VITAL SIGNS

Chapter 21 VITAL SIGNS



OBJECTIVES



• Define the key terms/concepts

• Describe factors that affect the vital signs

• Identify the variations in acceptable ranges for body temperature, pulse, respirations and blood pressure that occur from infancy to old age

• Describe advantages and disadvantages of using each body temperature site

• State the factors involved in the maintenance of the pulse and blood pressure

• Identify the sites commonly used to assess the pulse and state the reasons for their use

• State the factors necessary for an adequate supply of oxygen to the cells

• Identify the characteristics that should be included in a respiratory assessment

• Describe the various methods and sites to measure blood pressure


KEY TERMS/CONCEPTS


bradycardia

bradypnoea

Cheyne–Stokes breathing

cyanosis

dyspnoea

external and internal respiration

hypertension

hyperthermia

hypotension

hypothermia

hypoxia

Korotkoff sounds

Kussmaul’s breathing

oxygen saturation

respiration

tachycardia

tachypnoea

vital signs



CHAPTER FOCUS


Assessment is an essential part of the nursing process, as it enables the nurse to obtain information about the client that will facilitate the identification of problems relating to their health status. When the client’s actual or potential problems or concerns are identified, steps can be taken to plan appropriate care to meet their needs.


Continued assessment enables the nurse to determine the progress being made by the client, any change in the client’s condition, and the effectiveness of the nursing care plan in meeting the client’s needs. Accurate assessments made, recorded and reported by nurses also assist the medical officer in making a diagnosis, planning a program of treatment or altering a plan of treatment in light of reported changes in a client’s condition. Information on the nursing process is provided in Chapter 19 and should be referred to in conjunction with this chapter.


Vital signs are a quick and efficient way of monitoring a client’s condition or identifying problems and evaluating the client’s response to interventions. The nurse has an essential role to play in assessing clients and in recording and reporting the findings. To assess a client effectively the nurse requires knowledge of the acceptable ranges in measurements of vital signs to identify any deviations or abnormalities. This chapter focuses on use of the physical senses and equipment to assess a patient’s physical and mental condition and the signs and symptoms that may be indicative of change.




LIVED EXPERIENCE


The last time I was admitted into hospital I had a young student nurse look after me. The student was very meticulous and looked after all my needs. The only time that I felt uncomfortable and a little scared was the first time he took my blood pressure. He pumped up the cuff, with an intense look on his face, and deflated it. He then proceeded to do this three times and then, without telling me what was wrong, left the room with a panicked look on his face, telling me that he would have to go and get his teacher. I was so worried — I thought there was something wrong with me and that I wouldn’t be able to go home. As I sat there waiting, thinking the worst, the student came back with the teacher and it turned out that he hadn’t switched on the stethoscope!


Bill, age 57



GUIDELINES FOR TAKING VITAL SIGNS


The vital signs (temperature, respirations, pulse and blood pressure) indicate the body’s ability to regulate body temperature, maintain blood flow, and oxygenate body tissues. Oxygen saturation is an additional vital sign obtained through pulse oximetry that reflects the ability of the cardiac and respiratory system to maintain adequate oxygenation. Pain assessment is considered a fifth vital sign (see Chapter 35) (Elkin et al 2008). When checking vital signs, or ‘taking an individual’s observations’, a nurse must be able to measure the vital signs correctly, understand and interpret the values, communicate the findings appropriately and begin interventions as required. Vital signs are taken:


• When a client is first admitted to a health care facility

• On a routine schedule according to a medical officer’s order or hospital policy

• When assessing a client during home health visits

• Before and after a surgical procedure

• Before and after an invasive diagnostic procedure

• Before and after administration of certain medications that affect the cardiovascular, respiratory or temperature control function

• When a client’s general physical condition changes

• Before and after nursing interventions influencing a vital sign

• When a client reports non-specific symptoms of physical distress; for example, ‘feeling funny’

• Before, during and after a transfusion of blood products (Elkin et al 2008).

