Pulse Medical Lecture PDF

# Pulse ## Dr Zeinab Hussein Bakr ## Introduction - The stimulus for conduction of the heart normally starts as an electrical impulse in the sinoatrial (SA) node of the right atrium. - In adults the SA node initiates the impulse 60-100 times per minute. The electrical impulse then spreads quickly t...

# Pulse ## Dr Zeinab Hussein Bakr ## Introduction - The stimulus for conduction of the heart normally starts as an electrical impulse in the sinoatrial (SA) node of the right atrium. - In adults the SA node initiates the impulse 60-100 times per minute. The electrical impulse then spreads quickly through the conduction system to the remainder of the heart so that the heart muscle fibers contract in a synchronous fashion. ## Description of Image An image of the human heart is shown, illustrating the flow of blood out of the right ventricle and into the pulmonary valve. The image also shows the flow of oxygenated blood, from the lungs, into the left atrium, then the left ventricle. The left ventricle is where oxygenated blood exits the heart through the aortic valve. ## Definitions of Pulse - Waves of blood forced through arteries by contraction of the left ventricle. - Waves of blood created by alternating expansion and recoil of arteries during each cardiac cycle. ## Physiology and Regulation - The blood flows through the body in a continuous circuit. The cardiac centers located in the medulla of the brain stem control the heart through sympathetic or parasympathetic innervations. - The cardiac centers speed up or slow down the heart rate in response to sensory impulses from the heart, for example, if there is excessive stretch of the aortic arch by an increase blood volume, sensory impulses travel to the cardiac center causing a reflex slowing of the heart rate through the parasympathetic nervous system. ## Pulse Variables - **Stroke volume (SV):** it is the amount of blood ejected /beats (70 ml) - **Cardiac out put (CO):** it is the amount of blood pushed by the ventricles/minute. - CO = SV X HR - **Blood Volume Changes and Heart Rate:** - ↑ blood volume → ↓ HR - ↓blood volume → ↑ HR (as in hemorrhage). - **Pulse Wave Transmission:** - The heart functions to maintain a relatively constant circulatory blood flow approximately 70 to 72ml of blood enters the aorta with each ventricular contraction (stroke volume). - With each stroke volume ejection, the walls of the aorta distend, creating a pulse wave that travel rapidly toward the distal ends of the arteries. - When a pulse wave reaches a peripheral artery, it can be palpated by passing the artery lightly against underlying bone or muscle. ## Characteristics of Pulse - Characteristics of pulse include: rate or frequency, rhythm or regularity and volume or amplitude or strength. - **Rate:** - Is the number of pulsations felt over artery per minute. - When assessing the pulse, the nurse must consider the variety of factors influencing pulse rate. ## Factors Affecting Pulse Rate - **Age** - **Sex:** Pulse rate in female slightly more than in male because female is much nervous than male till menopause. - **Exercise and muscular activity:** Exercise and muscular activity increase pulse rate, while rest and sleep decrease pulse rate. - **Temperature:** Pulse rate raises about 10 beats/min for every degree of temperature elevation. Also, prolonged application of heat increase pulse rate. - **Stress and emotions:** Stress and emotions such as fear, anger, anxiety or surprise increase sympathetic stimulation, which increases the overall activity of the heart. - **Medications:** - Positive chronotropic drugs increase pulse rate such as atropine. - Negative chronotropic drugs decrease pulse rate such as digitalis (lanoxin). - **Hemorrhage:** Loss of blood increases sympathetic stimulation increasing pulse rate. - **Position changes:** Pulse rate in standing or sitting position is higher than in lying down position. - **Pulmonary conditions:** Any diseases causing poor oxygenation increase pulse rate. - **Disease conditions:** - Some diseases increase pulse rate such as infection, thyrotoxicosis, pulmonary embolism, and anemia. - Some diseases decrease pulse rate such as heart block. ## Rhythm - Pulse rhythm refers to the time intervals between each pulse beats. - Normally, the pulse has a regular rhythm or equal intervals of time between beats. When an interval is interrupted by an early or late or missed beat this create an abnormal rhythm or (arrhythmia - dysrhythmia). ## Pulse Deficit - To document arrhythmia, a physician may order an electrocariogram (ECG). - An inefficient contraction of the heart that fails to transmit a pulse wave to the peripheral pulse site creates a "pulse deficit" to assess a pulse deficit the nurse assess radial and apical rates and then compare rates. - **Pulse deficit:** “The differences between the apical and radial pulse rates". ## Volume - The strength of a pulse reflects the volume of blood ejected against the arterial wall with each heart contraction and the condition of the arterial vascular system leading to the pulse site. - Normally, the pulse strength remains the same with each heart beat. - Pulse strength may be graded or described as normal, thready, weak or bounding. - **A weak pulse:** is the pulse which is difficult to palpate and easy to lose during palpation. - **A normal pulse:** is the pulse which is full, easily palpable and not easily obliterated by the assessor's fingers. - **Strong A bounding pulse:** is the pulse which is easily palpated and difficult to obliterate. ## Pulse Assessment Methods - **Palpation:** The pulse is palpated with the tip of the middle three fingers of one hand. Light pressure is used to locate the area of strongest pulsation to count the rate, determine the rhythm and volume per minute. - **Auscultation:** Auscultation of apical pulse by a stethoscope provides the most accurate assessment of the pulse rate, it is useful when the peripheral pulses are difficult to assess or when the rhythm of the pulse is irregular. ## Stethoscope - The 4 major parts of the stethoscope are: the earpiece, binaural, tubing and chest piece. The chest piece consists of a bell and a diaphragm. ## Pulse Sites - An image of the human body showing several pulse sites was provided. ## Abnormalities of Pulse - **Tachycardia:** Is an abnormally elevated pulse rate, above 100 beat per minute in adults. - **Bradycardia:** Is an abnormally slow pulse rate, below 60 beat per minute in adults. - **Pulsus bigeminus (bigeminy):** Premature beat (weak) alternate with normal sinus beat (strong). - **Pulsus trigeminus(Trigeminy):** Premature beat alternate with two normal sinus beats. - **Ventricular tachycardia:** In which the pulse is weak (heart rate 150-250 beat per minute), discharging of impulses from hyper excitable focus in the ventricles not from SA node. It is characterized by palpitation. - **Atrial fibrillation:** In which the pulse is irregular, very weak to be felt at wrist, there is pulse deficit and palpitation. This condition due to discharging impulses from multiple excitable areas in atria which work separately with no coordination, but AV node and bundle of his cannot conduct a very high rate of atrial excitation.