Use of home cardiorespiratory monitors in infants

INTRODUCTION — Home cardiorespiratory (CR) monitors have been available for approximately 40 years and were originally intended to prevent sudden infant death syndrome (SIDS) in at-risk infants. Since then, it has become clear that the CR monitor is not an effective tool to prevent SIDS [1].

Nonetheless, there is some justification for the use of CR monitors in selected infants with other underlying disorders. Selection of infants for monitoring depends upon the infant's underlying problem and the capabilities of the monitor. In many cases, the primary utility of the monitor is diagnostic (ie, to distinguish genuine from false CR events and document the nature and frequency of CR events) rather than therapeutic (ie, to provide an alarm that allows intervention to terminate events).

The appropriate use of CR monitors for specific disorders, the capabilities and limitations of the devices, and the management of infants with CR monitors will be reviewed here. The pathophysiology, evaluation, and other approaches to managing the disorders for which CR monitoring is sometimes considered are discussed separately. (See "Sudden infant death syndrome: Risk factors and risk reduction strategies" and "Acute events in infancy including brief resolved unexplained event (BRUE)" and "Management of apnea of prematurity".)

DEVICES AND CAPABILITIES

●Standard home CR monitors – Standard home CR devices detect when the heart rate falls below or above a preset range or when there is no chest wall movement for a preset length of time. Most monitors also record waveforms during events (documented monitoring), which can facilitate diagnosis and decisions about when to stop monitoring. Oxygen saturation measurements can be monitored separately or are included on some CR monitors, if specifically requested.

These devices directly measure central apnea by the lack of respiratory effort. They do NOT detect obstructive apnea in the absence of bradycardia.

Thus, the clinical utility of the monitor depends upon the pathophysiology of the underlying disorder. It will be more useful for infants at risk for central apnea or bradycardia (eg, apnea of prematurity) than for disorders in which apnea or bradycardia are late consequences of hypoxemia. If oxygen saturation measurements are included, the device may provide somewhat earlier recognition of events in infants with primary respiratory disease (eg, those with a tracheostomy or neuromuscular disease), provided that caretakers can respond in time to reverse the problem [2].

●Direct-to-consumer marketed "wellness" devices – A new class of smartphone-integrated infant physiologic monitors are being marketed directly to consumers, which have sensors built into socks, clothing, or diaper clips. Although caregivers may feel reassured by these monitors and there is no contraindication, there is no evidence that they reduce the risk of sudden infant death syndrome (SIDS) or any other risk [1]. Furthermore, these devices have many false-negative readings, which might promote caregiver complacency and decreased adherence to safe sleep guidance. They also have many false-positive alarms, which might promote caregiver anxiety. If a family chooses to use one of these devices, it is important to emphasize that the device is not a substitute for following safe sleep guidance. (See "Sudden infant death syndrome: Risk factors and risk reduction strategies", section on 'No benefit from home monitors'.)

The remainder of this topic review refers to standard CR monitors and not to these "wellness" devices.

MONITORING DECISIONS — The decision as to whether or not CR monitoring should be considered in an individual infant varies with the underlying disorder.

Asymptomatic infants with risk factors for sudden infant death syndrome — Sudden infant death syndrome (SIDS) is defined as the sudden death of an infant younger than one year of age that remains unexplained despite a thorough case investigation, including autopsy, examination of the death scene, and review of the clinical history [3]. Although prematurity is one of several risk factors for SIDS, the mechanism and timing of SIDS are distinct from those of apnea of prematurity. (See "Sudden infant death syndrome: Risk factors and risk reduction strategies".)

In the 1970s, it was proposed that prolonged central apnea was an early and, perhaps, primary event in the pathogenesis of SIDS [4]. This "apnea hypothesis" was based on observations of recurrent brief apneic episodes during sleep in several infants, which resolved as the infants matured. Infants with these features were thought to be at risk for SIDS, and CR monitoring was proposed in an effort to prevent death.

Since then, several important advances have indicated that apnea is not an initial event in the pathogenesis of SIDS and that CR monitoring is unlikely to prevent most events:

●Several infants have died with home CR monitoring devices in place, and a body of literature has emerged presenting the data from so-called "death tracings" [5-7]. The data obtained from death tracings suggest that bradycardia occurs first and is followed by terminal apnea. It is hypothesized that hypoxia precedes the recorded bradycardia [8,9].

●The American Academy of Pediatrics (AAP) launched the "Back to Sleep" campaign advocating supine sleeping in 1992 [10]. Since that time, the SIDS rates in the United States have decreased by over 50 percent [1]. (See "Sudden infant death syndrome: Risk factors and risk reduction strategies", section on 'Epidemiology'.)

●Increasing attention has been focused on the issue of child abuse and infanticide masquerading as recurrent acute unexplained events or SIDS [11-14]. A widely publicized case of five successive deaths in a family in New York resulted in greater recognition of this entity, especially in families with more than one occurrence among siblings [15].

