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Chapter 30

Vital Signs

As indicators of health status, vital sign measurements indicate the effectiveness of circulatory, respiratory, neural, and endocrine body functions. Because of the importance of these functions, these measurements are referred to as vital signs.

Pain, a subjective symptom, is often called the fifth vital sign and is frequently measured with the others.

Measurement of vital signs provides data to determine a patient’s usual state of health (baseline data). Many factors, such as the temperature of the environment, the patient’s physical exertion, and the effects of illness cause vital signs to change, sometimes outside an acceptable range.

An alteration in vital signs signals a change in physiological function and the need for medical or nursing intervention.

Vital signs and other physiological measurements are the basis for clinical decision making and problem solving.

Measuring is your responsibility

Equipment use; ensure it is working properly

Know patient’s usual range and medical Hx

Control environmental factors

Use systematic approach

Collaborate to decide frequency

Used for administering medications

Analyze results, identify significant findings

Instruct patient in vital sign assessment

Guidelines for Measuring Vital Signs

Know expected values of vital signs. interpret your patient’s values, communicate findings appropriately, and begin interventions as needed.

[Review Box 30-1, Vital Signs: Acceptable Ranges for Adults, with students.]

Use the following guidelines to incorporate measurements of vital signs into nursing practice:

Measuring vital signs is your responsibility. You may delegate measurement of vital signs in selected situations, but you must review results and interpret their significance.

Assess equipment to ensure that it is working correctly and provides accurate findings.

Select equipment on the basis of the patient’s condition and characteristics (e.g., do not use an adult-size blood pressure [BP] cuff for a child).

Know the patient’s usual range of vital signs.

Know your patient’s medical history, therapies, and prescribed medications. Some illnesses or treatments cause predictable changes in vital signs. Some medications affect one or more vital signs.

Control or minimize environmental factors that affect vital signs.

Use an organized, systematic approach when taking vital signs.

Each procedure requires a step-by-step approach to ensure accuracy.

On the basis of the patient’s condition, collaborate with health care providers to decide the frequency of vital sign assessment.

Use vital sign measurements to determine indications for medication administration. Know the acceptable ranges for your patients before administering medications.

Analyze the results of vital sign measurement on the basis of patient’s condition and past medical history.

Verify and communicate significant changes in vital signs. Baseline measurements provide a starting point for identifying and accurately interpreting possible changes.

[Review Box 30-2, When to Measure Vital Signs, with students.]

Ms. Coburn is a 26-year-old schoolteacher. Her maternal grandparents immigrated to America from Brazil. She smokes one pack of cigarettes a day and has smoked since she was 16. She is 20 lbs overweight.

She made an appointment because she started to have headaches and frequently felt tired.

Case Study

Throughout the chapter, think about how Ms. Coburn’s history will affect her vital signs.

Body Temperature: Physiology

Body temperature:

Heat produced - heat lost = body temperature

Acceptable temperature range:

98.6° F to 100.4° F or 36° C to 38° C

Temperature sites:

Oral, rectal, axillary, tympanic membrane, temporal artery, esophageal, pulmonary artery

Despite extremes in environmental conditions and physical activity, temperature control mechanisms of humans keep body core temperature (temperature of the deep tissues) relatively constant. No single temperature is normal for all people.

For healthy young adults the average oral temperature is 37° C (98.6° F). In the elderly population, the average core temperature ranges from 35° to 36.1° C (95° to 97° F) as a result of decreased immunity.

The time of day also affects body temperature, with the lowest temperature at 6:00 a.m. and the highest temperature at 4:00 p.m. in healthy people.

Invasive measurements such as with a pulmonary artery catheter are considered core temperatures; whereas axillary temperatures are reflective of the surface temperature of the body.

It is important to remember that a consistent body temperature measurement from a single site allows you to monitor patterns of your patient’s body temperature.

[Shown is Figure 30-1: Ranges of normal temperature values and abnormal temperature alterations.]

Body Temperature Regulation

Neural and vascular control	Heat production
Heat loss (radiation, conduction, convection, evaporation)	Skin temperature regulation
Behavioral control

A process called thermoregulation controls the physiological and behavioral mechanisms that regulate heat loss and heat production. The relationship is regulated by these mechanisms.

Neural and vascular control is governed by the hypothalamus, located between the cerebral hemispheres. The hypothalamus works like a thermostat in establishing a comfortable body “set point.” The anterior hypothalamus controls heat loss, and the posterior hypothalamus controls heat production. Mechanisms of heat loss include sweating, vasodilation (widening) of blood vessels, and inhibition of heat production. The body redistributes blood to surface vessels to promote heat loss.

Heat production is a by-product of metabolism, a series of chemical reactions that take place in the body. Food is the primary source of the body’s metabolic process. Heat production occurs through the basal metabolic rate (BMR) and voluntary movements, as well as through shivering and nonshivering thermogenesis, which is reported in neonates.

Heat loss occurs through the processes of radiation, conduction, convection, and radiation. [Ask the class to define each of these.]

Radiation is the transfer of heat from the surface of one object to the surface of another without direct contact between the two. As much as 85% of the surface area of the human body radiates heat to the environment.

Conduction is the transfer of heat from one object to another through direct contact.

Convection is the transfer of heat away by air movement.

Evaporation is the transfer of heat energy when a liquid is changed to a gas as in diaphoresis or sweating.

Diaphoresis is visible perspiration primarily occurring on the forehead and upper thorax, although you can see it in other places on the body.

Skin temperature is an effect of its role in body insulation, vasoconstriction, and temperature sensation. Skin, subcutaneous tissue, and fat keep heat inside the body. People with more body fat have better insulation than do slim and muscular people.

Behavioral control depends on a person’s ability to control body temperature through:

The degree of temperature extremes.

The ability to sense comfort or discomfort.

Processes or emotions.

The person’s mobility or ability to add or remove clothing.

Miguel is a 42-year-old Hispanic nurse who works at the clinic Ms. Coburn is visiting. He enjoys providing health-related teaching to the patients and has provided Mrs. Coburn care for 2 years.

During the visit, Miguel assesses Ms. Coburn’s symptoms. He asks her about her headache and fatigue, then takes her vital signs. Her temperature is 98° Fahrenheit.

Case Study (Cont.)

[Ask students: What other vital signs does Miguel need to check? Discuss.]

Factors Affecting Body Temperature

Age

Exercise

Hormone level

Circadian rhythm

Stress

Environment

Temperature alterations

Age has a great effect on body temperature. Newborns’ temperature control mechanisms are immature. They can lose up to 30% of heat through their heads. Until a child reaches puberty, temperature regulation is unstable. Also, note that it is not unusual for older adults to reach temperatures no higher than 96.8° F.

Oral temperatures of 35° C (95° F) are sometimes found in older adults in cold weather. However, the average body temperature of older adults is approximately 35° to 36.1° C (95° to 97° F). Older adults are particularly sensitive to temperature extremes because of deterioration in control mechanisms, particularly poor vasomotor control (control of vasoconstriction and vasodilation), reduced amounts of subcutaneous tissue, reduced sweat gland activity, and reduced metabolism.

Exercise stimulates muscle activity and requires an increased blood supply and increased carbohydrate and fat breakdown. Exercise will increase heat production and body temperature.

