Section I - Diagnosis and Medical Management

About Home Monitoring

"Memory" or "documenting" monitors have made the basic home cardiorespiratory monitor obsolete in the management of children with apnea or apnea related problems. The memory monitor provides for the storage and later retrieval of information about monitor alarms (central apnea, bradycardia, tachycardia, loose lead) and equipment use (on/off dates and times). The content and formatting of this information will vary by monitor manufacturer, but there are a number of common elements. The physician can know when the monitor was used, the total number of alarms for the recording period and the breakdown of the alarms by type, alarm threshold and the length of the alarm. Most importantly, the reports include waveforms of the transthoracic impedance signal (TTI) and the heart rate trend or QRS complex for a selection of the patient alarms. The physician consequently can discriminate between patient alarms and actual patient events, e.g. apnea, bradycardia. The memory monitor has not obviated the need for parental observations at the time of an alarm, e.g. infant's position, activity, feeding history, response to stimulation, etc. The size of the monitor's memory and the manner in which the situation of "full memory" is handled will vary by monitor manufacturer. The home medical equipment (HME) company or an apnea specialist can give the primary physician this type of information. Many memory monitors are designed to record a pulse oximetry signal with the use of an extra cable. The option is infrequently elected due to the current limits of pulse oximetry technology.

Monitor settings should be designated by the prescribing physician. Settings should be age-adjusted for prematurity and should reflect physiologic limits (see Glossary-Bradycardia). Neither the basic nor the memory cardiorespiratory monitor can be used to detect obstructive apnea because neither detects airflow or oxygenation.

"Downloading" is the term that has been adopted to describe the retrieval of the information from the monitor's memory. The HME companies which rent the monitors will perform this service at a home visit. Downloading requires a computer and the manufacturer's software. Downloads are done when ordered by a physician. In general, monthly downloads are desirable for most patients unless clinical circumstances dictate otherwise. Once retrieved the information can be printed out or transferred to a computer disk to be forwarded to a designated physician interpreter. An apnea specialist (see Appendix) should provide an interpretation of this data (usually in written form) to the patient's managing physician. The apnea specialist should also be available to answer questions and provide support to this physician in other areas of patient management. A number of apnea specialists also offer patient evaluations through regional apnea clinics (see Appendix).

Cardiorespiratory monitors, like all medical devices should only be prescribed after appropriate evaluation of the patient. As with all such devices, there are certain indications for use and other conditions for which monitoring is not appropriate. The prescribing physician is responsible for documenting indications for use, arranging appropriate training for the patient's caretakers, determining the frequency of downloading, and determining when monitoring should be discontinued. All of these duties may be performed in consultation with an apnea specialist. Instructions for caregivers and recommendations for follow-up are described in section II of this booklet - Discharge Planning and Home Management.