title: Very long apnea events in preterm infants.
abstract: Apnea is nearly universal among very low birth weight (VLBW) infants, and the associated bradycardia and desaturation may have detrimental consequences. We describe here very long (>60 s) central apnea events (VLAs) with bradycardia and desaturation, discovered using a computerized detection system applied to our database of over 100 infant years of electronic signals. Eighty-six VLAs occurred in 29 out of 335 VLBW infants. Eighteen of the 29 infants had a clinical event or condition possibly related to the VLA. Most VLAs occurred while infants were on nasal continuous positive airway pressure, supplemental oxygen, and caffeine. Apnea alarms on the bedside monitor activated in 66% of events, on average 28 s after cessation of breathing. Bradycardia alarms activated late, on average 64 s after cessation of breathing. Before VLAs oxygen saturation was unusually high, and during VLAs oxygen saturation and heart rate fell unusually slowly. We give measures of the relative severity of VLAs and theoretical calculations that describe the rate of decrease of oxygen saturation. A clinical conclusion is that very long apnea (VLA) events with bradycardia and desaturation are not rare. Apnea alarms failed to activate for about one-third of VLAs. It appears that neonatal intensive care unit (NICU) personnel respond quickly to bradycardia alarms but not consistently to apnea alarms. We speculate that more reliable apnea detection systems would improve patient safety in the NICU. A physiological conclusion is that the slow decrease of oxygen saturation is consistent with a physiological model based on assumed high values of initial oxygen saturation.
authors.affiliation: Department of Physics, College of William and Mary, Williamsburg, Virginia; mmohr@email.wm.edu.
authors.forename: Mary A
authors.initials: MA
authors.lastname: Mohr
authors.affiliation: Department of Pediatrics (Neonatology), University of Virginia, Charlottesville, Virginia;
authors.forename: Brooke D
authors.initials: BD
authors.lastname: Vergales
authors.affiliation: Department of Physics, College of William and Mary, Williamsburg, Virginia; Samsung Advanced Institute of Technology, Suwon, South Korea;
authors.forename: Hoshik
authors.initials: H
authors.lastname: Lee
authors.affiliation: Division of Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia;
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Clark
authors.affiliation: Division of Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia; Department of Statistics, University of Virginia, Charlottesville, Virginia;
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Lake
authors.affiliation: Department of Physics, College of William and Mary, Williamsburg, Virginia;
authors.forename: Anne C
authors.initials: AC
authors.lastname: Mennen
authors.affiliation: Department of Pediatrics (Neonatology), University of Virginia, Charlottesville, Virginia;
authors.forename: John
authors.initials: J
authors.lastname: Kattwinkel
authors.affiliation: Department of Pediatrics (Neonatology), University of Virginia, Charlottesville, Virginia;
authors.forename: Robert A
authors.initials: RA
authors.lastname: Sinkin
authors.affiliation: Division of Cardiovascular Medicine, University of Virginia, Charlottesville, Virginia; Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia; and Department of Molecular Physiology, University of Virginia, Charlottesville, Virginia.
authors.forename: J Randall
authors.initials: JR
authors.lastname: Moorman
authors.affiliation: Department of Pediatrics (Neonatology), University of Virginia, Charlottesville, Virginia;
authors.forename: Karen D
authors.initials: KD
authors.lastname: Fairchild
authors.affiliation: Department of Physics, College of William and Mary, Williamsburg, Virginia;
authors.forename: John B
authors.initials: JB
authors.lastname: Delos
mesh_terms: D001049:Apnea / Q000503:physiopathology*; D001919:Bradycardia / Q000188:drug therapy / Q000503:physiopathology; D002110:Caffeine / Q000494:pharmacology; D045422:Continuous Positive Airway Pressure / Q000379:methods; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D019102:Infant, Very Low Birth Weight / Q000502:physiology*; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods; D010100:Oxygen / Q000008:administration & dosage; D012119:Respiration / Q000187:drug effects
chemical_list: D002110:Caffeine; D010100:Oxygen
keywords: apnea; bradycardia; hypoxia; neonatal