Women experience greater fluctuations in body temperature than men. Hormonal variations occur during the menstrual cycle and menopause. Women may experience hot flashes caused by an inability to control vasodilation and vasoconstriction.

Body temperature normally changes 0.5° to 1° C (0.9° to 1.8° F) during a 24-hour period. The temperature is usually lowest between 1:00 and 4:00 a.m. During the day body temperature rises steadily to a maximum temperature value at about 4:00 p.m. and then declines to early-morning levels. The circadian rhythm does not change with age but will change for those who work the night shift. This usually takes 1 to 3 weeks.

Physical and emotional stress increase body temperature through hormonal and neural stimulation.

The environment influences body temperature. When entering a warm room, a person’s body heat will rise. If outside without warm clothing, a person’s body temperature may be low as a result of radiant and conductive heat loss.

Temperature alterations are related to excessive heat production, excessive heat loss, minimal heat production, minimal heat loss, or any combination of these.

[These are discussed on a subsequent slide.]

[Shown is Figure 30-2: Temperature cycle for 24 hours.]

Fever (pyrexia)

Heat-loss mechanisms are unable to keep pace with excessive heat production

Febrile

Afebrile

Temperature Alterations

Fever is usually not harmful if it stays below 39° C (102.2° F) in adults or below 40° C (104° F) in children.

Fever determination is based on several temperature readings at different times of the day compared with the usual value for that person at that time.

Pyrogens elevate body temperature, acting as antigens, and triggering immune system responses. The hypothalamus raises the set point, and the body conserves heat, which causes chills, fevers, and feels cold. The chill phase resolves when the new set point, a higher temperature, is achieved.

During the next phase, the plateau, the chills subside, and the person feels warm and dry. If the new set point is “overshot” or the pyrogens are removed, the third phase of a febrile episode occurs. The hypothalamus set point drops, initiating heat-loss responses. The skin becomes warm and flushed because of vasodilation. Diaphoresis assists in evaporative heat loss. When the fever “breaks,” the patient becomes afebrile.

Fever is an important defense mechanism. Mild temperature elevations as high as 39° C (102.2° F) enhance the immune system of the body.

Fever patterns differ, depending on the causative pyrogen.

[Review Box 30-3, Patterns of Fever, with students.]

The term fever of unknown origin (FUO) refers to a fever with an undetermined cause.

During a fever cellular metabolism increases, and oxygen consumption rises. Body metabolism increases 10% for every degree Celsius of temperature elevation.

Heart and respiratory rates increase to meet the metabolic needs of the body for nutrients. The increased metabolism uses energy that produces additional heat.

Hypothalamic Temperature Control

During a fever, cellular metabolism increases and oxygen consumption rises. Body metabolism increases 10% for every degree Celsius of temperature elevation. Heart and respiratory rates increase to meet the metabolic needs of the body for nutrients. The increased metabolism uses energy that produces additional heat.

If a patient has a cardiac or respiratory problem, the stress of a fever is great. A prolonged fever weakens a patient by exhausting energy stores. Increased metabolism requires additional oxygen. If the body cannot meet the demand for additional oxygen, cellular hypoxia (inadequate oxygen) occurs. Myocardial hypoxia produces angina (chest pain). Cerebral hypoxia produces confusion. Interventions during a fever include oxygen therapy.

Increased metabolism requires additional oxygen. If the body cannot meet the demand for additional oxygen, cellular hypoxia (inadequate oxygen) occurs. Myocardial hypoxia produces angina (chest pain). Cerebral hypoxia produces confusion. Interventions during a fever include oxygen therapy.

When water loss through increased respiration and diaphoresis is excessive, the patient is at risk for fluid volume deficit. Dehydration is a serious problem for older adults and children with low body weight. Maintaining optimum fluid volume status is an important nursing action.

[Shown is Figure 30-3: Effect of changing set point of hypothalamic temperature control during a fever.]

Hyperthermia

Heatstroke

Heat exhaustion

Hypothermia

Temperature Alterations (Cont.)

Hyperthermia is an elevated body temperature resulting from the body’s inability to promote heat loss or reduce heat production, resulting from an overload of the thermoregulatory mechanisms of the body.

Malignant hyperthermia is a hereditary condition of uncontrolled heat production that occurs when susceptible people receive certain anesthetic drugs.

Heatstroke (defined as a body temperature of 40° C [104° F] or more) depresses hypothalamic function, and occurs from prolonged exposure to the sun or high environmental temperatures.

This may be seen in those who spend time outside, such as athletes and construction workers.

Signs and symptoms include giddiness, confusion, delirium, excessive thirst, nausea, muscle cramps, visual disturbances, elevated body temperature, increased heart rate, and lower BP.

Vital signs reveal a body temperature sometimes as high as 45° C (113° F), with an increase in heart rate (HR) and lowering of BP. The most important sign of heatstroke is hot, dry skin.

Heat exhaustion occurs when profuse diaphoresis results in water and electrolyte loss. First aid includes transporting him or her to a cooler environment and restoring fluid and electrolyte balance.

Hypothermia occurs with exposure to cold. The core body temperature drops, and the body is unable to compensate.

When skin temperature drops below 34° C (93.2° F), the patient suffers uncontrolled shivering, loss of memory, depression, and poor judgment. As the body temperature falls lower, HR, respiratory rate, and BP fall. The skin becomes cyanotic.

Patients experience cardiac dysrhythmias, loss of consciousness, and unresponsiveness to painful stimuli if hypothermia progresses.

When you suspect hypothermia, assessment of core temperature is critical. A special low-reading thermometer is required because standard devices do not register below 35° C (95° F).

[Review Table 30-1, Classification of Hypothermia, with students.]

Frostbite occurs when the body is exposed to subnormal temperatures. Ice crystals form inside the cell, and permanent circulatory and tissue damage occurs.

Nursing Process

Assessment

Through the patient’s eyes

Sites

Thermometers

Fahrenheit or Celsius scale

Knowledge of the physiology of body temperature regulation is essential to assess and evaluate a patient’s response to temperature alterations and intervene safely.

Identify your patient’s values, beliefs, current treatments, and expectations regarding fever management. When possible, select the temperature site preferred by the patient. Include the patient’s preferences when selecting nonpharmacological interventions for hyperthermia.

Use a thermometer to obtain intermittent temperature measurements from the mouth, rectum, tympanic membrane, or temporal artery. Axillary temperature measurements are not recommended.

The temperature obtained varies, depending on the site used, but it is usually between 36° C (96.8° F) and 38° C (100.4° F). Rectal temperatures are usually 0.5° C (0.9° F) higher than oral temperatures.

[Review Skill 30-1, Measuring Body Temperature, with students.]

[Review Box 30-4, Advantages and Disadvantages of Select Temperature Measurement Sites, with students.]

Devices include electronic and disposable versions. You will practice with the devices used by your health care facility in the skills lab. Each temperature device has pros and cons.

Electronic advantages: Readings appear within seconds, easy to read. Disadvantage: Expense.

Disposable are useful for screening temperatures, especially in infants, young children, and patients who are intubated.

Maintaining cleanliness of the probes is an important consideration.

Thermometers use a Celsius or a Fahrenheit scale.

[Shown are Figure 30-4: Electronic thermometer. Blue probe is for oral use. Red probe is for rectal use; Figure 30-5: Temporal artery thermometer scanning child’s forehead; and Figure 30-6: Disposable, single-use thermometer strip.]

