What is a critical reading of a pulse oximeter used for?

A pulse oximeter is a non-invasive device designed to measure the oxygen saturation of a patient's blood. The primary function of this device is to assess how well oxygen is being transported throughout the body by hemoglobin. The readings provided by a pulse oximeter reflect the percentage of hemoglobin that is saturated with oxygen, which is vital for evaluating a patient's respiratory efficiency and determining how much oxygen is available to the body's tissues.

When assessing a patient's condition, knowing the oxygen saturation level is critical, especially in cases of respiratory distress or potential hypoxia. This information guides healthcare providers in making informed decisions about interventions, such as the need for supplemental oxygen or further respiratory support.

While assessing the respiratory rate, measuring arterial blood carbon dioxide levels, and detecting lung sounds are important components of a comprehensive respiratory assessment, they do not relate directly to the function of a pulse oximeter. Thus, the determination of oxygen saturation is the primary focus of this device, making it the correct answer to the question.