Chapter 8 Vital Signs - Shandong University



Chapter 5 Vital Signs

Vital signs reflect the body’s physiologic status and provide information critical to evaluate homeostatic balance. Vital signs include four critical assessment areas: temperature, pulse, respiration and blood pressure. These four signs form baseline assessment data necessary for an ongoing evaluation of a client’s condition. If the nurse has established the normal range for a client, deviations can be more easily recognized.

Many factors such as the temperature of the environment, physical exertion, and the effects of illness cause vital signs to change, sometimes outside normal range. Vital signs should be taken at regular intervals. The more critical the client’s condition, the more often these signs need to be taken and evaluated. They are not only indicators of a client’s present condition, but also provide clues to a positive or negative change in status. An alteration in vital signs may signal the need for medical or nursing intervention.

Vital signs are a quick and efficient way of monitoring a client’s condition or identifying problems and evaluating the client’s response to intervention. Vital signs and other physiological measurements are the basis for clinical problem solving. Assessment of vital signs allows the nurse to identify nursing diagnoses, implement planned interventions, and evaluate nursing effect. When the nurse learns the physiological variable values influencing vital signs and recognizes the relationship of vital sign changes to other physical assessment findings, precise determinations of the client’s health problems can be made. Careful measurement techniques ensure accurate findings.

Guidelines for Taking Vital Signs

The nurse assesses vital signs whenever a client enters a health care agency. Vital signs are included in a complete physical assessment or obtained individually to assess a client’s condition. The nurse must be able to measure vital signs correctly, understand and interpret the values, communicate findings appropriately, and begin interventions as needed. The following guidelines assist the nurse to incorporate vital sign measurement into nursing practice:

1. The nurse caring for the client is responsible for vital signs measurement. The nurse should obtain the vital signs, interpret their significance, and make decisions about interventions.

2. Equipment should be functional and appropriate for the size and the age of the client. Equipment should be selected based on the client’s condition and characteristics. For example, an adult-size blood pressure cuff should not be used for a child.

3. The nurse should know the client’s normal range of vital signs. A client’s usual values may differ from the standard range for that age or physical state. The client’s usual values serve as a baseline for comparison with findings taken later. Thus a nurse can detect a change in condition over time.

4. The nurse should know the client’s medical history, therapies, and prescribed medications. Some illnesses or treatments cause predictable vital sign changes. Most medications affect at least one of the vital signs.

5. The nurse should control or minimize environmental factors that may affect vital signs. Measuring the pulse after the client exercises may yield a value that is not a true indicator of the client’s condition.

6. The nurse should use a systematic approach when taking vital signs. Each procedure requires following a step-by-step approach to ensure accuracy.

7. The physician decides the frequency of vital signs assessment according to the client’s condition. In the hospital the physician orders a minimum frequency of vital sign measurements for each client. Following surgery or treatment interventions, vital signs are measured frequently to detect complications.

8. The nurse may use vital sign assessment to determine indications for medication administration. The physician may order certain cardiac drugs to be given only within a range of pulse or blood pressure. The nurse does not administer these drugs if vital sign assessment is outside of these limits. Taking vital signs to determine clinical changes and trends is useful in making therapeutic decisions.

9. The nurse should analyze the results of vital sign measurement. The nurse is often in the best position to assess all clinical findings about a client. Vital signs are not interpreted in isolation. The nurse must also know other physical signs or symptoms and be aware of the client’s ongoing health status.

10. The nurse should verify and communicate significant changes in vital signs. Baseline measurements allow a nurse to identify changes in vital signs. When vital signs appear abnormal, it may help to have another nurse or a physician repeat the measurement. The nurse informs the physician of abnormal vital signs and documents and reports vital sign changes to nurses working the next shift.

SectionⅠBody Temperature

Physiology of Body Temperature

The body temperature reflects the balance between the amount of heat produced by body processes and the amount of heat lost to the external environment. There are two kinds of body temperature: core temperature and surface temperature. The core temperature is the temperature of deep tissues, such as the cranium, thorax, abdominal cavity, and pelvic cavity, and remains relatively constant. The surface temperature is the temperature of the skin, the subcutaneous and the fat tissue. Surface temperature fluctuates depending on blood flow to the skin and the amount of heat lost to the external environment.

Heat Production

Thermoregulation requires the normal function of heat-production processes. Heat is produced in the body through metabolism. Cellular chemical reactions require energy in the form of ATP. The amount of energy used for metabolism is the metabolic rate. Activities requiring additional chemical reactions increase the metabolic rate. As metabolism increases, additional heat is produced. When metabolism decreases, less heat is produced. Heat production occurs during rest, voluntary movements, involuntary shivering, and nonshivering thermogenesis.

Voluntary movements such as muscular activity during exercise require additional energy. The metabolic rate can increase up to 2000 times normal. Heat production can increase up to 50 times normal.

Shivering is an involuntary body response to temperature differences in the body. The skeletal muscle movement during shivering requires significant energy. Shivering can increase heat production 4 to 5 times greater than normal. Heat is produced to equalize body temperature.

Nonshivering thermogenesis occurs primarily in neonates. Vascular brown adipose tissue present at birth is metabolized for heat production.

Heat Loss

Heat loss and heat production occur simultaneously. The skin’s structure and exposure to the environment result in constant, normal heat loss through radiation, conduction, convection, and evaporation.

Radiation is the transfer of heat between two objects without direct contact by electromagnetic waves. Blood flows from the core internal organs carrying heat to skin and surface blood vessels. The amount of heat carried to the surface depends on the extent of vasoconstriction and vasodilation regulated by the hypothalamus. Heat radiates from the skin to any surrounding cooler object. Radiation increases as the temperature difference between the objects increases.