●Epidemiologic studies and two decades of clinical experience have failed to show an effect of CR monitors in reducing the incidence of SIDS in infants presumed to be at risk [16,17].

●Studies using plethysmographic monitors capable of detecting both central and obstructive apnea in infants presumed to be at risk for SIDS displayed a high frequency of obstructed breathing, which would not be detected by conventional monitoring [18].

Thus, there are no data to support the therapeutic use of CR monitoring as a means of reducing the risk for SIDS in asymptomatic infants, regardless of SIDS risk factors that may be present (eg, prior sibling SIDS death, or prematurity). However, the physiologic parameters recorded by CR monitors may have some diagnostic value by defining the types of physiologic abnormalities occurring in some subgroups of infants, including symptomatic preterm infants, infants with brief resolved unexplained events, and infants with other underlying disorders, as discussed below.

Counseling parents of asymptomatic infants with risk factors for SIDS who request a home monitor may be challenging. We suggest that the clinician engage parents in a focused conversation that describes the potential negative consequences of using a home monitor and makes it clear that they should not consider a monitor to be a SIDS prevention strategy. However, we also suggest acknowledging that parents appropriately feel the need to watch their baby closely and that all parents have to decide how best to watch and check on their baby. In rare cases, where it is believed that the parents cannot cope using conventional strategies to watch their baby (ie, having the baby sleep in the parents' room, periodically entering the sleep room, or using standard baby room listening devices), it may be reasonable to support the parents' desire to watch their baby with a home CR monitor. However, in such cases, it is critical to emphasize the need for the parents to follow recommended infant care practices related to reducing SIDS risk and to ensure that they have a clear understanding of the reason for using the monitor and the plan for when it should be discontinued. (See 'Counseling of parents' below and "Sudden infant death syndrome: Risk factors and risk reduction strategies", section on 'Prevention'.)

Preterm infants with persistent symptoms related to apnea of prematurity — Apnea of prematurity is defined as the sudden cessation of breathing that lasts for at least 20 seconds or is accompanied by bradycardia or a drop in oxygen saturation in an infant younger than 37 weeks postmenstrual age [19]. (See "Management of apnea of prematurity".)

Most apneic events are central (ie, cessation of respiratory effort), and the disorder is thought to be caused by immaturity of respiratory control mechanisms. The breathing pattern matures with increasing postmenstrual age. Nonetheless, preterm infants continue to have more episodes of prolonged apnea than infants born at term until approximately 43 weeks postmenstrual age [18].

Premature infants with persistent apnea of prematurity but who are otherwise ready for hospital discharge are candidates for home CR monitoring. Implementation of monitoring requires counseling and training of the caretakers, follow-up and review of events by a professional, and determination of an end point for monitoring. (See 'Implementation' below.)

Infants with brief resolved unexplained events — A brief resolved unexplained event (BRUE) is an acute, unexpected change in an infant's breathing behavior that was frightening to the caretaker and is characterized by some combination of apnea, color change, change in muscle tone, choking, or gagging. Infants experiencing BRUEs represent a heterogeneous group of patients of varying ages with diverse pathophysiology. Although a relationship between BRUEs and SIDS was initially suggested, studies during the past two decades have failed to confirm a causal relationship. (See "Acute events in infancy including brief resolved unexplained event (BRUE)", section on 'Prognosis'.)

A specific cause for the BRUE can be identified in most infants after a careful history, physical examination, and appropriate laboratory evaluation. In most of these cases, home CR monitoring does not have additional diagnostic value. (See "Acute events in infancy including brief resolved unexplained event (BRUE)".)

The decision for home monitor observation should be made on a case-by-case basis, depending upon the presumed cause of the BRUE after a careful investigation, the estimated risk of recurrence, and after considering with the family the potential benefits, uncertainties, and stresses involved. In general, CR monitors would be less helpful for infants with presumed obstructive pathophysiology than for those with central apnea. In some cases, the potential value of the monitor lies in its ability to record physiologic data that may provide reassurance that clinically important events are not occurring.

Other indications — In infants with underlying diseases predisposing to respiratory failure, home CR monitoring may facilitate rapid recognition of central apnea, airway obstruction, respiratory failure, interruption of supplemental oxygen supply, or failure of mechanical respiratory support. Thus, infants with the following conditions are candidates for monitoring:

●Tracheostomy or airway abnormalities (see "Congenital anomalies of the intrathoracic airways and tracheoesophageal fistula")

●Neurologic or metabolic disorders affecting respiratory control

●Chronic lung disease (eg, bronchopulmonary dysplasia), especially those requiring supplemental oxygen, positive airway pressure, or mechanical ventilatory support (see "Bronchopulmonary dysplasia (BPD): Management and outcome")

In some infants, oxygen saturation monitoring alone or in conjunction with a CR device may provide more useful diagnostic information than a CR monitor alone. None of the available home CR monitors reliably detect obstructive apnea [18].

