RSBI Calculator
The RSBI Calculator estimates the Rapid Shallow Breathing Index based on respiratory rate and tidal volume. This tool helps clinicians quickly assess weaning readiness from mechanical ventilation. Whether you are evaluating a patient for extubation or conducting a spontaneous breathing trial, this calculator provides a reliable bedside assessment to improve clinical decision-making.
How RSBI Is Calculated
The RSBI measures breathing efficiency by comparing the respiratory rate to the volume of air moved in each breath. It helps determine if a patient maintains adequate ventilation without support. Ideally, perform this calculation while the patient is on minimal or no pressure support.
RSBI = Respiratory Rate (breaths/min) ÷ Tidal Volume (L)
Where:
- Respiratory Rate = Number of breaths taken in one minute
- Tidal Volume = Amount of air moved per breath (converted to liters)
First, count the patient's breaths per minute during a spontaneous breathing trial to establish the baseline work of breathing. Next, measure the average tidal volume in milliliters and convert it to liters. Dividing the rate by the volume reveals how much effort the patient exerts to maintain ventilation. A lower score indicates efficient breathing, while a higher score suggests respiratory fatigue or distress. This method remains a standard, evidence-based predictor for weaning outcomes.
What Your RSBI Means
The RSBI score indicates the likelihood of successfully removing a patient from mechanical ventilation. A lower score generally suggests the patient can breathe effectively on their own.
Ready for Weaning (Below 105): An RSBI under 105 breaths/min/L strongly suggests the patient is likely ready for extubation. This score indicates a breathing pattern that is slow and deep enough to maintain oxygen levels without machine support. Clinicians often proceed with weaning protocols when this threshold is met.
High Risk of Failure (105 or Above): An RSBI of 105 or higher signals rapid, shallow breathing. This pattern often predicts that the patient will struggle to breathe unassisted and has a high risk of failing the spontaneous breathing trial. In this case, continued ventilatory support is usually necessary.
Important: Patient categories, such as those with COPD or elderly individuals, may have slightly different acceptable thresholds. Always use clinical judgment alongside this index to account for these specific patient factors.
This tool is intended for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.
To get the most accurate reading, ensure the patient is on minimal or no pressure support during the measurement period.