Sphygmomanometer
Sphygmomanometer
Definition
Purpose
Description
Normal results
Definition
A sphygmomanometer is a device for measuring blood pressure.
Purpose
The sphygmomanometer is designed to monitor blood pressure by measuring the force of the blood in the heart where the pressure is greatest. This occurs during the contraction of the ventricles, when blood is pumped from the heart to the rest of the body (systolic pressure). The minimal force is also measured. This occurs during the period when the heart is relaxed between beats and pressure is lowest (diastolic pressure).
A sphygmomanometer is used to establish a baseline at a healthcare encounter and on admission to a hospital. Checking blood pressure is also performed to monitor the effectiveness of medication and other methods to control hypertension, and as a diagnostic aid to detect various diseases and abnormalities.
Description
A sphygmomanometer consists of a hand bulb pump, a unit that displays the blood pressure reading, and an inflatable cuff that is usually wrapped around a person’s upper arm. Care should be taken to ensure that the cuff size is appropriate for the person whose blood pressure is being taken. This improves the accuracy of the reading. Children and adults with smaller or larger than average-sized arms require special-sized cuffs appropriate for their needs. A stethoscope is also used in conjunction with the sphygmomanometer to hear the blood pressure sounds. Some devices have the stethoscope already built in.
A sphygmomanometer can be used or encountered in a variety of settings:
- home
- hospital
KEY TERMS
Aneroid monitor— A monitor that works without fluids, i.e. without mercury.
Blood pressure— The tension of the blood in the arteries, measured in millimeters of mercury (mm Hg) by a sphygmomanometer or by an electronic device.
Diastolic— Minimum arterial blood pressure during ventricular relaxation or rest.
Systolic— Maximum arterial blood pressure during ventricular contraction.
- primary care clinic or professional office
- ambulance
- dental office
- pharmacy and other retail establishment
There are three types of equipment in common use for monitoring blood pressure.
- A mercury-based unit has a manually inflatable cuff attached by tubing to the unit that is calibrated in millimeters of mercury. During blood pressure measurement, the unit must be kept upright on a flat surface and the gauge read at eye level. Breakage of the unit may cause dangerous mercury contamination and would require specialist removal for disposal. Due to the hazards of mercury, the use of mercury-based sphygmomanometers has declined sharply since 2000.
- An aneroid unit is mercury free and consists of a cuff that can be applied with one hand for self-testing; a stethoscope that is built in or attached; and a valve that inflates and deflates automatically with the data displayed on an easy-to-read gauge that will function in any position. The unit is sensitive and if dropped may require recalibration.
- An automatic unit is also mercury free and is typically battery operated. It has a cuff that can be applied with one hand for self-testing, and a valve that automatically inflates and deflates. Units with manual inflation are also available. The reading is displayed digitally and a stethoscope is not required. This is useful for persons who are hearing impaired, for emergency situations when staff is limited, and for automatic input into instruments for storage or graphical display. A wrist monitor is also available for home testing. Some more expensive models also remember and print out recordings. The automatic units tend to be more portable than bulkier mercury devices.
Operation
The flow, resistance, quality, and quantity of blood circulating through the heart and the condition of the arterial walls are all factors that influence blood pressure. If blood flow in the arteries is restricted, the reading will be higher.
Blood pressure should be routinely checked every one to two years. It can be checked at any time, but is best measured when a person has been resting for at least five minutes, so that exertion prior to the test will not unduly influence the outcome of the reading.
To record blood pressure, the person should be seated with one arm bent slightly, and the arm bare or with the sleeve loosely rolled up. With an aneroid or automatic unit, the cuff is placed level with the heart and wrapped around the upper arm, one inch above the elbow. Following the manufacturer’s guidelines, the cuff is inflated and then deflated while an attendant records the reading.
