Neurodevelopmental impact of hydrocortisone exposure in extremely low birth weight infants: outcomes at 1 and 2 years.

OBJECTIVE: Postnatal steroids are used in neonatal intensive care units despite known side effects. Hydrocortisone (HC) use persists as it is believed to have less deleterious effects on neurodevelopmental (ND) outcome compared to other steroids. The literature is sparse with respect to the ND impact of HC use in recent years. Hence, we sought to examine the effect of HC use on ND outcome in a contemporary cohort of extremely low birth weight (ELBW) infants. STUDY DESIGN: A total of 175 ELBW infants (86 HC exposed, 89 steroid naive) born in 2008 to 2010 were compared for mortality, morbidity and ND outcome at 8 and 20 months corrected age. Outcome measures included neurologic exam and results of the Bayley Scales of Infant and Toddler Development-III (BSITD-III). Multiple regression analyses adjusted for the effect of other risk factors on outcome. RESULT: Overall, 65 (75%) of the HC and 74 (83%) of the no-HC groups survived to discharge. HC infants were smaller (mean birth weight (BW) 719 ± 127 g vs 837 ± 99 g) and of lower gestational age (GA) (mean GA 26.0 ± 1.7 weeks vs 27.5 ± 1.8 weeks) compared to the no-HC group. Patients in the HC group were more likely to be a multiple, have a severely abnormal head ultrasound, bronchopulmonary dysplasia, retinopathy of prematurity, necrotizing enterocolitis and receive treatment for patent ductus arteriosus and hypotension than those in the no-HC group. Of the HC group, the mean age at treatment was 20 ± 19 days, mean duration of treatment 49 ± 37 days. At 8 months, the HC group had lower mean motor (87 ± 18 vs 95 ± 15, P = 0.028) and fine motor (9 ± 2.9 vs 10.5 ± 2.6, P = 0.005) and higher rate of subnormal motor (44 vs 15%, P = 0.002) and fine motor scores (24 vs 6.5%, P = 0.017). In regression analyses, HC exposure >7 days was significantly related to worse outcome on fine motor scores at 8 months while cumulative days of HC exposure was a predictor of worse outcome on language at 8 months and motor outcome at 20 months. Each additional day of HC exposure increased the odds of subnormal receptive and expressive language in the first year of life by 4 and 2%, respectively, and increased odds of subnormal motor function by 2% in the 2nd year of life. CONCLUSION: HC exposure for >7 days is associated with worse performance in fine motor skills in the first year of life, while cumulative HC exposure negatively impacts receptive and expressive language skills in the first year and motor skills in the second year of life after adjusting for neonatal and social risk factors.

Reducing necrotizing enterocolitis in very low birth weight infants using quality-improvement methods.

OBJECTIVE: Owing to a rise in necrotizing enterocolitis (NEC, stage ⩾ 2) among very low birth weight (VLBW, birth weight <1500 g) infants from 4% in 2005 to 2006 to 10% in 2007 to 2008, we developed and implemented quality improvement (QI) initiatives. The objective was to evaluate the impact of QI initiatives on NEC incidence in VLBW infants. STUDY DESIGN: In September 2009, we developed an NEC QI multidisciplinary team that conducted literature reviews and reviewed practices from other institutions to develop a feeding protocol, which was implemented in December 2009. The team tracked intervention compliance and occurrence of NEC stage ⩾ 2. In May 2010, we reviewed our nasogastric tube practice and relevant literature to develop a second intervention that reduced nasogastric tube indwelling time. The infants were divided into three groups: baseline (January 2008 to Novovember 2009, n219), QI phase 1 (December 2009 to May 2010, n62) and QI phase 2 (June 2010 to November 2011, n170). RESULT: The NEC incidence did not decrease after implementation of the feeding protocol in QI phase 1 (19.4%) but did decline significantly after changing nasogastric tube management in QI phase 2 (2.9%). Multivariable logistic regression analysis demonstrated a significant relationship between QI phase and the incidence of NEC. CONCLUSION: QI initiatives were effective in decreasing NEC incidence in our high human milk-feeding NICU. Nasogastric tube bacterial contamination may have contributed to our peak in NEC incidence.

