General Points to Consider in Vital Sign Measurement

Therapeutic Environment and Informed Consent

It is important to seek informed consent while creating a therapeutic and safe environment during all encounters with clients. You will usually begin by introducing yourself by name and designation so the client knows who you are. Next, explain what you are going to do and always ask permission to touch the patient before beginning vital sign measurement. For example, an appropriate introduction may look like this:

“Hello, I am (state first and last name). I am a (state designation, such as “I am a registered nurse”). Today, I am here to take your vital signs. It will involve me touching your arm; are you okay with that?”

It is also important to ensure the client’s privacy by closing the curtains or the door to the room.

Infection Prevention and Control

Clean hands and equipment are essential to infection prevention when measuring vital signs. It helps reduce infectious diseases, particularly those associated with health care, which are infectious organisms acquired by a client while in the hospital. Common infections include clostridium difficile (C. diff), vancomycin-resistant enterococcus (VRE), and methicillin-resistant staphylococcus aureus (MRSA).

Ensuring your hands are clean is the best way to prevent and control infection. Hand hygiene can include cleaning hands with hand gel (see Figure 1.1) and handwashing. (see Figure 1.2). Use an alcohol-based sanitizer before and after contact with clients. Place gel on your hands and rub all hand surfaces for at least fifteen seconds. When washing hands using soap and water, wet your hands and apply soap. Rub all hand surfaces for about fifteen seconds, then rinse your hands. If the tap is not automatic, then turn it off with a paper towel.

Pain Assessment

A pain assessment is conducted at the same time as the measurement of vital signs because pain can influence the vital signs. Pain can activate the sympathetic nervous system and increase pulse, respiration, and blood pressure. Pain is a complex issue, and a comprehensive discussion of pain assessment is beyond the scope of this text.

Briefly, because pain is subjective, self-reports are the most effective way to assess pain. The choice of pain assessment tool depends on the client's situation: health care providers often use a numeric rating scale such as “rate your pain on a scale of zero to ten with zero being no pain and ten being the worst pain that you have ever felt.” The response is often recorded on the vital sign record and expanded on in the narrative notes. Another common tool is the PQRSTU mnemonic in which each letter corresponds to a series of questions.

• P – Provocative/Palliative (such as “What makes the pain worse? What makes the pain better?”)
• Q – Quality/Quantity (such as “Can you describe what the pain feels like? How bad is the pain?)
• R – Region/Radiation (such as :Where is the pain located? Does it radiate anywhere else?)
• S – Severity (as noted above, rate the pain on a scale of zero to ten)
• T – Timing/Treatment (When did the pain begin? Is it constant? Have you taken anything to help the pain? If so, what?)
• U – Understanding (What do you think is causing the pain?)

Order of Vital Sign Measurement

The order of vital sign measurement is influenced by the client situation. Health care providers often place the pulse oximeter probe on a client while proceeding to take pulse, respiration, blood pressure, and temperature. However, in some situations, this order is modified and the health care provider needs to critically assess the situation to prioritize the vital sign measurement order. For example, with newborns and infants, it is best to proceed from least invasive to most invasive, so it is best to begin with respiration, pulse, oxygen saturation, temperature and if required, blood pressure. In an emergency situation or if a person loses consciousness, it is best to begin with pulse and blood pressure. Generally, it is important to conduct a complete set of vital signs unless otherwise indicated.

Significance of Measurements

Determining the significance of vital sign measurements involves a process of diagnostic reasoning. The health care provider analyzes client data and makes decisions about whether the vital signs are normal or abnormal and whether the findings are significant. The following chapters provide normal vital sign ranges. The health care provider also considers agency policy, if applicable, about vital sign ranges to assess any abnormal variations and clinical significance. Additionally, the health care provider considers the client’s baseline vital signs to obtain a better sense of the client’s ‘normal’ and allow comparison of trends over time. The diagnostic reasoning process also involves considering other available objective and subjective data.

Documentation

Timely documentation of vital sign measurements is imperative as a form of communication to observe trends in vital sign measurements and to ensure effective intervention when needed. Documentation occurs on paper-based vital sign records or electronic systems depending on the agency. Health care providers follow the agency’s documentation policy and the professional standards of practice. If using a vital sign record, health care providers use the symbols noted on the legend of the record.

Temperature

What is Temperature?

Temperature refers to the degree of heat or cold in an object or a human body. In humans, the brain’s hypothalamus acts as the body’s thermostat and is responsible for regulating its temperature (OER #2). See Figure 3.1 of the hypothalamus.

The human body is constantly adapting to internal health states and environmental conditions, and the hypothalamus is programmed to tell the body to generate heat if the body temperature is low. For example, the hypothalamus can activate peripheral vasoconstriction and shivering (contraction of skeletal muscles) to prevent a decrease in body temperature. The hypothalamus can also reduce heat if the body temperature is too high. For example, it can activate peripheral vasodilation to increase heat loss and cause a person to perspire, which cools the body.

Why is Temperature Measured?

Health care providers measure a client’s temperature because it can give information about their state of health and influence clinical decisions. Accurate measurements and interpretation are vital so that hyperthermia and hypothermia can be identified and appropriate interventions determined.

Hyperthermia refers to an elevated body temperature. It can be related to an internal or external source. External sources that increase body temperature could include exposure to excessive heat on a hot day or being in a sauna or hot tub. Internal sources that may increase body temperature include fever caused by an infection or tissue breakdown associated with physical trauma (such as surgery or myocardial infarction) or some neurological conditions (such as cerebral vascular accident, cerebral edema, or a brain tumor). Hyperthermia that is associated with an infectious agent, such as a bacteria or virus (like the flu) is referred to as febrile. Unresolved hyperthermia can lead to cell damage.

Hypothermia refers to a lowered body temperature. It is usually related to an external source such as being exposed to the cold for an extended period of time. Hypothermia is sometimes intentionally induced during surgery, or for certain medical conditions, to reduce the body’s need for oxygen. Unresolved hypothermia can slow cellular processes and lead to loss of consciousness.

Methods of Measurement

Methods of measuring a client’s body temperature vary based on the patient’s developmental age, cognitive functioning, level of consciousness, state of health, safety, and agency or unit policy. The health care provider chooses the best method after considering client safety, accuracy, and least invasiveness, all contingent on the client’s health and illness state. The most accurate way to measure core body temperature is an invasive method through a pulmonary artery catheter. This is only performed in a critical care area when constant measurements are required along with other lifesaving interventions.

Methods of measurement include oral, axillary, tympanic, rectal, and dermal routes.

Oral temperature can be taken with clients who can follow instructions, so this kind of measurement is common for clients over the age of four, or even younger children if they are cooperative. Another route other than oral (such as tympanic or axillary) is preferable when a client is on oxygen delivered via a face mask because this can alter the temperature.

For children younger than four, axillary temperature is commonly measured unless a more accurate reading is required.

Rectal temperature is another accurate way to measure body temperature (Mazerolle, Ganio, Casa, Vingren, & Klau, 2011). The rectal route is recommended by the Canadian Pediatric Society for children under two years of age (Leduc & Woods, 2017). However, this method is not used on infants younger than thirty days or premature infants because of the risk of rectal tearing. If the rectal method is required, the procedure is generally only used by nurses and physicians.

Dermal routes are alternative methods of measurement that may be used in some agencies and practice areas. This method can involve holding the device and sliding it over the skin of the forehead and then down over the temporal artery in one motion. Dermal strips can also be placed on the forehead to measure skin temperature, but they are not yet widely used, and it isn’t certain if this method is accurate yet. More recently, there has been an increase in non contact infrared thermometers, particularly in the era of COVID-19 and other highly transmissible diseases. Depending on the type, these thermometers can be held at a short distance from the forehead or temporal area to measure temperature. Alternatively, some handheld thermal scanners that use an infrared camera can be held at a greater distance to screen large masses of people. Please refer to the manufacturer’s suggested reference range for non contact infrared thermometers and thermal scanners.