If the blood pressure is monitored manually, a cuff is placed level with the heart and wrapped firmly but not tightly around the arm one inch (2-3 cm)above the elbow over the brachial artery. Wrinkles in the cuff should be smoothed out. Positioning a stethoscope over the brachial artery in front of the elbow with one hand and listening through the earpieces, the health professional inflates the cuff well above normal levels (to about 200 mm Hg), or until no sound is heard. Alternatively, the cuff should be inflated 10 mm Hg above the last sound heard. The valve in the pump is slowly opened. Air is allowed to escape no faster than 5 mm Hg per second to deflate the pressure in the cuff to the point where a clicking sound is heard over the brachial artery. The reading of the gauge at this point is recorded as the systolic pressure. The sounds continue as the pressure in the cuff is released and the flow of blood through the artery is no longer blocked. At this point, the noises are no longer heard. The reading of the gauge at this point is noted as the diastolic pressure. “Lub-dub” is the sound produced by the normal heart as it beats. Every time this sound is detected, it means that the heart is contracting once. The sounds are created when the heart valves click to close. When one hears “lub,” the atrioventricular valves are closing. The “dub” sound is produced by the pulmonic and aortic valves.
With children, the clicking sound does not disappear but changes to a soft muffled sound. Because sounds continue to be heard as the cuff deflates to zero, the reading of the gauge at the point where the sounds change is recorded as the diastolic pressure.
Blood pressure readings are recorded with the systolic pressure first, then the diastolic pressure (e.g. 120/70).
Interpretation
Blood pressure readings must be interpreted in relation to a person’s age, physical condition, medical history, and medications being used.
Maintenance
Devices should be checked and calibrated annually by a qualified technician to ensure accurate readings. This is especially important for automatic sphygmomanometers.
Normal results
One elevated reading does not mean that hypertension is present. Repeated measurements may be required if hypertension is suspected. The blood pressure measurement is recorded and compared with normal ranges for an individual’s age and medical condition, and a decision is made on whether any further medical intervention is required.
Resources
BOOKS
Bickley, L. S., P. G. Szilagyi, and J. G. Stackhouse. Bates’ Guide to Physical Examination & History Taking. 8th ed. Philadelphia: Lippincott Williams & Wilkins, 2002.
Chan, P. D., and P. J. Winkle. History and Physical Examination in Medicine. 10th ed. New York: Current Clinical Strategies, 2002.
Seidel, Henry M. Mosby’s Physical Examination Handbook. 4th ed. St. Louis: Mosby-Year Book, 2003.
Swartz, Mark A., and William Schmitt. Textbook of Physical Diagnosis: History and Examination. 4th ed. Philadelphia: Saunders, 2001.
PERIODICALS
Doyle, L. W., B. Faber, C. Callanan, and R. Morley. “Blood Pressure in Late Adolescence and Very Low Birth Weight.” Pediatrics 111, no. 2 (2003): 252–257.
Jones, D. W., L. J. Appel, S. G. Sheps, E. J. Roccella, and C. Lenfant. “Measuring Blood Pressure Accurately: New and Persistent Challenges.” Journal of the American Medical Association 289, no. 8 (2003): 1027–1030.
O’Brien, E. “Demise of the Mercury Sphygmomanometer and the Dawning of a New Era in Blood Pressure Measurement.” Blood Pressure Monitoring 8, no. 1 (2003): 19–21.
Pickering, T. G. “What Will Replace the Mercury Sphygmomanometer?” Blood Pressure Monitoring 8, no. 1 (2003): 23–25.
ORGANIZATIONS
American Academy of Family Physicians. 11400 Tomahawk Creek Parkway, Leawood, KS 66211-2672. (913) 906-6000. Email: [email protected]. http://www.aafp.org.
American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007-1098. (847) 434-4000. Fax: (847) 434-8000. Email: [email protected]. http://www.aap.org/default.htm.
American College of Physicians. 190 N. Independence Mall West, Philadelphia, PA 19106-1572. (800) 523-1546, x 2600 or (215) 351-2600. http://www.acponline.org.
American Medical Association. 515 N. State Street, Chicago, IL 60610. (312) 464-5000. http://www.ama-assn.org.
