Orris

Pulse

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Here is a complete clinical overview of the Pulse:

The Pulse - Clinical Overview

Physiology

Blood ejected into the aorta with each cardiac cycle creates a pressure wave. Critically, this wave travels at 3-5 m/sec, while blood itself flows at only ~0.5 m/sec. So when you palpate a peripheral pulse, you are feeling a pressure wave, not blood flow itself. - Roberts and Hedges' Clinical Procedures in Emergency Medicine
The character and contour of the arterial pulse depend on four main factors:
  • Stroke volume
  • Ejection velocity
  • Vascular compliance
  • Systemic vascular resistance
(Harrison's Principles of Internal Medicine, 22e)

What to Assess

Six key parameters are evaluated on every pulse examination (S Das, Manual on Clinical Surgery):
ParameterWhat it reflects
RateFast (tachycardia) or slow (bradycardia)
RhythmRegular or irregular
Tension / ForceDiastolic and systolic blood pressure
VolumePulse pressure
CharacterUnderlying cardiac/vascular pathology
Arterial wall conditione.g., atherosclerotic thickening
Normal pulse rate in adults: 60-100 bpm. Count for a full minute if irregularity is present; in a regular rhythm, count for 15 seconds and multiply by 4.

Pulse Pressure

Pulse pressure = Systolic BP - Diastolic BP (normal ~40 mmHg)
  • Widened pulse pressure (≥60 mmHg): anemia, exercise, hyperthyroidism, aortic regurgitation (AR), AV fistula, patent ductus arteriosus, increased intracranial pressure
  • Narrowed pulse pressure (≤20 mmHg): hypovolemia, aortic stenosis, pericardial tamponade, early septic shock (increased peripheral vascular resistance), reduced stroke volume

Pulse Characters and Their Causes

The carotid artery is the best site to assess pulse character. Below are the key abnormal pulse types, illustrated by the waveform diagram from Harrison's:
Carotid pulse waveform configurations: A=Normal, B=Anacrotic (aortic stenosis), C=Bisferiens (severe AR), D=Bisferiens (HOCM), E=Dicrotic
Pulse TypeCharacterCause
Pulsus parvus et tardusWeak, small, delayed upstrokeSevere aortic stenosis (AS)
Anacrotic pulseSlow, notched upstrokeSevere AS
Corrigan's / Water-hammer pulseSharp rise, rapid fallChronic severe aortic regurgitation (AR), thyrotoxicosis
Bisferiens pulseTwo systolic peaksSevere AR, HOCM
Dicrotic pulseTwo peaks - one systolic, one diastolicSepsis, intraaortic balloon pump
Pulsus paradoxusSystolic BP falls >10 mmHg on inspirationPericardial tamponade, massive PE, severe COPD, tension pneumothorax
Pulsus alternansBeat-to-beat variation in pulse amplitudeSevere LV systolic dysfunction

Pulsus Paradoxus - Measurement

Detected by sphygmomanometer:
  1. Inflate cuff, deflate slowly
  2. Note the pressure at which Korotkoff sounds are first heard (expiration only)
  3. Note the pressure at which sounds are heard throughout the cycle
  4. A difference >10 mmHg = pulsus paradoxus
  5. It is palpable at brachial/femoral when the pressure difference exceeds 15 mmHg
  • Harrison's Principles of Internal Medicine, 22e

Palpation Sites

Pulses are routinely examined at:
  • Radial (most common for rate/rhythm)
  • Carotid (best for character - palpate below thyroid cartilage to avoid carotid sinus massage)
  • Brachial (best for amplitude/contour)
  • Femoral, Popliteal, Posterior tibial, Dorsalis pedis (peripheral vascular assessment)
Caution: Never palpate both carotid arteries simultaneously - this can compromise cerebral blood flow. Auscultate for a bruit before vigorous carotid palpation.

Clinical Significance

  • Absent radial pulse in trauma = strongly suggests hypotension
  • Absence of both radial and femoral pulses = significant predictor of hypotension in hypovolemic shock
  • Reduction in pulse pressure is an early indicator of reduced central blood volume, even before systolic BP drops
  • In patients with nonpulsatile LVADs (HeartMate II/III, HVAD, etc.), pulses may be absent despite adequate perfusion - assess skin warmth and capillary refill instead
  • Roberts and Hedges' Clinical Procedures in Emergency Medicine
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