What are Normal Temperature Ranges?

The human body’s core temperature (internal body temperature) is measured in degrees Celsius (ºC) or Fahrenheit (ºF).

In adults, the normal core body temperature (referred to as normothermia or afebrile) is 36.5–37.5ºC or 97.7–99.5ºF (OER #2).

A wider temperature range is acceptable in infants and young children, and can range from 35.5–37.7ºC or 95.9–99.8ºF. Infants and children have a wider temperature range because their heat control mechanisms are less effective. They are at risk for heat loss for many reasons including having less subcutaneous fat than adults, a larger body surface area in comparison to weight (and larger head size in proportion to the rest of the body), immature metabolic mechanisms (for example, they may be unable to shiver), and limited ability to produce heat through activity. They are also at risk of excessive heat production due to crying and restlessness as well as external factors such as being wrapped in too many blankets.

Older adults tend to have lower body temperatures and are at risk for hypothermic states. Reasons for this may include having less subcutaneous tissue acting as insulation, loss of peripheral vasoconstriction capacity, decreased cardiac output with resultant lowered blood flow to the extremities, decreased muscle mass resulting in reduced heat production capacity, and decreased metabolic responses.

See Table 3.1 for normal temperature ranges based on method. The normal ranges vary slightly for each of the methods. It is important to consider a client’s baseline temperature as some individuals present with a temperature slightly above or below these ranges. To make an informed clinical judgment, examine the client’s records to determine a trend in temperature. A pattern of high or low temperature findings may reveal a baseline for your client. As a health care provider, it is important to determine the significance of the temperature by also considering influencing factors and the client’s overall state of health.

Other factors that influence temperature include diurnal rhythm, exercise, stress, menstrual cycle, and pregnancy. The diurnal cycle causes a fluctuation of 1ºC, with temperatures lowest in the early morning and highest in the late afternoon. During exercise, body temperature rises because the body is using energy to power the muscles. Temperature can rise as a result of stress and anxiety, due to stimulation of the sympathetic nervous system and increased secretion of epinephrine and norepinephrine. Body temperature varies throughout a woman’s menstrual cycle as well due to hormonal fluctuations, rising after ovulation until menstruation by about 0.5–1ºC. Body temperature is slightly elevated during pregnancy as a result of increased metabolism and hormone production such as progesterone production.

Oral Temperature

The normal oral temperature is 35.8–37.3ºC (OER #1) or 96.4–99.1ºF. Oral temperature measurement is common and reliable because it is close to the sublingual artery. An oral thermometer is shown in Figure 3.2. The device has blue coloring, indicating that it is an oral or axillary thermometer as opposed to a rectal thermometer, which has red coloring.

Technique

Remove the probe from the device and place a probe cover (from the box) on the oral thermometer without touching the probe cover with your hands. Place the thermometer in the client’s mouth under the tongue and instruct client to keep mouth closed and not to bite on the thermometer (OER #1). Ensure the thermometer probe is in the posterior sublingual pocket under the tongue, slightly off-center. Leave the thermometer in place for as long as is indicated by the device manufacturer (OER #1). The thermometer will beep within a few seconds when the temperature has been taken: most oral thermometers are electronic and provide a digital display of the reading. Discard the probe cover in the garbage (without touching the cover) and place the probe back into the device. See Figure 3.3 of an oral temperature being taken.

What should the health care provider consider?

Health care providers often measure the oral temperature, particularly when the client is conscious and can follow directions. Measurement of the oral temperature is not recommended for individuals who are unconscious, unresponsive, confused, have an endotracheal tube secured in the mouth, and/or cannot follow instructions.

Certain factors can make the oral route less accurate with the potential for falsely high or falsely low findings. If the client has recently consumed hot or cold food or drink, chewing gum, or has smoked prior to measurement, the health care provider should use another route such as tympanic or axillary. Selecting an alternate route under these circumstances is the most helpful in a fast-paced clinical environment and the most respectful of the client’s time. If another route is not available, health care providers should wait 15–25 minutes to take the oral temperature following consumption of a hot or cold drink or food. The temperature of the drink or food also factors into the wait period. Extreme heat or cold will require longer wait times for oral temperature assessment. Health care providers should wait about five minutes if the client is chewing gum or has just smoked since both of these activities can increase temperature.

Tympanic Temperature

The normal tympanic temperature is usually 0.3–0.6°C higher than an oral temperature (OER #1). It is accurate because the tympanic membrane shares the same vascular artery that perfuses the hypothalamus (OER #1). A tympanic thermometer is shown in Figure 3.4.

Technique

Remove the tympanic thermometer from the casing and place a probe cover (from the box) on the thermometer tip without touching the probe cover with your hands. Only touch the edge of the probe cover (if needed), to maintain clean technique. Turn the device on. Ask the client to keep head still. For an adult or older child, gently pull the helix up and back to visualize the ear canal. For an infant or younger child (under three years old), gently pull the lobe down. The probe is inserted just inside the opening of the ear. Never force the thermometer into the ear and do not occlude the ear canal (OER #1). Only the tip of the probe is inserted in the opening—this is important to prevent damage to the ear canal. Activate the device; it will beep within a few seconds to signal it is done. Discard the probe cover in the garbage (without touching the cover) and place the device back into the holder. See Figure 3.5 of a tympanic temperature being taken.

What should the health care provider consider?

The tympanic temperature method is a quick and minimally invasive way to take temperature. Although research has proven the accuracy of this method, some pediatric institutions prefer the accuracy of the rectal temperature. The Canadian Pediatric Society found equal evidence for and against the use of tympanic temperature route (Leduc & Woods, 2017). It concluded that tympanic temperature is one option for use with children, but suggested using rectal temperature for children younger than two, particularly when accuracy is vital. The tympanic temperature is not measured when a client has a suspected ear infection. It is important to check your agency policy regarding tympanic temperature.

Axillary Temperature

The normal axillary temperature may be as much as 1ºC lower than the oral temperature (OER #1). An axillary thermometer is the same electronic device as an oral thermometer, and both have a blue end.

Technique

Remove the probe from the device and place a probe cover (from the box) on the thermometer without touching the cover with your hands. Ask the client to raise the arm away from his or her body. Place the thermometer in the client’s armpit (OER #1), on bare skin, as high up into the axilla as possible, with the point facing behind the client. Ask the client to lower his or her arm and leave the device in place for as long as is indicated by the device manufacturer (OER #1). Usually the device beeps in 10–20 seconds. Discard the probe cover in the garbage (without touching the cover) and place the probe back into the device. See Figure 3.6 of an axillary temperature being taken.

What should the health care provider consider?

The axillary route is a minimally invasive way to measure temperature. It is commonly used in children. It is important to ensure that the thermometer is as high up in the axilla as possible with full skin contact and that the client’s arm is then lowered down.

Rectal Temperature

The normal rectal temperature is usually 1ºC higher than oral temperature (OER #1). A rectal thermometer has a red end to distinguish it from an oral  or axillary thermometer. A rectal thermometer is shown in Figure 3.7.

Technique

First, ensure the client’s privacy. Wash your hands and put on gloves. For infants, lie them down in a supine position and raise their legs up toward the chest. You can encourage a parent to hold the infant to decrease movement and provide a sense of safety. With older children and adults, assist them into a side lying position. Remove the probe from the device and place a probe cover (from the box) on the thermometer. Lubricate the cover with a water-based lubricant, and then gently insert the probe 2–3 cm inside the rectal opening of an adult, or less depending on the size of the client. The device beeps when it is done.

What should the health care provider consider?

Measuring rectal temperature is an invasive method. Some suggest its use only when other methods are not available (OER #1), while others suggest that the rectal route is a gold standard in the infant population because of its accuracy. The Canadian Pediatric Society (Leduc & Woods, 2017) has referred to research indicating that rectal temperatures may remain elevated after a client’s core temperature has started to return to normal, but after reviewing all available evidence, still recommends measuring rectal temperature for children under the age of two, particularly when accuracy is vital. Rectal temperature is not measured in infants under one month of age or premature newborns.