OTHER
“High Blood Pressure.” Medline Plus Health Information. [cited March 12, 2003]. http://www.nlm.nih.gov/medlineplus/highbloodpressure.html.
“Hypertension.” The Franklin Institute Online. [cited March 12, 2003]. <http://sln.fi.edu/biosci/healthy/pressure.html>.
“Your Guide to Lowering High Blood Pressure.” National Heart, Lung and Blood Institute (National Institutes of Health). [cited March 12, 2003]. http://www.nhlbi.nih.gov/hbp
L. Fleming Fallon, Jr., MD, DrPH
Sphygmomanometry seeBlood pressure measurement
Spina bifida surgery seeMeningocele repair
Spinal fluid analysis seeCerebrospinal fluid (CSF) analysis
Sphygmomanometer
Sphygmomanometer
Definition
A sphygmomanometer is a device for measuring blood pressure.
Purpose
The sphygmomanometer is designed to monitor blood pressure by measuring the force of the blood in the heart where the pressure is greatest. This occurs during the contraction of the ventricles, when blood is pumped from the heart to the rest of the body (systolic pressure). The minimal force is also measured. This occurs during the period when the heart is relaxed between beats and pressure is lowest (diastolic pressure).
A sphygmomanometer is used to establish a baseline at a healthcare encounter and on admission to a hospital. Checking blood pressure is also performed to monitor the effectiveness of medication and other methods to control hypertension, and as a diagnostic aid to detect various diseases and abnormalities.
Description
A sphygmomanometer consists of a hand bulb pump, a unit that displays the blood pressure reading, and an inflatable cuff that is usually wrapped around a person's upper arm. Care should be taken to ensure that the cuff size is appropriate for the person whose blood pressure is being taken. This improves the accuracy of the reading. Children and adults with smaller or larger than average-sized arms require special sized cuffs appropriate for their needs. A stethoscope is also used in conjunction with the sphygmomanometer to hear the blood pressure sounds. Some devices have the stethoscope already built in.
A sphygmomanometer can be used or encountered in a variety of settings:
- home
- hospital
- primary care clinic or professional office
- ambulance
- dental office
- pharmacy and other retail establishment
There are three types of equipment in common use for monitoring blood pressure.
- A mercury-based unit has a manually inflatable cuff attached by tubing to the unit that is calibrated in millimeters of mercury. During blood pressure measurement , the unit must be kept upright on a flat surface and the gauge read at eye level. Breakage of the unit may cause dangerous mercury contamination and would require specialist removal for disposal. Due to the hazards of mercury, the use of mercury-based sphygmomanometers has declined sharply since 2000.
- An aneroid unit is mercury free and consists of a cuff that can be applied with one hand for self-testing; a stethoscope that is built in or attached; and a valve that inflates and deflates automatically with the data displayed on an easy-to-read gauge that will function in any position. The unit is sensitive and if dropped may require recalibration.
- An automatic unit is also mercury-free and is typically battery-operated. It has a cuff that can be applied with one hand for self-testing, and a valve that automatically inflates and deflates. Units with manual inflation are also available. The reading is displayed digitally and a stethoscope is not required. This is useful for persons who are hearing-impaired, for emergency situations when staff is limited, and for automatic input into instruments for storage or graphical display. A wrist monitor is also available for home testing. Some more expensive models also remember and print out recordings. The automatic units tend to be more portable than bulkier mercury devices.
Operation
The flow, resistance, quality, and quantity of blood circulating through the heart and the condition of the arterial walls are all factors that influence blood pressure. If blood flow in the arteries is restricted, the reading will be higher.
Blood pressure should be routinely checked every one to two years. It can be checked at any time but is best measured when a person has been resting for at least five minutes, so that exertion prior to the test will not unduly influence the outcome of the reading.