Peripheral vasodilation increases blood flow to the skin to increases radiant heat loss. Peripheral vasoconstriction minimizes radiant heat loss. Up to 85% of the human body’s surface area radiants heat to the environment. However, if the surroundings are warmer than the skin, the body absorbs heat through radiation.

The nurse increases heat loss through radiation by removing clothing or blankets. The client’s position enhances radiation heat loss (e.g., standing exposes a great radiating surface area and lying in a fetal position minimizes heat radiation). Covering the body with dark, closely woven clothing also reduces the amount of radiation heat lost.

Conduction is the transfer of heat from one object to another with direct contact. When the warm skin touches a cooler object, heat is lost. When the temperatures of the two objects are the same, conductive heat loss stops. Heat conducts through solids, gases, and liquids. Conduction normally accounts for a small amount of heat loss. The nurse increases conductive heat loss when applying an ice pack or bathing a client with cool water. Applying several layers of clothing reduces conductive loss. The body gains heat by conduction when contact is made with materials warmer than skin temperature, such as applying a warm pack or bathing a client with warm water.

Convection is the transfer of heat away by air movement. Heat is first transferred to air molecules directly in contact with the skin. Air currents carry away the warmed air. As the air current velocity increases, convective heat loss increases. An electric fan promotes heat loss through convection. Convective heat loss increases when moistened skin comes into contact with slightly moving air.

Evaporation is the transfer of heat energy when a liquid is changed to a gas. During evaporation, approximately 0.6 calorie of heat is lost for each gram of water that evaporates. The body continuously loses heat by evaporation. About 600 to 900 ml a day evaporates from the skin and lungs, resulting in water and heat loss.

By regulating perspiration or sweating, the body promotes additional evaporative heat loss. Millions of sweat glands located in the dermis of the skin secrete sweat through tiny ducts on the skin’s surface. When body temperature rises, the anterior hypothalamus signals the sweat glands to release sweat. During exercise and emotional or mental stress, sweating is one way to lose excessive heat produced by the increased metabolic rate.

People who lack sweat gland function are unable to tolerate warm temperatures because they cannot cool themselves adequately. Diaphoresis is visual perspiration of the forehead and upper thorax. When diaphoresis occurs, the body temperature is reduced. A lowered body temperature inhibits sweat gland secretion.

Evaporation is the main heat loss when environment temperature is higher than body temperature.

Regulation of Body Temperature

Body temperature is precisely regulated by physiological and behavioral mechanisms. For the body temperature to stay constant, and within the normal range, the relationship between heat production and heat loss must be maintained. This relationship is regulated by neurological and cardiovascular mechanisms.

Neural and Vascular Control

The hypothalamus, located between the cerebral hemispheres, controls body temperature the same way a thermostat works in the home. A comfortable temperature is the “set point” at which a heating system operates. In the home a fall in environmental temperature activates the furnace, whereas a rise in temperature shuts the system down. The hypothalamus senses minor changes in body temperature. The anterior hypothalamus controls heat loss, and the posterior hypothalamus controls heat production.

When nerve cells in the hypothalamus become heated beyond the set point, impulses are sent out to reduce body temperature. Mechanisms of heat loss include sweating, vasodilation (widening of blood vessels), and inhibition of heat production. If the hypothalamus senses the body’s temperature lower than set point, signals are sent out to increase heat production by muscle shivering or heat conservation by vasoconstriction (narrowing of blood vessels) of surface blood vessels. Lesions or trauma to the hypothalamus or spinal cord, which carries hypothalamic messages, can cause serious alterations in temperature control.

Behavioral Control

Humans voluntarily act to maintain comfortable body temperature when exposed to temperature extremes. When the environmental temperature falls, a person can add clothing, move to a warmer place, raise the thermostat setting on a furnace, increase muscular activity by running in place, or sit with arms and legs tightly wrapped together. In contrast, when the temperature becomes hot, a person can remove clothing, stop activity, lower the thermostat setting on an air conditioner, seek a cooler place, or take a cool shower. The ability of a person to control body temperature depends on (1) the degree of temperature extreme, (2) the person’s ability to sense feeling comfortable or uncomfortable, (3) thought processes or emotions, and (4) the person’s mobility or ability to remove or add clothes. Body temperature control is difficult if any of these abilities are absent or lost. Infants can sense uncomfortable warm conditions but need assistance in changing their environment. Older adults may need help in detecting cold environments and minimizing heat loss. Illness and decreased level of consciousness or impaired thought processes result in an inability to recognize the need to change behavior for temperature control. When temperature becomes extremely hot or cold, health-promoting behaviors have a limited effect on controlling temperature.

Factors Affecting Body Temperature

The site of temperature measurement (oral, rectal, axillary, tympanic membrane, esophageal, pulmonary artery, or even urinary bladder) is one factor that determines the client’s temperature within a narrow range. For healthy young adults the average oral temperature is 37℃. In clinical practice, nurses learn the temperature range of individual client. No single temperature is normal for all people.

Table 8-1 Average Temperature and Normal Range

Site Average Temperature Normal Range

oral 37℃ 36.3~37.2℃ (97.3~99.0℉)

rectal 37.5℃ 36.5~37.7℃ (97.7~99.9℉)

axillary 36.5℃ 36.0~37.0℃ (96.8~98.6℉)

Many factors affect the body temperature. Changes in body temperature occur when the relationship between heat production and heat loss is altered by physiological or behavioral variables. The nurse must be aware of these factors when assessing temperature variations and evaluating deviations from normal.

Circadian rhythms

Body temperatures normally change 0.5 to 1℃ over 24 hours. Temperature drops between 2 and 6 AM and peaks between 1 and 6PM in clients who work days and sleep nignts. Temperature patterns are not automatically reversed in people who work at night and sleep during the day. It takes 1 to 3 weeks for the cycle to reverse. In general, the circadian temperature rhythm does not change with age.