1.You have delegated vital signs to assistive personnel. The assistant informs you that the patient has just finished a bowl of hot soup. The nurse’s most appropriate advice would be to:

A. take a rectal temperature.

B. take the oral temperature as planned.

C. advise the patient to drink a glass of cold water.

D. wait 30 minutes and take an oral temperature.

Quick Quiz!

Answer: D

Rationale: The consumption of hot liquids will affect oral temperature readings.

Nursing diagnosis

Cluster defining characteristics to form a nursing diagnosis

Examples of nursing diagnoses for patients with body temperature alterations

Risk for Imbalanced Body Temperature

Hyperthermia

Hypothermia

Ineffective Thermoregulation

Nursing Process (Cont.)

Once you determine a diagnosis, accurately select the related factor or etiology. The related factor allows you to develop/set appropriate patient goals and select appropriate nursing interventions.

[Review Box 30-5, Nursing Diagnostic Process: Ineffective Thermoregulation Related to Aging and Inability to Adapt to Environmental Temperature, with students.]

Planning

Goals and outcomes

Setting priorities

Teamwork and collaboration

Implementation

Health promotion

Nursing Process (Cont.)

During planning integrate the knowledge gathered from assessment and the patient history to develop an individualized plan of care.

Establish expected outcomes to gauge progress toward returning the body temperature to an acceptable range. In cases in which the temperature alteration requires helping patients modify their environment, goals may be long term. Short-term goals such as regaining normal range of body temperature improve patient health.

Set priorities of care with regard to the extent that the temperature alteration affects a patient. The severity of a temperature alteration and its effects, together with the patient’s general health status, influence your priorities in his or her care. Safety is a top priority. Often other medical problems complicate the care plan.

Patients at risk for imbalanced body temperature require an individualized care plan directed at maintaining normothermia and reducing risk factors.

Education is particularly important for parents, who need to know how to take action at home and whom to call when an infant or child develops a temperature imbalance.

Consider patient activity, temperature of the environment, and clothing. Teach patients to avoid strenuous exercise in hot, humid weather; drink fluids such as water or clear fruity juices before, during, and after exercise; and wear light, loose-fitting, light-colored clothes.

Teach patients to avoid exercising in areas with poor ventilation, wear a protective covering over the head when outdoors, and expose themselves to hot climates gradually.

Prevention is key for patients at risk for hypothermia. It involves educating patients, family members, and friends. Patients at risk include the very young; the very old; and people debilitated by trauma, stroke, diabetes, drug or alcohol intoxication, and sepsis.

Fatigue, dark skin color, malnutrition, and hypoxemia also contribute to the risk of frostbite.

Acute care

Fever

Heatstroke

Hypothermia

Restorative and continuing care

Evaluation

Get patient’s perspective, compare actual with expected outcomes, and determine whether goals were met

Nursing Process (Cont.)

The objective of therapy for fever is to increase heat loss, reduce heat production, and prevent complications. The choice of interventions depends on the cause; adverse effects; and the strength, intensity, and duration of the temperature elevation.

[Review Box 30-6, Nursing Interventions for Patients with a Fever, with students.]

The health care provider attempts to determine the cause of the elevated temperature by isolating the causative pyrogen. Sometimes it is necessary to obtain culture specimens for laboratory analysis such as urine, blood, sputum, and wound sites. Some antibiotic medications (for bacterial infections) are ordered to be given after cultures have been obtained. Administering antibiotics destroys pyrogenic bacteria and eliminates the body stimulus for the elevated temperature.

Most fevers in children are of viral origin, last only briefly, and have limited effects. However, children still have immature temperature control mechanisms, and temperatures can rise rapidly. Dehydration and febrile seizures occur during rising temperatures in children between 6 months and 3 years of age. The extent of the temperature, often exceeding 38.8° C (101.8° F), seems to be a more important factor than the rapidity of the temperature increase. Children are at particular risk for fluid volume deficit because they can quickly lose large amounts of fluids in proportion to their body weight. It is important to maintain accurate intake and output records, to weigh the patient daily, and to encourage fluids.

Sometimes a fever is a hypersensitivity response to a drug. Drug fevers are often accompanied by other allergy symptoms such as rash or pruritus (itching). Treatment involves withdrawing the medication.

Antipyretics are medications that reduce fever. Nonsteroidal antiinflammatory drugs (NSAIDs) such as acetaminophen, salicylates, indomethacin, and ketorolac reduce fever by increasing heat loss. Corticosteroids reduce heat production by interfering with the immune system and mask signs of infection. They are not used to treat a fever. However, they can suppress fever in response to a pyrogen.

Nonpharmacological therapy for fever uses methods that increase heat loss through evaporation, conduction, convection, or radiation.

Make sure that nursing measures to enhance body cooling do not stimulate shivering. Shivering is counterproductive and increases energy expenditure up to 400%. These methods provide no advantages over antipyretic medications.

Blankets cooled by circulating water delivered by motorized units increase conductive heat loss. Follow manufacturer instructions for applying these hypothermia blankets because of the risk for skin breakdown and “freeze burns.” Placing a bath blanket between the patient and the hypothermia blanket and wrapping distal extremities (fingers, toes, and genitalia) reduce the risk of injury to the skin and tissue from hypothermia therapy. Wrapping the patient’s extremities reduces the incidence and intensity of shivering. Medications such as meperidine or butorphanol reduce shivering.

Heatstroke is an emergency situation. First aid treatment includes moving the patient to a cooler environment, removing excess body clothing, placing cool wet towels over the skin, and using oscillating fans to increase convective heat loss. Emergency medical treatment includes providing intravenous (IV) fluids, irrigating the stomach and lower bowel with cool solutions, and using hypothermia blankets.

The priority treatment goal for hypothermia is to prevent a further decrease in body temperature. Removing wet clothes, replacing them with dry ones, and wrapping patients in blankets are key nursing interventions. In emergencies away from a health care setting, have the patient lie under blankets next to a warm person. A conscious patient benefits from drinking hot liquids such as soup and avoiding alcohol and caffeinated fluids. It is helpful to keep the head covered, to place the patient near a fire or in a warm room, or to place heating pads next to areas of the body (head and neck) that lose heat the quickest.

Educate the patient with a fever about the importance of taking and continuing any antibiotics as directed until the course of treatment is completed. Children and older adults are at risk for fluid volume deficit because they can quickly lose large amounts of fluid in proportion to their body weight. Identifying preferred fluids and encouraging oral fluid intake are important ongoing nursing interventions.

Evaluate your patient’s perspectives about the care provided. Including the patient in the evaluation demonstrates that you value his or her perspective and contributes to patient safety.

If therapies are effective, body temperature returns to an acceptable range, other vital signs stabilize, and the patient reports a sense of comfort.

Pulse

Palpable bounding of blood flow noted at various points on the body

The indicator of circulatory status

Pulse rate

Number of pulsing sensations in 1 minute

Electrical impulses originate from the sinoatrial (SA) node

Regulation of ventricular contraction and stroke volume

Pulse

Electrical impulses originating from the sinoatrial (SA) node travel through heart muscle to stimulate cardiac contraction. Approximately 60 to 70 mL of blood enters the aorta with each ventricular contraction.

