New desaturation index to evaluate neonatal apnea using polygraphy.
BACKGROUND
Polygraph recordings of neonatal apnea obtained using an Eden Trace II monitor were manually analyzed to devise a new desaturation index (DSI).


METHODS
Heart rate, thoracic respiratory movements, airflow, and blood oxygen saturation (SpO2) of 25 neonates in intensive care were monitored using polygraphy. The DSI was defined as the number of SpO2 decreases per hour of valid monitoring time. Neonates were divided into three groups according to DSI85: group A, DSI85 less than one decrease per hour (n = 12); group B, DSI85 ranging from one to nine decreases per hour (n = 8); and group C, DSI85 > or=10 decreases per hour (n = 5). Clinical characteristics and type of apnea in each group were compared statistically. Group C neonates were treated with aminophylline, and the effects of treatment were evaluated.


RESULTS
Gestational age at birth, birthweight, age at monitoring and valid monitoring time did not differ significantly between the three groups, but mean SpO2, DSI70, the frequency of central apnea and periodic breathing did. Oxygen desaturation in group B and particularly group C was predominantly attributable to periodic breathing rather than central apnea. Aminophylline produced significant improvement in periodic breathing but exerted no significant effect on the other types of apnea. Both DSI85 and DSI70 were strongly correlated (r = 0.833).


CONCLUSIONS
Polygraphic study of neonates at risk revealed marked arterial oxygen desaturation, even among those with periodic breathing. This novel DSI represents a useful tool for evaluating apnea and periodic breathing in neonates and for assessing treatment efficacy.
Minowa
Hideki
H
Division of Pediatrics, Nara Hospital, Kinki University School of Medicine, Ikoma City, Japan. minowa@nara.med.kindai.ac.jp
Uchida
Yumiko
Y
Ebisu
Reiko
R
Yoshibayashi
Muneo
M
Takahashi
Yukihiro
Y
Yoshioka
Akira
A
D000628:Aminophylline / Q000627:therapeutic use; D001049:Apnea / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology; D001785:Blood Gas Monitoring, Transcutaneous / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D010100:Oxygen / Q000097:blood*
D000628:Aminophylline; D010100:Oxygen