When taking vital signs the nurse should:


• Take the vital signs, interpret their significance and make decisions about client care

• Check that the equipment is functional and appropriate

• Know the acceptable range for all vital signs

• Know the client’s usual range of vital signs

• Know the client’s medical history, therapies and medications prescribed

• Control or minimise environmental factors that may affect the vital signs

• Use an organised systematic approach

• Describe the frequency of vital sign assessment on the basis of the client’s condition

• Analyse the results of vital sign measurement

• Know other physical signs or symptoms and be aware of the client’s ongoing health status

• Verify and communicate significant changes in vital signs to the Registered Nurse (RN) and the medical officer.


INTERPRETING OBSERVATIONS


Interpreting specific observations depends on:


• Comparison with the acceptable ranges for a given group of people

• Knowledge of the results of previous observations of a particular client

• The sum total of all observations at the time of the present observation.

For example, to interpret the significance of a client’s pulse rate the nurse needs to know the acceptable pulse rate for people of that client’s age group, and the client’s previous pulse rate. Pulse and other observations or assessments, such as blood pressure, temperature, respirations, colour and degree of mental alertness, provide information that enables more accurate interpretation of a client’s condition. Therefore, while a single observation provides some information about a client, several observations enable a more accurate assessment of their condition.


Interpreting any observation involves a decision as to its significance. The nurse has a responsibility to report observations to the nurse in charge, who makes a decision, for example, to assess the client more frequently, take immediate action or notify the medical officer.



BODY TEMPERATURE


Measuring body temperature provides the nurse with an objective assessment of the body’s ability to maintain temperature regulation, identifies deviations from the acceptable range and monitors any changes.


The human body is warm blooded, with inbuilt mechanisms that maintain a balance between heat production and heat loss. As a result the internal or core temperature is stable. During ill-health the balance may be upset and considerable stress may be placed on the body’s adaptive mechanisms if the temperature does not remain within the acceptable range. The temperature range of a normal adult depends on age, physical activity, status of hydration, and state of health, including the presence of infection (Elkin et al 2008).



REGULATION OF BODY TEMPERATURE


Body temperature is controlled by both voluntary actions and involuntary mechanisms. The surface temperature of the body varies with changes in the environmental temperature, and people adjust to these changes by adapting their immediate surroundings; for example, selecting appropriate clothing, moving away from or towards the source of heat or cold, and altering the temperature of heaters or coolers can help to provide a comfortable environmental temperature.


Core temperature is maintained by inbuilt mechanisms concerned with the production of heat and its dissipation. These regulatory mechanisms, which ensure a balance between heat production and loss is achieved, are situated in the hypothalamus, where neurons respond to changes in the temperature of the blood circulating through the brain. There are also temperature receptors in the skin and some internal organs, which transmit signals to the central nervous system to help control body temperature.



HEAT PRODUCTION AND HEAT LOSS


Heat is continually being produced by the process of cellular metabolism and is constantly being lost to the environment through the following processes.



Radiation


Body heat is transferred to cooler objects in the environment. Loss of heat by radiation means loss in the form of infrared rays. If the temperature of the body is higher than the temperature of the environment, more heat is radiated from the body.



Conduction


Only small quantities of heat are lost from the body by direct conduction from the body’s surface to other objects, for example, a bed or a chair. Loss of heat by conduction to the air represents a large proportion of the body’s heat loss, unless the temperature of the air immediately adjacent to the skin is the same as the temperature of the skin.



Convection


Convection is the dispersion of heat by air currents. The body usually has a small amount of warm air next to it. This warm air rises and is replaced by cooler air. People always lose a small amount of heat through convection.



Evaporation


Insensible evaporation of water directly through the skin results from continual diffusion of water molecules, regardless of body temperature. When the body becomes overheated, large quantities of sweat are secreted onto the surface of the skin to provide rapid evaporative cooling of the body.



Balancing heat production and heat loss


Heat balance occurs when the rates of heat production and loss are equal. When the body temperature rises, impulses from the hypothalamus to the skin arterioles are decreased, causing vasodilation, with loss of heat occurring from radiation, conduction, convection, and evaporation of sweat. When the body temperature falls, the impulses are increased, causing vasoconstriction of the skin arterioles, reducing heat loss and increasing the flow of blood to vital internal organs. Shivering is an important source of heat, which is initiated by impulses travelling to the skeletal muscles. These impulses cause increased skeletal muscle tone, resulting in increased muscle metabolism and increased rate of heat production.



