Peripheral Pulse

Definition/Introduction

A peripheral pulse refers to palpating the high-pressure wave of blood moving away from the heart through vessels in the extremities following systolic ejection. This phenomenon is often readily palpated and serves as a useful clinical tool, comprising one of the most commonly performed physical examination maneuvers at every level of medical care. Palpation occurs at various locations of the upper and lower extremities, including the radial, brachial, femoral, popliteal, posterior tibial, and dorsalis pedis arteries, and most commonly evaluates the rate, rhythm, intensity, and symmetry. Peripheral pulses can be used to identify many different types of pathology. Finally, modern medical technology allows for further evaluation of pulses beyond palpation, such as using Doppler ultrasound to characterize the pulse waveform. 

Physiology

During ventricular systole, a high-amplitude wave of blood is ejected across the aortic valve towards the periphery. This high-pressure wave distends the arteries, especially compliant “elastic” or “conducting” arteries, which tend to be larger and closer to the heart. The subsequent release of that distention somewhat sustains the systolic wave of blood throughout the body, creating a spike followed by a downward-sloping plateau in a pulsatile waveform. 

This waveform is propagated throughout the arterial system and can be felt and sometimes seen easily in several areas of the periphery. Higher pressures lead to greater palpated intensity as the peripheral vasculature distends more forcefully and to a higher degree. This phenomenon guides many clinical uses of the attribute of “intensity” when evaluating pulses. 

Heart rate (HR) has several determinants. The baseline heart rate is higher in pediatric patients, is usually increased with exertion, and is affected by the respiratory cycle. The intensity of the peripheral pulse is affected by blood pressure and other physiological factors such as ambient temperature. For example, colder temperatures cause vasoconstriction leading to decreased intensity.[1]  Outside the normal variation in rhythm that occurs with the respiratory cycle, the heart rate should be regular in the absence of pathology. 

Pathological conditions can alter the rate, rhythm, intensity, and symmetry of the peripheral pulses, a fact that healthcare providers can exploit when evaluating a patient. 

Physical Examination Technique

Pulses may be accurately measured when the clinician places their fingertips on the skin overlying the vessel and focuses on different aspects of the pulse. The traditional method of using only the fingertips and not the thumb during palpation is not supported by the reported literature.[2] If possible, the limb under evaluation should have support throughout palpation.  

Evaluation of the peripheral pulse begins with an initial gestalt about whether the pulse is bounding or weak, fast or slow, irregular or regular, and equal or unequal bilaterally. The intensity of the pulse is noted and subjectively graded on a scale of 0 to 4. By convention, “plus” always follows the number (e.g., 1+). Zero refers to a nonpalpable pulse, 1+ is a barely detectable pulse, 2+ is slightly diminished but greater than 1+, 3+ is a normal pulse and should be easily palpable, and 4+ is “bounding” (stronger than usual).[1]

After noting intensity, the clinician will focus on the rhythm, feeling long enough to be certain that the only variation in rhythm may be the minor fluctuation that occurs with the respiratory cycle. Finally, the rate can be measured: the clinician observes a timepiece while counting the total number of palpable beats that occur during a predetermined amount of time. Generally, 15 seconds is the minimum acceptable time (multiplied by four to get the number of beats per minute), with more extended periods producing greater accuracy, particularly for irregular rhythms. If relevant, the clinician can auscultate the heart while palpating a peripheral pulse to ascertain if every pulse gets transmitted as a palpable beat. 

 The choice of where to palpate a peripheral pulse depends on factors including but not limited to the age of the patient, patient body habitus, and the clinical situation (e.g., resuscitation, routine vitals at an office visit, evaluation for peripheral arterial disease, etc.). In addition, it may be relevant to compare bilateral pulses for symmetry and the difference between upper and lower extremity pulses. 

What follows will be a specific description of various peripheral pulses and where to find them. Diagrams can assist in learning where to find the pulses through palpation, and many can be found online, including in the citations for this article.[1] It is essential to recognize the presence of anatomic variation between patients; a clinician may encounter the physiologic absence of a particular pulse in an expected region. The carotid pulse is omitted from this discussion; although it is a significant pulse point, it is beyond the scope of an article focusing exclusively on peripheral pulses.  

In the upper extremities, the two most commonly palpated peripheral pulses are those of the radial and brachial arteries. Examiners frequently evaluate the radial pulse during a routine examination of adults, as this pulse is easily accessible and palpation is unobtrusive. Like other distal peripheral pulses (such as those in the feet), the radial pulse may be quicker to show signs of pathology. Palpation is at the anterior wrist, just proximal to the base of the thumb. The brachial artery is often the site of evaluation during cardiopulmonary resuscitation of infants. It is palpated proximal to the elbow between the medial epicondyle of the humerus and the distal biceps tendon. The carotid artery is the preferred pulse point used during the resuscitation of adults. 

In the lower extremities, the commonly evaluated peripheral pulses are those of the femoral, posterior tibial, dorsalis pedis, and sometimes the popliteal arteries. The femoral pulse may be the most sensitive in septic shock assessment and is routinely checked during resuscitation.[3]  It is palpated distal to the inguinal ligament less than halfway from the pubis to the anterior superior iliac spine. The posterior tibial pulse may be the most difficult to palpate, especially among less experienced clinicians.[4] It is located immediately posterior to the medial malleolus.[5] The dorsalis pedis is at the anterior aspect of the foot, lateral to the extensor hallucis tendon, and is generally within 1 cm of the bony prominence of the navicular bone.[6] Therefore, asking the patient to extend their first toe can help elevate this landmark and make the pulse easier to identify. However, it may be absent due to an anatomical variation in 10% of the general population.[1]  Finally, the popliteal pulse is present in the popliteal fossa, slightly lateral of the midline. 

In addition to manual palpation, medical technologies can detect pulse and study the waveform objectively. Some of the more commonly used technologies with this capability include Doppler ultrasound and arteriography, while other technologies for monitoring peripheral vasculature are also emerging.[5] Arteriography and ultrasound are two methods that can provide a discrete waveform. Doppler ultrasound is non-invasive, so it is often an option if the clinician cannot palpate a pulse manually.

Issues of Concern