Cardiorespiratory events in extremely low birth weight infants: neurodevelopmental outcome at 1 and 2 years.

OBJECTIVE: To examine the association between cardiorespiratory events (CRE) and neurodevelopmental (ND) outcome at 8 and 20 months corrected age (CA) in a contemporary extremely low birth weight (ELBW )cohort. STUDY DESIGN: Retrospective chart review of 98 ELBW infants born in 2009 to 2010 who completed ND assessments at 8 and 20 months CA. Neonatal, sociodemographic, CRE and ND data were collected. ND outcome measures included neurologic examination and results from the Bayley Scales of Infant and Toddler Development-III. Multiple regression analyses adjusted for the impact of neonatal risk factors on ND outcome. RESULT: After adjusting for neonatal and social variables, greater frequency of CRE was related to worse language scores at 8 months, while CRE of greater severity were related to worse language at 20 months CA. CONCLUSION: CRE in ELBW infants have impact on language development in the first two years of life.

Genetic segregation analysis of autonomic nervous system dysfunction in families of probands with idiopathic congenital central hypoventilation syndrome.

Idiopathic congenital central hypoventilation syndrome (CCHS) is a very rare syndrome with major respiratory complications. Hypothesizing that CCHS is the most severe manifestation of general autonomic nervous system dysfunction (ANSD), we applied a case-control family study design to investigate the genetics of ANSD. Fifty-two probands with CCHS were identified, as well as 52 age-, race-, and gender-matched controls. ANSD phenotypic features were characterized in the cases, controls, and their family members. Our earlier studies found that most ANSD symptoms were more likely in CCHS cases and their relatives than in controls and their relatives (P < 0.05). The goal of the current study was to determine if the familiality of ANSD was consistent with a genetic pattern. We performed major locus segregation analysis of ANSD utilizing regressive models. CCHS probands were assumed to be affected; controls and relatives were designated as affected if they had two or more relevant symptoms. The hypothesis of "no transmission and no familial effects" was rejected in both case and control families. Case families were consistent with transmission of a major effect; control families were not (the difference in the pattern of results was significant, P < 0.0001). In the total data set, the best-fitting model was codominant Mendelian inheritance of a major gene for ANSD. These case-control family studies support our hypothesis that CCHS is the most severe manifestation of a general ANSD, with a family pattern consistent with Mendelian transmission, and demonstrate the potential utility of the approach to studies of other, similarly intractable disorders.

Case/control family study of autonomic nervous system dysfunction in idiopathic congenital central hypoventilation syndrome.

Children with idiopathic congenital central hypoventilation syndrome (CCHS) have a complex phenotype consistent with an imbalance of the autonomic nervous system (ANS). Since CCHS may be genetic in origin, we hypothesized that relatives of individuals with CCHS may exhibit symptoms of ANS dysfunction (ANSD), albeit in a milder form. We tested this hypothesis by assessing aspects of ANS function in relatives of CCHS cases vs. relatives of matched controls with a scripted questionnaire. Only those 35 symptoms of ANSD exhibited by > or =5% of the CCHS cases were included in the analysis as the basis for determining ANSD affection status. Two different arbitrary ANSD affection status definitions are presented in detail: any case, control, or relative with positive findings (1) in two or more symptoms, or (2) in two or more systems. The subjects included in the analysis totaled 2,353, including 56 CCHS cases, 56 age-, gender-, and race-matched controls, and their families. Under each of the two arbitrary ANSD affection statuses, CCHS cases and parents of cases were more likely to be affected than controls and parents of controls (P < 0.001 for both comparisons), 16% of the CCHS siblings had the ANSD phenotype with two or more symptoms, compared to 4% of control siblings (P = 0.03). Aunts and uncles of the CCHS cases were also significantly more likely to have two or more ANSD symptoms than were aunts and uncles of the controls (P= 0.009). These results support our hypothesis and also indicate that relatives of the CCHS cases tended to manifest a milder spectrum of ANSD, with fewer systems and/or fewer symptoms than the cases.

