|Apnea monitors are devices that help to detect apnea in child. They are used both in NICU and home setting. They especially useful in infants having frequent apneic spells and are at the risk of dying.
Apnea is defined as pause in breathing more then 20 seconds. It may be significant if pause is less than 20 seconds but is associated with a significant drops in the heart rate.
Apnea may be of 3 types:-
1) Central - There is no breathing, no chest movements and no air passes through the mouth or nose.
2) Obstructive - The chest is moving but no air passes due to obstruction.
Apnea monitors have to detect both decrease in chest movements as well as function of other physiological parameters (e.g. heart rate) that are affected by the apnea in the baby.
Most of the apnea monitors sound alarm if the baby stops breathing for 20 seconds or if the heart rate drops to less than 80 beats per minute.
Missed alarms:- In some situations the alarms may not go off even the baby has stopped breathing. If the monitor is kept next to electrical appliances like TV sets, air conditioners and remote telephone, the alarm may not sound. These instruments should be kept at least a foot away from the monitor. Also sometimes the monitor may be accidentally disconnected and alarm may not go off. Babies who sleep along with their parents in the bed may have an unnoticed apneic spell as the monitor may pick up movements of the parents and not sound.
False alarms:- Another problem that can occur is that the alarm may sound frequently even when the baby is breathing. What may occur is that the baby may be breathing very shallow and the abdominal breathing may not cause the chest to move where the electrodes are attached. Another cause may be loose wires. It may also be difficult to determine between false and real apnea episodes. Sometimes the alarm itself will wake up the baby and the breathing may start again.
Some apnea monitors come with computer memories that can store information such as the length of the time the monitor did not detect breathing and the heart rate recording. It may be useful to determine the further treatment to be given to the baby.