title: Anemia, apnea of prematurity, and blood transfusions.
abstract: OBJECTIVE
  To compare the frequency and severity of apneic events in very low birth weight (VLBW) infants before and after blood transfusions using continuous electronic waveform analysis.
  
  
  METHODS
  We continuously collected waveform, heart rate, and oxygen saturation data from patients in all 45 neonatal intensive care unit beds at the University of Virginia for 120 weeks. Central apneas were detected using continuous computer processing of chest impedance, electrocardiographic, and oximetry signals. Apnea was defined as respiratory pauses of >10, >20, and >30 seconds when accompanied by bradycardia (<100 beats per minute) and hypoxemia (<80% oxyhemoglobin saturation as detected by pulse oximetry). Times of packed red blood cell transfusions were determined from bedside charts. Two cohorts were analyzed. In the transfusion cohort, waveforms were analyzed for 3 days before and after the transfusion for all VLBW infants who received a blood transfusion while also breathing spontaneously. Mean apnea rates for the previous 12 hours were quantified and differences for 12 hours before and after transfusion were compared. In the hematocrit cohort, 1453 hematocrit values from all VLBW infants admitted and breathing spontaneously during the time period were retrieved, and the association of hematocrit and apnea in the next 12 hours was tested using logistic regression.
  
  
  RESULTS
  Sixty-seven infants had 110 blood transfusions during times when complete monitoring data were available. Transfusion was associated with fewer computer-detected apneic events (P < .01). Probability of future apnea occurring within 12 hours increased with decreasing hematocrit values (P < .001).
  
  
  CONCLUSIONS
  Blood transfusions are associated with decreased apnea in VLBW infants, and apneas are less frequent at higher hematocrits.
authors.affiliation: Department of Pediatrics, University of Virginia, Charlottesville, VA, USA.
authors.forename: Kelley
authors.initials: K
authors.lastname: Zagol
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Lake
authors.forename: Brooke
authors.initials: B
authors.lastname: Vergales
authors.forename: Marion E
authors.initials: ME
authors.lastname: Moorman
authors.forename: Alix
authors.initials: A
authors.lastname: Paget-Brown
authors.forename: Hoshik
authors.initials: H
authors.lastname: Lee
authors.forename: Craig G
authors.initials: CG
authors.lastname: Rusin
authors.forename: John B
authors.initials: JB
authors.lastname: Delos
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Clark
authors.forename: J Randall
authors.initials: JR
authors.lastname: Moorman
authors.forename: John
authors.initials: J
authors.lastname: Kattwinkel
mesh_terms: D000465:Algorithms; D000740:Anemia / Q000453:epidemiology*; D001049:Apnea / Q000453:epidemiology* / Q000503:physiopathology; D001803:Blood Transfusion; D002307:Cardiography, Impedance; D015897:Comorbidity; D004562:Electrocardiography; D006400:Hematocrit; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007231:Infant, Newborn; D019102:Infant, Very Low Birth Weight / Q000502:physiology; D016015:Logistic Models; D010092:Oximetry; D010100:Oxygen / Q000097:blood
chemical_list: D010100:Oxygen