FACTORS AFFECTING BODY TEMPERATURE


In health, a range of processes and activities affect body temperature. These include age, diurnal variations, exercise, hormones, stress and environment. Factors that lower the body temperature include exposure to a cold damp environment, insufficient warm clothing, and an under-secretion of the hormone thyroxine. Factors that raise the body temperature include:


• Exposure to a hot humid environment

• Strenuous muscular activity

• Intake of foods high in fat or carbohydrates

• Strong emotions such as anger

• An over-secretion of the hormone thyroxine

• Insufficient fluid intake.

Actions to assist the physiological processes of body temperature control include:


• Maintaining immediate surroundings at a comfortable temperature

• Adapting clothing to suit the climate

• Adjusting intake of food and fluids to suit the climate

• Adjusting the level of physical exercise.


ASSESSING BODY TEMPERATURE


To assess a client’s temperature the nurse uses both observational skills and a clinical thermometer. Using the senses of sight and touch the nurse can observe the client’s skin colour and temperature. Correct use of the thermometer will provide an accurate measurement of body temperature. As a result, the nurse is able to plan and implement appropriate nursing actions to assist the client in maintaining body temperature.


The frequency with which a client’s temperature is measured depends on continued assessment of their individual needs, and the nursing policies of the institution (Clinical Interest Box 21.1). Residents of long-term care facilities generally do not have their temperature measured as often as acutely ill people who require more frequent monitoring of their condition. Measuring the individual’s temperature together with assessment of the other vital signs is an important method of determining their general condition. Assessment of these vital signs enables the nurse to establish baseline measurements that can be compared with future readings, and to monitor the individual’s response to treatment.



CLINICAL INTEREST BOX 21.1 Measuring temperature in older adults



• The temperature of older adults is at the lower end of normal temperature range: 36°C

• Temperatures considered within acceptable range may reflect a fever in an older adult

• Older adults are sensitive to slight changes in temperature


MEASURING BODY TEMPERATURE


Several types of clinical thermometers are used to measure body temperature. The most commonly used types are electronic, tympanic electronic and chemical dot single use or reusable. Electronic thermometers (Figure 21.1) are most commonly used in health care facilities. The electronic thermometer is battery operated and a cover is placed over the probe before use and disposed of after the temperature has been measured. An electronic thermometer enables an accurate temperature reading to be obtained within a few seconds and may also be used when it is necessary to monitor a client’s temperature continuously. A signal device indicates when the temperature has registered, and the reading may be obtained from either a digital display or a printout. All types of thermometer are calibrated in the Centigrade scale.


image

Figure 21.1 An electronic thermometer


(photo courtesy of Welch Allyn Australia Pty Ltd)



BODY TEMPERATURE SITES


Body temperature may be measured using the oral, tympanic membrane or axillary sites, on the skin or in the groin. The taking of rectal temperature with a rectal thermometer is rarely performed because of the trauma and pain it causes individuals and because of the risk of cross-contamination. It is no longer performed on neonates.



Tympanic site


The tympanic membrane is now the most commonly used site for taking temperature. An otoscope-like speculum with an infrared sensor tip detects heat radiated from the tympanic membrane. Within 2–5 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 (Figure 21.2). The advantages of using this site is that it is easily accessible; minimal client repositioning; unaffected by oral intake of food, fluids or smoking and can be used with clients with tachypnoea without affecting breathing. Disadvantages of using this site are that: it can be uncomfortable and involves the risk of injuring the tympanic membrane if the probe is inserted too far; repeated measurements can vary and the presence of cerumen (wax) and purulent discharge can affect the reading; it requires removal of hearing aid before measurement; it requires disposable sensor cover available only in one size; it does not obtain continuous measurement and can be affected by ambient temperature devices; for example, heaters (Elkin et al 2008).


image

Figure 21.2 Measuring temperature with tympanic thermometer


(Potter & Perry 2008: 514)



