Description

The respiratory rate to tidal volume ratio is a bedside measure of the extent of shallow breathing. Shallow breathing is a common finding in patients in whom weaning from a mechanical ventilator fails.


 

respiratory rate to tidal volume ratio =

= (respiratory rate in breaths per minute) / (tidal volume in liters)

 

where:

• Gluck and Corgian (1996) refer to this parameter as Rapid Shallow Breathing (RSB).

 

Interpretation:

• Yang et al found that a ratio of <= 105 indicates successful weaning from mechanical ventilation, while a ratio of > 105 predicts failure to wean from mechanical ventilation.

• Chatila et al found a ratio of <= 100 predicted successful weaning, with the ratio calculated 30-60 minutes after weaning more accurate in predicting outcome than that measured 1 minute after weaning.

 

Limitations:

• While useful in adults, Khan et al did not find this as useful in infants or children.

 


To read more or access our algorithms and calculators, please log in or register.