Respiration Monitoring Can Help Predict Health Crises
Abnormal respiratory rates and changes in respiratory rate are a broad indicator of major physiological instability, and in many cases, respiratory rate is one of the earliest indicators of this instability. Therefore, it is critical to monitor respiratory rate as an indicator of patient status.
Regular documentation of the respiratory rate may assist in identifying patients at risk of serious adverse events such as cardiac arrest and unplanned ICU admission, with high levels of specificity. Respiratory rate performs at least as accurately in identifying patients at risk of these adverse events as pulse rate and the systolic blood pressure. In fact, abnormal respiratory rate is one of the best independent predictors of cardiac arrest.
A respiratory rate of greater than 24 breaths per minute is able to identify approximately 50% of patients at risk of serious adverse events with 95% specificity.
Failures in Many Organ Systems Are Indicated by Changes in Respiration
Although the main function of the respiratory system is gas exchange, a broad range of factors can affect ventilation. In fact, the respiratory system’s function can be altered by changes in a variety of organ systems, including the nervous system, the cardiovascular system, the respiratory system, and the excretory system. This makes the respiratory rate a broad indicator of imbalance in these organ systems, as well as an indicator of respiratory disorders.
Trends in respiratory rate can indicate progression of cardiopulmonary illnesses, including acute respiratory distress syndrome, pulmonary edema, pulmonary embolism, pneumonia, COPD, and severe heart failure. Changes in respiratory rate can also indicate sepsis, systemic inflammation, low blood volume, and malfunctions of the excretory system or central nervous system disorders, including intracranial pressure, neurogenic, pain, and opioid-induced respiratory depression.
A raised respiratory rate is associated with life-threatening conditions such as shock and cardiac failure.
Hospitals are Demanding Better Respiratory Monitoring Solutions
More and more hospitals are implementing Medical Emergency Teams (METs), Rapid Response Teams (RRTs), and Critical Care Outreach (CCO) teams. These are different names for systems which use vital signs and clinical observations to detect physiological instability, and when this instability is detected, a cross-functional team of medical practitioners works to stabilize the patient early enough to prevent critical events such as cardiac arrests, respiratory arrests, and unplanned ICU admissions.
Literature describing these systems consistently indicates that respiratory rate is one of the most important vital signs in predicting critical events. Both excursions from a baseline respiratory rate and rates above and below accepted limits can be use to predict critical events.
As the vital signs are watched more closely with the goal of effectively implementing a MET, RRT, or CCO team, the poor measurement and tracking of respiratory rate has been uncovered. In most patients, respiratory rate is measured via visual assessment, and the literature shows that respiratory rate tends to be measured haphazardly, roughly estimated, or skipped in most patients.
Because of these points, hospitals are clamoring for an accurate, automated respiratory rate measurement that can be used in vital signs assessments. Hospitals realize that respiratory rate is at least as important as the other vital signs they are measuring, and should be measured as often and as regularly as every other vital sign.
Respiratory Rate Can Indicate Exacerbations of Chronic Illness
Respiratory rate can be used to detect exacerbations and/or changes in the severity of chronic illnesses, such as Chronic Obstructive Pulmonary Disease (COPD) and Congestive Heart Failure (CHF).
According to the American Thoracic Society, in patients with COPD, respiratory rate rises as COPD gets more severe. The GOLD guidelines for COPD recommend use of non-invasive ventilation when respiratory rate climbs higher than 25 breaths per minute, and invasive ventilation when respiratory rate is greater than 35 breaths per minute.
In patients with CHF, an increase in respiratory rate can warn of impending pulmonary edema, or fluid in the lungs, which is a common debilitating symptom of CHF.
Pulse Oximetry Cannot Replace Respiration Rate Measurement
Pulse oximetry is not a foolproof method: it combines the inaccuracies of this method of measurement of arterial saturation and the limitations of arterial saturation as an assessment of the cardiorespiratory status of the patient.
The accuracy of pulse oximetry as an indicator of serious adverse events in unknown, and there is no evidence to suggest that measurement of pulse oximetry can be used as a replacement for measurement of the respiratory rate for this purpose.
A normal reading of saturation in the presence of an increased inspired oxygen concentration gives no information about the adequacy of ventilation. Falls in saturation under these circumstances will occur late and are non-diagnostic. Under no circumstances should the pulse oximeter be relied on as the sole monitor to detect such events as esophageal intubation, cardiac arrest, breathing system disconnections, or failure of the oxygen supply.
Recommendations for Monitoring Respiration
Patient safety experts recommend regular, accurate measurement of respiratory rate for many, if not all patients. Below are some quotes of recommendations:
"Current scientific evidence suggests that the respiratory rate should be measured and documented whenever any other vital sign measurements are performed."
(National Confidential Enquiry into Patient Outcome and Death, 2005)
"Monitoring the respiratory rate is essential, as it may predict cardiorespiratory arrest" (Resuscitation Council (UK), 2005)
"... every patient receiving parenteral opioids should be monitored with, at a minimum, pulse oximetry and a continuous measure of respiratory rate." (Anesthesia Patient Safety Foundation, 2007)
