Any respiratory rate (RR) greater than 20/min in an adult patient may be cause for concern, particularly in the setting of potentially serious disease and absence of an obvious cause such as pain or fever.
Our patient’s RR is outside the commonly cited normal range of 12-20/min. It indicates increased alveolar ventilation which may in turn be caused by hypoxia, hypercapnea, or metabolic acidosis, all portending possibly poor outcome, if left untreated.1 It’s no surprise that an abnormal RR is often the ﬁrst sign of clinical deterioration.2 RR is also the least likely of the vital signs to be affected by polypharmacy (eg, NSAIDs affecting temperature, beta-blockers affecting heart rate and blood pressure).
Another reason for not dismissing an RR of 22 in our patient is the common practice of guessing rather than measuring the RR by healthcare providers in part likely due to the more “labor-intensive” nature of measuring RRs compared to other vital signs and lack of appreciation for its importance in assessing severity of disease. 1 Of note, in an experimental study of doctors viewing videos of mock patients, over 50% failed to detect abnormal RR when using the “spot” technique of estimating without a timer.3 Even when presented with a RR of 30/min, over 20% of doctors reported it as normal (12-20/min)!
Final tidbit: Do you want to know what a RR of 20/min really feels like? Take a breath every 3 seconds. If you are like most, it doesn’t feel “normal”!
1. Cretikos MA, Bellomo R, Hillman K. Respiratory rate: the neglected vital sign. MJA 2008;188:657-59. https://www.ncbi.nlm.nih.gov/pubmed/18513176
2. Flenady T, Dwer T, Applegarth J. Accurate respiratory rates count: So should you! Australas Emerg Nurs J 2017; 20:45-47. https://www.ncbi.nlm.nih.gov/pubmed/28073649
3. Philip KEJ, Pack E, Cambiano V et al. The accuracy of respiratory rate assessment by doctors in a London teaching hospital: a cross-sectional study. J Clin Monit Comput2015;29:455-60. https://www.ncbi.nlm.nih.gov/pubmed/25273624