Section Summary

Temperature is an important vital sign because it provides current data about the client’s health and illness state. Changes in body temperature act as a cue for health care providers’ diagnostic reasoning.

There are many ways to measure temperature. In determining the best method, the health care provider considers agency policy, the client’s age and health and illness state, and the reason for taking the temperature. Health care providers must use the correct technique when measuring temperature, because this can influence client data.

When determining the relevance of the temperature, the health care provider considers the client’s baseline data and the situation. Diagnostic reasoning about temperature always involves considering additional data including other vital sign measurements and subjective and objective client data.

Pulse and Respiration

What is Pulse?

Pulse refers to a pressure wave that expands and recoils the artery when the heart contracts, or beats. It is palpated at many points throughout the body. The most common locations to accurately assess pulse as part of vital sign measurement include radial, brachial, carotid, and apical pulse as shown in Figure 3.8. The techniques vary according to the location, as detailed later.

The heart pumps a volume of blood per contraction into the aorta. This volume is referred to as stroke volume. Age is one factor that influences stroke volume, which ranges from 5–80 mL from newborns to older adults.

Pulse is measured in beats per minute, and the normal adult pulse rate (heart rate) at rest is 60–100 beats per minute (OER #1, OER #2). Newborn resting heart rates range from 100–175 bpm. Heart rate gradually decreases until young adulthood and then gradually increases again with age (OER #2). A pregnant woman's heart rate is slightly higher than her value before pregnancy (about 15 beats). See Table 3.2 for normal heart rate ranges based on age.

Why is Pulse Measured?

Health care providers measure pulse because it provides information about a client’s state of health and influences diagnostic reasoning and clinical decision-making.

Tachycardia

Tachycardia refers to an elevated heart rate, typically above 100 bpm (OER #2) for an adult. Developmental considerations are important to consider, such as higher resting pulse rates in infants and children. For adults, tachycardia is not normal in a resting state but may be detected in pregnant women or individuals experiencing extreme stress (OER #2). Tachycardia can be benign, such as when the sympathetic nervous system is activated with exercise and stress. Caffeine intake and nicotine can also elevate the heart rate. Tachycardia is also correlated with fever, anemia, hypoxia, hyperthyroidism, hypersecretion of catecholamines, some cardiomyopathies, some disorders of the valves, and acute exposure to radiation (OER #2).

Bradycardia

Bradycardia is a condition in which the resting heart rate drops below 60 bpm (OER #2) in adults. In newborns, a resting heart rate below 100 bpm is considered bradycardia. However, a sleeping neonate’s pulse may be as low as 90 bpm. People who are physically fit (like trained athletes) typically have lower heart rates (OER #2). If the client is not exhibiting other symptoms, such as weakness, fatigue, dizziness, fainting, chest discomfort, palpitations, or respiratory distress, bradycardia is generally not considered clinically significant (OER #2). However, if any of these symptoms are present, this may indicate that the heart is not providing sufficient oxygenated blood to the tissues (OER #2). Bradycardia can be related to an electrical issue of the heart, ischemia, metabolic disorders, pathologies of the endocrine system, electrolyte imbalances, neurological disorders, prescription medications, and prolonged bed rest, among other conditions (OER #2). Bradycardia is also related to some medications, such as beta-blockers and digoxin.

What Pulse Qualities are Assessed?

The pulse rhythm, rate, force, and equality are assessed when palpating pulses.

Pulse Rhythm

The normal pulse rhythm is regular, meaning that the frequency of the pulsation felt by your fingers follows an even tempo with equal intervals between pulsations. If you compare this to music, it involves a constant beat that does not speed up or slow down, but stays at the same tempo. Thus, the interval between pulsations is the same. However, sinus arrhythmia is a common condition in children, adolescents, and young adults. Sinus arrhythmia involves an irregular pulse rhythm in which the pulse rate varies with the respiratory cycle: the heart rate increases at inspiration and decreases back to normal upon expiration. The underlying physiology of sinus arrhythmia is that the heart rate increases to compensate for the decreased stroke volume from the heart’s left side upon inspiration.

Pulse Rate

The pulse rate is counted by starting at one, which correlates with the first beat felt by your fingers. Count for thirty seconds if the rhythm is regular (even tempo) and multiply by two to report in beats per minute. Count for one minute if the rhythm is irregular. In children, pulse is counted for one minute considering that irregularities in rhythm are common.

Pulse Force

The pulse force is the strength of the pulsation felt when palpating the pulse. For example, when you feel a client’s pulse against your fingers, is it gentle? Can you barely feel it? Alternatively, is the pulsation very forceful and bounding into your fingertips? The force is important to assess because it reflects the volume of blood, the heart’s functioning and cardiac output, and the arteries’ elastic properties. Remember, stroke volume refers to the volume of blood pumped with each contraction of the heart (meaning each heart beat). Thus, pulse force provides an idea of how hard the heart has to work to pump blood out of the heart and through the circulatory system.

Pulse force is recorded using a four-point scale:

• 3+ Full, bounding
• 2+ Normal/strong
• 1+ Weak, diminished, thready
• 0 Absent/non-palpable

Practice on many people to become skilled in measuring pulse force. While learning, it is helpful to assess pulse force along with an expert because there is a subjective element to the scale. A 1+ force (weak and thready) may reflect a decreased stroke volume and can be associated with conditions such as heart failure, heat exhaustion, or hemorrhagic shock, among other conditions. A 3+ force (full and bounding) may reflect an increased stroke volume and can be associated with exercise and stress, as well as abnormal health states including fluid overload and high blood pressure.

Pulse Equality

Pulse equality refers to whether the pulse force is comparable on both sides of the body. For example, palpate the radial pulse on the right and left wrist at the same time and compare whether the pulse force is equal. Pulse equality is assessed because it provides data about conditions such as arterial obstructions and aortic coarctation. However, the carotid pulses should never be palpated at the same time as this can decrease and/or compromise cerebral blood flow.

Radial Pulse

Technique

Use the pads of your first three fingers to gently palpate the radial pulse (OER #1). The pads of the fingers are placed along the radius bone, which is on the lateral side of the wrist (the thumb side; the bone on the other side of the wrist is the ulnar bone). Place your fingers on the radius bone close to the flexor aspect of the wrist, where the wrist meets the hand and bends. See Figure 3.9 for correct placement of fingers. Press down with your fingers until you can best feel the pulsation. Note the rate, rhythm, force, and equality when measuring the radial pulse (OER #1).

Carotid Pulse

May be taken when radial pulse is not present or is difficult to palpate (OER #1).

Technique

Ask the client to sit upright. Locate the carotid artery medial to the sternomastoid muscle (between the muscle and the trachea at the level of the cricoid cartilage, which is in the middle third of the neck). With the pads of your three fingers, gently palpate the carotid artery, one at a time. See Figure 3.10 for correct placement of fingers.

What should the health care provider consider?

Although other pulses can be taken at the same time to assess equality, the carotid pulses are never taken at the same time. Gently palpate one artery at a time so that you do not stimulate the vagus nerve and compromise arterial blood flow to the brain. Avoid palpating the upper third of the neck, because this is where the carotid sinus area is located. You want to avoid pressure on the carotid sinus area because this can lead to vagal stimulation, which can slow the heart rate, particularly in older adults.

Brachial Pulse

Brachial pulse rate is indicated during some assessments, such as with children, in whom it can be difficult to feel the radial pulse. A Doppler can be used to locate the brachial pulse if needed.

Technique

The brachial pulse can be located by feeling the bicep tendon in the area of the antecubital fossa. Move the pads of your three fingers medial (about two cm) from the tendon and about 2–3 cm above the antecubital fossa to locate the pulse. See Figure 3.11 for correct placement of fingers along the brachial artery.

What should the health care provider consider?

It can be helpful to hyper-extend the arm in order to accentuate the brachial pulse so that you can better feel it. You may need to move your fingers around slightly to locate the best place to most accurately feel the pulse. You will usually need to press fairly firmly to palpate the brachial pulse.

