Which client behavior indicates a need for further instruction on the use of a metered-dose inhaler (MDI)?

The behavior indicating a need for further instruction on using a metered-dose inhaler (MDI) is the client's rapid inspiration while using the device. Proper technique with an MDI involves coordinating the activation of the inhaler with a slow, deep inhalation. This ensures that the medication is effectively delivered to the lungs for optimal absorption.

When a client inspires rapidly, they may not create the necessary airflow to properly aerosolize the medication, potentially leading to less effective treatment. The aim is to maximize drug deposition in the lungs, which requires a controlled and deliberate inhalation.

In contrast, activating the MDI with inspiration, holding the breath for a brief moment post-inhalation, and shaking the MDI before use are all appropriate behaviors. These actions contribute to the effectiveness of the treatment by ensuring that the medication is properly administered and absorbed.