Age

Temperature regulation is labile during infancy because of immature physiological mechanisms. This can continue until puberty. Infant temperature may respond drastically to changes in the environmental. Special care is needed to protect newborns from environmental temperature change.

With aging the normal mean temperature is lower. Thus a temperature that seems normal in a young adult may represent a fever in an older adult. The older adult has a narrower range of body temperature than the younger adult. With aging, control mechanisms deteriorate and sensitivity to temperature extremes increases.

Hormone level

Women generally have greater variations in body temperature than men.

Hormone changes during ovulation and menstruation cause body temperature fluctuations. When progesterone level is low, the body temperature is lower than the baseline level. During ovulation, greater amounts of progesterone enter into the circulatory system and raise the body temperature to previous baseline level or by about 0.3℃ to 0.6℃ above basal temperature.

Body temperature changes also occur in women during menopause. Women who have stopped menstruating may experience period of intense body heat and sweating lasting from 30 seconds to 5 minutes. There may be intermittent increase in skin temperature of up 4℃ during these periods, referred to as hot flashes. This is due to the instability of the vasomotor controls for vasodilatation and vasoconstriction.

Exercise

Muscle activity requires an increased blood supply and an increased carbohydrate and fat breakdown. This increased metabolism causes an increase in heat production. Any form of exercise can increase body temperature. Prolonged, strenuous exercise can temporarily raise body temperatures up to 38.3℃ to 40℃.

Medication

Some medications can influence temperature, such as anaesthetic and febrifuge.

Stress

Physical or emotional stress, such as anxiety, can raise body temperature through hormonal and neural stimulation. Stimulation of the sympathetic nervous system can increase the production of epinephrine and norepinephrine, thereby increasing metabolic activity and heat production. Nurse may anticipate that a highly stressed or anxious client could have an elevated body temperature.

Environment

Environmental temperature extremes can raise or lower body temperature. The changes depend on the extent of exposure, air humidity, and the presence of convection currents.

Ingestion of hot/cold liquids

Drinking hot or cold liquids can cause slight variations in actual oral temperature readings.

Smoking

Smoking cigarettes or cigars can increase body temperature measurement.

Alterations in Body Temperature

Elevated Body Temperature

Changes in body temperature outside the normal range affect the set point. These changes can be related to excess heat production, excessive heat loss, minimal heat production, minimal heat loss, or any combination of these alterarions. The nature of the change affects the type of clinical problems a client experiences.

Fever

A body temperature above the usual range is called fever or hyperthermia. It occurs because heat loss mechanisms are unable to keep pace with excess heat production, resulting in an abnormal rise in body temperature. A single temperature reading may not indicate a fever, so some people recommend determining a fever based on several temperature reading at different times of the day compared to the normal for that person at that time, in addition to physical signs and symptoms of infection.

A true fever results from an alteration in the hypothalamic set point. Pyrogens such as bacteria cause a rise in body temperature. When they enter the body, pyrogens act as antigens, triggering the immune system. Hormone-like substances are released to promote the body’s defense against infection. These hormones also trigger the hypothalamus to raise the set point. To meet the new higher set point, the body produces and conserves heat. Several hours may pass before the body temperature reaches the new point. During this period the person experiences chills, shivers, and feels cold, even though the body temperature is rising. The chill phase resolves when the new set point, a higher temperature, is achieved. During the next phase, the plateau, the chills subside and a person feels warm and dry. If the new set point has been “over shot” or the pyrogens are removed, the third phase of a febrile episode occurs. The skin becomes warm and flushed because of vasodilation. Diaphoresis assists in evaporative heat loss. When the fever “breaks”, the client becomes afebrile.

Fever is an important defense machanism. Mild temperature elevations up to 39℃ enhance the body’s immune system. A fever is usually not harmful if it stays below 39℃. During a febrile episode, white blood cell production is stimulated. Increased temperature reduces the concentration of iron in the blood plasma, suppressing the growth of bacteria. Fever also fights viral infections by stimulating interferon, the body’s natural virus-fighting substance.

During a fever, cellular metabolism increases and oxygen consumption rises. The body metabolism increases 13% for every Celsius degree of temperature elevation. Heart and respiratory rates increase to meet the metabolic needs. The increased metabolism uses energy that produces additional heat. A prolonged fever can weaken a client by exhausting energy stores. Increased metabolism requires additional oxygen. If the demand for additional oxygen cannot be met, cellular hypoxia (inadequate oxygen) occurs. Cerebral hypoxia produces confusion. Interventions during a fever may include oxygen therapy. The regulatory mechanism used to compensate for fever places a client at risk for fluid volume deficit. Water loss through increased respiration and diaphoresis can be excessive. Dehydration can be a serious problem for older adults and children with low body weights. Maintaining optimum fluid volume status is an important nursing action.

Heat exhaustion occurs when profuse diaphoresis results in excess water and electrolyte loss. Caused by environmental heat exposure, the signs and symptoms of fluid volume deficit are common during heat exhaustion. First aid includes transporting the client to a cooler environment and restoring fluid and electrolyte balance.

An elevated body temperature related to the body’s inability to promote heat loss or reduce heat production is hyperthermia. Any disease or trauma to the hypothalamus can impair heat loss mechanisms. Malignant hyperthermia is a hereditary condition of uncontrolled heat production. Malignant hyperthermia occurs when susceptible persons receive certain anesthetic drugs.

