a large, multicenter study of newborn cry analysis and Sudden Infant Death Syndrome, we examined the effects of in utero cocaine exposure on ten acoustical cry characteristics. Newborn cry recording and medical record review was performed for 23,948 newborns. Cocaine use during pregnancy (determined by record review) was identified in 438 (1.8%) women (310 by self-report only; 128 newborns also had positive urine assay). A demographically similar group of 373 newborns, selected from the 23,510 newborns without known cocaine exposure, made up the comparison group. Cry analysis was technically possible for 768 recordings: 404 cocaine-exposed and 364 non-exposed controls. Comparison of cocaine-exposed vs control newborns, after adjustment for potential confounding variables, found significant differences including: fewer cry utterances (P = .001), more short cries (P = .02), and less crying in the hyperphonation mode (P = .01), for the cocaine-exposed neonates. As reported in other studies, cocaine-exposed newborns also were significantly lower in birth weight, length, and head circumference. Newborns who had positive urine tests for cocaine suffered the greatest effects on both cry and growth parameters. These findings suggest a pattern of underaroused neurobehavioral function and are consistent with the emerging picture of the adverse neurobehavioral effects of cocaine. Developmental outcome studies are in progress to determine if acoustical analysis of the newborn cry can be used to identify cocaine-exposed newborns who are at highest risk for poor outcome.

Newborn acoustic cry characteristics of infants subsequently dying of sudden infant death syndrome.

OBJECTIVE: To test the hypothesis that the occurrence of a neonatal cry exhibiting a high first formant is a risk factor for sudden infant death syndrome (SIDS) and to evaluate the association between SIDS and other acoustic cry variables. METHOD: We recorded cries and obtained medical and demographic data for 21,880 apparently healthy term newborns. Two cries were recorded between days 2 and 7 of life, after a painful stimulus at the time of routine blood drawing. Acoustic variables were measured with an automated computer-based analysis system. Twelve infants died of SIDS. Age at death ranged from 19 days to 6.5 months. Autopsies were performed in all cases. At least one cry was analyzed for all 12 infants who died of SIDS and 20,167 infants without SIDS. Two cries were analyzed for 9 infants who died of SIDS and 14,235 infants without SIDS. RESULTS: Newborns whose first cries exhibited a high first formant were more likely to die of SIDS than infants whose first cries did not have this characteristic (relative risk, 3.5; 95% confidence interval [CI], 1.1 to 12). The relative risk for SIDS increased to 8.8 (95% CI, 2.2 to 35) for newborns whose second cries showed that this characteristic persisted. Newborns with the combination of both a high first formant and a high number of mode changes on both of two cries had a relative risk of 32 (95% CI, 8.7 to 120). CONCLUSIONS: We have shown an association between alterations in neonatal cry acoustics and SIDS. Cry analysis represents a potentially important research tool that, when studied in relation to other physiologic measures, may lead to an improved understanding of SIDS.

The effect of epoch length and smoothing on infant sleep and waking state architecture for term infants at 42 to 46 weeks postconceptional age.

STUDY OBJECTIVES: Epoch lengths from 20 seconds to 1 minute, and smoothing strategies from zero to three minutes are encountered in the infant sleep and waking literature. The present study systematically examined the impact of various epoch lengths and smoothing strategies on infant sleep state architecture. DESIGN: Overnight polysomnographic recordings were visually assessed by epoch as wake or as each of four sleep state parameters: electroencephalographic patterns, respiration, body movement, and eye movement. From these findings, sleep and waking states were assigned for each of six combinations of epoch length (30-second or 1-minute) and smoothing window length (none, 3-epoch, or 5-epoch). SETTING: N/A. PARTICIPANTS: Subjects were 91 term infants, 42-46 weeks postconceptional age, from the Collaborative Home Infant Monitoring Evaluation (CHIME) study. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: A greater epoch length resulted in more active and less quiet sleep as a percentage of total study; however, the size of the smoothing window did not affect the percentage of sleep/waking states. In general, the greater the epoch length and the greater the smoothing window length, the fewer the number of, the greater the mean duration of, and the greater the longest continuous episode of sleep/waking states. Analysis of significant interactions indicated that a 1-minute epoch length relative to a 30-second epoch length resulted in increasingly longer episodes of quiet and especially active sleep with a greater smoothing window length. CONCLUSIONS: Smoothing strategy significantly altered sleep state architecture in infants and may explain part of the variability in infant sleep state findings between laboratories.

