Certified Transport Registered Nurse Certification Practice Exam 2025 - Free Practice Questions and Study Guide

The pulse oximeter is the device specifically designed to measure peripheral capillary oxygen saturation (SpO2) in a non-invasive manner. It works by emitting light through a pulsating capillary bed, typically found in a fingertip or earlobe, and analyzes the absorption of light on the hemoglobin molecules in the blood. This measurement is crucial in assessing a patient's respiratory function and oxygenation status, allowing for timely interventions if oxygen levels fall below a safe threshold.

While the blood gas analyzer provides a comprehensive evaluation of blood gases, including oxygen levels, it requires blood samples and is an invasive procedure. The capnometer is used to measure the concentration of carbon dioxide in exhaled air, which provides different information related to respiratory function. The spirometry device assesses lung function by measuring the volume and flow of air during inhalation and exhalation, but it does not directly measure oxygen saturation levels.

In summary, the pulse oximeter is essential for continuous monitoring of oxygen saturation, making it the correct answer in this context.