Which device is necessary for a respiratory therapist to determine a patient's RSBI?

The correct choice for determining a patient's Rapid Shallow Breathing Index (RSBI) is the vane respirometer. The RSBI is calculated by measuring the respiratory rate (breaths per minute) and the tidal volume (in liters) of a patient. The vane respirometer is designed to measure the volume of air inhaled and exhaled during breaths, allowing the therapist to capture the necessary tidal volume data.

Calculating the RSBI involves dividing the respiratory rate by the tidal volume, which is why accurate tidal volume measurements are essential. The vane respirometer provides this measurement effectively, enabling the therapist to make informed decisions regarding the patient's respiratory status.

Other devices mentioned, such as the end-tidal CO2 monitor, are used for different purposes, such as measuring the concentration of carbon dioxide in exhaled breath and assessing ventilation efficiency. A positive/negative pressure manometer is primarily used to measure pressures in ventilation systems and is not suitable for directly measuring tidal volume. The peak flow meter is used to assess maximal expiratory flow rates, typically in asthmatic patients, but it does not provide the information needed to calculate RSBI.

Thus, the vane respirometer is crucial for determining the RSBI, as it specifically measures