This article explores the monitoring of respiratory rates in adult patients. This is a significant physical assessment skill because breathing is usually the first vital sign to alter in the deteriorating patient (Hunter and Rawlings-Anderson, 2008). Ascertaining a baseline respiration function will permit an accurate respiration assessment to be carried out, tailored to the individual patient (Simpson, 2006).
The observation and recording of respiratory rate is the numerical calculation of breaths per minute (bpm) and informs the overall physical assessment of respiration. Assessment and recording of respiratory rate must be accurate and is an essential nursing skill. The respiratory rate is one of the six vital signs (Box 1). Evidence suggests that, of all the vital signs, change in respiratory rate is an early sign of deterioration in a patient and failing to recognise such a change can result in poor outcomes (Cretikos et al, 2008).
Box 1.The six vital signs
- Heart rate
- Blood pressure
- Temperature
- Respiratory rate
- Oxygen (O2) saturation
- Level of consciousness
Terminology
Health professionals use several terms to describe irregular respiratory rates, including:
- Bradypnoea: abnormally slow
- Tachypnoea: elevated and rapid
- Dyspnoea: shortness of breath with an elevated, normal or decreased respiratory rate
- Hyperpnoea: abnormally deep and laboured. It may occur with or without rapid breathing
- Apnoea: absence of breathing.
Respiration
The function of respiration is to ensure that the tissues and cells of the body receive sufficient oxygen to support the process of aerobic metabolism and the removal of carbon dioxide, the waste product of metabolism (Dougherty and Lister, 2011). The supply of oxygen to, and removal of carbon dioxide from, the cells helps to maintain the body's normal internal homeostasis.
In effective respiration, ventilation and gaseous exchange occurs, ensuring that the normal range of oxygen saturation of the blood is 94–98% (SpO2) (O'Driscoll et al, 2017) and that this is maintained at rest with a respiratory rate of 12–20 bpm (Hartley, 2018).
As well as supporting the provision of oxygen to cells and tissues, respiration also assists with the removal of the waste product carbon dioxide (CO2) from the body. This is done by exhalation. If cell metabolism occurs when a patient has low oxygen in their blood saturations (hypoxaemia), anaerobic respiration will result, producing lactic acid, leading to compensatory homeostasis and a deteriorating patient.
Neurological control of respiration
Respiration begins in the neurological system rather than the respiratory system. Consequently, a patient requires normal neurology to have the ability to breathe effectively. Within the brain, the medulla oblongata regulates respiration by detecting the partial pressure of carbon dioxide (PCO2) and oxygen levels (PO2) within the blood. The rate and speed of involuntary respiration is controlled by the pons, part of the brain stem. Finally, the midbrain (also called the mesencephalon) controls autonomic functions including breathing.
Respiratory rate
The respiratory rate is the movement of air in and out of the lungs. This is described as ventilation, with a breath in referred to as inspiration and a breath out referred to as expiration. Normal respiratory rate in an adult is 12−18 bpm. Expiration, breathing out, takes twice as long as the breath in, or inspiration (Dougherty and Lister, 2011). One breath should be counted for every breath in (inhalation) and breath out (exhalation).
When assessing a patient's respiratory rate, it is important to place the numerical value in the context of the patient's presenting condition and symptoms. Normal values only establish a baseline that would be expected in a healthy adult and give the nurse a reference point from which to make a comparison and determine the patient's usual respiratory rate. Table 1 sets out normal rates and common abnormalities.
Table 1. Normal and abnormal respiratory rate values in adults
| Count the respiratory rate for one full minute. An increasing respiratory rate is a marker of illness and a warning that the patient may deteriorate suddenly | |
|---|---|
| Normal range for adults | 12–20 breaths per minute (bpm) |
| Bradypnoea | <12 bpm |
| Tachypnoea | >20 bpm |
Measuring respiratory rate
A patient's respiratory rate should be measured when he or she is at rest and not following vigorous activity. While undertaking any clinical assessment, nurses must use a ‘look, listen and feel’ approach. It is important to ‘see and treat’ to prevent deterioration (Resuscitation Council UK, 2019). This highlights the importance of noticing a patient's condition and any deterioration. What nurses fail to notice will have consequences in terms of nursing practice and contribute to poor standards of nursing care and, in turn, poor patient outcomes (Watson and Rebair, 2014).