With each stroke volume ejection, the walls of the aorta distend, creating a pulse wave that travels rapidly toward the distal ends of the arteries. The pulse wave moves 15 times faster through the aorta and 100 times faster through the small arteries than the ejected volume of blood. When a pulse wave reaches a peripheral artery, you can feel it by palpating the artery lightly against underlying bone or muscle. The pulse is the palpable bounding of blood flow in the peripheral artery. The number of pulsing sensations occurring in 1 minute is the pulse rate.

The volume of blood pumped by the heart during 1 minute is the cardiac output, the product of heart rate (HR) and stroke volume (SV) of the ventricle. A change in HR or SV does not always change the output of the heart or the amount of blood in the arteries.

When factors are unable to alter stroke volume, a change in HR results in a change in cardiac output, which affects BP. As HR increases, the heart has less time to fill. As HR increases without a change in stroke volume, BP decreases. As HR slows, filling time is increased and BP increases. The inability of BP to respond to increases or decreases in HR indicates a possible health problem. Report this to the health care provider.

Mechanical, neural, and chemical factors regulate the strength of ventricular contraction and its SV. But when these factors are unable to alter SV, a change in HR causes a change in cardiac output, which affects BP. As HR increases, there is less time for the ventricular chambers of the heart to fill. As HR increases without a change in SV, BP decreases. As HR slows, filling time is increased, and BP increases. The inability of BP to respond to increases or decreases in HR indicates a possible health problem.

An abnormally slow, rapid, or irregular pulse alters cardiac output. Assess the ability of the heart to meet the demands of body tissue for nutrients by palpating a peripheral pulse or by using a stethoscope to listen to heart sounds (apical rate).

Assessment of Pulse

Sites: temporal, carotid, apical, brachial, radial, ulnar, femoral, popliteal, posterior tibial, and dorsalis pedis

Use of stethoscope

You will select the most appropriate and age-specific site to measure the pulse.

Typically, the radial artery is used because it is easy to palpate.

When a patient’s condition suddenly worsens, the carotid site is recommended for quickly finding and assessing the pulse.

If the radial pulse is abnormal or intermittent resulting from dysrhythmias or if it is inaccessible because of a dressing or cast, assess the apical pulse.

When a patient takes medication that affects the HR, the apical pulse provides a more accurate assessment of heart function.

The brachial or apical pulse is the best site for assessing an infant’s or a young child’s pulse because other peripheral pulses are deep and difficult to palpate accurately.

[Review Table 30-2, Pulse Sites, with students.]

When measuring the apical site, you will need to use a stethoscope. The five major parts of the stethoscope are the earpieces, binaurals, tubing, bell chest piece, and diaphragm chest piece.

To ensure the best reception of sound, the earpieces follow the contour of the ear canal pointing toward the face when the stethoscope is in place.

The polyvinyl tubing is flexible and 30 to 40 cm (12 to 18 inches) in length. Longer tubing decreases the transmission of sound waves.

The chest piece consists of a bell and a diaphragm that you rotate into position.

The diaphragm is the circular, flat portion of the chest piece covered with a thin plastic disk. It transmits high-pitched sounds created by the high-velocity movement of air and blood.

The bell is the bowl-shaped chest piece usually surrounded by a rubber ring. The bell transmits low-pitched sounds created by the low-velocity movement of blood. Auscultate heart and vascular sounds with the bell.

Before measuring a pulse, review the patient’s baseline rate for comparison.

[Review Table 30-3, Acceptable Ranges of Heart Rate, with students.]

[Shown is Figure 30-7: Parts of stethoscope.]

Assessment of Pulse (Cont.)

Character of the Pulse

Rate

Rhythm

Strength

Quality

Postural changes affect the pulse rate because of alterations in blood volume and sympathetic activity. The HR temporarily increases when a person changes from a lying to a sitting or standing position.

When assessing the pulse, consider the variety of factors influencing the pulse rate.

[Review Table 30-4, Factors Influencing Pulse Rate, with students.]

Assess the apical rate by listening to heart sounds Identify the first and second heart sounds (S1 and S2). At normal slow rates S1 is low pitched and dull, sounding like a “lub.” S2 is higher pitched and shorter, creating the sound “dub.” Count each set of “lub-dub” as one heartbeat. Using the diaphragm or bell of the stethoscope, count the number of lub-dubs occurring in 1 minute.

Two common abnormalities in pulse rate are tachycardia and bradycardia. Tachycardia is an abnormally elevated HR, above 100 beats/min in adults. Bradycardia is a slow rate, below 60 beats/min in adults.

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 you and a colleague assess radial and apical rates simultaneously and then compare rates. The difference between the apical and radial pulse rates is the pulse deficit.

Normally a regular interval occurs between each pulse or heartbeat. An interval interrupted by an early or late beat or a missed beat indicates an abnormal rhythm or dysrhythmia.

A dysrhythmia threatens the ability of the heart to provide adequate cardiac output, particularly if it occurs repetitively.

You identify a dysrhythmia by palpating an interruption in successive pulse waves or auscultating an interruption between heart sounds.

To document a dysrhythmia, the health care provider often orders an electrocardiogram (ECG), Holter monitor, or telemetry monitor.

Children often have a sinus dysrhythmia, which is an irregular heartbeat that speeds up with inspiration and slows with expiration. This is a normal finding that you can verify by having the child hold his or her breath; the HR usually becomes regular.

The strength or amplitude 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.

Document the pulse strength as bounding (4); full or strong (3); normal and expected (2); diminished or barely palpable (1); or absent (0). Include assessment of pulse strength in the assessment of the vascular system.

Assess radial pulses on both sides of the peripheral vascular system, comparing the characteristics of each.

Assess all symmetrical pulses simultaneously except for the carotid pulse. Never measure the carotid pulses simultaneously because excessive pressure occludes blood supply to the brain.

[Review Skill 30-2, Assessing Radial and Apical Pulses, with students.]

[Shown are Figure 30-8: Positioning diaphragm of stethoscope firmly an securely when auscultating high-pitched heart sounds; and Figure 30-9: Positioning bell of stethoscope lightly on skin to hear low-pitched heart sounds.]

Nursing Process and Pulse Determination

Activity intolerance	Anxiety	Acute Pain
Decreased cardiac output	Deficient/excess fluid volume	Impaired gas exchange
Ineffective peripheral tissue perfusion

Pulse assessment determines the general state of cardiovascular health and the response of the body to other system imbalances.

Tachycardia, bradycardia, and dysrhythmia are defining characteristics of many nursing diagnoses, including the ones shown on the slide.

The nursing care plan includes interventions based on the nursing diagnosis identified and related factors.

When the related factor is inactivity following prolonged illness, interventions focus on increasing the patient’s daily exercise routine.

Once the plan is implemented, evaluate patient outcomes by assessing his or her pulse.

2. You notice that a teenager has an irregular pulse. The best action you should take includes:

A. reading the history and physical.

B. assessing the apical pulse rate for 1 full minute.

C. auscultating for strength and depth of pulse.

D. asking whether the patient feels any palpitations or faintness of breath.

Quick Quiz!

Answer: B

Rationale: If you detect an abnormal rate while palpating a peripheral pulse, the next step is to assess the apical rate.

Ventilation = Movement of gases into and out of the lung.

Diffusion= Movement of oxygen and carbon monoxide between alveoli and red blood cells.

Perfusion = Distribution of red blood cells to and from the pulmonary capillaries.

Physiological control; hypoxemia.