Apical Pulse

Apical pulse is auscultated with a stethoscope over the chest where the heart’s mitral valve is best heard. In infants and young children, the apical pulse is located at the fourth intercostal space at the left midclavicular line. In adults, the apical pulse is located at the fifth intercostal space at the left midclavicular line (OER #1). See Figure 3.12 below.

Apical pulse rate is indicated during some assessments, such as when conducting a cardiovascular assessment and when a client is taking certain cardiac medications (such as digoxin) (OER #1). Sometimes the apical pulse is auscultated pre- and post-medication administration. It is also a best practice to assess apical pulse in infants and children up to five years of age because radial pulses are difficult to palpate and count in this population. It is typical to assess apical pulses in children younger than eighteen, particularly in hospital environments. Apical pulses may also be taken in obese people, because their peripheral pulses are sometimes difficult to palpate.

Technique

Position the client in a supine (lying flat) or in a seated position. Physically palpate the intercostal spaces to locate the landmark of the apical pulse. Ask the female client to reposition her own breast tissue to auscultate the apical pulse. For example, the client gently shifts the breast laterally so that the apical pulse landmark is exposed. Alternatively, the health care provider can use the ulnar side of the hand to reposition the breast tissue and auscultate the apical pulse. Ensure draping to protect the client’s privacy.

Either the bell or diaphragm are used to auscultate the client’s heart rate and rhythm. There is a pediatric-size stethoscope for infants. Typically, apical pulse rate is taken for a full minute to ensure accuracy; this is particularly important in infants and children due to the possible presence of sinus arrhythmia. In adults, if you are assessing the apical pulse due to an irregular rhythm then count for one minute. Upon auscultating the apical pulse, you will hear the sounds “lub dup”—this counts as one beat. Continue counting the apical pulse and note the rate and rhythm.

What is Respiration?

Respiration refers to a person’s breathing and the movement of air into and out of the lungs (OER #2). The respiratory system provides oxygen to body tissues for cellular respiration, removes the waste product carbon dioxide, and helps maintain acid–base balance (OER #2). Inspiration is the process that causes air to enter the lungs, and expiration is the process that causes air to leave the lungs (OER #2). A respiratory cycle (or one breath while you are measuring respiratory rate) is one sequence of inspiration and expiration (OER #2).

Respiration is assessed for quality, rhythm, and rate.

The quality of a person’s breathing is normally relaxed and silent. Health care providers assess use of accessory muscles in the neck and chest and indrawing of intercostal spaces (also referred to as intercostal tugging), which can indicate respiratory distress. Respiratory distress can also cause nasal flaring, and the person often moves into a tripod position. The tripod position involves leaning forward and placing arms/hands and/or upper body on one’s knees or on the bedside table.

Respiration normally has a regular rhythm. A regular rhythm means that the frequency of the respiration follows an even tempo with equal intervals between each respiration. If you compare this to music, it involves a constant beat that does not speed up or slow down, but stays at the same tempo.

Respiratory rates vary based on age. The normal resting respiratory rate for adults is 10–20 breaths per minute (OER #1). Children younger than one year normally have a respiratory rate of 30–60 breaths per minute, but by the age of ten, the normal rate is usually 18–30 (OER #2). By adolescence, the respiratory rate is usually similar to that of adults, 12–18 breaths per minute (OER #2). The normal respiratory rate for children decreases from birth to adolescence (OER #2). Respiratory rates often increase slightly over the age of sixty-five.

Estimated respiratory rates vary based on the source. Table 3.3 lists a generous range of normal respiratory rates based on age. It is important to consider the client and the situation to determine whether the respiratory rate is normal. Health care providers take into consideration the client’s health and illness state and determinants such as rest/sleep, awake/active, presence of pain, and crying when assessing the respiratory rate.

Technique

The respiratory rate is counted after taking the pulse rate so that the client is not aware that you are taking it (OER #1). Once you have finished counting the pulse, leave your fingers in place and then begin assessing respiration. Observe the chest or abdomen rise and fall. One respiration includes a full respiratory cycle (including both inspiration and expiration). Thus, the rise and the fall of the abdomen or chest is counted as one full breath. Count for 30 seconds if the rhythm is regular or for a full minute if irregular (OER #1). Report the respiration as breaths per minute, as well as whether breathing is relaxed, silent, and has a regular rhythm. Report whether chest movement is symmetrical.

What should the health care provider consider?

Assess the movement of the chest with adults, and the movement of the abdomen with newborns and infants. Adults are normally thoracic breathers (the chest moves) while infants are normally diaphragmatic breathers (the abdomen moves). Some adults are abdominal breathers. Breathing rates are counted for one minute with infants because the respiratory rhythm (tempo) can vary significantly. For example, the breathing rates of infants can speed up and slow down with some short periods of apnea (pauses in breathing).

When assessing respiration, ensure that thick and bulky clothing is removed so you can clearly see the rise and fall of the chest or abdomen. Although respiratory rates are best counted at rest, sometimes this is not possible (such as when in an emergency situation and with a child who is crying). In this case, document the situation. While assessing respirations, it is important to note signs of respiratory distress, which can include loud breathing, nasal flaring, and intercostal retractions. See Figure 3.13 for signs of respiratory distress. These signs require further assessment and intervention.

Section Summary

Measurement of pulse and respiration is important because these vital signs provide current data about the client’s health and illness state. Changes in pulse and respiration act as cues for health care providers’ diagnostic reasoning.

Pulse can be measured in many locations. When determining the best location, health care providers consider the client’s age and health and illness state, as well as the reason for taking the pulse.

When determining the relevance of pulse and respiration data, health care providers consider the client’s baseline data and the situation. Diagnostic reasoning about pulse and respiration always considers additional information, including other vital sign measurements and subjective and objective client data.

Oxygen Saturation

What is Oxygen Saturation?

Oxygen saturation refers to the percentage of hemoglobin molecules saturated with oxygen. Hemoglobin molecules can each carry four oxygen molecules; the oxygen binds or attaches to hemoglobin molecules. Oxygen saturation provides information about how much hemoglobin is carrying oxygen, compared to how much hemoglobin is not carrying oxygen.

Why is Oxygen Saturation Measured?

Health care providers measure oxygen saturation because it provides information about a client’s state of health. The body’s tissues and organs require oxygen for metabolism, and oxygen saturation can reveal whether there is sufficient oxygen in the blood or whether the client is in a state called hypoxemia (insufficient oxygen in the blood).

Oxygen saturation levels can influence clinical decisions about whether the client is receiving sufficient oxygen and/or requires supplemental oxygen. Oxygen saturation levels are also monitored during and after surgeries and treatments and to assess a client’s capacity for increased activity.

How is Oxygen Saturation Measured?

Oxygen saturation can be measured using a pulse oximetry device, which is a noninvasive method to measure arterial oxygen saturation level. See Figure 3.14 for a pulse oximeter. In critically-ill clients, a more invasive and continuous monitoring system is used to measure arterial blood gasses through an arterial line. An arterial line is a catheter that is inserted into an artery, usually the radial artery. It provides a way to access blood gasses including arterial oxygen saturation (SaO2). Here, we focus on pulse oximetry because it is identified as a vital sign.

A pulse oximetry device includes a sensor that measures light absorption of hemoglobin and represents arterial SpO2 (OER #1). Oxyhemoglobin and deoxygenated hemoglobin absorb light differently. The sensor measures “the relative amount of light absorbed by oxyhemoglobin and deoxygenated (reduced) hemoglobin” and compares the amount of “light emitted to light absorbed” (Jarvis, 2014, page 164). This comparison is then converted to a ratio and is expressed as a percentage of Sp02.

The sensor is attached using various devices. One is a spring-loaded clip attached to a finger or toe as shown in Figure 3.14. It is used when an intermittent measurement is required. However, this clip is too large for newborns and young children, so for this population, the sensor is taped to a finger or toe. This technique is also used for clients who require continuous monitoring.