Cardiorespiratory events recorded on home monitors: Comparison of healthy infants with those at increased risk for SIDS.

CONTEXT: Home monitors designed to identify cardiorespiratory events are frequently used in infants at increased risk for sudden infant death syndrome (SIDS), but the efficacy of such devices for this use is unproven. OBJECTIVE: To test the hypothesis that preterm infants, siblings of infants who died of SIDS, and infants who have experienced an idiopathic, apparent life-threatening event have a greater risk of cardiorespiratory events than healthy term infants. DESIGN: Longitudinal cohort study conducted from May 1994 through February 1998. SETTING: Five metropolitan medical centers in the United States. PARTICIPANTS: A total of 1079 infants (classified as healthy term infants and 6 groups of those at risk for SIDS) who, during the first 6 months after birth, were observed with home cardiorespiratory monitors using respiratory inductance plethysmography to detect apnea and obstructed breathing. MAIN OUTCOME MEASURES: Occurrence of cardiorespiratory events that exceeded predefined conventional and extreme thresholds as recorded by the monitors. RESULTS: During 718 358 hours of home monitoring, 6993 events exceeding conventional alarm thresholds occurred in 445 infants (41%). Of these, 653 were extreme events in 116 infants (10%), and of those events with apnea, 70% included at least 3 obstructed breaths. The frequency of at least 1 extreme event was similar in term infants in all groups, but preterm infants were at increased risk of extreme events until 43 weeks' postconceptional age. CONCLUSIONS: In this study, conventional events are quite common, even in healthy term infants. Extreme events were common only in preterm infants, and their timing suggests that they are not likely to be immediate precursors to SIDS. The high frequency of obstructed breathing in study participants would likely preclude detection of many events by conventional techniques. These data should be important for designing future monitors and determining if an infant is likely to be at risk for a cardiorespiratory event.

Cardiac rhythm disturbances among children with idiopathic congenital central hypoventilation syndrome.

The objective of this study was to determine whether subjects with congenital central hypoventilation syndrome (CCHS) had an increased frequency of cardiac arrhythmias and decreased heart rate variability when compared to subjects without a known deficit in control of breathing, and that these abnormalities would be exaggerated by anesthesia. Continuous ambulatory Holter recordings were obtained in patients with CCHS and compared to two otherwise healthy control groups without a deficit in control of breathing: one with an intact airway (n = 11) and a second group with a tracheostomy (n = 6). Holter recordings were obtained before, during (under general anesthesia), and after bronchoscopy. Fourteen children with CCHS (age: 9.3 +/- 4.4 years mean +/- S.D.) were studied, and 7 underwent bronchoscopy. Seventeen control children were studied (age 6.6 +/- 3.6 years): 11 without a tracheostomy, and 6 with a tracheostomy who also underwent bronchoscopy. Maximum heart rate during baseline recording was significantly lower in the CCHS subjects as compared to controls (P = 0.0001). At baseline the difference in the number of arrhythmias/24 hr/subject in all CCHS vs. all control subjects was significant (P = 0.0002); for the subjects who had bronchoscopy, CCHS vs. control, the difference was also significant (P = 0.03). In addition, there was a significant decrease in the number of events/24 hr/subject among the CCHS subjects between baseline and post-bronchoscopy (P = 0.0288). The predominant arrhythmias were sinus bradycardia and transient asystole. The longest asystole in a CCHS subject was 6.50 sec, and in a control subject, 1.42 sec (at baseline the means of the longest asystole were 2.69 +/- 1.4 vs. 1.24 +/- 0.13; P = 0.003 in the CCHS vs. control groups). Other indices of heart rate variability were significantly reduced in the CCHS subjects (P < 0.05). These results substantiate our hypothesis that subjects with CCHS have more arrhythmias than controls, an increased frequency of bradyarrhythmias, and decreased cyclical sinus arrhythmia.