The oral site


The thermometer is placed under the person’s tongue, to one side of the frenulum, to ensure that it is in contact with a heat pocket, and the person closes their lips. The advantages of this site are: it is easily accessible; comfortable for the client; reflects rapid change in core temperature and provides accurate surface temperature reading. Some disadvantages of this site are: causes in delay in measurement if client has recently ingested hot/cold fluids or foods, smoked, or received oxygen by mask or nasal cannula (Elkin et al 2008). So that an accurate measurement can be obtained safely, the person must be:


• Able to close their lips completely and retain the thermometer in the correct position

• Able to breathe comfortably through their nose for the length of time the thermometer is in their mouth

• Rested and not have consumed cold or hot fluids in the previous 15–30 minutes.

The oral site is unsuitable for people who:


• Have an oral infection or painful mouth

• Have recently had oral surgery

• Experience any impairment of breathing or obstruction of the nasal passages

• Are unconscious.


The axilla


Using the axilla (Figure 21.3) provides a less accurate measurement of body temperature, but may be used when it is not possible to measure the temperature orally (Clinical Interest Box 21.2). It is safe and non-invasive and can be used with newborns and unconscious clients. The thermometer is placed in the axilla in contact with two dry skin surfaces and is kept in place in the axilla by bringing the person’s arm over their chest. A disadvantage of using this site is that the thermometer must be left in place for a long time to obtain an accurate measurement; it can be affected by exposure to the environment and requires continuous positioning by the nurse (Elkin et al 2008).


image

Figure 21.3 Taking temperature from the axilla


(Elkin et al 2008)



CLINICAL INTEREST BOX 21.2 Axillary temperature in paediatrics



• Axillary temperature cannot be relied on to detect fevers in infants and young children

• Axillary or skin temperature is safest for newborns. The thermometer must be kept in place for 5 minutes

• Infants are sensitive to slight changes in environmental temperatures


The skin


Various types of single-use disposable thermometers are available. A temperature-sensitive strip of tape is placed on the forehead or abdomen to record the heat of the body (Figure 21.4). These are often used in newborn nurseries. Directions on the package explain how to use these thermometers. Most disposable thermometers will register the temperature within 60 seconds. The advantages of this site is that it is inexpensive; provides continuous reading and is safe and non-invasive. The disadvantages are that measurement lags behind other sites during temperature changes; sometimes affected by environmental temperature and diaphoresis or sweat can impair adhesion (Elkin et al 2008).


image

Figure 21.4 Disposable thermometers A: A temperature-sensitive skin tape. B: Disposable, single-use thermometer strip


(photo B: Potter & Perry 2008)



STEPS IN OBTAINING AN ACCURATE MEASUREMENT OF BODY TEMPERATURE


To obtain an accurate measurement of body temperature and to promote the client’s comfort and safety, the nurse should:


• Select the appropriate site

• Check that the thermometer is undamaged, not contaminated and is working properly

• Ensure that the person is informed of the procedure

• Ensure that the person is rested

• Position the person according to the site selected

• Wash hands to prevent cross-infection and ensure that the thermometer has been disinfected before the procedure

• Use the correct probe for the site selected when using an electronic thermometer.

Depending on the site being used, some variations occur in the time that the thermometer is left in position, the normal range of temperature, and the position in which the person is placed (Table 21.1). Because of variations between sites it is important to note on the observation or vital sign charts what method was used to take the temperature. For example, if the temperature was taken orally, the temperature would be recorded: 36.7 PO (Latin: per os [by mouth]).



TABLE 21.1 MEASURING BODY TEMPERATURE

image


PROCEDURE FOR MEASURING BODY TEMPERATURE


While the actual procedure for measuring temperature may vary slightly in different health care settings, the general principles remain the same. The nurse should assess the needs of each individual and refer to the institution’s policy manual for information about the technique and equipment. Table 21.2 lists guidelines for measuring temperature using each body site. Temperature measurements are usually recorded on graph-style charts (Figure 21.5). These enable the pattern of temperature variations to be observed readily.