An earlobe clip is another useful device for clients who cannot tolerate the finger or toe clip or have a condition that could affect the results, such as vasoconstriction and poor peripheral perfusion. Another type of device is taped across the forehead and left in place for continuous monitoring. See Figure 3.15.

What are Normal Oxygen Saturation Levels?

The acceptable oxygen saturation range is 97–100% (OER #1).

Older adults typically have lower oxygen saturation levels than younger adults. For example, someone older than 70 years of age may have an oxygen saturation level of about 95%, which is an acceptable level.

It is important to note that the oxygen saturation level varies considerably based on a person’s state of health. Thus, it is important to understand both baseline readings and underlying physiology associated with certain conditions to interpret oxygen saturation levels and changes in these levels.

• People who are obese and/or have conditions such as lung and cardiovascular diseases, emphysema, chronic obstructive pulmonary disease, congenital heart disease and sleep apnea tend to have lower oxygen saturation levels.
• Smoking can influence the accuracy of pulse oximetry in which the SpO2 is low or falsely high depending on whether hypercapnia is present. With hypercapnia, it is difficult for the pulse oximeter to differentiate oxygen in the blood from carbon monoxide (caused by smoking).
• Oxygen saturation levels may decrease slightly when a person is talking.
• Oxygen saturation may remain normal (97% and higher) for people with anemia. However, this may not indicate adequate oxygenation because there is less hemoglobin to carry an adequate supply of oxygen for people who have anemia. The inadequate supply of oxygen may be more prominent during activity for people with anemia.
• Falsely low oxygen saturation levels may be associated with hypothermia, decreased peripheral perfusion, and cold extremities. In these cases, an ear lobe pulse oximeter device or arterial blood gasses would provide a more accurate oxygen saturation level. However, arterial blood gasses are usually only taken in critical care or emergency settings.

Section Summary

Measuring oxygen saturation via pulse oximetry is a noninvasive way to quickly assess a client’s oxygen level. The results reflect a person’s oxygenation status and provide data for health care providers’ diagnostic reasoning.

The sensor can be attached in many ways, including clipping and taping probes to the finger, toe, earlobe, and forehead. The type and location of the apparatus is selected based on the client’s age, the presence of vasoconstriction, the adequacy of peripheral perfusion, whether intermittent or continuous monitoring is required, and the client’s health and illness state.

When determining the relevance of the oxygen saturation reading, health care providers consider the client’s health and wellness state. Specifically, they consider other data related to oxygenation including respiratory quality, rate, and rhythm; pulse; skin color and temperature; and the client’s subjective description of ease or difficulty breathing. Decreases in oxygen saturation readings are potentially life-threatening and require immediate intervention.

Blood Pressure

What is Blood Pressure?

Blood pressure is the force of blood exerted against the arterial walls, and is reported in millimeters of mercury (mm Hg). Try turning your kitchen tap on just a little bit, and then full blast. Compare the varying forces of water pressure as you adjust the tap. This comparison will give you a better sense of blood pressure.

The pressure against the arterial walls (the blood pressure) changes depending on whether the heart is contracting and pushing blood out into the arteries or whether the heart is in a resting phase and filling with blood. There is always force against the arterial walls, even when the heart is in a resting phase. The systolic pressure is the maximum pressure on the arteries during left ventricular contraction (systole) (OER #1). The left ventricle is a lower chamber of the heart responsible for pumping blood out to the body. The diastolic pressure is the resting pressure on the arteries between each cardiac contraction (OER #1) when the heart’s chambers are filling with blood (diastole).

Stroke volume is the amount of blood ejected from the left ventricle in a single contraction. Stroke volume provides information about the functioning of the heart. Stroke volume is influenced by age and typically ranges from 5–80 mL. Newborns have a stroke volume of about 5 mL per contraction while adults have a stroke volume of about 30–70 mL per contraction; the stroke volume increases as individuals grow and their hearts become stronger and can pump more volume per contraction. Direct measurement of stroke volume involves an invasive approach in which a catheter is passed into the pulmonary artery via a large neck vein; this monitoring device is only used during critical care situations.

Indirect measurement of stroke volume involves assessing the pulse pressure, which is the difference between the systolic and diastolic values and signifies the force required by the heart each time it contracts. For example, if someone’s blood pressure is 120/80 mm Hg, the pulse pressure is 40 mm Hg. A higher pulse pressure can indicate arterial stiffness, which often happens as a result of aging or cardiovascular disease. A higher pulse pressure can also be indicative of aortic valvular insufficiency where the diastolic pressure is unusually low and the systolic pressure is mildly elevated or unchanged. A lower pulse pressure can be a marker of poor heart function, where cardiac output is decreased.

Why is Blood Pressure Measured?

• A person’s blood pressure provides insight into the functioning of the body.
• Healthy body functioning is influenced by healthy blood pressure.
• The findings can provide information about the integrity of arteries and heart functioning, which can lead the health care provider to conduct additional assessments.
• High blood pressure can cause the arteries to become weak and damaged and cause the heart to become weak and enlarged.
• Low blood pressure can decrease perfusion of nutrients and oxygen to the body’s cells, influencing ability to function and potentially causing cellular death.
• Chronic high blood pressure can contribute to conditions such as vascular disease, myocardial infarction, cerebral stroke, kidney disease, and dementia.

Factors That Influence Blood Pressure

Five factors influence blood pressure:

1. Cardiac output
2. Peripheral vascular resistance
3. Volume of circulating blood
4. Viscosity of blood
5. Elasticity of vessel walls

Blood pressure increases with increased cardiac output, peripheral vascular resistance, volume of blood, viscosity of blood, and rigidity of vessel walls.

Blood pressure decreases with decreased cardiac output, peripheral vascular resistance, volume of blood, viscosity of blood, and elasticity of vessel walls.

Cardiac Output

Cardiac output is the volume of blood flow from the heart through the ventricles, and is usually measured in liters per minute (L/min). Cardiac output can be calculated by the stroke volume multiplied by the heart rate. Any factor that causes cardiac output to increase, by elevating heart rate or stroke volume or both, will elevate blood pressure and promote blood flow. These factors include sympathetic stimulation, the catecholamines epinephrine and norepinephrine, thyroid hormones, and increased calcium ion levels. Conversely, any factor that decreases cardiac output, by decreasing heart rate or stroke volume or both, will decrease arterial pressure and blood flow. These factors include parasympathetic stimulation, elevated or decreased potassium ion levels, decreased calcium levels, anoxia, and acidosis.

Peripheral Vascular Resistance

Peripheral vascular resistance refers to compliance, which is the ability of any compartment to expand to accommodate increased content. A metal pipe, for example, is not compliant, but a balloon is. The greater the compliance of an artery, the more effectively it can expand to accommodate surges in blood flow without increased resistance or blood pressure. Veins are more compliant than arteries and can expand to hold more blood. When vascular disease causes stiffening of arteries, which is called atherosclerosis or arteriosclerosis, compliance is reduced and resistance to blood flow is increased. The result is more turbulence, higher pressure within the vessel, and reduced blood flow. This increases the work of the heart.

Volume of Circulating Blood

Volume of circulating blood is the amount of blood moving through the body. Increased venous return stretches the walls of the atria where specialized baroreceptors are located. Baroreceptors are pressure-sensing receptors. As the atrial baroreceptors increase their rate of firing and stretch due to the increased blood pressure, the cardiac center responds by increasing sympathetic stimulation and inhibiting parasympathetic stimulation to increase heart rate. The opposite is also true.

Viscosity of Blood

Viscosity of blood is a measure of the blood’s thickness and is influenced by the presence of plasma proteins and formed elements in the blood. Blood is viscous and somewhat sticky to the touch. Its viscosity is approximately five times greater than water. Viscosity is a measure of a fluid’s thickness or resistance to flow, and is influenced by the presence of the plasma proteins and formed elements within the blood. The viscosity of blood has a dramatic effect on blood pressure and flow. Consider the difference in flow between water and honey. The more viscous honey would demonstrate a greater resistance to flow than the less viscous water. The same principle applies to blood.

