The Overlooked Vital Sign: The Power of an Accurate Respiratory Rate
By Pat O’Malley PhD, RN, CNS
Normal respiratory rate in adults ranges from 12 to 20 breaths per minute. Rate should be measured over one minute; this is best practice. While calculating rate, assess depth, use of accessory muscles, and pattern (Kennedy, 2007).
The Evidence
Compared to blood pressure, pulse, heart rate and rhythm, and oxygen saturation, respiratory rate appears to be a minor vital sign. Evidence from a United Kingdom study titled National Confidential Enquiry into Patient Outcome and Death (NCEPOD) found that pulse, blood pressure and temperature were the most frequently documented vital signs, with RR the least recorded (Parkes, 2011).
Additionally, documented respiratory rates often lack variance; that is, the respiratory rate does not vary across the patient record; (e.g., 14, 14, 14) suggesting measurement errors and over-reliance on technology measures (Parkes, 2011).
In one study of 594 patients visiting an emergency department over a three-day period, chart reviews revealed that respiratory rate was only recorded for 29 percent of all patients and documentation was highly correlated with presenting complaint. For patients presenting with shortness of breath, 91 percent had a respiratory rate documented compared to 63 percent of patients with chest pain. For the 71 patients who presented with abdominal pain, only 31 percent had a respiratory rate recorded (Parkes, 2011).
Increasing evidence suggests that an accurate respiratory rate may be the most sensitive sign of patient condition and the best early predictor of patient deterioration. Furthermore, an accurate respiratory rate is more valuable than pulse oximetry values (Parkes, 2011; Cretikos et al., 2008).
Careful monitoring trends of accurate respiratory rates can provide precious early evidence of subtle changes associated with sepsis, organ failure, cardiac arrest and death. A person with a sustained respiratory rate greater than 20 breaths per minute is not well. A sustained respiratory rate greater than 24 per minute is a warning of a possible serious adverse event in the next 24 hours (Cretikos et al., 2008).
Implications for Practice
- Appreciate that an accurate respiratory rate is a powerful tool to identify patients at risk of adverse events such as sepsis or arrest.
- Pulse oximetry is not a replacement for measuring respiratory rate. Respiratory rate is a more sensitive measure.
- Adult patients with a respiratory rate greater than 24 breaths per minute should be monitored more closely even if the other vital signs are normal.
- Adult patients with a respiratory rates greater than 22-24 breaths per minute, in combination with other evidence of physiological instability (e.g., hypotension or a change in level of consciousness), the physician or ACT team should be notified concomitant with increased monitoring.
Research Implications
Several years ago, Miami Valley Hospital Nurse Manager Beth Larsen, RN, and staff completed a project examining outcomes associated with end-tidal carbon dioxide (ETCO2) monitoring in the trauma stepdown unit. This fine study found ETCO2 monitoring was effective in preventing patient controlled analgesia adverse events. However, the data analysis also revealed that ETCO2 provided an accurate measure of respiratory rate and accurately captured the variance in that rate over time. Secondary analysis of patients with elevated respiratory rates revealed findings of pneumonia or infection rather than pain as the source. Beth and her staff have presented this project in multiple venues stressing the importance of evidence-based respiratory rate monitoring.
References
Cretikos, M.A., Bellomo, R., Hillman, K., Chen, J., Finfer, S., & Flaboris, A. (2008). Respiratory rate: the neglected vital sign. Medical Journal of Australia, (11): 657-659.
Fieselmann, J.F., Hendryx, M.S., Helms, C.M., & Wakefiled, D.S. (2008) Respiratory rate predicts cardiopulmonary arrest for internal medicine patients. Journal of General Internal Medicine, 8(7): 354-360.
Goldhill, D.R., McNarry, A.F., Mandersloot, G., McGinley, A. (2005). A physiologically-based early warning score for ward patients: the association between score and outcome. Anaesthesia, 60(6): 547-553.
Jacob, J.A. (2016). New Sepsis Diagnostic Guidelines Shift Focus to Organ Dysfunction. The Journal of American Medical Association, 316(4): 379-380.
Kennedy, S. (2007). Detecting changes in the respiratory status of ward patients. Nursing Standard, (21):42-46.
Parkes, R. (2011). Rate of respiration: the forgotten vital sign. Emergency Nurse, 19(2): 12-17.
Subbe, C.P., Davies, R.G., Williams, E., Rutherford, P., Gemmell, L. (2003). Effect of introducing the Modified Early Warning score on clinical outcomes, cardio-pulmonary arrests and intensive care utilisation in acute medical admissions. Anaesthesia, 58(8): 797-802.
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Source: Premier Health Nursing
