Transient Episodes of Bradycardia, and Periodic Breathing in Preterm Infants
Apnea, Joan E.
Hodgman, MD; Felipe Gonzalez, MD; Toke Hoppenbrouwers, PhD; Luis A. Cabal, MD
\s=b\ The occurrence of central apnea of 15 seconds or longer, transient episodes of bradycardia (TEB), and periodic breathing were studied in 66 healthy premature infants when at least 1 week old and between 32 and 36 weeks postconceptual age. Eight-hour cardiorespiratory recordings were visually scanned for the presence of thesee patterns. Central apnea of 15 seconds or longer was seen in almost half of the infants. The TEB were numerous, and the majority were not associated with central apnea; however, all but five of the apneic episodes that lasted 15 seconds or longer were accompanied by a TEB. Infants spent as much as 40% of their time in periodic breathing. The frequency with which these patterns are seen in healthy premature infants strongly suggests that they are normal findings. Our results do not support the opinion that brief periods of apnea are abnormal when accompanied by a TEB.
(AJDC. 1990;144:54-57) the advent of continuous cardio^/"ith respiratory monitoring of the pre¬ mature
and sometimes seemingly ominous pat¬ terns have been identified in the respi¬ ratory and cardiac tracings. Most com¬ monly noted are apnea, transient episodes of bradycardia (TEB), and pe¬ riodic breathing (PB).111 Before attrib¬ uting pathologic significance to these patterns, their occurrence in the healthy infant needs to be established. Quantification of these patterns is still
incomplete. Many previous reports
have been based on small numbers of infants who are at varying ages or have included those who are symptomatic. Few investigators have examined all of these patterns simultaneously in the same infants. The purpose of this study was to define the incidence of central apnea, TEB, and PB in a carefully se¬ lected large group of healthy premature Accepted for publication March 9,1989. From the University of Southern California School of Medicine and Los Angeles County\p=m-\ University of Southern California Medical Center, Los Angeles, Calif. Reprint requests to LAC/USC Medical Center, Women's Hospital, Room L-919, 1240 N Mission Rd, Los Angeles, CA 90033 (Dr Hodgman).
infants between 32 and 36 weeks postconceptional age in a nursery setting. SUBJECTS AND METHODS
Daily admissions to the intensive and in¬ termediate care nurseries were reviewed to identify potential candidates for the study. Sixty-six consecutive healthy premature in¬ fants appropriate for gestational age were selected for the study when they were at least 7 days old and 32 to 36 weeks of postconceptional age. The more mature infants (>34 weeks' gestational age) were frequently dis¬ charged by 1 week and were therefore un¬ available for study. Gestational age was determined by maternal history if the Dubowitz score12 agreed within 2 weeks. If there was a larger discrepancy, the gesta¬ tional age that was closest to the 50th percentile for head circumference using the Denver Intrauterine Growth Curve13 was assigned. Infants with the following clinical or bio¬ chemical findings that might predispose to apnea were excluded: a 5-minute Apgar score below 7, supplemental oxygen for more than 24 hours, assisted ventilation including continuous positive airway pressure, intracranial hemorrhage grades III or IV, sepsis proved by culture, diagnosed medical condi¬ tions, anemia (hematocrit value