Elasticity of Vessel Walls

Elasticity of vessel walls refers to the capacity to resume its normal shape after stretching and compressing. Vessels larger than 10 mm in diameter are typically elastic. Their abundant elastic fibers allow them to expand as blood pumped from the ventricles passes through them, and then to recoil after the surge has passed. If artery walls were rigid and unable to expand and recoil, their resistance to blood flow would greatly increase and blood pressure would rise to even higher levels, which would in turn require the heart to pump harder to increase the volume of blood expelled by each pump (the stroke volume) and maintain adequate pressure and flow. Artery walls would have to become even thicker in response to this increased pressure.

What are Blood Pressure Ranges?

Blood pressure is reported in mm Hg (pronounced millimetres of mercury), in which the systolic is the numerator and diastolic is the denominator. See Table 3.4 for an overview of estimated blood pressure ranges for healthy individuals.

Factors that influence blood pressure include age, sex, ethnicity, weight, exercise, emotions/stress, pregnancy, and diurnal rhythm as well as medication use and disease processes.

• The general pattern is that blood pressure rises with age, so normal variations tend to be higher for older adults.
• Blood pressure is similar in childhood for males and females. After puberty, females have lower blood pressure than males, whereas after menopause females have higher blood pressure than males.
• Research has revealed that ethnicity may be a predictor of blood pressure, but this causation is not necessarily biological, but rather sociocultural. When determining risk for high blood pressure, it is important to consider ethnicity as a contributing factor.
• The diurnal cycle influences blood pressure to be lower in the morning and increase throughout the day until early evening. Try it out: take your blood pressure when you wake up in the morning and then again in late afternoon, and note the difference. This is one reason why health care providers document the time a client’s blood pressure is taken.
• Blood pressure can be higher in people who are obese because the heart has to work harder to perfuse the body’s tissues.
• The sympathetic nervous system is stimulated by exercise, stress, anxiety, pain, anger, and fear, which increases blood pressure. Blood pressure returns to baseline within five minutes of rest following activity. Try it out. Have a peer take your blood pressure. Then, run on the spot or do some other cardiac activity for five minutes. Have the peer take your blood pressure again, and then lie down and rest for five minutes. Take the blood pressure again. Note the changes.
• Blood pressure varies throughout the duration of pregnancy. It decreases about halfway through the first trimester until mid-pregnancy due to progesterone effects that relax the walls of blood vessels, causing decreased peripheral vascular resistance. It returns to pre-pregnancy values toward the end of pregnancy.

How is Blood Pressure Measured?

Blood pressure is measured in many ways including manual/auscultatory, automatic/electronic, cellular phone applications, and arterial catheters. Whatever method is used, blood pressure must be measured using validated equipment. It has been found that blood pressure is often not measured accurately in clinical practice, particularly when using the auscultatory/manual method. It is important to ensure correct technique to obtain an accurate measurement. Hypertension Canada (2020) recommends electronic blood pressure measurement as the preferred method in clinical practice.

Client Positioning

Blood pressure is generally taken in a sitting or supine position with the bare arm at heart level (OER #1). Certain health states prevent some clients from sitting, such as clients who are critically ill, unstable, or postoperative. Thus, health care providers document the client’s positioning (whether they are sitting, supine, or standing). If sitting, the feet are placed flat on the floor with the back resting comfortably against a chair. The health care provider checks to ensure that the client’s legs are not crossed, because this can increase blood pressure. The client sits resting for five minutes before you take the blood pressure. This waiting period is not feasible when the client’s condition is deteriorating or a STAT blood pressure is required. Because the client should be resting, you should ask them not to talk or move. Additionally, you should not ask them to hold any of your equipment during the blood pressure measurement.

Cuff Types and Sizes

Manual and automatic blood pressure measurement involves using a blood pressure cuff with a sphygmomanometer. Many cuff sizes are available to fit newborns, children, adults, people with smaller and larger arms, and people with cone-shaped arms. The cuff is typically wrapped around the upper arm. However, there is also a cuff that can be placed on the thigh when the arm is not feasible. See Figure 3.16 of varying blood pressure cuff sizes. Wrist devices can be used for blood pressure estimation when clients have a large upper arm circumference (Nerenberg, 2018). When taking the measurement, make sure that the arm and wrist are supported at heart level (Nerenberg, 2018).

It is important to choose a cuff size that matches the client’s arm size, rather than their age. See Table 3.5 about cuff sizing.

Manual Blood Pressure Measurement

A health care provider uses a stethoscope and a blood pressure cuff with a sphygmomanometer to measure blood pressure manually. The stethoscope is used to listen to the blood pressure sounds, which are called Korotkoff sounds.

Stethoscope Usage and Korotkoff Sounds

The stethoscope is used on bare skin so that a client’s clothing does not affect the sounds. The stethoscope does not make sounds louder; it simply blocks out extraneous noises so you can better hear the Korotkoff sounds. These sounds are heard through a stethoscope applied over the brachial artery when the blood pressure cuff is deflating. You will not hear anything when you first place the stethoscope over the brachial artery because unobstructed blood flow is silent. The Korotkoff sounds appear after you inflate the cuff (which compresses the artery and blood flow) and then begin to deflate the cuff. The Korotkoff sounds are the result of the turbulent blood caused by the inflated cuff compressing the artery and oscillations of the arterial wall when the heart beats during cuff deflation.

Here are a few tips:

• Use a high quality stethoscope with durable, thick tubing. Avoid stethoscopes with long tubing because this can distort sounds.
• Ensure quiet surroundings so that you can better hear the Korotkoff sounds.
• Make sure that the slope of the stethoscope earpieces point forward or toward your nose.
• Use a stethoscope that has both bell and diaphragm capacity. See Figure 3.17 for bell and diaphragm.

• Clean the stethoscope prior to use including the ear pieces and the bell and diaphragm.
• The bell of the stethoscope is suggested because it is used for low-pitched sounds like blood pressure. However, some health care providers use the diaphragm for several reasons: that is how they learned to take blood pressure; they believe this helps them hear the Korotkoff sounds better; and the diaphragm covers a larger surface area than the bell.
• Hold the bell lightly against the skin with a complete seal or hold the diaphragm firmly against the skin with a complete seal.
• You must ensure that the bell or diaphragm is open before using. 

Determining Maximum Inflation Pressure

Health care providers determine the maximum inflation pressure before they take blood pressure. The maximum inflation pressure is the number on the sphygmomanometer that the cuff is inflated to when measuring blood pressure. If you do not determine the maximum pressure inflation, an auscultatory gap could go unrecognized, and as a result the blood pressure could be underestimated (lower than the actual value).

An auscultatory gap is a silent interval when the Korotkoff sounds go absent and then reappear while you are deflating the cuff during blood pressure measurement. This gap is an abnormal finding and can occur due to arterial stiffness and arteriosclerotic disease. It is typically observed in people with a history of hypertension who have been treated with prolonged antihypertensive medication.

To determine the maximum inflation pressure, start by palpating the brachial or radial pulse while inflating the cuff. Inflate the cuff 30 mm Hg quickly past the point when you obliterate the pulse (meaning you no longer feel the pulse). If you still cannot feel the pulse, use that value to start auscultating—that value is the maximum inflation pressure number.

When taking blood pressure, if an auscultatory gap is observed, document the first systolic sound and diastolic sound only. Report the presence of an auscultatory gap in narrative notes.

Blood Pressure Measurement Techniques

For beginners, it is a good idea to start with the two-step technique and then move onto the one-step technique as you develop your skills.

Two-step technique

First step: Determining maximum pressure inflation

Palpate the radial or brachial artery, inflate the blood pressure cuff until the pulse is obliterated, and then inflate 30 mm Hg more (OER #1). Note that this number is considered the maximum pressure inflation. Next, deflate the cuff quickly.

