Chapter 10: Vital Signs

Vital Signs

Include temperature, respiratory rate, pulse, and blood pressure (bp)

Mechanism of temperature regulation

• Cellular metabolism requires stable core, or “deep body”

• Feedback mechanism regulated by the hypothalamus

• Balance heat production with heat loss

• Various routes of temperature measurement reflect body’s core temperature

Mean temperature of core

37 C at rest.

What is considered the thermostat of the body?

Hypothalamus

Normal temperature is influenced by

• Diurnal cycle

• Menstruation cycle

• Exercise

• Age

How does the diurnal cycle affect normal temperature?

Causes 1° F to 1.5° F, with trough occurring in

early morning hours and peaks occurring in late

afternoon to early evening

How does the menstruation cycle affect normal temperature?

progesterone secretion, occurring with ovulation at midcycle, causes a 0.5° F to 1.0° F rise in temperature that continues until menses

How does age affect normal temperature?

Wider normal variations occur in infant and young child due to less effective heat control mechanisms; in older adults, temperature usually lower than in other age groups, with a mean of 36.2° C (97.2° F) via oral route

How does exercise/physical activity affect normal temperature?

Normal temperature variations are wider in infants and young children because

They have less effective/underdeveloped heat control mechanisms

In older adults, temperature is usually higher. True or false?

False.

Mean normal temperature in older adults via oral route

36.2 C (97.2 F)

Which temperature reading route is the most accurate

Rectal

Why is oral temperature accurate to take?

Oral sublingual site has rich blood supply from carotid arteries that quickly responds to changes in inner core temeprature

Normal oral temperature in a resting person

37° C (98.6° F), with a range of 35.8° C to 37.3° C (96.4° F to 99.1° F)

Rectal temperature mean

Rectal measures 0.4° C to 0.5° C (0.7° F to 1° F) higher

Where should the mercury-free glass thermometer be placed in a oral temperature procedure>

Place down to 35.5° C (96° F) and place it at base of tongue in either of posterior sublingual pockets; not in front of tongue.

What should you tell the patient when you are conducting an oral temp reading?

Keep their mouth closed

How long to keep oral thermometer in person’s mouth if afebrile?

3-4 minutes

How long to keep oral thermometer in person’s mouth if febrile?

Up to 8 minutes; take other vital signs during this time.

How long should you wait to take oral temp if person has just taken hot or iced liquids?

15 min

How long should you wait to take oral temps if patient has just smoked?

2 min

When should rectal temperature be taken?

Only when other routes are not practical due to clinical presentation.

Which temperature reading route is the most convenient and accurate?

Oral

Rectal temperature procedure

Wear gloves and insert lubricated rectal probe (red-tipped) cover on an electronic thermometer only 2 to 3 cm (1 in) into adult rectum, directed toward umbilicus.

When measuring rectal temperature with a glass thermometer, leave it in place for ______ minutes.

2 1/2

What are the disadvantages to the rectal temp route?

Patient discomfort, time consuming, and disruptive nature of activity

Tympanic membrane temperature procedure

Gently place covered probe tip in person’s ear canal; temperature can be read in 2 to 3 seconds. Put patient into Pinna positioning → up and back for adult or straight; down for a child under 3 → straighten ear canal

Tympanic Membrane Thermometer (TMT)

Senses infrared emissions of tympanic membrane (eardrum)

What is the vascular supply that both the tympanic membrane and hypothalamus share?

Internal carotid artery

Temporal Artery Thermometer (TAT)

Senses infrared emissions from temporal artery. Takes multiple readings and produces average result. Reports temps in F and C

How long does TAT reading take?

Approximately 6 sec

How long does TMT reading take?

2-3 sec

Pulse

Palpable flow felt in the periphery as a result of pressure wave generation from stroke volume Provides indicator of rate and rhythm of heartbeat as well as local data on condition of artery.

If rhythm is regular

Count number of beats in 30 seconds and

multiply by 2.

The 30-second interval is most accurate and efficient when heart rates are normal or rapid and when rhythms are regular. True or false?

True.