Heart rate variability in preterm brain-injured and very-low-birth-weight infants.

Heart rate variability (HRV) reflects the complex interplay of the sympathetic and parasympathetic innervation of the heart. Developmental maturation of the fetus and newborn results in predictable alterations in the neural cardiac control of heart rate. Furthermore, patterns of HRV are closely correlated to clinical outcome in several pathologic situations. The first aim of this study was to characterize the maturational patterns of HRV in a group of developmentally at-risk newborns (those with severe hemorrhagic or ischemic brain injury and extremely immature, low-birth-weight infants). Secondly, we sought to determine whether a correlation exists between HRV and length of hospital stay, diagnosis of cerebral palsy, and neurodevelopmental test scores at 1-year corrected age. Time domain indices of HRV were computed longitudinally from 32 to 37 weeks of corrected gestational age in 19 very low birth weight, preterm infants. Among the 19 infants studied, 7 infants had no evidence of brain injury, 7 infants had periventricular leukomalacia (PVL), 3 infants had grade III/IV intraventricular hemorrhage (IVH), and 2 infants had both IVH and PVL. Neurologic injuries were documented using ultrasound and neurodevelopmental progress was followed through 1 year of corrected gestational age. A multivariate repeated measures analysis was performed to determine the relationship between the type of perinatal brain injury and neurodevelopmental status at 1 year of corrected gestational age. The type of perinatal brain injury was highly correlated to specific patterns of HRV with multivariate regression models producing adjusted r(2) values ranging from 0.63 to 0.99. The type of perinatal brain injury was highly correlated to the developmental outcome measures (p < 0.0000) with PVL patients having the lowest neurodevelopmental scores, IVH patients having the highest scores, and noninjured infants having midrange, grossly normal values. Using ANOVA, HRV was correlated to outcome, but individual comparisons revealed statistical significance only for the noninjured group (p < 0.04). However, multivariate models, which characterized outcome within each brain injury group, were highly significant (adjusted r (2) ranged from 0.23 to 0.89). In summary, the type of perinatal brain injury determined the pattern of HRV and HRV was highly correlated to length of hospital stay and neurodevelopmental function assessed at 1 year of corrected gestational age.

Developmental intervention for preterm infants diagnosed with periventricular leukomalacia.

Preterm infants with periventricular leukomalacia (PVL) were evaluated to determine whether multi-sensory stimulation is safe and to assess whether it improved neurobehavior and neurodevelopment. Thirty preterm infants with documented PVL were randomly assigned to control (n= 15) or experimental (Group E) (n= 15) groups at 33 weeks post-conceptional age. Group E infants received 15 minutes of auditory, tactile, visual, and vestibular (ATVV) intervention twice a day, five days a week, for four weeks during hospitalization. Repeated measures ANOVA demonstrated that Group E infants experienced significant increases in heart and respiratory rate and a 0.72% drop in hemoglobin saturation, coinciding with a significant behavioral state shift from sleep to alertness during intervention. No differences were identified in neurobehavioral function and neurodevelopment, indicating that Group E suffered no injury. Group E had an average hospital stay nine days shorter than that of controls, with the associated cost savings of $213,840. The earlier hospital discharge indicates that ATVV intervention promotes alertness without compromising physiologic status in vulnerable infants.

SIDS risk factor awareness: assessment among nursing students.

