Rapid shallow breathing index
The rapid shallow breathing index (RSBI) is a tool that is used in the weaning of mechanical ventilation on intensive care units. The RSBI is defined as the ratio of respiratory frequency to tidal volume (f/VT). People on a ventilator who cannot tolerate independent breathing tend to breathe rapidly (high frequency) and shallowly (low tidal volume), and will therefore have a high RSBI.[1]
Equation
Measurement
Measurement is done with a handheld spirometer attached to the endotracheal tube while a patient breathes room air for one minute without any ventilator assistance.[2]
Example
As an example, a patient who has a respiratory rate of 25 breaths/min and a tidal volume of 250 mL/breath has an RSBI of (25 breaths/min)/(0.25 L) = 100 breaths/min/L
History
The concept was introduced in a 1991 paper by physicians from the University of Texas Health Science Center at Houston and Stritch School of Medicine at Loyola University in Chicago.[1]
Weaning Readiness
An RSBI score of less than 65[3] indicating a relatively low respiratory rate compared to tidal volume is generally considered as an indication of weaning readiness.
References
- 1 2 Yang KL, Tobin MJ (May 1991). "A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation" (PDF). N. Engl. J. Med. 324 (21): 1445–50. doi:10.1056/NEJM199105233242101. PMID 2023603.
- ↑ Yang KL, Tobin MJ (1991). "A prospective study of indexes predicting the outcome of trials of weaning from mechanical ventilation.". N Engl J Med 324 (21): 1445–50. doi:10.1056/NEJM199105233242101. PMID 2023603.
- ↑ Meade M, Guyatt G, Cook D, Griffith L, Sinuff T, Kergl C, et al. (2001). "Predicting success in weaning from mechanical ventilation.". Chest 120 (6 Suppl): 400S–24S. doi:10.1378/chest.120.6_suppl.400s. PMID 11742961.