pulse

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Pulse evaluation at the radial artery.

In medicine, one's pulse represents the tactile arterial palpation of the heartbeat by trained fingertips. 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 can also be measured by listening to the heart beat directly (auscultation), traditionally 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.^[1] 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.

Pressure waves generated by the heart in systole moves the arterial walls. Forward movement of blood occurs when the boundaries 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 is 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 are 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.

Normal pulse rates

Normal pulse rates at rest, in beats per minute (BPM):^[2]

The pulse rate can be used to check overall heart health and fitness level. Generally lower is better, but bradycardias can be dangerous. Symptoms of a dangerously slow heartbeat include weakness, loss of energy and fainting.^[3]

Evaluation

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

• Pulsus alternans: an ominous medical sign that indicates progressive systolic heart failure. To trained fingertips, the examiner notes a pattern of a strong pulse followed by a weak pulse over and over again. This pulse signals a flagging effort of the heart to sustain itself in systole.
• Pulsus bigeminus: indicates a pair of hoofbeats within each heartbeat. Concurrent auscultation of the heart may reveal a gallop rhythm of the native heartbeat.
• Pulsus bisferiens: an unusual physical finding typically seen in patients with aortic valve diseases. If the aortic valve does not normally open and close, trained fingertips will observe two pulses to each heartbeat instead of one.
• Pulsus tardus et parvus: a slower than normal rise in the tactile pulse caused by an increasingly stiff aortic valve. Loss of compliance in the aortic valve makes it progressively harder to open, thus requiring increased generation of blood pressure in the left ventricle.
• Pulsus paradoxus: a condition in which some heartbeats cannot be detected at the radial artery during the inspiration phase of respiration. It is caused by an exaggerated decrease in blood pressure during this phase, and is diagnostic of a variety of cardiac and respiratory conditions of varying urgency.
• Tachycardia: an elevated resting heart rate. In general an electrocardiogram (ECG) is required to identify the type of tachycardia.

The strength of the pulse can also be reported:^[4][5]

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

A collapsing pulse is a sign of hyperdynamic circulation.

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).

Chinese medicine has focused on the pulse in the upper limbs for several centuries. The concept of Pulse Diagnosis is essentially a treatise based upon palpation and observations of the radial and ulnar volar pulses at the readily accessible wrist.

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 and 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

• Heart rate
• Pulse meter

References