TABLE 21.2 GUIDELINES FOR MEASURING BODY TEMPERATURE






































































































Action Rationale
Review and carry out the standard steps in Appendix 1
Measuring body temperature with a tympanic membrane electronic thermometer
Assist client in assuming a comfortable position, with head turned away from the nurse Ensures comfort and exposes auditory canal for accurate temperature measurement
Observe for ear wax (cerumen) in client’s ear canal Lens cover of speculum must not be impeded by earwax (will not obtain an accurate measurement). Switch to other ear or select an alternative measurement site
Remove thermometer from charging base and slide disposable speculum cover over otoscope-like tip until it locks into place Base provides a battery power. Soft plastic probe cover prevents transmission of microorganisms
If holding handheld unit with right hand, obtain temperature from client’s right ear; left handed persons should obtain temperature from client’s left ear The less acute angle of approach the better the probe will seal inside the auditory canal
Insert speculum into ear canal, following manufacturer’s instructions for tympanic probe positioning. Pull pinna backward, up and out for an adult, move thermometer in a figure-eight pattern, fit probe snug in canal and do not move point towards the nose Correct positioning of probe will ensure accurate readings
As soon as probe is in place, depress scan button. Leave thermometer probe in place until an audible signal is given and client’s temperature appears on the digital display Depression of scan button causes infrared energy to be detected
Carefully remove speculum from auditory meatus. Push ejection button on unit to discard plastic probe cover into an appropriate receptacle Reduces transmission of microorganisms
Return handheld unit to charging base Protects sensor tip from damage and keeps unit charged ready for next use
Assist client in reassuming a comfortable position Restores comfort and sense of wellbeing
Wash hands Reduces risk of transmission of microorganisms
Discuss findings with client as needed Promotes participation in care and understanding of health status
Record the time and temperature on the vital signs chart. Record measurements in the nurse’s notes if the temperature was elevated Verifies that temperature was taken and makes measurement data available
Measurement of body temperature with electronic thermometer
Oral temperature
Remove thermometer from charging unit. Slide disposable plastic probe cover over thermometer probe until cover locks in place Charging provides battery power. Soft plastic cover prevents transmission of microorganisms
Gently place thermometer probe under the tongue in posterior sublingual pocket lateral to centre of jaw Heat from superficial blood vessels in sublingual pocket produces temperature reading
Ask client to hold thermometer probe with lips closed Maintains proper position of thermometer during recording
Leave thermometer probe in place until audible signal occurs and client’s temperature appears on digital display To ensure accurate reading, probe must stay in place until signal occurs
Remove thermometer probe from under client’s tongue, push ejection button and discard plastic probe cover into an appropriate receptacle Reduces risk of transmission of microorganisms
Return thermometer to storage position of thermometer unit and return to charger Maintains battery charge
Discuss findings with client as needed Promotes participation in care and understanding of health status
Record the time and temperature on the vital signs chart. Record measurements in the nurse’s notes if temperature was elevated Verifies that temperature was taken and makes measurement data available
Axillary temperature
Remove thermometer from charging unit. Slide disposable plastic probe cover over thermometer probe until cover locks in place Charging provides battery power. Soft plastic cover prevents transmission of microorganisms
Raise client’s arm away from torso and make sure the axilla is dry Moisture may interfere with accurate reading
Place thermometer into centre of axilla, lower arm over probe and place arm across client’s chest Maintains position of thermometer against blood vessels in axilla
Hold thermometer in place until audible signal occurs and client’s temperature appears on digital display, remove probe from axilla To ensure an accurate reading
Push ejection button on thermometer probe stem to discard plastic probe cover into an appropriate receptacle. Reduces risk of transmission of microorganisms
Return thermometer to storage position of thermometer unit and return to charger Maintains battery charge
Discuss findings with client as needed Promotes participation in care and understanding of health status
Record the time and temperature on the vital signs chart. Record measurements in the nurse’s notes if temperature was elevated Verifies that temperature was taken and makes measurement data available
Special note:
• In an infant or young child it may be necessary to hold the arm against the child’s side when using axillary method. If infant is in a side-lying position, the lower axilla will record the higher temperature

• Do not use axilla if skin lesions are present because local temperature may be altered and area may be painful to touch

image

Figure 21.5 A vital signs graph-style chart



ALTERATIONS IN BODY TEMPERATURE


Body temperature reflects body function, and a deviation from acceptable temperature range is an indication of body dysfunction. An imbalance between the production and loss of heat results in a rise or fall in normal body temperature. An elevated temperature is referred to as hyperthermia, pyrexia or fever. A temperature above 41°C is referred to as hyperpyrexia. A temperature below the acceptable range is referred to as hypothermia.