Respiration

Human survival depends on the ability of oxygen (O2) to reach body cells and carbon dioxide (CO2) to be removed from the cells. Respiration is the mechanism the body uses to exchange gases between the atmosphere and the blood and the blood and the cells.

Analyzing respiratory efficiency requires integrating assessment data from all three processes. Assess ventilation by determining respiratory rate, depth, rhythm and end-tidal carbon dioxide (ETCO2) value. Assess diffusion and perfusion by determining oxygen saturation.

Respiration includes three processes: ventilation, diffusion, and perfusion. You will analyze respiratory efficiency and ventilation by assessing respiratory rate, depth, and rhythm.

Breathing is a passive process. The brain stem regulates involuntary control. The body regulates ventilation through CO2 and O2 and hydrogen ion concentrations in arterial blood. If oxygen falls below acceptable parameters, respiratory rate and depth of ventilation will increase.

Hypoxemia is a low blood level of oxygen. Hypoxemia helps to control ventilation in patients with chronic lung disease. Because low levels of arterial O2 provide the stimulus that allows a patient to breathe, administration of high oxygen levels is fatal for patients with chronic lung disease. Because low levels of arterial O2 provide the stimulus that allows a patient to breathe, administration of high oxygen levels is fatal for patients with chronic lung disease.

Movements During Breathing

Mechanics of breathing

Although breathing is normally passive, muscular work is involved in moving the lungs and chest wall. Normally, 500 mL of air is inhaled in a breath (this is referred to as tidal volume). Inspiration is an active process. Expiration is passive. Inspiration is an active process.

During inspiration, the respiratory center sends impulses along the phrenic nerve, causing the diaphragm to contract. Abdominal organs move downward and forward, increasing the length of the chest cavity to move air into the lungs. The diaphragm moves approximately 1 cm, and the ribs retract upward from the midline of the body approximately 1.2 to 2.5 cm.

During a normal, relaxed breath, a person inhales 500 mL of air. This amount is referred to as the tidal volume.

During expiration, the diaphragm relaxes and the abdominal organs return to their original positions. The lung and chest wall return to a relaxed position. Expiration is a passive process. The sigh, a prolonged deeper breath, is a protective physiological mechanism for expanding small airways and alveoli not ventilated during a normal breath.

Accurate assessment of respirations depends on the recognition of normal thoracic and abdominal movements. During quiet breathing, the chest wall gently rises and falls. Contraction of the intercostal muscles between the ribs or contraction of the muscles in the neck and shoulders (the accessory muscles of breathing) is not visible. During normal quiet breathing, diaphragmatic movement causes the abdominal cavity to rise and fall slowly.

[Shown is Figure 30-10: Illustration of diaphragmatic and chest wall movement during inspiration and expiration.]

Easy to assess

Respiratory rate: breaths/minute

Ventilatory depth: deep, normal, shallow

Ventilatory rhythm: regular/irregular

Assessment of Ventilation

Accurate measurement requires observation and palpation of chest wall movement.

[Review Box 30-7, Factors Influencing Character of Respirations, with students.]

Do not let a patient know that you are assessing respirations. A patient aware of the assessment can alter the rate and depth of breathing. Assess respirations immediately after measuring pulse rate, with our hand still on the patient’s wrist as it rests over the chest or abdomen.

When assessing a patient’s respirations, keep in mind the patient’s usual ventilatory rate and pattern, the influence any disease or illness has on respiratory function, the relationship between respiratory and cardiovascular function, and the influence of therapies on respirations.

[Review Skill 30-3, Assessing Respirations, with students.]

Capnography is the measurement of exhaled carbon dioxide throughout exhalation. At the end of exhalation, the ETCO2 measurement approximates the PaCo2 in a healthy patient, normally 35 to 35 mm Hg.

Observe a full inspiration and expiration when counting ventilation or respiration rate. The usual respiratory rate varies with age. The usual range of respiratory rate declines throughout life. A respiratory rate above 27 breaths/min is an important risk factor for cardiac arrest.

[Review Table 30-5, Acceptable Ranges of Respiratory Rate, with students.]

Use an apnea monitors when needed.

Assess the depth of respirations by observing the degree of excursion or movement in the chest wall. Describe ventilatory movements as deep or shallow, normal or labored. A deep respiration involves a full expansion of the lungs with full exhalation.

Respirations are shallow when only a small quantity of air passes through the lungs and ventilatory movement is difficult to see. Use more objective techniques if you observe that chest excursion is unusually shallow.

[Review Table 30-6, Alterations in Breathing Patterns, with students.]

Determine breathing pattern by observing the chest or the abdomen. Labored respirations usually involve the accessory muscles of respiration visible in the neck.

With normal breathing a regular interval occurs after each respiratory cycle. Infants tend to breathe less regularly.

While assessing respirations, estimate the time interval after each respiratory cycle. Respiration is regular or irregular in rhythm.

Assessment of Diffusion and Perfusion

Measure oxygen saturation of the blood

Measurement of arterial oxygen saturation

Blood flow through the pulmonary capillaries provides red blood cells for oxygen attachment. After oxygen diffuses from the alveoli into the pulmonary blood, most of the oxygen attaches to hemoglobin molecules in red blood cells. Red blood cells carry the oxygenated hemoglobin molecules through the left side of the heart and out to the peripheral capillaries, where the oxygen detaches, depending on the needs of the tissues.

The percent of hemoglobin that is bound with oxygen in the arteries is the percent of saturation of hemoglobin (or SaO2) It is usually between 95% and 100%.

The saturation of venous blood (SvO2) is lower because the tissues have removed some of the oxygen from the hemoglobin molecules. Factors that interfere with or increase tissue oxygen demand affect the usual value for SvO2, which is 70%.

A pulse oximeter permits the indirect measurement of oxygen saturation. The pulse oximeter is a probe with a light-emitting diode (LED) connected by cable to an oximeter.

The LED emits light wavelengths that the oxygenated and deoxygenated hemoglobin molecules absorb differently. A photodetector in the probe detects the amount of oxygen bound to hemoglobin molecules, and the oximeter calculates the pulse saturation (SpO2). SpO2 is a reliable estimate of SaO2 when the SaO2 is greater than 70%. A saturation of less than 90% is a clinical emergency.

The photodetector is in the oximeter probe. Selecting the appropriate probe is important to reduce measurement error.

Digit probes are spring loaded and conform to various sizes.

Earlobe probes have greater accuracy at lower saturations and are least affected by peripheral vasoconstriction.

Oxygen saturation measurement using a forehead probe is quicker than finger probes and more accurate in conditions that decrease blood flow.

Factors that affect light transmission or peripheral arterial pulsations affect the ability of the photodetector to measure SpO2 correctly.

[Review Box 30-8, Factors Affecting Determination of Pulse Oxygen Saturation (SpO2), with students.]

[Review Skill 30-4, Measuring Oxygen Saturation (Pulse Oximetry), with students.]

[Shown is Figure 30-11: Portable pulse oximeter with digital probe.]

Miguel continues to take Ms. Coburn’s vital signs.

Ms. Coburn’s respiratory rate is 14 breaths per minute, and her pulse is 86 beats per minute.

Case Study (Cont.)

[Ask students: Are these vital signs within normal limits? Discuss.]