Infant polysomnography: reliability. Collaborative Home Infant Monitoring Evaluation (CHIME) Steering Committee.

Infant polysomnography (IPSG) is an increasingly important procedure for studying infants with sleep and breathing disorders. Since analyses of these IPSG data are subjective, an equally important issue is the reliability or strength of agreement among scorers (especially among experienced clinicians) of sleep parameters (SP) and sleep states (SS). One basic issue of this problem was examined by proposing and testing the hypothesis that infant SP and SS ratings can be reliably scored at substantial levels of agreement, that is, kappa (kappa) > or = 0.61. In light of the importance of IPSG reliability in the collaborative home infant monitoring evaluation (CHIME) study, a reliability training and evaluation process was developed and implemented. The bases for training on SP and SS scoring were CHIME criteria that were modifications and supplements to Anders, Emde, and Parmelee (10). The kappa statistic was adopted as the method for evaluating reliability between and among scorers. Scorers were three experienced investigators and four trainees. Inter- and intrarater reliabilities for SP codes and SSs were calculated for 408 randomly selected 30-second epochs of nocturnal IPSG recorded at five CHIME clinical sites from healthy full term (n = 5), preterm (n = 4), apnea of infancy (n = 2), and siblings of the sudden infant death syndrome (SIDS) (n = 4) enrolled subjects. Infant PSG data set 1 was scored by both experienced investigators and trained scorers and was used to assess initial interrater reliability. Infant PSG data set 2 was scored twice by the trained scorers and was used to reassess inter-rater reliability and to assess intrarater reliability. The kappa s for SS ranged from 0.45 to 0.58 for data set 1 and represented a moderate level of agreement. Therefore, rater disagreements were reviewed, and the scoring criteria were modified to clarify ambiguities. The kappa s and confidence intervals (CIs) computed for data set 2 yielded substantial inter-rater and intrarater agreements for the four trained scorers; for SS, the kappa = 0.68 and for SP the kappa s ranged from 0.62 to 0.76. Acceptance of the hypothesis supports the conclusion that the IPSG is a reliable source of clinical and research data when supported by significant kappa s and CIs. Reliability can be maximized with strictly detailed scoring guidelines and training.

Nutritional deficiencies and blunted erythropoietin response as causes of the anemia of critical illness.

PURPOSE: The purpose of this article was to determine the prevalence of iron, vitamin B12, and folate deficiency and to evaluate the erythropoietin (EPO) response to anemia in a cohort of long-term intensive care unit (ICU) patients. MATERIALS AND METHODS: All patients admitted to three academic medical center multidisciplinary ICUs were screened for eligibility into a randomized trial of EPO for the treatment of ICU anemia. On their second or third ICU day, patients enrolled in this trial had EPO levels drawn and were screened for iron, B12, and folate deficiency. Weekly EPO levels were obtained throughout patients' ICU stay. RESULTS: A total of 184 patients were screened for iron, B12, and folate deficiency. Sixteen patients (9%) were iron deficient by study criteria, 4 (2%) were B12 deficient, and 4 (2%) were folate deficient. Mean hemoglobin and reticulocyte percents of the remaining 160 patients were 10.3 +/- 1.2 g/dL and 1.66 +/- 1.09%, respectively. In most patients, serum iron and total iron binding capacity levels were very low, whereas ferritin levels were very high. Mean and median day 2 EPO levels were 35.2 +/- 35.6 mIU/mL and 22.7 mIU/mL, respectively (normal = 4.2-27.8). Serial EPO levels in most persistently anemic patients remained within the normal range. CONCLUSIONS: In this cohort, screening for iron, B12, and folate deficiency identified potentially correctable abnormalities in more than 13% of patients and should be considered in those who are anticipated to have long ICU stays. Even at an early point of critical illness, most patients had iron studies consistent with anemia of chronic disease (ACD), as well as a blunted EPO response that may contribute to this ACD-like anemia of critical illness.

