Which technique is useful for assessing a child's respiratory rate?

Counting the breaths over one minute while the child is alert is the most effective technique for assessing a child's respiratory rate because it provides a direct measure of how many breaths the child takes in a fixed period. When a child is alert, they are more likely to have a consistent breathing pattern, allowing for an accurate count. This method also reflects the child's respiratory activity in the context of their current state, including any potential anxiety or exertion that could temporarily affect their breathing.

Observing chest movement during sleep can lead to an inaccurate assessment because breathing patterns can change significantly during different sleep stages. A pulse oximeter measures oxygen saturation, which gives information about some aspects of respiratory function but does not provide a direct count of respiratory rate. Listening for wheezing sounds with a stethoscope is primarily concerned with assessing the presence of obstructive airway conditions rather than providing a quantitative measure of respiratory rate. Each of these other methods may add valuable information regarding respiratory health but do not serve the primary purpose of counting breaths effectively.