Respiratory assessment data are defining characteristics of many nursing diagnoses, including the following:

Activity Intolerance

Ineffective Airway Clearance

Anxiety

Ineffective Breathing Pattern

Impaired Gas Exchange

Acute Pain

Ineffective Peripheral Tissue Perfusion

Dysfunctional Ventilatory Weaning Response

Nursing Process and Respiratory Vital Signs

Measurement of respiratory rate, pattern, and depth, along with SpO2, assesses ventilation, diffusion, and perfusion.

The nursing care plan includes interventions based on the nursing diagnosis identified and the related factors.

You select interventions on the basis of the related factor. After intervening, evaluate patient outcomes by assessing the respiratory rate, ventilatory depth, rhythm, and SpO2.

3. A postoperative patient is breathing rapidly. You should immediately:

A. call the physician.

B. count the respirations.

C. assess the oxygen saturation.

D. ask the patient if he feels uncomfortable.

Quick Quiz!

Answer: C

Rationale: Shortness of breath is an indicator of hypoxemia. Assessing the oxygen saturation will let the nurse know if the patient’s breathing status is a result of hypoxemia.

Force exerted on the walls of an artery by pulsing blood under pressure from the heart

Systolic = Maximum peak pressure during ventricular contraction

Diastolic = Minimal pressure during ventricular relaxation

Pulse pressure = Difference between systolic and diastolic pressures

Blood Pressure

BP is the force exerted on the arterial wall by pulsing blood under pressure from the heart.

Blood flows throughout the circulatory system as a result of pressure changes. It moves from an area of high pressure to one of low pressure. Systemic or arterial BP, the BP in the system of arteries in the body, is a good indicator of cardiovascular health.

The contraction of the heart forces the blood under high pressure into the aorta. The peak of maximum pressure when ejection occurs is the systolic pressure. When the ventricles relax, the blood remaining in the arteries exerts a minimum or diastolic pressure. Diastolic pressure is the minimal pressure exerted against the arterial walls at all times.

The standard unit for measuring BP is millimeters of mercury (mm Hg). This measurement indicates the height to which the BP raises a column of mercury. Record BP with the systolic reading before the diastolic reading (e.g., 120/80).

The difference between systolic and diastolic pressures is the pulse pressure. For a BP of 120/80, the pulse pressure is 40.

[Review Skill 30-5, Measuring Blood Pressure, with students.]

Physiology of Arterial Blood Pressure

Factors Affecting Arterial Blood Pressure

Cardiac output

Peripheral resistance

Blood volume

Viscosity

Elasticity

BP reflects the interrelationships of cardiac output, peripheral vascular resistance, blood volume, blood viscosity, and artery elasticity.

BP depends on cardiac output. When volume increases in an enclosed space such as a blood vessel, the pressure in that space rises. Thus as cardiac output increases, more blood is pumped against arterial walls, causing the BP to rise.

Cardiac output increases as a result of an increase in HR, greater heart muscle contractility, or an increase in blood volume. Changes in HR occur faster than changes in heart muscle contractility or blood volume. A rapid or significant increase in HR decreases the filling time of the heart. As a result BP decreases.

BP depends on peripheral vascular resistance. Peripheral vascular resistance is the resistance to blood flow determined by the tone of vascular musculature and diameter of blood vessels. The smaller the lumen of a vessel, the greater is the peripheral vascular resistance to blood flow. As resistance rises, arterial BP rises. As vessels dilate and resistance falls, BP drops.

The volume of circulating blood affects blood pressure. Normal circulating volume is 5000 mL. An increase in volume exerts more pressure against arterial walls. When a person’s circulating blood volume falls, as in the case of hemorrhage or dehydration, the BP falls.

The thickness or viscosity of blood affects the ease with which blood flows through small vessels. The hematocrit, or percentage of red blood cells in the blood, determines blood viscosity. When the hematocrit rises and blood flow slows, arterial BP increases. The heart contracts more forcefully to move the viscous blood through the circulatory system.

Normal arterial walls are elastic and easily distensible. As blood pressure increases, the diameter of the vessels increases to accommodate the pressure. As pressure within the arteries increases, the diameter of vessel walls increases to accommodate the pressure change. Arterial distensibility prevents wide fluctuations in BP.

Reduced elasticity results in greater resistance to blood flow. As a result, when the left ventricle ejects its SV, the vessels no longer yield to pressure. Instead a given volume of blood is forced through the rigid arterial walls, and the systemic pressure rises. Systolic pressure is more significantly elevated than diastolic pressure as a result of reduced arterial elasticity.

Each hemodynamic factor significantly affects the others. The complex control of the cardiovascular system normally prevents any single factor from permanently changing the BP.

Factors Influencing Blood Pressure

Age	Stress
Ethnicity	Gender

BP is not a constant. Many factors influence blood pressure. One measurement cannot adequately reflect a patient’s usual BP.

Normal BP levels vary throughout life.

[Review Table 30-7, Average Optimal Blood Pressure for Age, with students.]

An adult’s BP tends to rise with advancing age. Values of 120 to 139 systolic and 80 to 89 diastolic mm Hg are considered prehypertension.

[Review Table 30-8, Classification of Blood Pressure for Adults Ages 18 and Older, with students.]

Stress created by anxiety, fear, pain, and emotions causes sympathetic stimulation, which increases heart rate, cardiac output, and vascular resistance.

The incidence of hypertension is higher in African-Americans than in European Americans. Genetic and environmental factors are often contributing factors. Hypertension-related deaths are also higher among African-Americans.

No clinical differences between boys and girls have been noted. However, after puberty, males tend to have higher blood pressure. After menopause, women tend to have higher blood pressure than men of similar age.

Factors Influencing Blood Pressure (Cont.)

Daily variation	Medications
Activity, weight	Smoking

BP varies throughout the day, with lower BP during sleep between midnight and 3:00 a.m. Between 3:00 a.m. and 6:00 a.m. there is a slow and steady rise in BP. When a patient awakens, there is an early-morning surge. It is highest during the day between 10:00 a.m. and 6 p.m. No two people have the same pattern or degree of variation.

Medications will directly or indirectly alter blood pressure. Before BP assessment ask whether the patient is receiving antihypertensive, diuretic, or other cardiac medications, which lower BP.

[Review Table 30-9, Antihypertensive Medications, with students.]

Activity and weight are directly linked. A period of exercise can reduce blood pressure for several hours. Inadequate exercise contributes to weight gain and perhaps obesity, which can trigger hypertension.

Smoking results in vasoconstriction, a narrowing of blood vessels. BP rises when a person smokes and returns to baseline about 15 minutes after stopping smoking.

More common than hypotension

Thickening of walls

Loss of elasticity

Family history

Risk factors

Hypertension

Hypertension is more common than hypotension. Hypertension is often asymptomatic. Prehypertension is diagnosed in adults when an average of two or more readings on at least two subsequent visits is between 120 and 139 mm Hg systolic and 80 and 89 mm Hg diastolic. Diastolic readings greater than 90 mm Hg and systolic readings greater than 140 mm Hg define hypertension.

[Review Table 30-10, Recommendations for Blood Pressure Follow-Up, with students.]

Hypertension is associated with thickening and loss of elasticity in the arterial walls. Peripheral vascular resistance increases within thick and inelastic vessels. The heart continually pumps against greater resistance. As a result blood flow to vital organs such as the heart, brain, and kidney decreases.