When observing a patient, the nurse should note the following:
- Does the patient appear uncomfortable?
- Are they using accessory muscles to breathe?
- Are they wheezing or producing any other audible abnormal breathing sounds?
- Does the patient appear to be hyperventilating (a respiratory rate of >20 bpm)?
- Are they scared, anxious or in pain?
- Is the patient confused or oriented?
It is imperative that there is precision when counting and documenting a respiratory rate because it is a significant predictive identifier of serious health problems, patient deterioration and life-threatening events.
Subbe et al (2003) have shown that changes in respiratory rate in an unstable patient are more significant in identifying a deteriorating patient than changes in heart rate or blood pressure. This adds further importance to the prioritisation of accurate respiratory rate measurement. Both recording respiratory rate accurately and acknowledging its importance as a vital sign have been described as poor, therefore it is considered the ‘ignored vital sign’ (Elliott, 2016).
In clinical practice it may be tempting to count respiratory rate for a shorter period than 60 seconds and generate a value by doing a multiplication to work out the number of bpm—counting for 10 seconds and then multiplying by 6 or counting for 30 seconds and multiplying by 2, for example. Using these shortcuts can result only in an estimate of the patient's respiratory rate, not in an accurate measurement, and consequently this is not a valid or reliable approach. Evidence suggests that, because respiratory rate is one of the few vital signs that cannot be automated (measured accurately by a machine), nurses are tempted to use shortcuts. The lack of automation may also explain why nurses do not prioritise respiratory rate over other vital signs (Mok et al, 2015; Kelly, 2018).
Documentation
In 2017, the National Early Warning Score 2 (NEWS2) was released by the Royal College of Physicians for use with adult patients in secondary care. It is a tool that is in place to identify and rescue patients, to prevent ‘failure to rescue’ and to identify deteriorating patients. It acknowledges the use of a structured Airway Breathing Circulation Disability and Exposure (ABCDE) assessment, and has been validated and endorsed by NHS England and NHS Improvement. A patient's NEWS2 score should contain an accurate respiratory rate.
Abnormalities in breathing
Abnormalities in rate, rhythms and pattern of respiration care take many forms and are influenced by a range of factors:
Periodic breathing in adults
A type of periodic breathing called Cheyne-Stokes breathing may be observed in adults and is not normal. It may be caused by congestive heart failure, carbon monoxide poisoning, a low sodium level in the blood (hyponatraemia) and high altitude. It may be heard in the final stages of a dying patient (NHS website, 2019).
Abnormal respiratory rates
Both an increased and decreased respiratory rate can be a sign that something is amiss in the body (British Thoracic Society and Scottish Intercollegiate Guidelines Network, 2019). There are many causes of both a rapid and a slow rate. It is important to note that the normal ranges are for people at rest. Respiratory rates normally increase during exercise.
Increased rates
An increased respiratory rate (>20 breaths per minute) in adults could have many causes. Most are related to ventilation perfusion problems. The more common causes include:
- Fever: an increased rate of breathing with a fever is the body's attempt to lose heat by breathing faster. This is important, both because a rapid respiratory rate can be a sign of a worsening infection and because a fever needs to be considered in interpreting the respiratory rate
- Dehydration: dehydration alone can result in a rapid rate of breathing
- Asthma: a person's respiratory rate is often increased during an asthma attack. Even small increases in the rate can be a sign of worsening asthma, and the patient's respiratory rate should be monitored closely (Global Initiative for Asthma, 2019)
- Chronic obstructive pulmonary disease (COPD): this is a common cause of a rapid respiratory rate, especially in people with a history of smoking
- Hyperventilation: people may breathe more rapidly in response to stress, pain, anger or during a panic attack
- Lung conditions: conditions such as lung cancer, pulmonary emboli (PE) (blood clots in the legs that travel to the lungs), and other lung diseases often raise respiratory rate
- Infections: common and uncommon infections such as the flu, pneumonia, and tuberculosis can result in rapid breathing
- Respiratory acidosis: an increase in the acidity of the blood results in the increased production of carbon dioxide, and hence an increased rate of breathing. This can occur when a person has a condition resulting in metabolic acidosis such as diabetes (diabetic ketoacidosis)
- Drug overdoses: overdosing on drugs will alter respiratory drive. Common examples may include: overuse of opioids, sedatives, aspirin or amphetamines
- Heart conditions: in some heart conditions such as heart failure, ventilation perfusion mismatching may occur, causing an increased respiratory rate because of a compensatory mechanism.