Second step: Measure blood pressure

Now, you can start to measure blood pressure. Place the bell of the cleaned stethoscope over the brachial artery (OER #1) using a light touch and complete seal. Inflate the cuff to the maximum pressure inflation number (OER #1). Open the valve slightly. Deflate the cuff slowly and evenly (OER #1) at about 2 mm Hg per second.

Note the points at which you hear the first appearance of Korotkoff sounds (systolic blood pressure) (OER #1) and the point at which the Korotkoff sounds go silent (diastolic blood pressure) (Hypertension Canada, 2020). These sounds are called Korotkoff sounds and vary in quality from tapping, swooshing, muffled sounds, and silence. The pressure at which the first Korotkoff sound is noted signifies the systolic pressure, while the pressure at which the Korotkoff sounds are no longer heard marks the diastolic pressure.

What Should the Health Care Provider Consider?

Manual blood pressure is reported in even numbers. Health care providers always measure blood pressure with pulse because these vital signs are closely related. Data from both are needed to make accurate and informed clinical decisions.

What Should You Do if You Cannot Feel the Brachial Pulse?

• To locate the brachial pulse, palpate the bicep tendon, move medially about 2 cm, and move up about 2–3 cm.
• Use three fingers including your index and middle finger to feel for the pulse.
• You will usually need to press fairly firmly to palpate the brachial pulse and may need to modify the pressure. If you press too hard, you will obliterate the pulse (make it disappear) and if you press too lightly, you will not be able to feel the pulse.
• You may need to reposition your fingers to find the best place to feel the pulse along the brachial artery.
• Place the client’s arm with the palm up and elbow extended. You can flex the elbow in varying degrees to relax the muscle and accentuate the pulse.
• Cup your opposite hand under the client’s elbow.

What Should You Do if You Cannot Hear the Korotkoff Sounds?

• Use your bell and make full contact with skin.
• Make sure the bell is positioned over the brachial artery.
• Ensure the room is quiet.
• Concentrate on expected sounds (swooshing, tapping, muffled sounds).
• Try different earbuds (hard or soft) on your stethoscope.

Common Errors When Taking Blood Pressure

Many errors must be avoided when measuring blood pressure, including the following:

• Failure to determine maximum pressure inflation can produce a falsely low systolic reading.
• Deflating the cuff too slowly can produce a falsely high diastolic, and deflating the cuff too quickly can produce a falsely low systolic or falsely high diastolic reading.
• Inaccurate cuff sizes for the client’s arm size and shape can result in measurement error: a cuff that is too narrow can produce a falsely high blood pressure whereas a cuff that is too loose can produce a falsely low blood pressure.
• A falsely low blood pressure can result from the arm being positioned above the level of the heart and a falsely high blood pressure can result from the arm being positioned below the level of the heart.

Hypotension

A number of factors can cause hypotension (low blood pressure). Hypotension is considered less than 95/60 mm Hg in a normotensive adult. However, low blood pressure measurements are always interpreted in the context of a client’s baseline and past blood pressure readings as well as their current health state. Common symptoms associated with hypotension are lightheadedness, loss of consciousness, blurry vision, clammy skin, and fatigue.

Orthostatic Hypotension

Orthostatic hypotension is a drop in blood pressure when the client moves from lying to sitting to a standing position.

Have you ever stood up quickly and felt dizzy for a moment? This is because, for one reason or another, blood is not getting to your brain, so it is briefly deprived of oxygen. When you change position from sitting or lying down to standing, your cardiovascular system has to adjust for a new challenge, keeping blood pumping up into the head while gravity is pulling more and more blood down into the legs. The reason for this is a sympathetic reflex that maintains the output of the heart in response to postural change. This sympathetic reflex keeps the brain well oxygenated so that cognitive and other neural processes are not interrupted. Sometimes this does not work properly. If the sympathetic system cannot increase cardiac output, then blood pressure into the brain will decrease, and a brief neurological loss can be felt. This can be brief, such as a slight ‘dizziness’ when standing up too quickly, or could lead to a loss of balance and neurological impairment for a period of time. The name for this is orthostatic hypotension, which means that blood pressure falls below the homeostatic set point when standing. It can be the result of standing up faster than the reflex can occur, which may cause a benign ‘head rush,’ or it may be the result of an underlying cause.

There are two basic reasons why orthostatic hypotension occurs. First, blood volume is too low and the sympathetic reflex is not effective. This hypovolemia may be the result of dehydration or medications that affect fluid balance, such as diuretics or vasodilators. The second underlying cause of orthostatic hypotension is autonomic failure. Several disorders can result in compromised sympathetic functions, ranging from diabetes to multiple system atrophy (a loss of control over many systems in the body), and addressing the underlying condition can improve the hypotension. Orthostatic hypotension is more common with advancing age and can be aggravated by antihypertensive medications.

How to Assess Orthostatic Hypotension

Orthostatic hypotension is assessed by measuring orthostatic or postural blood pressure and pulse changes. This procedure is done by assessing when the client moves from supine to sitting to standing. There are variations in how this procedure is done in terms of timing. Here is a common way to proceed:

1. The client rests supine for three minutes.
2. Take blood pressure and pulse in supine position.
3. The client sits up with feet dangling.
4. Take blood pressure and pulse within two minutes of position change.
5. The client stands up.
6. Take blood pressure and pulse within two minutes of position change.

How to Evaluate the Findings 

Normal variation is a 10 mm Hg decrease in blood pressure from lying to standing and an increase in pulse of 10–15 bpm.

A decrease in blood pressure from lying to standing of systolic ≥ 20 mm Hg or diastolic ≥ 10 mm Hg is identified as orthostatic hypotension.

An increase in pulse from lying to standing of ≥ 20 bpm is identified as an orthostatic pulse.

Hypertension

Chronically elevated blood pressure is known clinically as hypertension. It is defined as chronic and persistent blood pressure measurements of 140/90 mm Hg or above (OER #2) in the average adult. However, the specific measurement in which hypertension is diagnosed depends on many factors. As per Hypertension Canada (Nerenberg, et al., 2018), some of these factors include whether it is the first or second visit to have blood pressure assessed and whether the blood pressure is assessed using automatic or manual measurement devices. It is always important to look at the most current guidelines related to hypertension. 

Hypertension is typically a silent disorder, so hypertensive clients may not recognize the seriousness of their condition and may decide not to follow their treatment plan. The result is often a heart attack or stroke. Hypertension may also lead to an aneurysm (ballooning of a blood vessel caused by a weakening of the wall), peripheral arterial disease (obstruction of vessels in peripheral regions of the body), chronic kidney disease, or heart failure. (OER #2)

Common errors in measurement and natural fluctuations in blood pressure can result in readings that erroneously suggest hypertension. Some of the errors are due to the operator (the health care provider) and others are due to client anxiety and situational determinants. As a health care provider, it is important to review your technique to assess possible measurement errors and assess the client for factors that could elevate blood pressure. If the client’s blood pressure is elevated, repeat the measurement for accuracy and take the blood pressure in the opposite arm.

Because hypertension is a silent disorder, health care providers measure blood pressure at regular intervals. The intervals depend on the client’s health status and risk factors. Before a diagnosis of hypertension is made, blood pressure is monitored over days, weeks, or months either in the office using an automatic blood pressure machine or at home using an ambulatory blood pressure machine.

Clients demonstrating features of a hypertensive urgency or emergency (such as hypertensive encephalopathy, acute coronary syndrome, acute ischemic stroke, intracranial hemorrhage) are diagnosed as hypertensive and treated immediately.

Guidelines to Determine Hypertension

Hypertension Canada (Leung, et al., for Hypertension Canada, 2017) states that when assessing chronic high blood pressure, readings must be done under the following conditions:

• No acute anxiety, stress, or pain

• No caffeine, smoking, or nicotine in the preceding 30 minutes

• No use of substances containing adrenergic stimulants such as phenylephrine or pseudoephedrine (may be present in nasal decongestants or ophthalmic drops)

• Bladder and bowel comfortable

• No tight clothing on arm or forearm

• Quiet room with comfortable temperature

• Rest for at least five minutes before measurement

• Ask the client to stay silent prior and during the procedure

Section Summary

Blood pressure measurement is important because it provides objective data about the client’s health and illness state. Changes in blood pressure act as a cue for health care providers’ diagnostic reasoning. Blood pressure fluctuates with internal and external factors. Therefore, it is important to take more than one measurement before making clinical decisions.

