How to Use RSBI Calculator
Enter respiratory rate in breaths per minute and tidal volume in liters. The RSBI Calculator divides rate by tidal volume and compares the result with the commonly cited 105 threshold.
Tidal volume should be entered in liters. If the ventilator or worksheet lists 450 mL, enter 0.45 L. Entering 450 would make the result meaningless.
RSBI is usually interpreted during spontaneous breathing or weaning assessment, not during heavily supported mandatory ventilation.
Formula & Theory — RSBI Calculator
The RSBI Calculator uses the following formula or scoring rule:
RSBI = respiratory rate ÷ tidal volume(L)Rapid shallow breathing means a patient breathes frequently while moving a small volume each breath. The numerator rises, the denominator falls, and RSBI increases.
A value below about 105 has traditionally been considered more favorable for ventilator liberation, but it is only one part of readiness assessment.
Mental status, gas exchange, secretion burden, hemodynamics, cough strength, and underlying disease also affect extubation decisions.
Use Cases for RSBI Calculator
The RSBI Calculator is useful in specific situations such as:
- checking an RSBI value from a spontaneous breathing trial
- teaching why small tidal volume raises RSBI
- converting tidal volume from mL to L before calculation
- including RSBI in a ventilator-weaning worksheet