Cardiopulmonary monitoring at home: the CHIME monitor.

A new physiologic monitor for use in the home has been developed and used for the Collaborative Home Infant Monitor Evaluation (CHIME). This monitor measures infant breathing by respiratory inductance plethysmography and transthoracic impedance; infant electrocardiogram, heart rate and R-R interval; haemoglobin O2 saturation of arterial blood at the periphery and sleep position. Monitor signals from a representative sample of 24 subjects from the CHIME database were of sufficient quality to be clinically interpreted 91.7% of the time for the respiratory inductance plethysmograph, 100% for the ECG, 99.7% for the heart rate and 87% for the 16 subjects of the 24 who used the pulse oximeter. The monitor detected breaths with a sensitivity of 96% and a specificity of 65% compared to human scorers. It detected all clinically significant bradycardias but identified an additional 737 events where a human scorer did not detect bradycardia. The monitor was considered to be superior to conventional monitors and, therefore, suitable for the successful conduct of the CHIME study.

Efficacy of oral antibiotics for the treatment of persistent otitis media with effusion.

We followed 137 children who were found to have persistent otitis media with effusion (POME) one month after the diagnosis of acute otitis media. Subjects were randomly assigned to either treatment with erythromycin ethylsuccinate and sulfisoxizole or to no treatment. Follow-up utilizing pneumatic otoscopy and tympanometry showed that treated patients were more likely to have normal findings, and less likely to develop acute otitis media during the month following treatment. These data indicate that children with POME one month following acute otitis media may benefit from an additional course of antibiotics.

Survival in commercially insured multiple sclerosis patients and comparator subjects in the U.S.

OBJECTIVE: Compare survival in patients with multiple sclerosis (MS) from a U.S. commercial health insurance database with a matched cohort of non-MS subjects. METHODS: 30,402 MS patients and 89,818 non-MS subjects (comparators) in the OptumInsight Research (OIR) database from 1996 to 2009 were included. An MS diagnosis required at least 3 consecutive months of database reporting, with two or more ICD-9 codes of 340 at least 30 days apart, or the combination of 1 ICD-9-340 code and at least 1 MS disease-modifying treatment (DMT) code. Comparators required the absence of ICD-9-340 and DMT codes throughout database reporting. Up to three comparators were matched to each patient for: age in the year of the first relevant code (index year - at least 3 months of reporting in that year were required); sex; region of residence in the index year. Deaths were ascertained from the National Death Index and the Social Security Administration Death Master File. Subjects not identified as deceased were assumed to be alive through the end of 2009. RESULTS: Annual mortality rates were 899/100,000 among MS patients and 446/100,000 among comparators. Standardized mortality ratios compared to the U.S. population were 1.70 and 0.80, respectively. Kaplan-Meier analysis yielded a median survival from birth that was 6 years lower among MS patients than among comparators. CONCLUSIONS: The results show, for the first time in a U.S. population, a survival disadvantage for contemporary MS patients compared to non-MS subjects from the same healthcare system. The 6-year decrement in lifespan parallels a recent report from British Columbia.

Factors associated with caregivers' choice of infant sleep position, 1994-1998: the National Infant Sleep Position Study.