Decreased respiratory rate
A lowered respiratory rate, defined as a rate less than 12 bpm (Resuscitation Council UK, 2019) can also be a sign for concern. Some causes of a decreased rate include:
- Use of narcotics: whether used for medical purposes or illegally, narcotics can suppress respiration
- Alcohol: consumption of alcohol decreases respiratory rate
- Abnormal metabolic processes: respiratory rate can decrease to balance the effects of abnormal metabolic processes in the body
- Sleep apnoea: people with this condition often have episodes of apnoea and a decreased breathing rate mixed with episodes of an elevated breathing rate
- Neurological conditions: damage to the brain, such as strokes and head injuries, often results in a decreased respiratory rate.
Dyspnoea (breathlessness)
It is important to note that the rate of breathing is separate from the sensation of feeling short of breath (breathlessness). Sometimes the respiratory rate may affect whether someone feels dyspnoeic, but at other times may not. Someone may feel short of breath with a very rapid respiratory rate but may not feel short of breath with a very low respiratory rate.
Restrictive, obstructive, infective or traumatic problems associated with the respiratory system will result in respiratory dysfunction. Shortness of breath or difficulty in breathing are often symptoms reported when the body attempts to maintain and/or compensate for gas exchange abnormalities. Abnormalities in arterial blood gas (ABG) composition associated with respiratory metabolic failures drive these pattern changes, although some patterns can be driven by disease and degeneration of respiratory control networks.
Causes of breathlessness
Breathlessness is a symptom, and there are many possible underlying causes.
The assessment of patients presenting with symptoms of breathlessness is described in Box 2. According to the British Lung Foundation (BLF) (2019), the four main causes are: lung conditions, heart conditions, anxiety and being unfit.
Box 2.Assessment of patients presenting with breathlessnessAssessmentAn initial Airway, Breathing, Circulation assessment should be performed. The person's blood pressure, pulse, respiratory rate, temperature, level of consciousness, peak expiratory flow rate and oxygen saturation should be assessed and, if possible, an electrocardiogram (ECG) performed.People with the following symptoms should be admitted as an emergency:
- Severe or life-threatening acute asthma attack (follow-up in the community is essential after discharge)
- Features of a pulmonary embolus or pneumothorax
- Rapid onset or worsening of symptoms of suspected heart failure
- Suspected sepsis
- ECG suggesting a cardiac arrhythmia or myocardial infarction
Emergency hospital assessment should also be considered for people with:
- Suspected community-acquired pneumonia
- An exacerbation of chronic obstructive pulmonary disease (COPD)
- Breathlessness with an unclear cause
The following features are associated with the presence or risk of serious illness and usually require emergency hospital admission:
- Stridor
- Altered level of consciousness or acute confusion
- Significant respiratory effort
- Elevated respiratory rate
- Oxygen saturation less than 92%
- Cyanosis
- Tachycardia
- Hypotension
- Peak expiratory flow rate less than 50% of predicted
- Immunosuppression or other significant comorbidity
- Pregnancy or postnatal period
- Elderly or very frail people
- People who are unable to cope at home
- Poor or deteriorating general condition
Source: adapted from National Institute for Health and Care Excellence, 2017, including information from: National Clinical Guidance Centre, 2010; National Institute for Health and Care Excellence, 2017; 2019a; 2019b; British Thoracic Society and Scottish Intercollegiate Guidelines Network, 2019
Lung conditions
Lung conditions cause breathlessness in different ways. Some conditions cause the airways to become inflamed and narrowed, or fill the airways with phlegm, so it is harder for air to move in and out of the lungs. Others make the lungs stiff and less elastic, so it is harder for them to expand and fill with air.
