Automated respiratory inductive plethysmography to evaluate breathing in infants at risk for postoperative apnea

Abstract

Although respiratory inductive plethysmography (RIP) is the method of choice for the assessment of sleep disordered breathing, it has not been applied to the study of infants at risk for postoperative apnea (POA). The purpose of this study was to apply RIP to evaluate breathing in these infants. An additional purpose was to implement, simultaneously, three novel algorithms to detect movement artifact, respiratory pauses, and thoracoabdominal asynchrony, since their combined output both detects respiratory pauses and classifies them as obstructive or central in origin. A prospective study design was employed to record the analogue output of RIP, saturation, and finger plethysmography in a convenience sample of infants. The data record underwent a dual analysis: 1) automated detection of respiratory events; and 2) visual coding of the cardiorespiratory data. A novel index, coined pause density, was calculated as the sum of all respiratory pauses. Twenty infants, whose mean postconceptional ages and weights were 44.47 +/- 2.88 weeks and 4.21 +/- 0.99 kg, respectively, were recruited. Data recording ranged from four to 24 hr. Ten infants (term = 5) experienced POA: central apnea = 5, mixed obstructive apnea = 6, and two former premature infants experienced both. Twenty-five central apneic events were detected, and the majority followed a sigh. Infants who experienced apnea also had high values of pause density. Respiratory inductive plethysmography may provide a useful method to evaluate breathing in infants at risk for POA. The study of short respiratory pauses may prove useful in predicting apnea risk.