To record blood pressure, the person should be seated with one arm bent slightly, and the arm bare or with the sleeve loosely rolled up. With an aneroid or automatic unit, the cuff is placed level with the heart and wrapped around the upper arm, one inch above the elbow. Following the manufacturer's guidelines, the cuff is inflated and then deflated while an attendant records the reading.
If the blood pressure is monitored manually, a cuff is placed level with the heart and wrapped firmly but not tightly around the arm one inch above the elbow over the brachial artery. Wrinkles in the cuff should be smoothed out. Positioning a stethoscope over the brachial artery in front of the elbow with one hand and listening through the earpieces, the health professional inflates the cuff well above normal levels (to about 200 mm Hg), or until no sound is heard. Alternatively, the cuff should be inflated 10 mm Hg above the last sound heard. The valve in the pump is slowly opened. Air is allowed to escape no faster than 5 mm Hg per second to deflate the pressure in the cuff to the point where a clicking sound is heard over the brachial artery. The reading of the gauge at this point is recorded as the systolic pressure. The sounds continue as the pressure in the cuff is released and the flow of blood through the artery is no longer blocked. At this point, the noises are no longer heard. The reading of the gauge at this point is noted as the diastolic pressure. "Lub-dub" is the sound produced by the normal heart as it beats. Every time this sound is detected, it means that the heart is contracting once. The sounds are created when the heart valves click to close. When one hears "lub," the atrioventricular valves are closing. The "dub" sound is produced by the pulmonic and aortic valves.
With children, the clicking sound does not disappear but changes to a soft muffled sound. Because sounds continue to be heard as the cuff deflates to zero, the reading of the gauge at the point where the sounds change is recorded as the diastolic pressure.
Blood pressure readings are recorded with the systolic pressure first, then the diastolic pressure (e.g. 120/70).
Interpretation
Blood pressure readings must be interpreted in relation to a person's age, physical condition, medical history, and medications being used.
Maintenance
Devices should be checked and calibrated annually by a qualified technician to ensure accurate readings. This is especially important for automatic sphygmomanometers.
Normal results
One elevated reading does not mean that hypertension is present. Repeated measurements may be required if hypertension is suspected. The blood pressure measurement is recorded and compared with normal ranges for an individual's age and medical condition, and a decision is made on whether any further medical intervention is required.
Resources
books
Bickley, L. S., P. G. Szilagyi, and J. G. Stackhouse. Bates' Guide to Physical Examination & History Taking. 8th ed. Philadelphia: Lippincott Williams & Wilkins, 2002.
Chan, P. D., and P. J. Winkle. History and Physical Examination in Medicine. 10th ed. New York: Current Clinical Strategies, 2002.
Seidel, Henry M. Mosby's Physical Examination Handbook. 4th ed. St. Louis: Mosby-Year Book, 2003.
Swartz, Mark A., and William Schmitt. Textbook of Physical Diagnosis: History and Examination. 4th ed. Philadelphia: Saunders, 2001.
periodicals
Doyle, L. W., B. Faber, C. Callanan, and R. Morley. "Blood Pressure in Late Adolescence and Very Low Birth Weight." Pediatrics 111, no. 2 (2003): 252–257.
Jones, D. W., L. J. Appel, S. G. Sheps, E. J. Roccella, and C. Lenfant. "Measuring Blood Pressure Accurately: New and Persistent Challenges." Journal of the American Medical Association 289, no. 8 (2003): 1027–1030.
O'Brien, E. "Demise of the Mercury Sphygmomanometer and the Dawning of a New Era in Blood Pressure Measurement." Blood Pressure Monitoring 8, no. 1 (2003): 19–21.
Pickering, T. G. "What Will Replace the Mercury Sphygmomanometer?" Blood Pressure Monitoring 8, no. 1 (2003): 23–25.
organizations
American Academy of Family Physicians. 11400 Tomahawk Creek Parkway, Leawood, KS 66211-2672. (913) 906-6000. <[email protected]>. <http://www.aafp.org>.
American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007-1098. (847) 434-4000. Fax: (847) 434-8000. <[email protected]>. <http://www.aap.org/default.htm>.
