A non ventilated preterm baby in incubator is under observation. Which is the best way to monitor the baby's breathing and detect apnaea ?

The respiratory monitor based on impednace technique measures changes in the electrical resistance during breathing. The electrode is fixed on the chest wall to pick up signals which are displayed as respiratory rate. Capnography - lit is a simple non invasive method to assess arterial CO,. It is used to assess the placement of ET tube in esophagus or trachea.