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Intelligent Management System for Apnea
Identification, 10-9037
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Principal Investigators
Xiao Zhao
Keith A. Bartels
Inclusive Dates: 07/01/97 - 10/01/99
Background - Apnea, or the cessation of
breathing, is recognized as a clinical problem affecting premature babies. Current
technology for automatic apnea detection involves monitoring the baby's blood oxygen
saturation percentage (SpO2). When the SpO2
level falls below a preset level for an extended time, the automatic monitoring system
sounds an alarm to alert a care giver. A more desirable monitoring system would be one
that predicts the onset of apnea before breathing stops so that the undesired drop in SpO2
can be avoided.
Approach - The vital signs of 12 premature
infants with histories of apnea were monitored in the neonatal intensive care unit of a
local hospital. The specific vital signs monitored were EKG, respiration, SpO2,
heart rate, and respiration rate. The vital-sign information was obtained from the
standard infant monitors in use at the hospital using an SwRI-designed and programmed
data-acquisition system. Along with the babys vital signs, measurements on the
sound, light, and motion levels near the infant were also acquired using SwRI sensors and
hardware designed specifically for this project.
The data-acquisition procedure was approved by the
Institutional Review Board, and permission was obtained from the parents of each baby
prior to data acquisition. Each of the babies had a history of apneic events, and four
hours of data were obtained from each baby. After 12 data sets were acquired, the data
were examined in the time and frequency domains for trends or events that could be used to
predict the occurrence of apnea.
Accomplishments - A comprehensive review
of all data sets showed no features, either in the time or frequency domains, that clearly
predicted the onset of an apneic episode. However, one characteristic of the data was
identified that may be indicative of problems in the development of a newborn baby's
control of breathing, namely that all of the babies showed a periodic change in their
vital signs. For example, the magnitudes of the heart and respiration rates varied,
sometimes by more than 100 percent, with a periodicity of about 2.5 minutes. This
periodicity had not been previously reported in the scientific literature, and one
hypothesis is that it may be an indicator of a developmental problem in breathing control.
Because no control babies could be included in this initial study, the research team was
unable to identify this feature as unique to premature infants with breathing problems. A
journal article is currently being prepared in conjunction with the study neonatologist.
This article will be used to support a grant application to the National Institute of
Health for further study of this phenomenon.

Institute bioengineers collaborated with San Antonio
neonatologists to develop an intelligent software program to identify apnea in premature
infants.
Biosciences and
Bioengineering Program
1999 IR&D Home
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