Rapid Shallow Breathing Index (RSBI)
Compute the Yang-Tobin rapid shallow breathing index (RSBI = respiratory rate in breaths/min divided by tidal volume in litres) for a mechanically ventilated patient on a spontaneous breathing trial.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Respiratory rate
- 24 breaths/min
- Tidal volume
- 350 mL
Result: RSBI 68.6 - likely to tolerate weaning (< 105).
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Respiratory rate
- Tidal volume
What this is
The original 1991 cohort found that an RSBI below 105 had a positive predictive value of about 0.78 for successful extubation and an RSBI above 105 a negative predictive value of about 0.95. Sophie Well returns the index and labels the threshold.
When to use it
Use this during or at the end of a spontaneous breathing trial (CPAP or T-piece) when you are deciding whether to proceed to extubation. RSBI is a screening number, not a green light - it should sit alongside the cuff-leak test, the mental-status check, an honest assessment of secretions and cough strength, and the original reason the patient was intubated. RSBI loses accuracy with chronic neuromuscular disease, severe COPD (where high RR is the baseline), recent paralytic exposure, and in patients on assist modes that augment Vt; in those settings the bedside gestalt outweighs the number.
How this is calculated
Yang KL, Tobin MJ. RSBI. NEJM 1991;324:1445-1450. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.