American College of Physicians. 190 N. Independence Mall West, Philadelphia, PA 19106-1572. (800) 523-1546, x 2600 or (215) 351-2600. <http://www.acponline.org>.
American Medical Association. 515 N. State Street, Chicago, IL 60610. (312) 464-5000. <http://www.ama-assn.org>.
other
"High Blood Pressure." Medline Plus Health Information. [cited March 12, 2003]. <http://www.nlm.nih.gov/medlineplus/highbloodpressure.html>.
"Hypertension." The Franklin Institute Online. [cited March 12, 2003]. <http://sln.fi.edu/biosci/healthy/pressure.html>.
"Your Guide to Lowering High Blood Pressure." National Heart, Lung and Blood Institute (National Institutes of Health). [cited March 12, 2003]. <http://www.nhlbi.nih.gov/hbp>
L. Fleming Fallon, Jr., MD, DrPH
Sphygmomanometer
Sphygmomanometer
Definition
A sphygmomanometer is a device for monitoring a person's blood pressure.
Purpose
The sphygmomanometer is designed to monitor the blood pressure by measuring the force of the blood in the heart where the pressure is greatest, during the contraction of the ventricles as blood is pumped from the heart to the rest of the body (systolic pressure), and during the period when the heart is relaxed between beats and pressure is lowest (diastolic pressure).
The device is used to establish a baseline at a healthcare encounter and on admission to the hospital. Checking blood pressure is also performed to monitor the effectiveness of medication and other methods to control hypertension, and as a diagnostic aid to detect various diseases and abnormalities.
Description
The sphygmomanometer consists of a hand bulb pump, a unit that displays the blood pressure reading, and an inflatable cuff that is wrapped around the patient's upper arm. Care should be taken to ensure the cuff is the correct size to give an accurate reading. Children and adults with smaller or larger than average-sized arms require special sized cuffs appropriate for their needs. A stethoscope is also used in conjunction with the sphygmomanometer to hear the blood pressure sounds. Some devices have the stethoscope already built in.
The sphygmomanometer can be used in a variety of settings:
- home
- hospital
- primary care, clinic, or clinician's office
- ambulance
- dental office
There are three types of equipment for monitoring blood pressure.
The mercury-based unit has a manually inflatable cuff attached by tubing to the unit that is calibrated in millimeters of mercury. During blood pressure measurement, the unit must be kept upright on a flat surface and the gauge read at eye level. Breakage of the unit may cause dangerous mercury contamination and would require specialist removal for disposal.
The aneroid unit is mercury free and consists of a cuff that can be applied with one hand for self-testing, a stethoscope that is built in or attached, and a valve that inflates and deflates automatically with the data displayed on an easy-to-read gauge that will function in any position. The unit is sensitive and if dropped, may require recalibration.
The automatic unit is also mercury free and is battery operated. It has a cuff that can be applied with one hand for self-testing, and a valve that inflates and deflates automatically. (Units with manual inflation are also available.) The reading is displayed digitally and a stethoscope is not required, therefore, the unit is useful for someone who is hearing impaired. A wrist monitor is also available for home testing. Some more expensive models also remember and print out recordings. The automatic units may be more portable than the bulkier mercury devices.
Blood pressure can be measured with any of the units, although mercury units are becoming less common due to the hazards of mercury.
Operation
The flow, resistance, quality, and quantity of blood circulating through the heart and the condition of the arterial walls are all factors that influence the blood pressure. If blood flow in the arteries is restricted, the reading will be higher.
Blood pressure should be routinely checked every one to two years. It can be checked at any time but is best performed when the patient has been resting for at least five minutes, so that exertion prior to the test will not unduly influence the outcome of the reading.
To record blood pressure, the patient should be seated with his left arm bent slightly, and the arm bare or with the sleeve loosely rolled up. With an aneroid or automatic unit, the cuff is placed level with the heart and wrapped around the upper arm, one inch above the elbow. Following the manufacturer's guidelines, the cuff is inflated and then deflated and the nurse records the reading.
