Monitoring Apnea of Prematurity: Validity of Nursing Documentation and Bedside Cardiorespiratory Monitor

Apnea of prematurity, defined as cessation of breathing for > 20 seconds, is extremely common among premature infants born ≤ 34 weeks’ gestational age.1,2 The underlying mechanism for apnea of prematurity is thought to be immaturity of respiratory control with incidence inversely proportional to gestational age and chronologic age.1–3 Therefore, it is a routine practice to continuously monitor premature infants’ ≤ 34 weeks’ gestational age for apnea of prematurity with bedside cardiorespiratory monitors until the resolution of apnea of prematurity. The bedside cardiorespiratory monitor uses impedance technology and detects respiration by translating changes in electrical properties of the thorax into a waveform that represents breathing.4 Bedside monitors also provide continuous heart rate monitoring using impedance technology and also display oxygen saturations measured using pulse oximetry.4 Bedside nurses usually document apnea in the medical records after visual evaluation of the infant when an apnea alarm is triggered, and this documentation is routinely used by neonatologist for the evaluation and management of central apnea including initiation, maintenance, and discontinuation of xanthine therapy and respiratory support. These observations are also commonly used to evaluate the apnea-free period of 5 to 10 days before ceasing apnea monitoring at the time of discharge to home.5 Previous studies have shown that nursing documentation of apnea is inaccurate when compared with documented event monitoring using event-recorder monitors that allow visual inspection and analysis of electronic cardiorespiratory waveform.6 Similarly, it has been shown that infant monitor alarms are not accurate when compared with documented event monitoring using event-recorder monitors for home monitoring.7,8 However, nursing documentation of apnea has not been prospectively evaluated and compared with bedside infant monitors over an extended period in individual premature infants in the neonatal intensive care unit (NICU) using objective assessment of apnea by visual inspection and analysis of continuous electronic cardiorespiratory waveform. Like the event-recorder monitor, a central monitor (Clinical Information Center, GE Medical Systems, General Electric Company, Milwaukee, WI), which may be available in some NICUs, uses impedance technology and provides documented event monitoring. It provides assessment of true apnea by visual inspection of electronic cardiorespiratory waveform, which is recorded in real time and stored in memory for 72 hours. We hypothesize that nursing documentation and bedside cardiorespiratory monitors do not provide accurate monitoring of true apnea when compared with visual inspection of continuous electronic cardiorespiratory waveform. Our objective was to evaluate the validity of bedside monitoring and nursing documentation of apnea events by comparing apnea events recorded by bedside cardiorespiratory monitor and by nursing documentation with those detected by visual inspection of continuous electronic waveform on central monitors over a 2-week period in premature infants. The study was approved by the local Institutional Research Board and parental consent was obtained for each subject.