Pulse

In medicine, a person's pulse represents the tactile arterial palpation of the heartbeat. Sphygmology is a term from perhaps the 2nd century AD that roughly translates as "all that is known about the pulse". The pulse may be palpated in any place that allows an artery to be compressed against a bone, such as at the neck (carotid artery), at the wrist (radial artery), behind the knee (popliteal artery), on the inside of the elbow (brachial artery), and near the ankle joint (posterior tibial artery). The pulse rate can also be measured by measuring the heart beat directly (auscultation), usually using a stethoscope.

Physiology

The pulse is a decidedly low tech/high yield and antiquated term still useful at the bedside in an age of computational analysis of cardiac performance. Claudius Galen was perhaps the first physiologist to describe the pulse. The pulse is an expedient tactile method of determination of systolic blood pressure to a trained observer. Diastolic blood pressure is non-palpable and unobservable by tactile methods, occurring between heartbeats.

Practitioners in Chinese Medicine are trained in Pulse Diagnosis and seek six different pulses in each wrist, each corresponding to specific organs of the body. The Chinese practitioner is trained to evaluate the frequency, rhythm and volume of the pulse and may characterize it as strong, thready, slippery or floating.^[1]

Pressure waves generated by cardiac systole move the artery walls, which are pliable and compliant. These properties form enough to create a palpable pressure wave.

The Heart Rate may be greater or lesser than the Pulse Rate depending upon physiologic demand. In this case, the heart rate are determined by auscultation or audible sounds at the heart apex, in which case it is not the pulse. The pulse deficit (difference between heart beats and pulsations at the periphery) is determined by simultaneous palpation at the radial artery and auscultation at the heart apex.

Pulse velocity, pulse deficits and much more physiologic data is readily and simplistically visualized by the use of one or more arterial catheters connected to a transducer and oscilloscope. This invasive technique has been commonly used in intensive care since the 1970s.

The rate of the pulse is observed and measured by tactile or visual means on the outside of an artery and is recorded as beats per minute or BPM.

The pulse may be further indirectly observed under Light absorbances of varying wavelengths with assigned and inexpensively reproduced mathematical ratios. Applied capture of variances of light signal from the Blood component Hemoglobin under oxygenated vs. deoxygenated conditions allows the technology of Pulse Oximetry.

Ranges

A normal pulse rate for a healthy adult, while resting, can range from 60 to 100 beats per minute (BPM) which means that the heart is slowed down because there is no activity which requires a higher heart rate, although well-conditioned athletes may have a healthy pulse rate much lower than 60 BPM, in the range of 30-45 BPM. Bradycardia occurs when the pulse rate is below 60 per minute but is only usually symptomatic when below 50BPM, whereas tachycardia occurs when the rate is above 100 BPM. During sleep, the pulse can drop to as low as 40 BPM; during strenuous exercise, it can rise as high as 150–200 BPM. Generally, pulse rates are higher in infants and young children. The resting heart rate for an infant is usually close to an adult's pulse rate during strenuous exercise (average 110 BPM for an infant).

Evaluation

A collapsing pulse is a sign of hyperdynamic circulation.

Several pulse patterns can be of clinical significance. These include:

• Pulsus alternans
• Pulsus bigeminus
• Pulsus bisferiens
• Pulsus tardus et parvus
• Pulsus paradoxus

The strength of the pulse can also be reported:^[2][3]

• 0 = Absent
• 1 = Barely palpable
• 2 = Easily palpable
• 3 = Full
• 4 = Aneurysmal or Bounding pulse

Common pulse sites

Upper limb

Front of right upper extremity

• Axillary pulse: located inferiorly of the lateral wall of the axilla
• Brachial pulse: located on the inside of the upper arm near the elbow, frequently used in place of carotid pulse in infants (brachial artery)
• Radial pulse: located on the lateral of the wrist (radial artery). It can also be found in the anatomical snuff box.
• Ulnar pulse: located on the medial of the wrist (ulnar artery).

Lower limb

• Femoral pulse: located in the inner thigh, at the mid-inguinal point, halfway between the pubic symphysis and anterior superior iliac spine (femoral artery).
• Popliteal pulse: Above the knee in the popliteal fossa, found by holding the bent knee. The patient bends the knee at approximately 124°, and the physician holds it in both hands to find the popliteal artery in the pit behind the knee (Popliteal artery).
• Dorsalis pedis pulse: located on top of the foot, immediately lateral to the extensor of hallucis longus (dorsalis pedis artery).
• Tibialis posterior pulse: located on the medial side of the ankle, 2 cm inferior and 2 cm posterior to the medial malleolus (posterior tibial artery). It is easily palpable over Pimenta's Point.

Head/neck

Arteries of the neck.

• Carotid pulse: located in the neck (carotid artery). The carotid artery should be palpated gently and while the patient is sitting or lying down. Stimulating its baroreceptors with low palpitation can provoke severe bradycardia or even stop the heart in some sensitive persons. Also, a person's two carotid arteries should not be palpated at the same time. Doing so may limit the flow of blood to the head, possibly leading to fainting or brain ischemia. It can be felt between the anterior border of the sternocleidomastoid muscle, above the hyoid bone and lateral to the thyroid cartilage.
• Facial pulse: located on the mandible (lower jawbone) on a line with the corners of the mouth (facial artery).
• Temporal pulse: located on the temple directly in front of the ear (superficial temporal artery).

Torso

• Apical pulse: located in the 4.5th or 5th left intercostal space, just outside the mid-clavicular line. In contrast with other pulse sites, the apical pulse site is unilateral, and measured not under an artery, but below the heart itself (more specifically, the apex of the heart).

See also

• Pulsus paradoxus
• Heart rate
• Pulse meter

References