Asystole and severe bradycardia in preterm infants.

UNLABELLED: Transient episodes of apnea and bradycardia are common in preterm infants. Pronounced asystole or sinus arrest, however, is relatively rare and the clinical significance of such events is unknown. OBJECTIVE: The purpose of our study was to: (1) evaluate the prevalence of severe bradycardic and asystolic events in infants studied with polygraphic cardiorespiratory monitoring, (2) characterize these events, and (3) correlate the events with other clinical findings. METHODS: A total of 583 studies were performed in 454 preterm infants at a post-conceptional age 37.4 +/- 2.5 (range 34-42 weeks). Asystolic pauses were defined as no QRS complex for >or=3 s consistent with a heart rate <20 beats per minute (bpm). Severe bradycardia was defined as no QRS for >or=2 s consistent with a heart rate of 21-30 bpm. RESULTS: Eight infants (29.5 +/- 3.9 weeks' gestational age, birth weight 1,283 +/- 445 g) met the criteria of having had at least 1 asystolic event (heart rate

Factors that influence use of a home cardiorespiratory monitor for infants: the collaborative home infant monitoring evaluation.

BACKGROUND: As part of the Collaborative Home Infant Monitoring Evaluation, a home monitor was developed to record breathing, heart rate, other physiologic variables, and the time the monitor was used. OBJECTIVE: To determine the frequency of monitor use, factors that influence use, and validity of a model developed to predict use. DESIGN: We developed a model to predict monitor use using multiple linear regression analysis; we then tested the validity of this model to predict adherence for the first week of monitoring and for the subsequent 4-week period (weeks 2-5). SETTING: Clinical research centers in Chicago, Ill; Cleveland, Ohio; Honolulu, Hawaii; Los Angeles, Calif; and Toledo, Ohio. Patients Preterm infants, infants younger than 1 month with a history of autopsy-confirmed sudden infant death syndrome in a sibling, and infants with an idiopathic apparent life-threatening event were divided into 2 cohorts based on enrollment date. Main Outcome Measure Mean hours of monitor use per week. RESULTS: In cohort 1, the variables available before monitoring were only weakly associated with total hours of monitor use in weeks 2 to 5 (total model r(2) = 0.08). However, when hours of monitor use in week 1 were included as a variable to predict monitor use in weeks 2 to 5, the r(2) increased to 0.64 for hours of monitor use per week. CONCLUSIONS: Our data show that monitor use in the first week was the most important variable for predicting subsequent monitor use. The study suggests that a major focus of home monitoring should be adherence in the first week, although it remains to be tested whether this adherence can be altered.

Cardiorespiratory events detected by home memory monitoring and one-year neurodevelopmental outcome.

OBJECTIVE: To determine if infants with cardiorespiratory events detected by home memory monitoring during early infancy have decreased neurodevelopmental performance. STUDY DESIGN: Infants (n = 256) enrolled in the Collaborative Home Infant Monitoring Evaluation also completed the Bayley Scales of Infant Development II at 92 weeks' postconceptional age. Infants were classified as having 0, 1 to 4, or 5+ cardiorespiratory events. Events were defined as apnea >or=20 seconds or heart rate <60 to 80 bpm or <50 to 60 bpm, for >or=5 to 15 seconds, depending on age. RESULTS: For term infants, having 0, 1 to 4, and 5+ cardiorespiratory events was associated with unadjusted mean Mental Developmental Index (MDI) values (+/-SD) of 103.6 (10.6), 104.2 (10.7), and 97.7 (10.9), respectively, and mean Psychomotor Developmental Index (PDI) values of 109.5 (16.6), 105.8 (16.5), and 100.2 (17.4). For preterm infants, having 0, 1 to 4, and 5+ cardiorespiratory events was associated with unadjusted mean MDI values of 100.4 (10.3), 96.8 (11.5), and 95.8 (10.6), respectively, and mean PDI values of 91.7 (19.2), 93.8 (15.5), and 94.4 (17.7). The adjusted difference in mean MDI scores with 5+ events compared with 0 events was 5.6 points lower in term infants ( P = .03) and 4.9 points lower in preterm infants ( P = .04). CONCLUSIONS: Having 5+ conventional events is associated with lower adjusted mean differences in MDI in term and preterm infants.

Clinical correlates, natural history and outcome of neonatal apnoea.

Apnoea is common in the newborn period and especially in preterm newborns. Bradycardia and desaturation of oxyhaemoglobin typically occur with apnoea. These abnormalities reflect an immature cardiorespiratory system and resolution of this immaturity can be expected within a predictable time frame. Infants who have apnoea in the newborn period are thought not to be at higher risk for sudden infant death syndrome (SIDS). Whether apnoea episodes are associated with a higher incidence of long-term handicap for these infants is not yet clear.