Prolonged exposure to the sun or high environmental temperatures can overwhelm the body’s heat loss mechanisms. Heat also depresses hypothalamic function. These conditions cause heat stroke, a dangerous heat emergency. Clients at risk include those who are very young or very old, or have cardiovascular disease, hypothyroidism, diabetes, or alcoholism. Also at risk are those who take medications that decrease the body’s ability to lose heat or who exercise or work strenuously. Signs and symptoms of heat stroke include giddiness, confusion, delirium, excess thirst, nausea, muscle cramps, visual disturbances, and even incontinence. The most important sign of heatstroke is hot, dry skin.

Victims of heatstroke do not sweat because of severe electrolyte loss and hypothalamic malfunction. Vital signs reveal a body temperature sometimes as high as 45℃, tachycardia, and hypotension. As the condition progresses, a client becomes unconscious with fixed, unreactive pupils. Permanent neurological damage occurs unless cooling measures are rapidly started.

Classification of Fever (Oral Temperature as an example)

Table 8-2 Classification of Fever

| C F |

|Mild 37.5℃一37.9℃ 99.5℉一100.2℉ |

|Moderate 38.0℃一38.9℃ 100.4℉一102.0℉ |

|Severe 39.0℃一40.9℃ 102.2℉一105.6℉ |

|Profound >41℃ >105.8℉ |

Patterns of Fever

Fevers also serve a diagnostic purpose. Fever patterns differ depending on the causative pyrogen. The increase or decrease in the amount of pyrogens results in fever spikes and declines at different times of the day. The duration and degree of fever depends on the pyrogen’s strength and the ability of the individual to respond.

Constant Fever

The body temperature sustains between 39~40℃ that demonstrates little fluctuation of less than 1℃ within 24 hours. It can be seen in pneumonia and typhoid.

Remittent Fever

The body temperature has great fluctuation above the normal more than 1℃ within 24 hours and cannot return to normal temperature level. It can be seen in septicemia and rheumatic fever.

Intermittent Fever

The body temperature fluctuates greatly in 24 hours, which may suddenly rise above the normal then suddenly fall to the normal or below the normal. The body temperature alternates regularly between a period of fever and a period of normal temperature levels. It can be seen in malaria and tuberculosis.

Irregular Fever

The body temperature irregularity alternates between a period of fever and a period of normal temperature values. It can be seen in influenza and cancer.

Hypothermia

A body temperature below the lower limit of normal 35℃ is called hypothermia．Heat loss during prolonged exposure to cold overwhelms the body’s ability to produce heat，causing hypothermia．Hypothermia is classified by core temperature measurements (Table 8-3)．It can be accidental or unintentional，such as falling through the ice of a frozen lake．Hypothermia may be intentionally induced during surgical procedures to reduce metabolic demand and the body’s need for oxygen．

Table 8-3 Classification of Hypothermia

| C F |

|Mild 32℃一35℃ 89.6℉一95.0℉ |

|Moderate 30℃一32℃ 86.0℉一89.6℉ |

|Severe < 30℃ < 80.0℉ |

|lethiferous 23一25℃ 73.4—77.0℉ |

Accidental hypothermia develops gradually and may go unnoticed for several hours. A client suffers uncontrolled shivering, loss of memory, depression, and poor judgment. As the body temperature falls below 34.4℃, heart and respiratory rates and blood pressure fall. The skin becomes cyanotic. If hypothermia progresses, a client experiences cardiac dysrhythmias, loss of consciousness, and becomes unresponsive to painful stimuli. The assessment of core temperature is critical when hypothermia is suspected．A special low-reading thermometer may be required because standard devices do not register below 35℃．

Nursing Process and Thermoregulation

Knowledge of the physiology of body temperature regulation helps a nurse to assess the client’s response to temperature alterations and to intervene safely．Independent measures can be implemented to increase or minimize heat loss, promote heat conservation，and increase client comfort．These measures add to the effects of medically ordered therapies during illness．Many measures can also be taught to family members, parents of children, or other caregivers.

Assessment

Sites

The four most common sites for measuring body temperature are the mouth, rectum, axillary and tympanic membrane.

To ensure accurate temperature readings, each site must be measured correctly. The temperature obtained varies depending on the site used but should be between 36.0℃ and 37.5℃. Rectal temperatures are usually 0.5℃ higher than oral temperatures. Axillary temperatures are usually 0.5℃ lower than oral temperatures. Each of the common temperature measurement sites has advantages and disadvantages. The nurse chooses the safest and most accurate site for the client. The same site should be used when repeated measurements are necessary.

Thermometers

There are three types of thermometers: mercury-in-glass thermometers, electronic thermometers, and disposable thermometers．Each device measures temperature in the centigrade or Fahrenheit scale．Electronic thermometers allow the nurse to convert scales by activating a switch．When it is necessary to convert temperature readings, the following formulas can be used：

1. To convert Fahrenheit to Centigrade，subtract 32°from the Fahrenheit reading and multiply the result by 5/9．

(F-32)×5/9=C

Example：(104℉一32℉)×5/9=40℃

2. To convert Centigrade to Fahrenheit，multiply the centigrade reading by 9/5 and add 32°to the product．

(9/5×C) +32=F

Example：(9/5×40℃)+32°=104℉

Glass Thermometer

The mercury-in-glass thermometer is the most familiar. It is a glass tube sealed at one end with a mercury-filled bulb at the other. Exposure of the bulb to heat causes the mercury to expand and rise in the enclosed tube．The 1ength of the thermometer is generally marked with centigrade calibrations．The range is about 35℃ to 42℃. The degrees on a thermometer are subdivided into gradients of 0.1℃. The farthest point reached by the mercury in the tube is the temperature reading．The mercury will not fluctuate or fall unless the thermometer is shaken vigorously．

Three types of glass thermometers are the oral, the axillary, and the rectal. The oral thermometer is slender, allowing for greater exposure of the bulb against the blood vessels in the mouth. The axillary thermometer is shorter and thicker than the oral type. It can be used to measure temperature at any site. The rectal thermometer has a blunt end designed to prevent trauma to the rectal tissues during insertion.

