RSBI
RSBI calculation is not needed to determine readiness for an SBT.
Extubation & ventilation tool
Rapid shallow breathing index for weaning context
RSBI Calculator for Weaning Assessment
Calculate the rapid shallow breathing index (RSBI) using respiratory rate and tidal volume in liters. The result describes the relationship between breathing frequency and tidal volume; it does not determine whether a patient is ready for an SBT or extubation.
The 2024 AARC clinical practice guideline suggests that calculating RSBI is not needed to determine readiness for a spontaneous breathing trial. This calculator is therefore presented as an optional breathing-pattern reference—not a pass/fail gate, an extubation predictor, or a reason to delay an otherwise appropriate SBT.
Inputs
Respiratory rate + tidal volume
Purpose
Describe rapid, shallow breathing
Current guidance
RSBI is not required for SBT readiness
Calculator inputs
Enter tidal volume as milliliters (e.g. 400).
What RSBI can and cannot do
Frame breathing pattern efficiency
RSBI combines respiratory rate and tidal volume into one number to help describe whether breathing is rapid and shallow versus more efficient.
Add optional context
It may describe the breathing pattern during a broader assessment, but it is not required for SBT readiness and should not delay an otherwise appropriate trial.
Results
Enter your values and click Calculate RSBI to generate results.
How to think about RSBI
RSBI is a quick way to combine respiratory rate and tidal volume into one bedside number. The classic teaching threshold is an RSBI below about 105, but that cutoff is historical and should not be presented as a required readiness criterion.
AARC’s 2024 guideline suggests that clinicians do not need RSBI to determine readiness for an SBT. A low result does not prove extubation readiness, and a high result should not automatically prevent a patient from receiving a standardized readiness assessment and appropriately monitored trial.
One tool in the toolbox
- • Consider cuff leak if airway edema is a concern
- • Check level of responsiveness and ability to protect the airway
- • Review FiO₂ / PEEP requirements and oxygenation stability
- • Be cautious in COPD: some patients can produce deceptively low RSBI values, so a “good” number does not guarantee extubation success
- • Assess cough strength and secretion burden
- • Review hemodynamic stability and fatigue
- • In selected higher-risk patients, consider whether a planned bridge to NIV after extubation is part of the strategy
- • Use the ABG Analyzer if gas exchange or acid-base status still matters in the decision
AARC 2024 spontaneous breathing trial guidance
What the current guideline actually recommends
Technique
An SBT may be conducted with or without low-level pressure support of 8 cm H₂O or less.
Timing
Use a standardized assessment and, when appropriate, complete the SBT before noon each day.
Oxygen
Do not increase FiO₂ during the SBT.
Evidence reviewed August 29, 2026. Local protocols and the treating team determine how readiness screening and trial monitoring are implemented.
RSBI frequently asked questions
What is the RSBI formula?
RSBI is respiratory rate in breaths per minute divided by tidal volume in liters.
Is an RSBI below 105 required before a spontaneous breathing trial?
No. The 2024 AARC guideline suggests that RSBI calculation is not needed to determine readiness for a spontaneous breathing trial. The value of 105 is a classic historical cutoff, not a required modern pass criterion.
Can a low RSBI confirm that a patient is ready for extubation?
No. A low RSBI does not confirm airway protection, cough strength, secretion clearance, mental status, hemodynamic stability, or successful spontaneous breathing trial performance.
Can a high RSBI automatically rule out an SBT?
No. RSBI should not function as an automatic gate. Current AARC guidance favors a standardized readiness assessment followed by an appropriately monitored spontaneous breathing trial when indicated.
Sources
- 1.Roberts KJ, Goodfellow LT, Battey-Muse CM, et al. AARC Clinical Practice Guideline: Spontaneous Breathing Trials for Liberation From Adult Mechanical Ventilation. Respiratory Care. 2024;69(7):891–901. doi:10.4187/respcare.11735.
- 2.Yang KL, Tobin MJ. A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation. New England Journal of Medicine. 1991;324(21):1445–1450. doi:10.1056/NEJM199105233242101.