Pulse is the wave of distension and elongation felt in an artery wall due to the contraction of the left ventricle forcing about 100 ml of blood into the already full aorta. When the aorta is distended, the wave passes along the walls of the arteries and can be felt at any point where an artery can be pressed against the radius on the anterior surface of the wrist. The other two most common sites on the body used are the temporal and facial arteries.
The temporal artery is felt one finger breadth in front of the opening to the ear and the facial artery two finger breadths in front of the angle of the jaw. These two places are used to take to take the pulse of infants or an adult who is under an anaesthetic and also when the radial pulse is not accessible.
The Normal Pulse
There may be quite a considerable variation in the pulse rate in health, which can be caused by a number of factors:
POSITION OF THE PERSON OR PATIENT
When the patient is standing up and moving about the pulse is more rapid than when he is lying down and relaxed.
SEX OF THE PATIENT
The pulse tends to be slightly more rapid in women than in men. The difference is usually about five heart beats per minute.
AGE OF THE PERSON
Here, there is the greatest variation. The pulse in the infant and the young child is much more rapid than the adult. For the newborn infants, they have 130 heart beats per minute. For twelve months old, they have 110 to 120 heart beats per minute. For two to five years, the have about 100 heart beats per minute. For five to ten years, they have about 90 heart beats per minute. For adult, they have 60 to 80 heart beats per minute. For old age people, their heart beats tend to become slower.
The ratio of the pulse rate to the respiration rate is usually fairly constant at about four pulse beats to each respiration, so that if the patient’s pulse is increased by about four beats per minute then the respiration rate will be found to be increased by one per minute. With every rise in temperature of 0.5 degree(1 degree F) there is usually an increase of about 10 pulse beats.
CHARACTERISTICS OF THE NORMAL PULSE
- Tension: The vessel should be feel soft under the nurse’s fingers. It should not feel hard and tortuous.
- The rate at which the heart is beating
- Rhythm: The regularity with which the heart beats occur. The length of time between each beat should be the same.
- Strength of the beat: It should require moderate pressure to obliterate the blood vessel.
HOW TO TAKE A PATIENT’S PULSE
- If there are contraindication in taking the patient’s pulse, the arm should be flexed at the elbow with the hand resting on the chest, the abdomen or the knee.
- The procedure should be explained to the patient who must be lying or sitting in a comfortable and relaxed position.
- If it is not possible to count the pulse at the radial artery, then it can be counted at the temporal or facial artery.
- The nurse places the first three fingers of one hand on the anterior aspect of the patient’s forearm just above the base of the thumb. The nurse should then feel the pulsations of the radial artery before starting to count beats and also should note the rhythm , volume and the state of the vessel wall. The nurse should note down the number of heart beats per minute using a watch.
ABNORMAL VARIATIONS IN THE PULSE
The pulse may vary in one or several of its characteristics
There are several terms applied to the rate of the pulse with which the nurse should be familiar with.
This is an abnormal slow action of the heart where the pulse may be as slow as 40 to 30 beats per minute. It occurs in most cases of the head injury, cerebral tumour and in diseases of the liver associated with jaundice. The transmission of the wave of expansion and elongation along the blood vessel wall is described as the pulse wave.
This is an increase in the heart rate above 100 beats per minute. This is found in certain heart disease like in Anaemias and in thyrotoxicosis. The tachycardia may be continuous or paroxysmal (occurring at irregular periods and for varying length of time).
In a dicrotic pulse, the beat seems to be followed immediately by another weaker beat. This is due to the fact that the muscle layer of the walls of the blood vessels has lost its tone. The second echo-like beat is caused by the blood rebounding off the closed aortic wave. Only the first beat should be counted to represent the number of heart beats. It is found in conditions of extreme postration.
Arrthythmia is the name given to irregularities in rhythm.
Intermittent pulse: This is when a pulsation is missed and may occur at regular or irregular intervals. The absence of a pulsation does not necessarily mean that there is an absence of heart beat. It may mean that certain heart beats have not been strong enough for the wave to reach the radial artery. To check this, the number of beats at the apex of the heart are counted using a stethoscope and during the same minute, the radial pulse is counted.
Two nurses are required to do this. On many occasions, this is not a serious symptom due to some digestive upset or excessive smoking or drinking of tea or coffee. It may lead to the diagnosis of some unsuspected heart diseases which should be reported if discovered.
This is the name given to the pulse when the intervals between the beats are uneven. The beats are not missed but on some occasions they run together while on others, they are widely separated.
These are extra beats produced by an excessive irritable cardiac muscle which causes an irregularity.
In the case of atrial fibrillation the atria are contracting so rapidly and so weakly that they seem to quiver. All the impulses of contraction are not transmitted to the ventricles but even so, the result is a rapid and very irregular pulse.
In sinus arrhythmia, the pulse is rapid during inspiration and slower during expiration. It occurs mainly in children and is of little significance. If the child is asked to hold his breath, the irregularity disappears.
VOLUME OR STRENGTH OF THE PULSE
A thready pulse is rapid, weak, and the blood flow is easily stopped by pressure.
A running pulse is rapid and of very poor tension. It is usually a sign of great prostration.
Corrigan’s pulse or water hammer pulse. This type of pulse is found in patients where the aortic valve is incompetent. The first half of the beat is normal but after reaching its peak, it suddenly collapses under the fingers.