The time delay for recordings and the easy breakability are disadvantages of mercury-in-glass thermometers. Advantages are the 1ow price, wide availability, and reliable accuracy．

Electronic Thermometer

The electronic thermometer consists of a rechargeable battery-powered display unit, a thin wire cord，and a temperature-processing probe covered by a disposable plastic sheath. 0ne form of electric thermometer uses a pencil-like probe. Separate nonbreakable probes are available for oral and rectal use．The oral probe can also be used for axillary temperature measurement．Within 20 to 50 seconds of insertion, a reading appears on the display unit. A sound signals when the peak temperature reading has been measured.

Another form of electronic thermometer is used exclusively for tympanic temperature. An otoscope-1ike speculum with an infrared sensor tip detects heat radiated from the tympanic membrane. Within 2 to 5 seconds of placement in the auditory canal, a reading appears on the display unit. A sound signals when the peak temperature reading has been measured.

The advantages of electronic thermometers are that they can be inserted immediately, their readings appear within seconds, and they are easy to read. Their expense is a major disadvantage．

Disposable Thermometer

Disposable, single-use thermometers are thin strips of plastic with chemically impregnated paper. They are used for oral or axillary temperatures, particularly with children．They are inserted the same way as an oral thermometer and used only once. Chemical dots on the thermometer change color to reflect the temperature reading．0nly 45 seconds are needed to record a temperature．

Another form of disposable thermometer is a temperature-sensitive patch or tape．Applied to the forehead or abdomen, the patch changes color at different temperatures．

Both forms of disposable thermometers are useful for screening temperatures, especially with newborns.

Nursing Diagnosis

The nurse identifies assessment findings and clusters defining characteristics to form a nursing diagnosis．For example，an increase in body temperature, flushed skin, skin warm to touch, and tachycardia indicate the diagnosis, hyperthermia．The nursing diagnosis identifies the client’s risk for altered body temperature or an actual temperature alteration．

Once a diagnosis is determined, the nurse must accurately select the related factor or etiology．The related factor allows the nurse to select appropriate nursing interventions．In the example of hyperthermia, a related factor of vigorous activity will result in much different interventions than a related factor of febrile illness．

Table 8-4 Nursing Diagnosis and Diagnosis Foundation

Nursing diagnosis Diagnostic foundation

Hyperthermia Increased body temperature above usual range

Flushed skin, skin warm to touch

Increased pulse and respiratory rate

Herpetic lesions of the mouth

Hypothermia Decreased body temperature

Pale, cool skin

Decreased pulse and respiratory rate

Feelings of cold and chill

Ineffective thermoregulation Older adult or infants, weak

Inability to adapt to environmental temperature

Planning

Clients at high risk for alterations in body temperature require an individualized care plan directed at maintaining normothermia and reducing risk factors．Education is important so clients can participate in maintaining normothermia．This is particularly the case for parents who need to know how to take action at home when an infant or child develops a temperature alteration．The

care plan for clients with actual temperature alterations focuses on restoring normothermia, minimizing complications, and promoting comfort．The severity of a temperature alteration will influence the nurse’s priorities in the care of a client. The nurse care plan supports the client’s goals.

Goal: Restore and maintain normothermia.

Outcome

Temperature maintained within normal range during environment changes

Goal: Minimize complications of altered body temperature.

Outcomes

Client’s blood pressure, pulse, and respirations are within normal limits

Client’s skin integrity maintained

Client’s nutritional intake meets body needs

Client’s mucous membranes are moist

Client is able to participate in ADL activities

Client’s skin is warm and pink

Client reports sense of rest and comfort

Goal: Reduce risk of altered body temperature.

Outcomes

Client identifies risk factors for altered body temperature

Client practices measures to prevent body temperature alteration

Implementation

Nursing Interventions for Client with Fever

Assessment

•Obtain body temperature during each phase of febrile episode．

•Assess for contributing factors such as dehydration, infection, or environmental temperature．

•Identify physiological response to temperature.

Obtain all vital signs．

Observe skin color．

Assess skin temperature．

Observe for shivering and diaphoresis．

Assess client comfort and well-being．

•Determine phase of fever一chill, plateau, fever break．

Intervention

•Promote heat loss and lower the temperature. Limit physical activity to decrease heat production, reduce external covering on client’s body to promote heat loss through radiation and conduction．If fever continues, physical therapies can be used to lower the temperature, such as applying ice packs to axilla and groin areas or bathing with alcohol-water solutions．Lower the temperature with medication if necessary. Take temperature after lowering the temperature physically for 30 minutes, record the readings.

•Intensify the observation of client’s conditions. Take temperature once every four hours for the client with severe fever, four times per day as body temperature reduces to 38.5℃ and twice per day for three days after body temperature returns normal. Observe the pattern, the extent and the course of fever. Observe client’s respiration, pulse, blood pressure, face color, shivering and diaphoresis when taking client’s temperature. Assess for contributing factors such as dehydration，infection，or environmental temperature．Observe therapeutic effect. Observe the intake of liquids and the output of urine. Contact physicians promptly when find abnormal conditions.

•Provide nutrients to meet increased energy needs．Provide measures to stimulate appetite，and offer well-balanced meals．Provide fluids at least 3000ml per day for client with normal cardiac and renal functionl to replace fluids lost through insensible water loss and sweating．

•Promote comfort and prevent complications. Allow rest periods. Control temperature of the environment without inducing shivering．Provide oral hygiene and keep oral moist to prevent oral infection. Keep clothing and bed sheet dry to increase comfort and heat loss through conduction and convection．

•Provide psychological care. Meet client’s reasonable requirements. Provide health education about fever.