Modifiable risk factors include obesity, smoking, alcohol consumption, and high salt. A person has no control over family history. Higher incidence of high blood pressure is seen in those with diabetes, older adults, and those of African-American descent.

When patients are diagnosed with hypertension, educate them about BP values, long-term follow-up care and therapy, the usual lack of symptoms, the ability of therapy to control but not cure it, and a consistently followed treatment plan that ensures a relatively normal lifestyle.

Systolic <90 mm Hg

Dilation of arteries

Loss of blood volume

Decrease of blood flow to vital organs

Orthostatic/postural

Hypotension

Hypotension occurs because of the dilation of the arteries in the vascular bed, the loss of a substantial amount of blood volume (e.g., hemorrhage), or the failure of the heart muscle to pump adequately (e.g., myocardial infarction).

Hypotension associated with pallor, skin mottling, clamminess, confusion, increased HR, or decreased urine output is life threatening and is reported to a health care provider immediately.

Orthostatic hypotension, also referred to as postural hypotension, occurs when a normotensive person develops symptoms and a drop in systolic pressure by at least 20 mm Hg or a drop in diastolic pressure by at least 20 mm Hg within 3 minutes of rising to an upright position. Patients who are dehydrated, anemic, or have experienced prolonged bed rest or recent blood loss are at risk for orthostatic hypotension, particularly in the morning.

Assess for orthostatic hypotension during measurements of vital signs by obtaining BP and pulse in sequence with the patient supine, sitting, and standing. Obtain BP readings within 3 minutes after the patient changes position.

While obtaining orthostatic measurements, observe for other symptoms of hypotension such as fainting, weakness, blurred vision, or light-headedness.

Orthostatic hypotension is a risk factor for falls, especially among elderly patients with hypertension.

When recording orthostatic BP measurements, record the patient’s position in addition to the BP measurement.

Ms. Coburn’s blood pressure is 164/98 mm Hg. Ms. Coburn asks “I think that’s close to where it was last time I came in. Is that okay?”

Case Study (Cont.)

[Ask students: How would you respond to Ms. Coburn’s question? Discuss: Ms. Coburn’s blood pressure is high which can put her at risk for health problems.]

After she sees the practitioner, her blood pressure should be taken again, and lifestyle changes should be discussed with her.

Miguel responds, “Ms. Coburn, your blood pressure is pretty high right now. After you see the nurse practitioner today, I am going to take your blood pressure again.

We are also going to talk about the changes you can begin to make to help you be healthier and feel better.”

Case Study (Cont.)

[Ask students: Is this what you would have said to Ms. Coburn? What types of changes do you think Miguel will suggest? Discuss.]

Measurement of Blood Pressure

Equipment

Sphygmomanometer

Aneroid manometer

Occlusive cuff

Release valve

A sphygmomanometer includes a pressure manometer, an occlusive cuff that encloses an inflatable rubber bladder, and a pressure bulb with a release valve that inflates the bladder.

The aneroid manometer has a glass-enclosed circular gauge containing a needle that registers millimeter calibrations. Before using the aneroid model, make sure that the needle points to zero and that the manometer is correctly calibrated.

The occlusive cuff comes in different sizes. The size selected is proportional to the circumference of the limb being assessed. Ideally the width of the cuff is 40% of the circumference (or 20% wider than the diameter) of the midpoint of the limb on which the cuff is used to measure BP. The inflatable bladder, contained in the occlusive cuff, encircles at least 80% of the upper arm of an adult and the entire arm of a child.

Place the lower edge of the cuff above the antecubital fossa, allowing room for positioning the stethoscope bell or diaphragm. Many adults require a large adult cuff. Using the forearm when a larger cuff is not readily available is not recommended and can result in an overestimate of systolic blood pressure up to 20 mm Hg. An improperly fitting cuff causes inaccurate BP measurements.

[Review Table 30-11, Common Errors in Blood Pressure Assessment, with students.]

The release valve of the sphygmomanometer needs to be clean and freely movable in either direction. A closed valve holds the pressure constant. A sticky valve makes pressure cuff deflation hard to regulate.

[Shown are Figure 30-12: Wall-mounted aneroid sphygmomanometer; and Figure 30-13: Guidelines for proper blood pressure cuff size. Cuff width 20% more than upper-arm diameter or 40% of circumference and two thirds of arm length.]

Measurement of Blood Pressure

Auscultation

Ultrasonic stethoscope

Palpation

The patient’s position during routine BP determination needs to be the same during each measurement to permit a meaningful comparison of values. Before obtaining the patient’s BP, attempt to control factors responsible for artificially high readings such as pain, anxiety, or exertion.

During the initial assessment obtain and record the BP in both arms. Normally there is a difference of 5 to 10 mm Hg between the arms. In subsequent assessments measure the BP in the arm with the higher pressure.

Pressure differences greater than 10 mm Hg indicate vascular problems and are reported to the health care provider or nurse in charge.

Ask the patient to state his or her usual BP. If the patient does not know, inform him or her after measuring and recording it.

The first sound is a clear rhythmical tapping corresponding to the pulse rate that gradually increases in intensity. Onset of the sound corresponds to the systolic pressure. A blowing or swishing sound occurs as the cuff continues to deflate, resulting in the second sound. The third sound is a crisper and more intense tapping. The fourth sound becomes muffled and low pitched as the cuff is further deflated; this sound is the diastolic pressure in infants and children. The fifth sound marks the disappearance of sound. In adolescents and adults the fifth sound corresponds with the diastolic pressure.

There are several sources for error.

The measurement of BP in infants and children is difficult for several reasons:

Different arm size requires careful and appropriate cuff size selection.

Readings are difficult to obtain in restless or anxious infants and children.

Placing the stethoscope too firmly on the antecubital fossa causes errors in auscultation.

When you are unable to auscultate sounds because of a weakened arterial pulse, you can use an ultrasonic stethoscope.

Indirect measurement of BP by palpation is useful for patients whose arterial pulsations are too weak to create sounds.

[Review Box 30-9, Procedural Guidelines: Palpating Systolic Blood Pressure, with students.]

When using the palpation technique, record the systolic value and how you measured it.

You can use the palpation technique along with auscultation.

In some patients with hypertension the sounds usually heard over the brachial artery when the cuff pressure is high disappear as pressure is reduced and then reappear at a lower level. This temporary disappearance of sound is the auscultatory gap. It typically occurs between the first and second sounds. The examiner needs to be certain to inflate the cuff high enough to hear the true systolic pressure before the auscultatory gap.

Palpation of the radial artery helps to determine how high to inflate the cuff. The examiner inflates the cuff 30 mm Hg above the pressure at which the radial pulse was palpated.

[Shown is Figure 30-14: The sounds auscultated during blood pressure measurement can be differentiated into five phases. In this example blood pressure is 140/90 mm Hg.]

Measurement of Blood Pressure (Cont.)

Lower-extremity blood pressure

Electronic blood pressure devices

Comparing upper-extremity BP with that in the legs is also necessary for patients with certain cardiac and BP abnormalities. The popliteal artery, palpable behind the knee in the popliteal space, is the site for auscultation.

The cuff needs to be wide and long enough to allow for the larger girth of the thigh. Placing the patient in a prone position is best. If such a position is impossible, ask the patient to flex the knee slightly for easier access to the artery. Position the cuff 2.5 cm (1 inch) above the popliteal artery, with the bladder over the posterior aspect of the midthigh.