IMPLEMENTATION

Counseling of parents

●Families must be informed of the purpose of the monitor and what it can and cannot do. It is a tool to alert them to check the baby when an alarm is triggered either by the baby's heart rate falling below a preset limit or by the monitor's not detecting chest wall movement for a preset number of seconds. Parents must know that the monitor cannot guarantee the safety of the infant and that infants have died while being monitored.

●Regardless of the indication for monitoring, caretakers should be counseled regarding sudden infant death syndrome (SIDS) risk reduction, especially with regard to infant sleep position; safe sleep environment to avoid suffocation, including appropriate bedding and sleep surface; avoidance of exposure to tobacco smoke; and the importance of regular medical check-ups. (See "Sudden infant death syndrome: Risk factors and risk reduction strategies", section on 'Prevention'.)

●Families should be aware of the stresses of monitoring. As an example, some parents feel they cannot leave the infant and child care can be difficult to find. False alarms can cause unnecessary sleep disruption.

●Families should be told how long to expect the baby to be monitored and what criteria will be used to discontinue monitoring. Factors to consider are:

•The expected course of the disorder for which the infant is being monitored (eg, apnea of prematurity tends to resolve by 43 weeks postmenstrual age)

•The risk of SIDS is very low after six months of age

•The risk of becoming entangled in lead wires is increased after infants are able to roll over and sit up

Professional support

●Caretakers must be taught how to perform cardiopulmonary resuscitation and other emergency responses to an alarm.

●Caretakers must have access at all times to technical support in case of problems with monitor function and to professional support to answer questions which may arise regarding the infant's status.

●The recorded monitor data should be downloaded on a monthly basis. This should be reviewed by a professional with expertise in interpreting waveforms who can distinguish between true and false events. Clinical judgment must be used to determine whether recorded apneas or bradycardias are significant [20,21].

End point of monitoring — The end point of monitoring varies with the indication for monitoring. In general, six to eight weeks of normal downloads and no clinical events is considered sufficient. Parental readiness to discontinue monitoring is also a factor.

●For infants monitored because of apnea of prematurity, monitoring can be discontinued if no true events have been detected on downloads and no important clinical events have occurred in several weeks, and if the infant is older than 43 weeks postmenstrual age [18]. Apnea of prematurity may persist longer in infants born very prematurely [22].

●For infants monitored because of underlying respiratory disease or anatomic airway abnormalities, the decision to continue monitoring depends primarily upon the frequency and severity of the events that trigger alarms.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Sudden unexpected infant death including SIDS".)

SUMMARY AND RECOMMENDATIONS

●History – Home cardiorespiratory (CR) monitors were originally intended to prevent sudden infant death syndrome (SIDS) in at-risk infants. Since then, it has become clear that they are not effective tools to prevent SIDS. (See 'Introduction' above.)

●Devices and capabilities – Standard home CR monitors detect heart rate and chest wall movement; oxygen saturation measurements can be monitored if specifically requested. The devices directly measure central apnea by the lack of respiratory effort. They do not detect obstructive apnea in the absence of bradycardia or a drop in oxygen saturation. (See 'Devices and capabilities' above.)

Direct-to-consumer marketed "wellness" devices are smartphone-integrated devices with sensors built into socks, clothing, or diaper clips. There is no evidence that they reduce the risk of SIDS or any other risk. Furthermore, these devices have many false-negative readings, which might promote caregiver complacency and decreased adherence to safe sleep guidance.

●Potential uses

•Preventing SIDS (no benefit) – Central apnea is not necessarily an initial event in the pathogenesis of SIDS. There is no evidence that SIDS can be prevented by CR monitoring of asymptomatic infants, whether or not SIDS risk factors are present (eg, prior sibling SIDS death, or prematurity). (See 'Asymptomatic infants with risk factors for sudden infant death syndrome' above.)

•Monitoring apnea of prematurity – Premature infants with persistent apnea of prematurity but who are otherwise ready for hospital discharge are candidates for home CR monitoring. The decision of whether to use a monitor depends on assessment of risks and benefits for the individual infant. Monitoring can generally be discontinued by 43 weeks postmenstrual age. (See 'Preterm infants with persistent symptoms related to apnea of prematurity' above and 'End point of monitoring' above.)

•Other possible indications – Home CR monitoring may facilitate rapid recognition of an acute respiratory or cardiac problem in infants with underlying diseases, including tracheostomy or airway abnormalities, neurologic or metabolic disorders affecting respiratory control, or chronic lung disease. For many of these infants, inclusion of oxygen saturation measurements with the CR device may allow for earlier recognition of events. (See 'Other indications' above.)

●Implementation – If CR monitoring is recommended, implementation requires counseling and training of the caretakers, and professional oversight to analyze recordings and clinical events and determine an appropriate end point for monitoring. (See 'Implementation' above.)