Nursing Interventions for Client with Heatstroke

The best treatment for heatstroke is prevention．The nurse teaches clients to avoid strenuous exercise in hot humid weather, to drink fluids such as clear fruit juices before, during，and after exercise，to wear light，loose-fitting，light-colored clothing，to avoid exercising in areas with poor ventilation，to wear protective covering over the head when outdoors，and to expose themselves to hot climates gradually．

First aid treatment for victims of heatstroke include moving the client to a cooler environment，reducing clothing covering the body, placing wet towels over the skin, and using oscillating fans to increase convective heat loss．Emergency medical treatment may include intravenous fluids and hypothermia blankets．

Nursing Interventions for Client with Hypothermia

The priority treatment for hypothermia is to prevent a further decrease in body temperature．

• Control environment temperature at 22~24℃.

• Elevate body temperature. Add clothes, wrap the client in blankets, and give heating blankets or hot packs to prevent heat loss. Provide hot 1iquids such as soup for a conscious client．

• Clients are monitored closely for cardiac irregularities and electrolyte imbalances. Observe the vital signs, take temperature once at least per hour until the temperature returns normal and stability.

• Eliminate pathogeny.

• Health education. Prevention is the key for clients at risk for hypothermia and frostbite．

Prevention involves educating clients, family members, and friends. Clients most at risk include the very young, the very old and persons debilitated by trauma, stroke, diabetes, drug or alcohol intoxication, sepsis, and Raynaud’s disease. Mentally ill or handicapped clients may fall victim to hypothermia because they are unaware of the dangers of cold conditions. Fatigue, skin color (blacks are more susceptible), malnutrition, and hypoxemia also contribute to the risk of frostbite. Persons without adequate home heating, shelter, diet, or clothing are also at risk.

Evaluation

All nursing interventions are evaluated by comparing the client’s actual response to the outcomes of the care plan．This reveals whether goals of care have been met．After any intervention the nurse measures the client’s temperature to evaluate for change．In addition, the nurse will use other evaluative measures such as palpation of the skin and assessment of pulse and respirations．If therapies are effective，body temperature will return to a normal range，other vital signs will stabilize and the client will report a sense of comfort．

Section Ⅱ Pulse

The pulse is the rhythmical throbbing of arteries produced by the regular contraction of the heart. The number of pulsing sensations occurring in per minute is the pulse rate．

Physiology and Regulation

Forming of Pulse

Blood flows through the body in a continuous circuit．Electrical impulses from the sinoatrial (SA) node travel through heart muscle to stimulate cardiac contraction．Approximately 60 to 70 ml (stroke volume) of blood enters the aorta with each ventricular contraction．The arterial walls expand to compensate for the increase in pressure. As the ventricle of the heart is in diastole, arterial walls return to original status by its own elasticity and peripheral resistance. The expansion and retraction of the aorta sends a wave through the walls of the arterial system that can be felt as a light tap on palpation. The pulse is the palpable bounding of the blood flow．A light tap can be felt by palpating an artery lightly against underlying bone or muscle．

Factors Influencing Pulse Rate

Normal pulse rate is the same as the rate of the ventricular contraction of the heart. Healthy adult pulse rate can range between 60~100 beats per minute in quiet state. Pulse rate can be affected by many factorts.

Age

Normally the pulse rate varies among different age group. The pulse rates are the fastest in infants; children’s pulse rates are faster than that of adults and adults’ pulse rates are fewer than that of older adults.

Table 8-5 Normal Pulse Rates at Varies Ages

Age normal range of pulse rate (beats/min)

Infants 120~160

Toddlers 90~140

Preschoolers 80~110

School agers 75~100

Adolescents to adults 60~100

Older adults 70~100

Sex

After puberty, the average male pulse rate is slightly lower than the female.

Exercise

The pulse rate normally increases with activity. Short-term exercise can increase pulse rate. Long-term exercise conditions the heart，resulting in lower rate at rest and quicker return to resting level.

Stress

In response to stress, sympathetic nervous stimulation increases the overall activity of the heart. Stress increases the rate as well as the force of the heartbeat. Fear and anxiety as well as the perception of severe pain stimulate the sympathetic system.

Position Change

When a person assumes a sitting or standing position, blood usually pools in dependent vessels of the venous system. Pooling results in a transient decrease in the venous blood returning to the heart and subsequent reduction in blood pressure and increase in heart rate. Pulse rate decreases when client is lying down.

Medications

Atropine can increase heart rate. Digitalis can decrease the heart rate.

Hemorrhage

Loss of blood increases pulse rate.

Temperature

Fever can cause an increased pulse rate. Decreased pulse rate is often seen with hypothermia.

Poor Oxygenation

Any condition resulting in poor oxygenation of blood increases pulse rate, such as chronic pulmonary disease or anemia.

Character of the Pulse and Observation of Abnormal Pulse

Pulse Rate

When assessing the pulse, the nurse must consider the variety of factors influencing pulse rate．A combination of these factors may cause significant changes．If the nurse detects an abnormal rate while palpating a peripheral pulse，the next step is to assess the heart rate．The heart rate provides a more accurate assessment of cardiac contraction．

Two common abnormalities in pulse rate are tachycardia and bradycardia．

Tachycardia is an abnormally elevated heart rate，above 100 beats per minute in quiet adults． It is seen in the clients with fever, anemia, hemorrhage and hyperthyroidism.

Bradycardia is a slow rate, below 60 beats per minute in quiet adults．It is seen in the clients with atrioventricular block, increased intracranial pressure, and hypothyroidism.

