What should parents do before using a peak flow meter for their child?

The correct action before using a peak flow meter is to place the sliding marker at the bottom of the scale. This step is crucial as it sets a baseline measurement for the child’s peak expiratory flow rate (PEF). Properly calibrating the device ensures that subsequent readings can be accurately compared to the initial value. If the sliding marker is not reset to zero, the readings taken may not reflect the true lung function of the child, potentially leading to misinterpretation of their respiratory status.

To ensure effective use of the peak flow meter, it’s also important that the child is in a comfortable position. However, the primary task before taking any measurement is to reset the device. Other options, such as inhaling rapidly before measurement or using the meter after eating, would not be appropriate practices, as they do not contribute positively to obtaining a valid reading and can lead to inaccurate results.