CONTEXT: The success and simplicity of the 1994 national "Back to Sleep" campaign to reduce sudden infant death syndrome provides an opportunity to study which elements determine whether a behavior will change in the desired direction in response to a public health intervention. OBJECTIVE: To examine sociodemographic characteristics, motivation, and message exposure to ascertain which factors influenced a caregiver's choice of infant sleep position after implementation of the campaign. DESIGN: Annual nationally representative telephone surveys conducted between 1994 and 1998. SETTING: The 48 contiguous United States. PARTICIPANTS: Nighttime caregivers of infants born within the 7 months prior to interview between 1994 and 1998. Approximately 1000 interviews were conducted each year. MAIN OUTCOME MEASURES: The position the infant was usually placed in for sleep, sleep position recommendations received from specific sources, and reasons reported for position choice. RESULTS: Between 1994 and 1998, prone placement declined from 44% to 17% among white infants and from 53% to 32% among black infants. Supine placement increased from 27% to 58% among white infants and from 17% to 31% among black infants. During this period, reports of supine recommendations from at least 1 source doubled from 38% to 79%. From 1995 to 1998, 86% of caregivers who placed the infant prone reported receiving only nonprone recommendations. Infant comfort was given as a reason for prone placement by 82% of these caregivers. In multivariate analysis, physician recommendation of "supine not prone" had the strongest influence and was associated with decreased prone placement (odds ratio [OR], 0.25 [95% confidence interval [CI], 0.16-0.39]) and increased supine placement (OR, 3.37 [95% CI, 2.38-4.76]). Recommendations from all 4 sources (the physician, neonatal nurse, reading materials, and radio/television) further increased the probability of supine placement (OR, 6.01 [95% CI, 4.57-7.90]). Other factors independently associated with increased prone and decreased supine placement included maternal black race, parity of more than 1, and living in a southern or mid-Atlantic state. CONCLUSIONS: According to our study, as of 1998, approximately one fifth of infants were still placed prone, and only half were placed supine. Recommendations of supine placement during infancy by physicians at well-baby checks and by neonatal nursery staff and print and broadcast media have increased the proportion of infants placed supine. Caregiver beliefs regarding perceived advantages of prone sleeping should be addressed to attain further reduction in prone placement.

Familial aggregation of low birth weight among whites and blacks in the United States.

BACKGROUND: Studies have shown that the birth weight of infants is correlated with the birth weights of their siblings and their mothers. We investigated whether the birth weights of mothers and index children were jointly associated with the risk of low birth weight in the siblings of the index children. METHODS: We used data on the live-birth cohort of the 1988 National Maternal and Infant Health Survey. The analysis included 1691 white and 1461 black mothers, each of whom had two or more live-born, singleton children. Multiple logistic regression with generalized-estimation equations was used to assess the risk of low birth weight among an index child's siblings. Four groups were studied: that in which neither the mother nor the index child had low birth weight (group 1), that in which only the mother had low birth weight (group 2), that in which only the index child had low birth weight (group 3), and that in which both the mother and the index child had low birth weight (group 4). There was adjustment for other maternal and infant covariates. RESULTS: Among white siblings in groups 1, 2, 3, and 4, 3.6, 8.3, 21.2, and 38.9 percent, respectively, had low birth weight, as compared with 8.0, 19.0, 31.1, and 57.1 percent of black siblings. When group 1 was used as the reference group, the adjusted odds ratios (and 95 percent confidence intervals) for low birth weight in groups 2, 3, and 4 were 2.5 (1.4 to 4.3), 6.8 (4.7 to 9.8), and 15.4 (9.2 to 25.5), respectively, among white siblings and 2.6 (1.8 to 3.8), 4.7 (3.5 to 6.4), and 13.9 (9.2 to 20.9) among black siblings. These associations were consistently found for birth weights below 1500 g and those ranging from 1500 to 2499 g in both races and after stratification for the mother's age, parity, education, cigarette-smoking status, and weight and height before pregnancy and the infant's sex. CONCLUSIONS: Although selection and recall biases cannot be excluded with certainty, our data suggest a strong familial aggregation of low birth weight among both whites and blacks in the United States.

Neurobehavioral syndromes in cocaine-exposed newborn infants.