OBJECTIVE: To test the hypotheses that nursing students (a) have limited knowledge of risk factors for sudden infant death syndrome (SIDS) and the American Academy of Pediatrics (AAP) recommendation of placing infants on their backs or sides for sleep, and (b) after careful education about SIDS, would retain this information and teach it to parents. DESIGN: A pretest questionnaire was used to identify knowledge of 13 risk factors and personal recommendation for sleep position. Participants attended a lecture on SIDS and received written educational material. A posttest was completed after 6 weeks. SETTING: Nursing students were assessed during their family practice course. PARTICIPANTS: Fifty-one 4th-year nursing students (mean age 28.4 years, SD=7.6) enrolled in the BSN program completed the pretest; 29 completed the identical posttest. INTERVENTION: A lecture on SIDS and SIDS risk factors with written educational material after the pretest. MAIN OUTCOME MEASURES: Pretest and posttest responses. RESULTS: The Mann-Whitney test and McNemar chi-square analyses were used to determine factors on the pretest which influenced the awareness of prone position and to compare pretest and posttest data. On the pretest, 69% of students were aware of the AAP recommendation but significantly more (92%) were aware on the posttest. Posttest responses increased significantly for 12 of the 13 risk factors; 41% of the students identified all 13 risk factors on the posttest, in contrast to 0% on the pretest. On both the pretest and posttest, 93% of students stated that it was important to discuss their infant's sleep position with parents. Posttest results showed that students unanimously recommend the side or back sleep position. CONCLUSION: Nursing students were aware of the AAP recommendation, yet their knowledge of other risk factors was limited. A careful educational process resulted in retention of information about the AAP recommendation and other risk factors. In addition, students were willing to teach parents to place their infants on the back or side to sleep.

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.

Influence of increased survival in very low birth weight, low birth weight, and normal birth weight infants on the incidence of sudden infant death syndrome in the United States: 1985-1991.

OBJECTIVE: To examine the relationship between infant survival and the rates sudden infant death syndrome (SIDS) in very low birth weight (VLBW), low birth weight (LBW), and normal birth weight (NBW) infants from 1985 to 1991. METHODS: The National Center for Health Statistics Birth Cohort Linked Birth/Infant Death Data Sets were used to determine birth weight, age at death, and cause of death for US-born singleton infants with birth weights of 500 g or more. RESULTS: Increasing infant and postneonatal survival rates were greatest in VLBW infants. In contrast, SIDS rates did not change in VLBW infants (3.66 to 3.69; P = .70) but declined in both LBW (3.51 to 3.32; P = .041) and NBW (1.07 to 1.03; P = .008) infants. Postneonatal SIDS rates (per 1000 neonatal survivors) did not change in VLBW (4.93 to 4.58; P = .58) or LBW (3.36 to 3.22; P = .07) infants but declined in NBW infants (1.00 to 0.97; P = .018). Although there were differences among the slopes of survival rates, there was no statistical evidence of differences in the slope of SIDS rates among the three groups. CONCLUSIONS: The marked increase in survival of VLBW infants increased the pool of babies at potential risk for SIDS. VLBW infants' SIDS rates have not changed while they have declined in NBW and LBW infants.

Pediatric hypoventilation syndromes.

Hypoventilation syndromes are an uncommon but important group of respiratory control disorders in infants and children. Congenital central hypoventilation syndrome (CCHS) is the principal and most important example. No specific anatomical or biochemical mechanism has yet been identified. This article summarizes current knowledge regarding CCHS in infants and children, and emphasizes the most recent and most important publications. The most recent advances in CCHS pertain to its genetics, pathophysiology, diagnosis, and treatment and provide state-of-the-art information regarding advances in diaphragm pacing, responses to exercise, and long-term outcome. CCHS is now being recognized more frequently, treatment is more successful, and long-term outcomes are encouraging with timely diagnosis, state-of-the-art treatment, and comprehensive follow-up at an experienced pediatric referral center.

Responses of preterm infants to unimodal and multimodal sensory intervention.

PURPOSE: To examine the immediate responses of preterm infants to two forms of unimodal [auditory only (A) and tactile only (T)] and two forms of multimodal sensory stimulation [auditory, tactile and visual (ATV); auditory, tactile, visual and vestibular (ATVV)]. METHOD: A convenience sample of 54 clinically stable preterm infants (33-34 postconceptional weeks) was randomly assigned to 1 of 5 experimental groups [Control (C); (A); (T); (ATV); and (ATVV)]. Stimulation was applied for 15 minutes once daily for 4 consecutive days. RESULTS: Outcome measures included pulse (PR) and respiratory rate (RR), oxygen saturation, behavioral state (BS), and body temperature. Repeated measures ANOVA identified significant differences among the groups during intervention for PR (p < .001), RR (p = .01), and BS (p < .02). Infants receiving any intervention with a tactile component showed increasing arousal (change in BS), and increased PR and RR during stimulation. Group T infants had higher proportions of PR > 180 while Group ATVV had higher proportions of PR < 140 (p = .0001). Group ATVV showed increased alertness following stimulation (24%) in contrast to having the least alertness during stimulation (11%). CONCLUSIONS: Tactile stimulation alone may be too arousing for these infants while the addition of vestibular stimulation may modulate arousal and facilitate optimal arousal prior to feeding.