Hyperthermia occurs when cells are injured, or invaded by pathogens that release chemical substances called pyrogens, which act on the hypothalamus and cause a rise in body temperature. Hyperthermia is a manifestation of metabolic disorder, infection, neurological disease, severe trauma or neoplasm. Hypothermia refers to a lowering of the temperature of the entire body. The thermal regulating centre in the hypothalamus is greatly impaired when the temperature of the body falls below 34.4°C. At this level, the activity of the cells is decreased, less heat produced and sleepiness and coma can develop. Those at risk of hypothermia include postoperative clients, who have been cooled during surgery, newborn infants, elderly or debilitated clients, and any person who is subjected to prolonged exposure to a cold environment (de Wit 2005). Alterations in body temperature produce certain physiological effects, as shown in Table 21.3.


TABLE 21.3 EFFECTS OF ALTERED BODY TEMPERATURE









Hyperthermia Hypothermia

Elevated temperature, pulse and ventilation rates (rigor may occur)

Warm flushed skin and sweating may be present

Restlessness, drowsiness or confusion

Aching muscles and joints

Headache

Photophobia

Loss of appetite

Increased thirst

Dehydration (if prolonged)
Subnormal temperature, decreased pulse and ventilation rates

Cool, pale or mottled dry skin

Drowsiness, shivering

Muscle weakness

Mental confusion

Unconsciousness (if prolonged)


NURSING CARE OF A CLIENT WITH ALTERED BODY TEMPERATURE



Hyperthermia


The aims of nursing a client with hyperthermia include:


• Reducing body temperature to an acceptable range

• Relieving any associated discomfort

• Encouraging rest to decrease the production of body heat

• Maintaining nutritional and fluid status.

These aims can be achieved by implementing certain nursing actions, which include:


• Assessing the client’s temperature after the administration of any prescribed medication such as antipyretics and antibiotics

• Sponging the client with tepid water. This procedure causes the superficial blood vessels to dilate and release heat, thereby reducing body temperature. The client is undressed and covered with a bath blanket. Using water at a temperature of 27–30°C each part of the client’s body is sponged. Long slow strokes should be used, leaving beads of water on the skin to encourage loss of heat by evaporation. The skin may be gently patted dry, but rubbing should be avoided, as this increases cell metabolism and heat production. During the sponge the client must be observed for shivering, pallor, mottling or cyanosis, or a rapid, weak or irregular pulse. If any adverse reactions occur, the sponge must be discontinued immediately. During, and on completion of, the sponge the client should be advised to avoid unnecessary movement, as muscular activity increases heat production. The client’s temperature, pulse and respirations should be measured 30 minutes after the sponge to assess the effectiveness of the procedure

• Promoting the client’s general comfort by providing loose, light, clean and dry nightwear and bed linen. To maintain clean and dry skin, the client’s hygiene needs must be attended to

• Regular mouth care, including mouth rinses and the application of a lip cream, which will help reduce any oral dryness associated with hyperthermia

• Ensuring that the room is quiet and free from harsh light and ventilated adequately

• Encouraging the client to rest or sleep as much as possible, as reducing the level of physical activity will decrease the production of body heat

• Continually checking the client’s skin colour, temperature and general condition to assess the effectiveness of nursing interventions

• Maintaining optimal nutritional status to cater for the increased metabolic demand associated with hyperthermia. The client should be provided with light appetising meals that provide essential nutrients. If appetite is poor, extra kilojoules may be provided by adding glucose to oral fluids

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Feb 12, 2017 | Posted by in NURSING | Comments Off on VITAL SIGNS

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