The effects of fetal cocaine exposure on newborn cry characteristics were studied in 80 cocaine-exposed and 80 control infants. The groups were stratified to be similar on maternal demographic characteristics and maternal use of other illegal substances and alcohol during pregnancy. The hypothesis was that excitable cry characteristics were related to the direct effects of cocaine, while depressed cry characteristics were related to the indirect effects of cocaine secondary to low birthweight. Structural equation modeling (EQS) showed direct effects of cocaine on cries with a longer duration, higher fundamental frequency, and a higher and more variable first formant frequency. Indirect effects of cocaine secondary to low birthweight resulted in cries with a longer latency, fewer utterances, lower amplitude, and more dysphonation. Cocaine-exposed infants had a lower birthweight, shorter length, and smaller head circumference than the unexposed controls. Findings were consistent with the notion that 2 neurobehavioral syndromes, excitable and depressed, can be described in cocaine-exposed infants, and that these 2 syndromes are due, respectively, to direct neurotoxic effects and indirect effects secondary to intrauterine growth retardation.

Multicenter randomized clinical trial of home uterine activity monitoring: pregnancy outcomes for all women randomized.

OBJECTIVE: Our purpose was to evaluate the impact of home uterine activity monitoring on pregnancy outcomes among women at high risk for preterm labor and delivery. STUDY DESIGN: Women at high risk for preterm labor at three centers were randomly assigned to receive high-risk prenatal care alone (not monitored) or to receive the same care with twice-daily home uterine activity monitoring without increased nursing support (monitored). There were 339 women with singleton gestations randomized with caregivers blinded to group assignment. The two groups were medically and demographically similar at entry into the study. RESULTS: Women in the monitored group had prolonged pregnancy survival (p = 0.02) and were less likely to experience a preterm delivery (relative risk 0.59; p = 0.04). Infants born to monitored women with singleton gestations were less likely to be of low birth weight (< 2500 gm; relative risk 0.47, p = 0.003), and were less likely to be admitted to a neonatal intensive care unit (relative risk 0.5, p = 0.01). CONCLUSION: These data show, among women with singleton gestations at high risk for preterm delivery, that the use of home uterine activity monitoring alone, without additional intensive nursing care, results in improved pregnancy outcomes, including prolonged gestation, decreased risk for preterm delivery, larger-birth-weight infants, and a decreased need for neonatal intensive care.

Efficacy of recombinant human erythropoietin in the critically ill patient: a randomized, double-blind, placebo-controlled trial.

OBJECTIVE: To determine whether the administration of recombinant human erythropoietin (rHuEPO) to critically ill patients in the intensive care unit (ICU) would reduce the number of red blood cell (RBC) transfusions required. DESIGN: A prospective, randomized, double-blind, placebo-controlled, multicenter trial. SETTING: ICUs at three academic tertiary care medical centers. PATIENTS: A total of 160 patients who were admitted to the ICU and met the eligibility criteria were enrolled in the study (80 into the rHuEPO group; 80 into the placebo group). INTERVENTIONS: Patients were randomized to receive either rHuEPO or placebo. The study drug (300 units/kg of rHuEPO or placebo) was administered by subcutaneous injection beginning ICU day 3 and continuing daily for a total of 5 days (until ICU day 7). The subsequent dosing schedule was every other day to achieve a hematocrit (Hct) concentration of >38%. The study drug was given for a minimum of 2 wks or until ICU discharge (for subjects with ICU lengths of stay >2 wks) up to a total of 6 wks (42 days) postrandomization. MEASUREMENTS AND MAIN RESULTS: The cumulative number of units of RBCs transfused was significantly less in the rHuEPO group than in the placebo group (p<.002, Kolmogorov-Smirnov test). The rHuEPO group was transfused with a total of 166 units of RBCs vs. 305 units of RBCs transfused in the placebo group. The final Hct concentration of the rHuEPO patients was significantly greater than the final Hct concentration of placebo patients (35.1+/-5.6 vs. 31.6+/-4.1; p<.01, respectively). A total of 45% of patients in the rHuEPO group received a blood transfusion between days 8 and 42 or died before study day 42 compared with 55% of patients in the placebo group (relative risk, 0.8; 95% confidence interval, 0.6, 1.1). There were no significant differences between the two groups either in mortality or in the frequency of adverse events. CONCLUSIONS: The administration of rHuEPO to critically ill patients is effective in raising their Hct concentrations and in reducing the total number of units of RBCs they require.

