Rapid Shallow Breathing Index (RSBI)
Rapid Shallow Breathing Index (RSBI) - a deterministic tool in Sophie Well's Clinical Math & Conversions group.
Open the Rapid Shallow Breathing Index (RSBI) → Runs in your browser. No signup, no tracking.
What this is
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. 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.
References
Yang KL, Tobin MJ. RSBI. NEJM 1991;324:1445-1450.
Worked example: RSBI 68.6 - likely to tolerate weaning (< 105).
Sophie Well is a reference and educational tool. Not medical, legal, or financial advice. Does not replace clinician judgment, professional billing review, or legal counsel.