Which device can the respiratory therapist use to calculate a patient's rapid shallow breathing index?

The rapid shallow breathing index (RSBI) is calculated by dividing the respiratory rate (RR) by the tidal volume (VT), typically measured in liters. To accurately determine these parameters, a device capable of measuring both respiratory rate and tidal volume is required.

A vane respirometer is specifically designed to measure the volume of air inspired or expired by a patient, providing crucial data on tidal volume. By recording the patient’s breathing rate while simultaneously measuring the volume of air moved, the vane respirometer allows the respiratory therapist to compute the RSBI effectively.

Other devices listed, while useful in various respiratory assessments, do not provide the necessary data for calculating the RSBI in the same direct manner. For example, a maximum inspiratory pressure manometer measures the strength of a patient's inspiratory effort but does not give insight into respiratory rate or tidal volume. An infrared CO2 detector is used primarily to measure carbon dioxide levels and can provide information about ventilation but does not measure volume correctly for RSBI calculation. Lastly, a pneumotachometer is capable of measuring flow and can be used in clinical settings, but it is less commonly employed for direct RSBI calculations compared to the functionality of a vane respirometer.

Hence, the vane respirometer