Pulse Rhythm

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

Intermittent Pulse

Intermittent Pulse is also called premature beat. It means one pulse missing during regular or irregular pulse patterns, in which the rhythm is irregular and uneven. It can be called bigeminy or trigeminy if one pulse absents every one or two normal pulses. This can be seen in cardiomyopathy, myocardial infarction, digitalis intoxication, and transient symptoms caused by excited emotion or fear. Intermittent pulse threatens the heart ability to provide adequate cardiac output, particularly if it occurs repetitively. The nurse identifies an intermittent pulse by palpating an interruption in successive pulse waves or auscultating an interruption between heart sounds. An electrocardiogram (ECG) is necessary to define the pulse dysrhythmia.

Children often have a sinus dysrhythmia, which is an irregular heartbeat that speeds up with inspiration and slows down with expiration. This is a normal finding and can be verified by having the child hold his or her breath; the heart rate should then become regular.

Pulse Deficit

The pulse deficit is that pulse rate is less than heart rate. An inefficient contraction of the heart that fails to transmit a pulse wave to the peripheral pulse site creates a pulse deficit．Pulse deficits are frequently associated with dysrhythmias．It can be seen in clients with atrial fibrillation. To assess a pulse deficit the nurse and a colleague assess radial and apical rates simultaneously and then compare rates．

Strength

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．Normally the pulse strength remains the same with each heartbeat．Pulse strength may be graded or described as strong, weak, thready, or bounding．It is included during assessment of the vascular system．

Bounding Pulse

Bounding pulse denotes an increased stroke volume, which can be palpated by fingertips slightly. It is often seen with fever, hyperthyroidism, and aortic incompetence.

Thready Pulse

The pulse is weak and diminished, which is barely palpated by fingertips. It often occurs with massive hemorrhage, shock, and aortic stenosis.

Alternating pulse

The pulse alternates between increased and diminished patterns along with strong and weak contraction of the ventricles. Common causes are hypertensive heart disease, myocardial infarction.

Water Hammer Pulse

The abrupt distension and quick collapse of the pulse is palpated following the increased cardiac output with resultant pulse pressure surges. It often occurs with hyperthyroidism, aortic incompetence.

Dicrotic Pulse

A pulse marked by a double beat, with the second beat weaker than the first. It can be an indication of dilated cardiomyopathy.It has a systole peak and a diastole peak (in contrast to pulsus bisferiens, which has two peaks in systole.)

Paradoxical Pulse

The pulse is obviously weak or not palpable on inspiration. It results from the declined strokes by the left ventricle on inspiration. Common causes are pericardial effusion and constrictive pericarditis.

Equality

The nurse should assess both radial pulses to compare the characteristics of each. A pulse in one extremity may be unequal in strength or absent in many diseases, such as thrombosis, aberrant blood vessels, or aortic dissection. The carotid pulse should not be measured simultaneously because excessive pressure may stop blood supply to the brain.

Nursing process and Pulse Determination

Assessment

When assessing the pulse, the nurse should collect the following data: the client’s general condition, such as age, sex, status of an illness and treatment; the pulse rate, rhythm, strength, equality, factors influencing pulse and arterial wall elasticity.

A healthy, normal artery feels straight, smooth, and soft. Older people often have inelastic that feel twisted and irregular upon palpation. Pulse assessment is helpful to determine the general state of cardiovascular health and the response to other system imbalances．

Nursing Diagnosis

Tachycardia，bradycardia，and dysrhythmias are defining characteristics of many nursing diagnosis and are considered along with other assessment data, such as activity intolerance, anxiety, fear, fluid volume deficit, gas exchange impaired, hyperthermia, and hypothermia.

Nursing Plan

The nursing care plan includes interventions based on the nursing diagnosis identified and the related factors; the expected outcomes generally are that the clients can tell the normal range and physiological changes of the pulse; and the clients can cooperate with the treatment and care.

Implementation

·Instruct the clients to rest to decrease heart energy consuming. Oxygen administration can be provided according to the client’s condition.

·Observe the clients’ condition closely. Instruct the clients to take medicine on time and observe the reactions of the medicine. Tell the clients to keep first-aid medicines along with them.

·Provide mental support. Let the clients to keep steady mood.

·Health education: Stop smoking and drinking alcohol, take light and digestible diet, keep bowels smooth. Teach the clients to monitor the pulse prior to taking medicines that affect the heart rate. Tell the clients to report any notable changes of heart rate or rhythm to health care provider. Teach the clients and family members the basic first-aid skills.

Evaluation

The nurse evaluates the therapeutic effect by assessing the pulse rate, rhythm, strength, and equality; the clients’ mental status, cooperation with treatment and nursing; and the clients’ knowledge about health．

Section Ⅲ Blood Pressure

Blood pressure is the lateral pressure on the walls of an artery by the flowing blood under pressure from the heart．Systemic or arterial blood pressure，the blood pressure in the system of arteries in the body, is a good indicator of cardiovascular health．Blood flows throughout the circulatory system because of pressure changes．It moves from an area of high pressure to an area of low pressure．

The heart’s contraction forces 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 blood pressure is millimeters of mercury (mmHg). The measurement indicates the height to which the blood pressure can raise a column of mercury. Blood pressure is recorded with the systolic reading before the diastolic (e.g, 120/80mmHg )．The difference between systolic and diastolic pressure is the pulse pressure．For a blood pressure of 120/80mmHg, the pulse pressure is 40mmHg．

Physiology of Arterial Blood Pressure

Blood pressure reflects the interrelationship among cardiac output，peripheral vascular resistance，blood volume，blood viscosity, and artery elasticity．

Cardiac Output

Cardiac output is the volume of blood pumped into the arteries by the heart during 1 minute.

