Blood pressure refers to the amount of force exerted on the walls of the blood vessels during the heart's pumping and resting stages. According to "The Fundamentals of Nursing," the pulse is a sensation that can be detected in various parts of the body and auscultated over the heart. It is the result of blood being ejected from the heart into blood vessels, which carries it to organs. Physicians and nurses evaluate both pulse and blood pressure regularly to assess general health.
Physiology
The heart's electrical conduction system regulates the pulse. A signal is produced in the sinoatrial node, and it travels through the heart muscle, causing contraction. This signal is produced roughly 60 to 100 times per minute, causing a heartbeat. The contraction of the heart and push of blood into the body's vessels is what can be heard and felt when assessing the pulse.
Blood pressure is regulated by a variety of body mechanisms and is the result of blood being ejected from the heart's left ventricle into arteries during systole. Systole refers to contraction of the heart and produces higher pressure against vessel walls. Diastole is the resting phase and results in less pressure being exerted. This is why a blood pressure reading appears as a fraction; the top systolic number indicates the amount of pressure during contraction, and the bottom diastolic number indicates pressure during rest.
Methods of Measurement
The blood pressure in the arteries is measured with a tool called a sphygmomanometer. This is the blood pressure cuff that is placed around the arm and the manometer that is attached to the cuff. Blood pressure can be measured in various places on the body; it is usually measured by placing the cuff over the brachial artery in the arm. According to the Mayo Clinic.com website, a health care professional uses a stethoscope and sphygmomanometer to measure blood pressure. This is done by positioning the cuff above the elbow once a pulse is found, placing the stethoscope in the antecubital space of the elbow and then inflating the cuff until the pulse is absent. Once this is done, a valve will be opened in the cuff, and it will deflate. During deflation, the health care professional listens for two distinct sounds and watches the measurements on the manometer that correspond with them. The first sound is the systolic pressure, and the second sound is the diastolic pressure.
A pulse can also be measured in multiple places on the body. According to Medline Plus, the pulse can be measured in the neck, temple, groin, wrist, back of the knee and in the foot. The health care professional may also measure the pulse with a stethoscope by placing it over the apex of the heart. Pulse rate is measured by counting the number of times a beat is heard or felt in one minute. The rhythm and quality of the pulse are also noted.
Interpretation
Rate, rhythm and quality of the pulse can help a health care professional determine a patient's general health and signify a healthy cardiovascular system or suggest disease. According to Medline Plus, a normal resting pulse rate for an adult should range from 60 to 100 beats per minute. A pulse should also have a normal rhythm, not skipping or having any irregular beats. It should not be weak or thready, but easily palpated, and moderate pressure should occlude it.
According to Mayo Clinic.com, a normal blood pressure for an adult is a systolic less than 120 and a diastolic below 80. A reading lower than this can indicate low blood pressure, which can signal pathology or be baseline for certain individuals. A reading higher than what is considered normal can indicate prehypertension or high blood pressure.
Changes in Blood Pressure and Pulse
Certain everyday activities can cause changes in pulse rate, such as exercise, stress or rest. This is also a characteristic of blood pressure. Lifestyle choices such as diet, activity level and smoking can affect cardiovascular health and lead to changes in blood pressure and pulse. The doctor should be informed of any irregular changes in blood pressure or pulse rate; they may indicate disease or may simply be the result of a normal biologic response.
Causes of Abnormal Blood Pressure and Pulse
A marked change in pulse or blood pressure can indicate disease or a medical emergency. For example, tachycardia or a rapid pulse accompanied by a decreasing blood pressure can indicate hemorrhage. This is happening because as the body loses blood and the pressure decreases in the vessels, the heart attempts to compensate by quickly pumping more blood into arteries, causing a faster pulse rate. Bradycardia refers to a slow pulse rate and can occur when someone is at rest or when the vagus nerve is stimulated, such as it is during a bowel movement. According to The Fundamentals of Nursing, factors that affect blood pressure include age, gender, exercise, emotional state and weight, with people in the obese category normally having higher blood pressure. A patient should discuss lifestyle, medications, diet and stress level with a doctor when she is assessing blood pressure and pulse, so that she can get an accurate picture of what may be causing any abnormal readings.
References
- Medline Plus: Pulse
- Mayo Clinic.com: Blood Pressure Test
- "Fundamentals of Nursing, The Art and Science of Nursing Care"; Carol Taylor, Carol Lillis, Priscilla LeMone, Pamela Lynn; 2008
