🫁 Rapid Shallow Breathing Index (RSBI)
Predict ventilator weaning success with the Rapid Shallow Breathing Index (RSBI).
Best measured during unsupported spontaneous breathing or after an SBT.
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When to use
Screen readiness for a spontaneous breathing trial and extubation.
How it works
RSBI = respiratory rate ÷ tidal volume (L). < 105 predicts successful weaning/extubation (~ 80%); < 65 high readiness; > 105 high failure risk.
Key points
- Best measured during unsupported spontaneous breathing or after an SBT.
- More sensitive than specific.
- Reflects only rate/volume — integrate with the overall picture.
References
- Yang KL, Tobin MJ. A prospective study of indexes predicting outcome of trials of weaning. NEJM 1991
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Respiratory rate (f) | 22 /min |
|---|---|
| Tidal volume (Vt) | 400 mL |
→RSBI55breaths/min/L
- RSBI：22 ÷ 0.4 L = 55 breaths/min/L (< 65: high weaning readiness)
- Action：High likelihood of successful weaning; with the overall picture (oxygenation, airway protection, mentation, hemodynamics) proceed to a spontaneous breathing trial (SBT)/extubation
- Note：RSBI = f / Vt (L); best measured during spontaneous breathing (no support, ~ 1 min) or after SBT. Sensitive but less specific (< 105 predicting success outperforms > 105 predicting failure); reflects only rate/volume, not inspiratory effort
Frequently asked questions
- What is Rapid Shallow Breathing Index (RSBI)?
- Predict ventilator weaning success with the Rapid Shallow Breathing Index (RSBI).
- How is Rapid Shallow Breathing Index (RSBI) calculated? What is the core formula?
- RSBI = respiratory rate ÷ tidal volume (L). < 105 predicts successful weaning/extubation (~ 80%); < 65 high readiness; > 105 high failure risk.
- When is Rapid Shallow Breathing Index (RSBI) used?
- Screen readiness for a spontaneous breathing trial and extubation.
- What are the key clinical points for Rapid Shallow Breathing Index (RSBI)?
- Best measured during unsupported spontaneous breathing or after an SBT. More sensitive than specific. Reflects only rate/volume — integrate with the overall picture.
- What are the limits and cautions when using Rapid Shallow Breathing Index (RSBI)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Rapid Shallow Breathing Index (RSBI) calculated in practice? Can you show a worked example?
- Inputs: Respiratory rate (f) 22 /min, Tidal volume (Vt) 400 mL → Result: RSBI 55 breaths/min/L（RSBI: 22 ÷ 0.4 L = 55 breaths/min/L (< 65: high weaning readiness), Action: High likelihood of successful weaning; with the overall picture (oxygenation, airway protection, mentation, hemodynamics) proceed to a spontaneous breathing trial (SBT)/extubation, Note: RSBI = f / Vt (L); best measured during spontaneous breathing (no support, ~ 1 min) or after SBT. Sensitive but less specific (< 105 predicting success outperforms > 105 predicting failure); reflects only rate/volume, not inspiratory effort）