It is always important to ensure correct techniques when taking blood pressure.

In determining the relevance of the blood pressure reading, the health care provider considers the client’s baseline blood pressure, previous readings, and health status. The blood pressure reading is always taken at the same time as a pulse. Diagnostic reasoning takes into account blood pressure, pulse, and subjective and objective client data.

Nursing Process

The nursing process is a critical thinking model based on a systematic approach to patient-centered care. Nurses use the nursing process to perform clinical reasoning and make clinical judgments when providing patient care. The nursing process is based on the Standards of Professional Nursing Practice established by the American Nurses Association (ANA). These standards are authoritative statements of the actions and behaviors that all registered nurses, regardless of role, population, specialty, and setting, are expected to perform competently.[8] The mnemonic ADOPIE is an easy way to remember the ANA Standards and the nursing process. Each letter refers to the six components of the nursing process: Assessment, Diagnosis, Outcomes Identification, Planning, Implementation, and Evaluation.

The nursing process is a continuous, cyclic process that is constantly adapting to the patient’s current health status. See Figure 3.20[9] for an illustration of the nursing process.

The ANA’s Standards of Professional Nursing Practice associated with each component of the nursing process are described below.

Assessment

Assessment is the first step of the nursing process (and the first Standard of Practice set by the American Nurses Association). This standard is defined as, “The registered nurse collects pertinent data and information relative to the health care consumer’s health or the situation.” This includes collecting “pertinent data related to the health and quality of life in a systematic, ongoing manner, with compassion and respect for the wholeness, inherent dignity, worth, and unique attributes of every person, including but not limited to, demographics, environmental and occupational exposures, social determinants of health, health disparities, physical, functional, psychosocial, emotional, cognitive, spiritual/transpersonal, sexual, sociocultural, age-related, environmental, and lifestyle/economic assessments.”

Nurses assess patients to gather clues, make generalizations, and diagnose human responses to health conditions and life processes. Patient data is considered either subjective (from the patient) or objective (data collected), and it can be collected from multiple sources. Secondary data is collected by any other person than the patient or from charts.

Diagnosis

Diagnosis is the second step of the nursing process (and the second Standard of Practice set by the American Nurses Association). This standard is defined as, “The registered nurse analyzes assessment data to determine actual or potential diagnoses, problems, and issues.” The RN “prioritizes diagnoses, problems, and issues based on mutually established goals to meet the needs of the health care consumer across the health–illness continuum and the care continuum.” Diagnoses, problems, strengths, and issues are documented in a manner that facilitates the development of expected outcomes and a collaborative plan.

Planning

Planning is the fourth step of the nursing process (and the fourth Standard of Practice set by the American Nurses Association). This standard is defined as follows: “The registered nurse develops a collaborative plan encompassing strategies to achieve expected outcomes.” The RN develops an individualized, holistic, evidence-based plan in partnership with the health care consumer, family, significant others, and interprofessional team. Elements of the plan are prioritized. The plan is modified according to the ongoing assessment of the health care consumer’s response and other indicators. The plan is documented using standardized language or terminology.

After expected outcomes are identified, the nurse begins planning nursing interventions to implement. Nursing interventions are evidence-based actions that the nurse performs to achieve patient outcomes. Just as a provider makes medical diagnoses and writes prescriptions to improve the patient’s medical condition, a nurse formulates nursing diagnoses and plans nursing interventions to resolve patient problems. Nursing interventions should focus on eliminating or reducing the related factors (etiology) of the nursing diagnoses when possible. Nursing interventions, goals, and expected outcomes are written in the nursing care plan for continuity of care across shifts, nurses, and health professionals.

Implementation of Interventions

Implementation is the fifth step of the nursing process (and the fifth Standard of Practice set by the American Nurses Association). This standard is defined as follows: “The registered nurse implements the identified plan.” The RN may delegate planned interventions after considering the circumstance, person, task, communication, supervision, and evaluation, as well as the state Nurse Practice Act, federal regulation, and agency policy.

Implementation of interventions requires the RN to use critical thinking and clinical judgment. After the initial plan of care is developed, continual reassessment of the patient is necessary to detect any changes in the patient’s condition requiring modification of the plan. The need for continual patient reassessment underscores the dynamic nature of the nursing process and is crucial to providing safe care.

During the implementation phase of the nursing process, the nurse prioritizes planned interventions, assesses patient safety while implementing interventions, delegates interventions as appropriate, and documents interventions performed.

Evaluation

Evaluation is the sixth step of the nursing process (and the sixth Standard of Practice set by the American Nurses Association). This standard is defined as follows: “The registered nurse evaluates progress toward attainment of goals and outcomes.” Both the patient status and the effectiveness of the nursing care must be continuously evaluated and the care plan modified as needed.

Evaluation focuses on the effectiveness of the nursing interventions by reviewing the expected outcomes to determine if they were met by the time frames indicated. During the evaluation phase, nurses use critical thinking to analyze reassessment data and determine if a patient’s expected outcomes have been met, partially met, or not met by the time frames established. If outcomes are not met or only partially met by the time frame indicated, the care plan should be revised. Reassessment should occur every time the nurse interacts with a patient, discusses the care plan with others on the interprofessional team, or reviews updated laboratory or diagnostic test results. Nursing care plans should be updated as higher priority goals emerge. The results of the evaluation must be documented in the patient’s medical record.

Ideally, when the planned interventions are implemented, the patient will respond positively and the expected outcomes are achieved. However, when interventions do not assist in progressing the patient toward the expected outcomes, the nursing care plan must be revised to more effectively address the needs of the patient. These questions can be used as a guide when revising the nursing care plan:

• Did anything unanticipated occur?
• Has the patient’s condition changed?
• Were the expected outcomes and their time frames realistic?
• Are the nursing diagnoses accurate for this patient at this time?
• Are the planned interventions appropriately focused on supporting outcome attainment?
• What barriers were experienced as interventions were implemented?
• Does ongoing assessment data indicate the need to revise diagnoses, outcome criteria, planned interventions, or implementation strategies?
• Are different interventions required?

Benefits of Using the Nursing Process

Using the nursing process has many benefits for nurses, patients, and other members of the health care team. The benefits of using the nursing process include the following:

• Promotes quality patient care
• Decreases omissions and duplications
• Provides a guide for all staff involved to provide consistent and responsive care
• Encourages collaborative management of a patient’s health care problems
• Improves patient safety
• Improves patient satisfaction
• Identifies a patient’s goals and strategies to attain them
• Increases the likelihood of achieving positive patient outcomes
• Saves time, energy, and frustration by creating a care plan or path to follow

By using these components of the nursing process as a critical thinking model, nurses plan interventions that are customized to the patient’s needs, plan outcomes and interventions, and determine whether those actions are effective in meeting the patient’s needs. In the remaining sections of this chapter, we will take an in-depth look at each of these components of the nursing process. Using the nursing process and implementing evidence-based practices are referred to as the “science of nursing.” Let’s review concepts related to the “art of nursing” while providing holistic care in a caring manner using the nursing process.

Section Summary

You have now learned how to perform each step of the nursing process according to the ANA Standards of Professional Nursing Practice. Critical thinking, clinical reasoning, and clinical judgment are used when assessing the patient, creating a nursing care plan, and implementing interventions. Frequent reassessment, with revisions to the care plan as needed, is important to help the patient achieve expected outcomes. Throughout the entire nursing process, the patient always remains the cornerstone of nursing care. Providing individualized, patient-centered care and evaluating whether that care has been successful in achieving patient outcomes are essential for providing safe, professional nursing practice.