Changes in sleep position during infancy: a prospective longitudinal assessment.

CONTEXT: Prone sleeping by infants has been associated with an increased risk of sudden infant death syndrome. OBJECTIVE: To document the prevalence of and identify risk factors for prone sleeping during the first 6 months of life. DESIGN: Prospective cohort study. SETTING: Eastern Massachusetts and northwest Ohio. STUDY PARTICIPANTS: A total of 7796 mothers of infants weighing 2500 g or more at birth. MAIN OUTCOME MEASURES: Maternal and infant characteristics related to prone sleeping at 1 month and 3 months of age. RESULTS: Between 1 month and 3 months of age, prone sleeping increased from 18% to 29%. At 1 month, prone sleeping was associated with the following maternal characteristics: non-Hispanic black or Hispanic race/ethnicity, younger age, less education, and higher parity. At 3 months, switching from nonprone to prone position was associated with mother's race/ethnicity of non-Hispanic black (odds ratio [OR], 1.7; 95% confidence interval [CI], 1.2-2.3) or Hispanic (OR, 1.5; 95% CI, 1.1-2.2); younger maternal age (compared with mothers >34 years: 18-24 years, OR, 1.6; 95% CI, 1.2-2.2; <18 years, OR, 2.2; 95% CI, 1.2-4.3); increasing parity (compared with 1 child: 2 children, OR, 1.5; 95% CI, 1.2-1.8; > or =3 children, OR, 1.7; 95% CI, 1.4-2.2); and infant sex (male sex, OR, 1.4; 95% CI, 1.2-1.7). CONCLUSIONS: If infant sleeping practices in the study communities are representative of practices throughout the United States, a substantial number of infants who slept nonprone at 1 month sleep prone at 3 months.

Factors associated with the transition to nonprone sleep positions of infants in the United States: the National Infant Sleep Position Study.

CONTEXT: Studies have demonstrated strong associations between the prone sleep position (on the stomach) and sudden infant death syndrome (SIDS). In 1992, the American Academy of Pediatrics recommended that infants be placed to sleep laterally (on their side) or supine (on their back) to reduce SIDS risk, and in 1994, the national public education campaign "Back to Sleep" was launched. OBJECTIVE: To determine the typical sleep position of infants younger than 8 months in the United States, the changes that occurred after these recommendations, and the factors associated with the placement of infants prone or supine. DESIGN: Annual nationally representative telephone surveys. SETTING: The 48 contiguous states of the United States. PARTICIPANTS: Nighttime caregivers of infants born within the last 7 months between 1992 and 1996. Approximately 1000 interviews were conducted per year. MAIN OUTCOME MEASURES: The position the infant was usually placed in for sleep, and the position the infant was most commonly found in when checked during the night's sleep. RESULTS: Ninety-seven percent of respondents in each wave of the survey usually placed their infant to sleep in a specific position. Infants were placed in the prone position by 70% of caregivers in 1992, prior to the campaign, but only 24% in 1996. Supine and lateral placements increased during this time period, from 13% in 1992 to 35% in 1996 and from 15% in 1992 to 39% in 1996, respectively. Significant predictors of prone placement included maternal race reported as black (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.68-3.26), mother's age 20 to 29 years (OR, 1.28; 95% CI, 1.09-1.50), region reported as the mid-Atlantic (OR, 1.41; 95% CI, 1.12-1.78) or southern states (OR, 1.47; 95% CI, 1.22-1.70), mothers with a previous child (OR, 1.68; 95% CI, 1.43-1.97), and infants younger than 8 weeks (OR, 0.63; 95% CI, 0.46-0.85). Infants aged 8 to 15 weeks were significantly more likely to be placed nonprone over time compared with the other age groups. Most of the risk factors for prone were significantly related in the opposite direction to supine placement. CONCLUSIONS: The prevalence of infants placed in the prone sleep position declined by 66% between 1992 and 1996. Although causality cannot be proved, SIDS rates declined approximately 38% during this period. To achieve further reduction in prone sleeping, efforts to promote the supine sleep position should be aimed at groups at high risk for prone placement.

