Pulse measurement is a key part of the assessment of a person's cardiovascular status and one of the primary vital signs assessed and recorded for every patient. Valuable information can be gained from the manual measurement of the pulse, which can be palpated at numerous sites across the body. It is therefore important to re-visit this key feature of patient assessment to ensure best practice is maintained.
This article will focus on explaining what a pulse is, the common pulse sites and correct technique in obtaining a pulse. Some, but not all, common interpretations and abnormalities will be discussed; however, these will not be explored in depth.
Learning Points
When the heart contracts and blood is ejected from the left ventricle, a pressure wave is generated and transmitted into the aorta and arterial tree. The flexible and elastic nature of artery walls enables this pulse wave transmission (Rawlings-Anderson and Hunter, 2008: Marieb and Hoehn, 2013). At certain points in the body, where arteries are either superficial or pass over a bone, these pulsations can be felt (Dougherty and Lister, 2015). In a healthy individual, the pulse rate represents the heart rate; however, there are circumstances whereby differences can occur such as with peripheral vascular disease or an acute arterial occlusion (Grossman and Porth, 2014; Waugh and Grant, 2018). If a peripheral artery is narrowed, damaged, occluded or diseased, the distal pulse may not represent the heart rate as a result of impaired blood supply. It is therefore important to check bilateral pulses to check for consistency (Gregory and Mursell, 2010). Manual assessment of the pulse is considered best practice as the clinician can assess for the rate, rhythm, volume and character.
Pulse locations
The most common and convenient site for pulse measurement is the radial artery due to the ease of access at the wrist and the rare requirement to remove clothing. Pulse rate and rhythm can be assessed at the radial artery, but because of its distal proximity to the heart, it is unsuitable to assess for volume or character (Docherty and Coote, 2006). The brachial, femoral and carotid pulse locations should be used to assess for volume and character as a result of their closer proximity to the heart, with the carotid artery being the preferred site. A full peripheral vascular examination should include assessment of all peripheral pulses. Pulse sites include the following:
Indications
Indications for pulse measurement are:
The procedure
The following is the generic procedure; differences with individual pulse sites are mentioned earlier within this article:
Interpretation
Rate
The average pulse rate in a healthy adult is between 60–100 beats per minute (bpm) (Helbock and Jerin, 2011). Pulse rates can differ depending on age (Table 1), physical fitness and pre-existing medical conditions.
| Age | Heart rate |
|---|---|
| <1 year | 110–160 bpm |
| 1–2 years | 100–150 bpm |
| 2–5 years | 95–140 bpm |
| 5–11 years | 80–120 bpm |
| >12 years | 60–100 bpm |
A pulse rate less than 60 bpm is termed a bradycardia; however, this may be normal for a healthy athletic adult. Conversely, a patient who has a chronic cardiac condition may have a resting pulse rate of 65 bpm and this may be slow for them, resulting in insufficient perfusion. There are various causes of bradycardia including hypothermia, certain medications (e.g. beta-blockers) or excess vagal tone.
A pulse greater than 100 bpm is called a tachycardia, with many causes including exercise, fever, anxiety, hypovolaemia and hypoxia (Innes et al, 2018). A resting heart rate consistently over 120 bpm indicates a form of arrhythmia (Julian et al, 2004). The pulse rate may vary with posture. For example, for a healthy male lying down, the pulse rate would be 66 bpm. Sat up, the pulse rate will be 70 bpm; and stood up, 80 bpm. This is because of the extra pressure required to eject blood from the left ventricle and changes in peripheral vascular resistance to maintain effective cardiac output (Marieb and Hoehn, 2013). It is therefore important to measure a person's pulse rate in the same position, recording any changes accordingly.
Rhythm
The normal pulse rate should be regular. However, in individuals under 40 years of age, sinus arrhythmia may occur where the pulse rate quickens with inspiration and decreases with expiration (Rawlings-Anderson and Hunter, 2008; Innes et al, 2018). The pulse will be either regular or irregular; however, there are variations in irregular rhythms. The pulse can be deemed regularly irregular; for example, every 3rd or 4th beat consistently dropped owing to a second degree heart block. Regular ectopic beats may result in a regularly irregular pulse. This can be difficult to palpate and is much clearer to establish on a cardiac monitor (Thomas and Monaghan, 2014). Irregularly irregular rhythms occur where there is no set pattern such as in atrial fibrillation (Julian et al, 2004).
Volume and character/waveform
Pulse volume is also referred to as the amplitude (Gregory and Mursell, 2010). The volume/strength of the pulse can be described as bounding, weak or thready (Helbock and Jerin, 2011). Each ventricular contraction ejects between 60–80 mls of blood, also known as the stroke volume (Waugh and Grant, 2018). The more central arteries are most suitable for assessing pulse volume (Innes et al, 2018).
A reduced stroke volume will cause a reduction in pulse volume and can be caused by hypovolaemia and left ventricular failure, resulting in a weak or thready pulse (Innes et al, 2018). Estimating the blood pressure through pulse measurement is unreliable and inaccurate; however, it can be an indicator of organ perfusion if a radial pulse is present (JRCALC, 2017). Subsequently, an increased stroke volume results in an increased pulse volume and can be caused by physiological (exercise, pregnancy) and pathological factors (hypertension, thyrotoxicosis, fever, anaemia). This may be felt as a bounding pulse. The waveform/character of the pulse reflects the shape of the pulsation (Innes et al, 2018). This can be difficult to palpate initially, with practise and experience required to determine specific differences.
Conditions associated with pulses include the following:
Conclusion
Pulse measurement is an important assessment to determine the cardiovascular status of a patient and to provide a baseline observation on initial examination. Pulse measurement should not be used in isolation, but alongside other observations and assessments to provide a global picture of the patient's presenting condition. Review of best practice is important in order to maintain accuracy in undertaking clinical procedures to optimise patient care.