The blood pressure depends on the cardiac output and peripheral vascular resistance. 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 blood pressure to rise．Cardiac output can increase as a result of greater heart muscle contractility, an increase in heart rate, or an increase in blood volume．

Peripheral Resistance

Blood circulates through a network of arteries, arterioles, capillaries, venules, and veins．Arteries and arterioles are surrounded by smooth muscle that contracts or relaxes to change the size of the lumen．The size of arteries and arterioles changes to adjust blood flow to the needs of 1ocal tissues．For example, when more blood is needed by a major organ, the peripheral arteries constrict, decreasing their supply of blood. More blood becomes available to the major organ because of the resistance change in the periphery. Normally, arteries and arterioles remain partially constricted to maintain a constant flow of blood. 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 peripheral vascular resistance to blood flow. As resistance rises, arterial blood pressure rises. As vessels dilate and resistance falls, blood pressure drops．

Blood Volume

The volume of blood circulating within the vascular system affects blood pressure．Most adults have a circulating blood volume of 5000 ml．Normally the blood volume remains constant．However, if volume increases, more pressure is exerted against arterial walls．For example, the rapid, uncontrolled infusion of intravenous fluids elevates blood pressure. When circulating blood volume falls, as in the case of hemorrhage or dehydration, blood pressure falls．

Blood Viscosity

The thickness or viscosity of blood affects the ease with which blood flows through small vessels. The viscosity of blood depends on the proportion of blood cells to plasma, especially red blood cells. When the viscosity rises and blood flow slows，arterial blood pressure increases．The heart must contract more forcefully to move the viscous blood through the circulatory system.

Elasticity of Vessel Walls

Normally the walls of an artery are elastic and easily distensible. As pressure within the arteries increases, the diameter of vessel walls increases to accommodate the pressure change. Arterial distensibility prevents wide fluctuations in blood pressure. With aging or certain diseases, the walls of arterioles lose their elasticity and are replaced by fibrous tissue. With a reduced elasticity there is greater resistance to blood flow. As a result, the systemic pressure rises. Systolic pressure is more significantly elevated than diastolic pressure as a result of reduced arterial elasticity．

Each factor significantly affects the others. For example, as arterial elasticity declines, peripheral vascular resistance increases. The complex control of the cardiovascular system normally prevents any single factor from permanently changing the blood pressure. For example, if the blood volume falls, the body compensates with an increased vascular resistance．

Factors Affecting Blood Pressure

Blood pressure is not constant but is continually influenced by many factors during the day. Understanding these factors ensures a more accurate interpretation of blood pressure readings. The factors affecting blood pressure include:

Age

With age, blood pressure tends to rise and systolic pressure is elevated more significantly. To the same age, blood pressure is generally higher in some over-weight and obese people than in normal weight ones.

Table 8-6 Average Blood Pressure at Various Ages

Age Blood Pressure (mm Hg)

Newborn (1 month) 84/54

1 year 95/65

6 years 105/65

10~13 years 110/65

14~17 years 120/70

Middle adult 120/80

Older adult 140~160/80~90

Gender

There is no clinically significant difference in blood pressure levels between boys and girls. After puberty, males have higher readings. This difference is thought to be due to hormonal variations. With menopause, women tend to have higher levels of blood pressure than men of the same age．

Diurnal Variations

Variations may include a lower blood pressure in the morning, rising throughout the day, peaking in late afternoon or evening, and 1owering at night．

Environment

Peripheral blood vessels meet cold and constrict, then blood pressure rises. Vessels meet hot and expand, and then blood pressure declines. Hereby blood pressure is higher in winter than in summer. Hot bath can decrease blood pressure.

Body Shape

The tall and the obese usually have higher blood pressure.

Position Change

Blood pressure in standing position is higher than that in sitting position. Blood pressure in sitting position is higher than that in lying position. A person may feel dizzy, tachycardia or faint when he change his position from lying position to standing position who is lying for a long time or take some antihypertensive medications—be called orthostatic hypotension.

Sites

Normally, systolic pressure is 10~20mmHg higher in right arm than that in left arm. The difference of 20mmHg between both arms can be seen in varied arteritis, congenital artery malformation, and thromboangiitis. Normally, systolic blood pressure is 20~40mmHg higher in lower limbs than in arms, but the diastolic pressure is the same. If the blood pressure in lower limbs is equal to or lower than that in the arm, it indicates lower limbs with arteriostenosis or arterial obstruction.

Exercise

Physical activity increases the cardiac output and hence blood pressure increases. Thus 20 to 30 minutes of rest following exercise is indicated before the blood pressure can be reliably assessed.

Stress

Anxiety, fear, and pain can initially increase blood pressure because of increased heart rate and increased peripheral vascular resistance．

Medications

Some medications directly or indirectly affect blood pressure. Antihypertensive medications including diuretics, beta-adrenergic blockers, vasodilators, ACE inhibitors，and calcium channel blockers lower blood pressure．

Any condition affecting the cardiac output, blood viscosity, and compliance of the arteries has a direct effect on the blood pressure.

Abnormal Blood Pressure

Hypertension

The most common alteration in blood pressure is hypertension. A blood that is persistently above normal is called hypertension. The diagnosis of hypertension in adults is made when an average of two or more diastolic readings on at least two subsequent visits is 90 mmHg or higher or when the average of two or more systolic readings on at least two subsequent visits is consistently higher than 140 mmHg．An elevated blood pressure of unknown causes is called primary hypertension. An elevated blood pressure of known causes is called secondary hypertension. Categories of hypertension have been developed and determine medical intervention

Table 8-8 Definition and Classification of Blood Pressure (WHO/ISH)

Category Systolic (mmHg) Diastolic (mmHg)

Optimal ................
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