Assessment of compliance with home cardiorespiratory monitoring in infants at risk of sudden infant death syndrome. Collaborative Home Infant Monitoring Evaluation (CHIME).

OBJECTIVES: Documented monitoring was used to evaluate prospectively (1) the level of compliance among infants in whom cardiorespiratory monitoring was clinically indicated and (2) factors that might influence compliance: diagnosis, socioeconomic status, maternal age and education, and alarms. STUDY DESIGN: Sixty-seven infants (51% female, 49% term) were sequentially enrolled, and monitoring was prescribed for the following indications: siblings of sudden infant death syndrome victims (16%), apnea of prematurity (45%), and apparent life-threatening events or apnea of infancy (39%). Demographic data, alarm and event data, and a summary report of monitor use from the first monitor download were obtained. RESULTS: Maternal age, education, and insurance status did not differ significantly by indication for monitoring. The median number of monitor alarms per 10 hours of use was 0.7 for apnea or bradycardia and 0.6 for loose lead alarms. Monitors were available for use in the home from 2 to 106 days (median, 11 days). Median hours of monitor use per full day in the home was 15.5 hours. Of 67 infants, 58 used the monitor for at least part of every day in the home. The number of hours of monitor use per day did not differ significantly by diagnostic category, chronologic age, alarms, maternal age, education, or insurance type. This study population of infants at increased risk of sudden infant death syndrome had excellent compliance; 75% of the infants were monitored more than 10.5 hours per day, and 25% were monitored more than 21 hours per day. CONCLUSIONS: Documented monitoring provides an objective measure of compliance. These data provide a potential goal for level of compliance with home cardiorespiratory monitoring.

Agreement among raters in assessment of physiologic waveforms recorded by a cardiorespiratory monitor for home use. Collaborative Home Infant Monitoring Evaluation (CHIME) Study Group.

There are numerous reports of cardiorespiratory patterns in infants on home monitors, but no data to determine whether "experts" agree on the description of these patterns. Therefore, we evaluated agreement among four experienced investigators and five trained technicians who assessed independently the same sample of physiologic waveforms recorded from infants enrolled in a multicenter study. The monitor used respiratory inductance plethysmography and recorded waveforms for apnea > or = 16 s or a heart rate < 80 beats/min for > or = 5 s. The investigators and technicians initially assessed 88 waveforms. After additional training, the technicians assessed another 113 additional waveforms. In categorizing waveforms as apnea present or absent, agreement among technicians improved considerably with additional training (kappa 0.65 to 0.85). For categorizing waveforms as having bradycardia present versus absent, the trends were the same. Agreement in measurement of apnea duration also improved considerably with additional training (intraclass correlation 0.33-0.83). Agreement in measurement of bradycardia duration was consistently excellent (intraclass correlation 0.86-0.99). Total agreement was achieved among technicians with additional training for measurement of the lowest heart rate during a bradycardia. When classifying apnea as including > or = 1, > or = 2, > or = 3, or > or = 4 out-of-phase breaths, agreement was initially low, but after additional training it improved, especially in categorization of apneas with > or = 3 or > or = 4 out-of-phase breaths (kappa 0.67 and 0.94, respectively). Although researchers and clinicians commonly describe events based on cardiorespiratory recordings, agreement amongst experienced individuals may be poor, which can confound interpretation. With clear guidelines and sufficient training raters can attain a high level of agreement in describing cardiorespiratory events.