Diaphragm pacing with a quadripolar phrenic nerve electrode: an international study.

We sought to determine the international experience with the quadripolar diaphragm pacer system and to test two hypotheses: the incidence of pacer complications would be (1) increased among pediatric as compared to adult patients; and (2) highest among active pediatric patients with idiopathic congenital central hypoventilation syndrome (CCHS). Data were collected via a questionnaire coupled with the Atrotech Registry data for a total of 64 patients (35 children and 29 adults) from 14 countries. Thoracic implantation of electrodes and bilateral pacer use each occurred in 94% of all subjects. Tetraplegic (vs pediatric CCHS) patients were more typically paced 24 hours/day (P = 0.001). Pacing duration averaged 2.0 +/- 1.0 years among children and 2.2 +/- 1.1 years among adults. Infections occurred among 2.9% of surgical procedures, all in pediatric CCHS patients (vs pediatric tetraplegic patients, P = 0.01). The incidence of mechanical trauma was 3.8%, without significant differences among patient groups. The incidence of presumed electrode and receiver failure were 3.1% and 5.9%, respectively, with internal component failure greater among pediatric CCHS than pediatric tetraplegic patients (P < 0.01). Intermittent or absent function of 0-4 electrode combinations occurred among 19% of all patients, with increased frequency among pediatric CCHS than pediatric tetraplegic patients (P < 0.03). Complication-free successful pacing occurred in 60% of pediatric and 52% of adult patients. In all, 94% of the pediatric and 86% of the adult patients paced successfully after the necessary intervention. Although pacer complications were not increased among pediatric as compared to adult patients, the incidence of complications was highest among the active pediatric patients with CCHS. Longitudinal study of these patients will provide invaluable information for modification and improvement of the quadripolar system.

Congenital central hypoventilation syndrome: mutation analysis of the receptor tyrosine kinase RET.

Congenital central hypoventilation syndrome (CCHS) usually occurs as an isolated phenotype. However, 16% of the index cases are also affected with Hirschsprung disease (HSCR). Complex segregation analysis suggests that CCHS is familial and has the same inheritance pattern with or without HSCR. We postulate that alteration of normal function of the receptor tyrosine kinase, RET, may contribute to CCHS based on RET's expression pattern and the identification of RET mutations in HSCR patients. To further explore the nature of the inheritance of CCHS, we have undertaken two main routes of investigation: cytogenetic analysis and mutation detection. Cytogenetic analysis of metaphase chromosomes showed normal karyotypes in 13 of the 14 evaluated index cases; one index case carried a familial pericentric inversion on chromosome 2. Mutation analysis showed no sequence changes unique to index cases, as compared to control individuals, and as studied by single strand conformational polymorphism (SSCP) analysis of the coding region of RET. We conclude that point mutations in the RET coding region cannot account for a substantial fraction of CCHS in this patient population, and that other candidate genes involved in neural crest cell differentiation and development must be considered.

Respiratory control disorders in infancy and childhood.

Current contributions to the literature on disorders of respiratory control in infancy and childhood are reviewed. These encompass studies of cardiorespiratory control in preterm and term infants, apparent life-threatening events in infants, and obstructive sleep apnea including etiology, diagnosis, and alternatives to surgical management. In addition, alveolar hypoventilation is discussed in children with congenital central hypoventilation syndrome, myelomeningocele, and Prader-Willi syndrome.

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.