## Lesson 3-1 General Information

### WHAT IS A PULSE?

A pulse is when the left ventricle of the heart contracts. When this happens, blood is suddenly pushed from the ventricle to the main artery (aorta). This sudden forcing of blood from the heart into the arteries causes two things to happen.

a. Artery Expansion. The sudden rush of blood increases the volume of blood in the arteries. In order to accept this increased volume, the arteries expand (stretch). As the arteries quickly contract (go back to normal size), blood is forced from the arteries, through the capillaries, and into the veins.

b. Pulse. In addition to the expansion of the arteries, a "wave" travels through the arteries. This wave is the pulse. All arteries have a pulse, but the pulse is easier to feel (palpate) when the artery is near the surface of the body.

### WHAT IS PULSE RATE?

The pulse rate is the number of times that you can feel a pulse wave passing a point in one minute. Since a pulse wave occurs whenever the heart beats, the pulse rate equals the heartbeat rate. However, "taking a patient's pulse" means more than just determining his pulse rate. It also includes noting certain other factors about the pulse.

### WHAT FACTORS ARE NOTED WHEN TAKING A PATIENT'S PULSE?

When taking a patient's pulse, you should note the patient's pulse rate, the strength of the pulse, and the regularity of the pulse. Most of the pulse characteristics discussed in this paragraph are illustrated in figure 3-1.

a. Pulse Rate.

(1) The normal adult has a pulse rate of about 72 beats each minute. Infants have higher average pulse rates. The normal pulse rate ranges based upon age are given below.

• Adults: 60 to 100 beats per minute.
• Children: 70 to 120 beats per minute.
• Toddlers: 90 to 150 beats per minute.
• Newborns: 120 to 160 beats per minute.

(2) Pulse rates that are outside the normal range are classified as tachycardia or bradycardia.

(a) Tachycardia. If the patient's pulse rate is over 100 beats per minute, the patient is said to have tachycardia. Tachycardia means "swift heart." Constant tachycardia could be a sign of certain diseases and heart problems. Often, however, tachycardia is only temporary. Temporary tachycardia can be caused by exercise, pain, strong emotion, excessive heat, fever, bleeding, or shock.

(b) Bradycardia. If the patient's pulse rate is below 50 beats per minute, the patient is said to have bradycardia. Bradycardia means "slow heart." Bradycardia can be sign of certain diseases and heart problems. Certain medicines, such as Digitalis, can result in bradycardia.

b.   Strength. The strength (force) of the pulse is determined by the amount of blood forced into the artery by the heartbeat. A normal pulse has a normal strength. You will be able to identify a normal strength pulse with practice.

(1) Bounding. If the heart is pumping a large amount of blood with each heartbeat, the pulse will feel very strong. This strong pulse is called "bounding" pulse (as in "by leaps and bounds"). A bounding pulse can be caused by exercise, anxiety, or alcohol consumption.

(2) Weak. If the heart is pumping only a small amount of blood with each heartbeat, the pulse will be harder to detect. This type of pulse is called weak, feeble, or thready. If the pulse is weak, you may have trouble finding (palpating) the pulse at first.

(3) Strong. A strong pulse is stronger than normal pulse, but is less than bounding. Shock and hemorrhage (serious bleeding) can cause a strong pulse.

c.   Rhythm. Rhythm refers to the evenness of the beats. In a regular pulse, the time between beats is the same (constant) and the beats are of the same strength.

(1) Irregular. A pulse is irregular when the rhythm does not have an even pattern. The time between beats may change, or the strength of the beats may change or the pulse may vary in both time between beats and strength.

(2) Intermittent. An intermittent pulse is a special type of irregular pulse. A pulse is intermittent when the strength does not vary greatly, but a beat is skipped (missed) either at regular or irregular intervals. If the missing beats in an intermittent pulse were present, then the pulse rhythm would be normal.

 NOTE: Examples of some pulse patterns are illustrated in figure 3-1.

Figure 3-1. Pulse patterns.

### WHICH ARTERY IS PALPATED WHEN A PULSE IS TAKEN?

There are several sites on the body where a pulse is normally taken. All arteries have a pulse, but it is easier to palpate (feel) the pulse at certain locations. It is easier to feel the pulse when the artery is near the surface of the skin and when there is firm tissue (such as a bone) beneath the artery. The three most common sites are the radial (wrist), carotid (throat), and brachial (inside of elbow). These and other sites are discussed below and illustrated in figure 3-2. The site or sites that you choose to use may vary depending upon the condition of the patient. For example, suppose that you are assisting someone who is bleeding severely from a wound in his thigh. After giving the person first aid to stop the bleeding, you will check the person's pulse at a point below the injury to make sure that your bandage has not cut off the blood circulation to the lower leg. You may take the pulse at the popliteal (behind the knee) site, the dorsalis pedis (top of the foot) site, and/or the posterior tibial (back of the ankle) site.

a.   Radial. The radial pulse (the pulse taken using the radial artery) is taken at a point where the radial artery crosses the bones of the wrist. If the patient's hand is turned so that the palm is up, the radial pulse is taken on the thumb side of top side of the wrist.

b.   Carotid. The carotid pulse is taken on either side of the trachea (windpipe). The best location is the grooves located to the right and to the left of the larynx (Adam's apple).

c.   Brachial. The brachial pulse is taken in the depression located about one-half inch above the crease on the inside (not the bony side) of the elbow. This site is used when taking the patient's blood pressure.

Figure 3-2. Sites for taking a pulse.

 NOTE: All pulse sites except apical exist on both sides of the body. For example, one radial site exists on the right wrist and one exists on the left wrist.

d.   Temporal. The temporal pulse is taken in the temple area on either side of the head. The temple area is located in front of the upper part of the ear. The pulse is felt just above a large, raised bony area called the zygomatic arch.

e.   Ulnar. Like the radial pulse, the ulnar pulse is taken at the wrist. The radial pulse is taken over the artery on the thumb side of the wrist while the ulnar pulse is taken on the other side of the wrist. Both pulses are taken on the palm side of the wrist. The radial artery is normally preferred over the ulnar artery for taking the pulse because the radial artery is somewhat larger.

f.  Femoral. The femoral pulse is taken in the groin area by pressing the right or left femoral artery against the ischium (the lower part of the pelvic bones located in the front part of the body).

g.   Popliteal. The popliteal pulse is taken in the middle of the area located on the inside of the knee (the area opposite the kneecap).

h.   Posterior Tibial. The posterior tibial pulse is taken at the top of the ankle or just above the ankle on the back, inside part of the ankle.

i.  Dorsalis Pedis. The dorsalis pedis pulse is taken on the top portion of the foot just below the ankle. The pulse is taken in the middle of this area (not to the inside or outside).

j.   Apical. Unlike the other sites, the apical pulse is not taken over an artery. Instead, it is taken over the heart itself. The apical pulse (actually, the heartbeat) can be felt over the apex of the heart (the pointed lower end of the heart.) This site is located to the (patient's) left of the breastbone and two to three inches above the bottom of the breastbone. The apical pulse is easily heard when a stethoscope is used.