Lung conditions that cause long-term (chronic) breathlessness include:
- COPD
- Asthma
- Interstitial lung disease, including pulmonary fibrosis
- Bronchiectasis
- Industrial or occupational lung diseases such as asbestosis (caused by being exposed to asbestos)
- Lung cancer.
Some lung conditions can also cause short-term (acute) breathlessness. These include:
- A flare-up of asthma or COPD
- A pulmonary embolism or blood clot on the lung
- A lung infection such as pneumonia or tuberculosis
- A pneumothorax (collapsed lung)
- A build-up of fluid in the lungs or the lining of the lungs—this might be because the heart is failing to pump efficiently or may be because of liver disease, cancer or infection.
Heart conditions
The BLF (2019) recognises that some people may experience long-term breathlessness caused by heart failure. This can be due to problems with the rhythm, valves or cardiac muscles of the heart. Heart failure can cause breathlessness because the heart is not able to increase its pumping strength in response to exercise, or because the lungs become congested and filled with fluid. Often this is worse when lying flat so breathlessness due to heart failure can be worse at night or when asleep.
Heart conditions that cause acute breathlessness include:
- Myocardial infarction
- Abnormal heart rhythm.
Anxiety
Some people feel short of breath when they are anxious or afraid. This is a normal response by the body to what the person perceives as a stressful situation—the body is preparing for action.
Being unfit
If a person is unfit, their muscles will get weaker, including those used to breathe. Weaker muscles need more oxygen to work, so the weaker the muscles, the more breathless a person will feel. Being an unhealthy weight can also make people feel breathless.
Being underweight makes the respiratory muscles weaker (BLF, 2019). Carrying more weight around the chest and abdomen will restrict lung movement. A body mass index of 25 or more will cause breathlessness, when compared to people with a healthy weight (BLF, 2019). People who are severely overweight can develop obesity hypoventilation syndrome. This is when poor breathing leads to lower oxygen levels and higher carbon dioxide levels in their blood.
Other reasons
Other causes of long-term breathlessness include:
- Smoking
- Conditions that affect how the muscles work, such as muscular dystrophy, myasthenia gravis or motor neurone disease
- Postural conditions that alter the shape of the spine, and affect how the ribs and lungs expand, such as scoliosis and kyphosis
- Anaemia, when a lack of iron in the body leads to fewer red blood cells
- Kidney disease
- Thyroid disease.
Conclusion
Accurate assessment and recording of respiratory rate is essential to establish a patient's status and to note any deterioration (Box 3). Nurses play a vital role in monitoring, detecting and reporting any concerns about a patient's breathing so that treatment can be provided.
Box 3.Respiratory rate: summary of evidence and recommendations
- Respiratory rate is the vital sign least often recorded and most frequently completely omitted from hospital documentation
- A raised respiratory rate is a strong and specific predictor of serious adverse events such as cardiac arrest and unplanned intensive care unit admission
- Pulse oximetry measurement is not a replacement for respiratory rate measurement
- All staff should be educated to measure the respiratory rate as an easy and specific assessment for critical illness and should be given guidance on appropriate action to be taken when abnormally high respiratory rates are recorded
- Hospital systems that encourage appropriate responses to a raised respiratory rate and other abnormal vital signs can be readily and rapidly implemented. Such systems help to raise and sustain awareness of the importance of vital signs
Source: Kelly, 2018
KEY POINTS:
- Know the rationale for monitoring respiratory rate
- Understand which patients' respiratory rate should be monitored
- Understand how to monitor a patient's respiratory rate
- Know normal and abnormal respiration rates and patterns