The procedure is identical to brachial artery auscultation. Systolic pressure in the legs is usually higher by 10 to 40 mm Hg than in the brachial artery, but the diastolic pressure is the same.

Electronic BP machines rely on an electronic sensor to detect the vibrations caused by the rush of blood through an artery.

[Review Box 30-10, Procedural Guidelines: Electronic Blood Pressure Measurement, with students.]

Use electronic devices when frequent BP assessment is necessary such as in patients who are critically ill or unstable, during or after invasive procedures, or when therapies require frequent monitoring.

[Review Box 30-11, Patient Conditions Not Appropriate for Electronic Blood Pressure Measurement, with students.]

The advantages of automatic devices are the ease of use and efficiency when repeated or frequent measurements are indicated. Automatic devices are not recommended for hypertensive patients, patients with irregular heart rates, or those who have experienced trauma.

Most electronic BP devices are unable to process sounds or vibrations of low BP. The range of device sophistication also makes BP measurement comparisons difficult.

[Shown are Figure 30-15: Lower-extremity blood pressure cuff positioned above popliteal artery at midthigh with knee flexed; and Figure 30-16: Automatic blood pressure monitor.]

Self-measurement of blood pressure

Aneroid sphygmomanometer

Digital readout devices that do not require use of a stethoscope

Stationary automatic BP devices are often found in public places such as grocery stores, fitness clubs, airports, or work sites; reliability is limited

Benefits

Disadvantages

Education

Measurement of Blood Pressure (Cont.)

The electronic devices are easier to manipulate but require frequent recalibration, more than once a year. Because of their sensitivity, improper cuff placement or movement of the arm causes electronic devices to give incorrect readings.

Benefits:

Sometimes elevated BP is detected in people previously unaware of a problem.

Can provide the pattern of BP values to their health care provider.

Helps with adherence to treatment.

The disadvantages of self-measurement include improper use of the device and risk of inaccurate readings. Some patients are needlessly alarmed with one elevated reading. Some patients with hypertension become overly conscious of their BP and inappropriately self-adjust medications.

Consumers can learn to use self-measurement devices if they have the information needed to perform the procedure correctly and if they know when to seek medical attention.

Hypotension, hypertension, orthostatic hypotension, and narrow or wide pulse pressures are defining characteristics of certain nursing diagnoses, including the following:

Activity Intolerance

Anxiety

Decreased Cardiac Output

Deficient/Excess Fluid Volume

Risk for Injury

Acute Pain

Ineffective Peripheral Tissue Perfusion

Nursing Process and Blood Pressure Determination

The assessment of BP along with pulse assessment evaluates the general state of cardiovascular health and responses to other system imbalances.

The nursing care plan includes interventions based on the nursing diagnosis identified and the related factors.

The related factor guides the choice of nursing interventions. Evaluate patient outcomes by assessing the BP following each intervention.

Miguel determines that the priority is to focus on hypertension and ways to prevent or control elevated BP. He states, “We need to watch your blood pressure closely over the next few weeks. In the meantime, remember, you decided that you are going to walk for at least 15 minutes 3 days a week; you are also going to try to eat foods with less salt and consider not smoking.”

Ms. Coburn says, “I don’t know if I can quit right now—I have a lot going on! But I can do the walking and watch my salt.”

Case Study (Cont.)

[Ask students: What outcome would you suggest for the interventions Ms. Coburn and Miguel have agreed upon? Discuss.]

It is important to use teaching strategies to inform Ms. Coburn not only of the lifestyle changes she must accommodate, but the reasons why each change is valuable.

4. When assessing the blood pressure of a school-age child, using an adult cuff of normal size will affect the reading and produce a value that is:

A. accurate.

B. indistinct.

C. falsely low.

D. falsely high.

Quick Quiz!

Answer: D

Rationale: Children should only have their blood pressure taken with an appropriately fitting cuff, otherwise it will skew the results. Specifically, if an adult cuff is used on a child, the resulting BP will be falsely high.

Monitor vital signs.

Include age-related factors.

Include environmental and activity factors.

Health Promotion and Vital Signs

The emphasis on health promotion and maintenance and discharge from hospital settings has resulted in an increase in the need for patients and their families to monitor vital signs in the home.

When considering how to teach patients and their families about vital sign measurements and their importance and significance, a patient’s age is an important factor. With an increase in the older-adult population there is a greater need for family caregivers to be aware of changes that are unique to older adults.

[Review Box 30-12, Patient Teaching: Health Promotion with students.]

[Review Box 30-13, Focus on Older Adult: Factors Affecting Vital Signs of Older Adults, with students.]

Ms. Coburn has returned several weeks later. She is feeling better and is optimistic about the changes she is making to improve her health. After talking with Miguel a minutes, Ms. Coburn tells him, “You know, I got one of those electronic blood pressure monitors for myself. If I’m going to do all of this, I might as well see my progress. I’m not sure what I’m looking for, though.”

Case Study (Cont.)

[Ask students: What evaluation strategies would you suggest for Miguel to use with Ms. Coburn? Discuss possibilities such as:

Demonstrate (if necessary) and observe Ms. Coburn practice taking her own blood pressure. Evaluate her technique and provide guidance as needed.

Ask Ms. Coburn to state three risk factors for hypertension.

Review Ms. Coburn’s walking activity since the last visit. Discuss motivators and offer encouragement to continue.

Ask Ms. Coburn which salty foods she is avoiding, and whether she needs information about the sodium content of foods.

Ask Ms. Coburn if she is ready to discuss quitting smoking.]

Record values on electronic or paper graphic.

Record in nurses’ notes any accompanying or precipitating symptoms.

Document interventions initiated on the basis of vital sign measurement.

If a vital sign is outside anticipated outcomes, write a variance note to explain, along with the nursing course of action.

In the nurse’s variance note, address possible causes of a fever.

Recording Vital Signs

Identify institution procedure for documenting on a graphic.

In addition to actual vital sign values, record in the nurses’ notes any accompanying or precipitating symptoms such as chest pain and dizziness with abnormal BP, shortness of breath with abnormal respirations, cyanosis with hypoxemia, or flushing and diaphoresis with elevated temperature.

Patients being managed on critical paths often have vital sign values listed as outcomes. If a vital sign value is above or below the anticipated outcomes, write a variance note to explain the nature of the variance and the nursing course of action.

Cleaning devices between patients decreases the risk for infection.

Rotating sites during repeated measurements of BP and pulse oximetry decreases the risk for skin breakdown.

Analyze trends for vital signs, and report abnormal findings.

Determine the appropriate frequency of measuring vital signs based on the patient’s condition.

Safety Guidelines for Nursing Skills

Ensuring patient safety is an essential role of the professional nurse.

To ensure patient safety:

Communicate clearly with members of the health care team.

Assess and incorporate the patient’s priorities of care and preferences.

Use the best evidence when making decisions about your patient’s care.

When performing the skills in this chapter, remember the following points to ensure safe, individualized patient-centered care:

Devices for measuring vital signs are often shared among patients.

BP cuffs and pulse oximetry sensors can apply excessive pressure to fragile skin.

Analyze trends for measuring vital signs, and report abnormal findings to the health care provider.

Determine the appropriate frequency of measuring vital signs based on the patient’s condition.