Calculate the Rapid Shallow Breathing Index (f/VT) as a spontaneous-breathing worksheet, with P/F ratio and checklist context rather than a stand-alone extubation order.
The Rapid Shallow Breathing Index (RSBI), introduced by Yang and Tobin in 1991, is one of the most widely used bedside indicators during ventilator-weaning review. It is calculated as respiratory rate divided by tidal volume during spontaneous breathing, and it helps summarize whether the current breathing pattern looks efficient or rapidly shallow.
An RSBI below 105 is a classic favorable reference cutoff. That said, extubation success also depends on airway protection, secretions, neurologic status, cardiovascular stability, and the spontaneous-breathing-trial setup being used.
This calculator keeps the RSBI, oxygenation context, minute ventilation, and a simple readiness checklist together. It should be read as a structured worksheet, not as a stand-alone extubation command.
RSBI helps turn spontaneous-breathing review into a measurable bedside check on respiratory effort. By pairing respiratory rate with tidal volume and showing related readiness parameters, the calculator makes the breathing-pattern context easier to review consistently.
RSBI = Respiratory Rate (breaths/min) / Tidal Volume (L) Traditional favorable reference cutoff: < 105 Minute Ventilation = RR × VT P/F Ratio = PaO₂ / FiO₂ (as fraction)
Result: RSBI = 62.9 breaths/min/L — favorable spontaneous-breathing pattern
RSBI = 22 / 0.35 = 62.9, which is below the classic 105 cutoff. The P/F ratio is 213 and minute ventilation is 7.7 L/min, so several worksheet items also sit in favorable ranges. Airway protection and full SBT tolerance would still need separate review.
RSBI is strongest as a screening signal, not a full extubation decision on its own. A low index supports the idea that the patient can sustain spontaneous breathing, but airway protection, cough, secretion burden, and mental status still matter.
Borderline or rising values during a spontaneous-breathing trial usually deserve more attention than a single early number. Trending the index alongside work of breathing and oxygenation is often more informative than treating one cutoff as absolute.
Minute ventilation, tidal volume per kilogram, and the P/F ratio help explain why a patient is succeeding or failing the breathing trial. Those measures can identify fatigue, low reserve, or gas-exchange problems that RSBI alone will not capture.
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This calculator computes the rapid shallow breathing index as respiratory rate divided by tidal volume in liters, then displays the result with minute ventilation, tidal-volume-per-kilogram context, and an optional P/F ratio. The checklist on the page is there to keep common readiness questions in view during a spontaneous-breathing review.
The output is intentionally framed as a worksheet. It does not decide when a patient should be extubated, because airway protection, mental status, secretion burden, hemodynamics, and the trial conditions all matter separately.
It is measured during spontaneous breathing, usually after the patient has been off substantial support long enough for the breathing pattern to settle. Respiratory rate is divided by tidal volume in liters.
The classic threshold is less than 105 breaths/min/L. Some units use lower cutoffs such as 80 when they want a more conservative favorable signal.
Yes. A low RSBI does not check cough strength, secretion burden, upper-airway edema, mental status, or post-extubation airway protection.
Both are used in practice, but the support level matters because pressure support can make RSBI look more favorable than a more unsupported trial.
Because extubation decisions are broader than breathing pattern alone. The checklist helps users keep oxygenation, minute ventilation, and general readiness in the same frame.