If the blood pressure is monitored manually, a cuff is placed level with the heart and wrapped firmly but not tightly around the arm one inch above the elbow over the brachial artery, with creases in the cuff smoothed out. With a stethoscope over the brachial artery in front of the elbow with one hand and listening through the earpiece, the cuff is inflated well above normal levels (to about 200 mm Hg), or until no sound is heard. The cuff is then inflated a further 10 mm Hg above the last sound heard. The valve in the pump is slowly opened no faster than 5 mm Hg per second to deflate the pressure in the cuff to the point where a tapping sound is heard over the brachial artery. This point is noted as the systolic pressure. The sounds continue as the pressure in the cuff is released and the artery is no longer occluded. At this point, the noises are no longer heard and this is noted as the diastolic pressure.
With children, the tapping noise changes to a soft muffled sound. That point is noted as the diastolic pressure, since sounds continue to be heard as the cuff deflates to zero.
Blood pressure results are recorded with the systolic pressure first, then the diastolic pressure (e.g., 120/70).
Maintenance
Devices should be checked and calibrated annually by a qualified technician to ensure accurate readings.
Health care team roles
The appropriate sized cuff should be used to give an accurate reading. Repeated measurements may be required if hypertension is suspected. One elevated reading does not mean that hypertension is present. The blood pressure measurement is recorded and compared with normal ranges for the patient's age and medical condition and a decision made on whether any further medical intervention is required.
Training
The method of recording blood pressure should be consistent, especially the diastolic pressure, as a different reading will be obtained if it is measured when the sounds change or when they disappear. All healthcare professionals should be aware of the normal values for blood pressure measurement based on age and medical history.
KEY TERMS
Aneroid monitor— A monitor that works without fluids, e.g., without mercury.
Blood pressure— The tension of the blood in the arteries measured in millimeters of mercury by a sphygmomanometer or by an electronic device.
Diastolic— Minimum arterial blood pressure during ventricular rest.
Systolic— Maximum arterial blood pressure during ventricular contraction.
Resources
PERIODICALS
Canzanello, Vincent J., Patricia L. Jensen, and Gary L. Schwartz. "Are Anaeroid Sphygmomanometers Accurate in Hospital and Clinic Settings?" Archives of Internal Medicine 161 (March 12, 2001): 729.
ORGANIZATIONS
American College of Nurse Practitioners, 503 Capitol Ct. NE #300, Washington, DC 20002. (202) 546-4825. [email protected]
OTHER
"About Blood Pressure." American Heart Association. National Center, 7272 Greenville Avenue, Dallas, TX 752311. (800) AHA-USA1.
"High Blood Pressure." www.MayoClinic.com. September 28, 2000.
"Home Monitoring of High Blood Pressure." American Heart Association, National Center, 7272 Greenville Avenue, Dallas, TX 752311. (800) AHA-USA1.
Rathe, Richard. "Vital Signs." University of Florida. December 19, 2000. 〈http://www.medinfo.ufl.edu/yea1/bcs/clist/vitals.html〉. (July 16, 2001).
"Reducing Mercury Use in Health Care: Promoting a Healthier Environment." 〈http://www.epa.gov/glnpo/bnsdocs/merchealth/indextext.html〉.
"What Is High Blood Pressure?" American Heart Association, National Center, 7272 Greenville Avenue, Dallas, TX 752311. (800) AHA-USA1.
sphygmomanometer
sphyg·mo·ma·nom·e·ter / ˌsfigmōməˈnämitər/ • n. an instrument for measuring blood pressure, typically consisting of an inflatable rubber cuff that is applied to the arm and connected to a column of mercury next to a graduated scale, enabling the determination of systolic and diastolic blood pressure by increasing and gradually releasing the pressure in the cuff.DERIVATIVES: sphyg·mo·ma·nom·e·try / -mətrē/ n.