Certified Respiratory Therapist Practice Exam

What is the preferred method for measuring carbon dioxide production in a mechanically ventilated patient?

1. Peak Expiratory Flow Rate

2. Capnography

3. Bloody Gas Percentage

4. DLCO Testing

The correct answer is: Capnography

The preferred method for measuring carbon dioxide production in a mechanically ventilated patient is capnography. This technique involves the continuous measurement of carbon dioxide concentration in exhaled air. Capnography is particularly beneficial in critical care settings because it provides real-time data on metabolic status and ventilatory effectiveness. By analyzing the exhaled carbon dioxide levels, healthcare providers can assess the patient's ventilation and make necessary adjustments to the ventilator settings. Additionally, capnography can help detect changes in a patient’s condition, such as the development of respiratory distress or the effectiveness of therapy. The waveform produced during capnography also allows clinicians to evaluate the pattern of carbon dioxide elimination, which is vital for troubleshooting issues related to ventilation. While measuring peak expiratory flow rate is useful for assessing airway conditions and lung function in some patients, it does not directly measure carbon dioxide production. Similarly, bloody gas percentage and DLCO testing are not relevant for assessing carbon dioxide levels in a mechanically ventilated patient, as they focus on different aspects of respiratory function.