Respiratory Rate
Respiratory rate is the number of breaths a person does in a minute. In adults, normal normal respiratory rate is between 14-20 breaths/minute.2 In 1993, Fieselmann and colleagues informed that a respiratory rate higher than 27 breaths/minute was the most important predictor of cardiac arrest in hospital wards.3 Subbe and colleagues found that, in unstable patients, relative changes in respiratory rate were much greater than changes in heart rate or systolic blood pressure, and thus that the respiratory rate was likely to be a better way of differentiating between stable patients and patients at risk.4 Goldhill and colleagues reported that 21% of ward patients with a respiratory rate of 25–29 breaths/minute assessed by a critical care outreach service died in hospital.5 Those with a higher respiratory rate had an even higher mortality rate.5