For irregular pulse

Count for a full minute

Pulse is assessed for

Rate, rhythm, force, and elasticity.

Current research indicates that normal heart rate in resting adult is

50-95 beats/min (bpm)

Heart rate varies with

Age and gender

Heart rate is more moderate in infancy and childhood and more rapid during adult and later years. True or false?

False.

In an adult, heart rate of less than 50 bpm is classified as

Bradycardia

After puberty, females have slightly slower heart rate than males. True or false?

False.

In well-trained athletes whose heart muscle develops along with skeletal muscles, bradycardia is normal. True or false?

True.

A more rapid heart rate, over 95 bpm is classified as?

Tachycardia

Stronger, more efficient heart muscle results in

Heart pushing out a larger stroke volume with each beat, thus requiring fewer beats per minute to maintain a stable cardiac output.

Tachycardia occurs normally with

Anxiety or with increased exercise to match body’s demand for increased metabolism

Normal pulse rhythm

Has regular, even tempo

Sinus arrhythmia

One irregularity commonly found in children and young adults. The heart rate varies with the respiratory cycle, speeding up at the peak of inspiration and slowing to normal with expiration. Inspiration momentarily causes a decreased stroke volume from the left side of the heart. To compensate, the heart rate increases. Sign of good cardiovascular health.

What do you do if any other irregularities are felt?

Auscultate heart sounds for a more complete assessment.

Force of pulse indicates

Strength of heart’s stroke volume

Weak, thready pulse reflects

A decreased stroke volume (e.g. as occurs with hemorrhagic shock)

Full, bounding pulse denotes

Increased stroke volume, as with anxiety, exercise, and some abnormal conditions.

3+

Full, bounding pulse

2+

Normal pulse

1+

Weak, thready pulse

0

Absent pulse

Do not mention to patient you will be counting respirations because

Most people are unaware of their breathing; sudden awareness may alter normal pattern. Instead, maintain your position of counting radial pulse and unobtrusively count respirations.

Count for ______ seconds for respirations, or a full _______ if you suspect an abnormality

30; minute

Average rate healthy adult

20 breaths/min; range 16 to 25 breaths/min

Normally exercise or anxiety increases

Pulse and respiratory rate

Blood pressure (BP)

Is force of blood pushing against side of its container, vessel wall

Systolic pressure

Measurement of the pressure of the blood in the arteries when the ventricles are contracted

Diastolic pressure

Measurement of the pressure of the blood in the arteries when the ventricles are relaxed.

Pulse pressure

Difference between systolic and diastolic; reflects stroke volume

Mean arterial pressure (MAP)

Pressure forcing blood into tissues, averaged over cardiac cycle

Average BP varies with

Age, sex, race, social determinants, diurnal rhythm, weight, exercise, emotions, stress

How does age affect BP?

Gradual rise into childhood and into adult years

How does sex affect BP?

After puberty, females show a lower BP than males; after menopause, females higher than males

How does race affect BP

Differences exist relative to combination of genetics and environment

How do social determinants affect BP

Effects of environment & social factors lead to increased risk of hypertension (HTN)

How does diurnal rhythm affect BP

Daily peak and trough levels r/t timing cycles

How does weight affect BP?

Obesity increases blood pressure as compared to normal weight recorded measurements of same age

How does exercise affect BP?

Will cause a transitory (short-lasting) increase in blood pressure

How do emotions affect BP?

Will increase in response to sympathetic nervous system response

How does stress affect BP?

Will increase in response to increased stress and tension

What are the 5 factors that determine BP level?

• Cardiac output (CO)

• Peripheral vascular resistance

• Volume of circulating blood

• Viscosity

• Elasticity of vessel walls

How does CO affect BP?

Increase in CO leads to increase in BP whereas decrease in CO leads to decrease in BP

How does peripheral vascular resistance affect BP?

Increased resistance (vasoconstriction) leads to increase in BP whereas decrease in resistance(vasodilation) leads to decrease in BP

How does the volume of circulating blood affect BP

Fluid retention leads to increased BP whereas hemorrhages leads to decreased BP

An increase in viscosity is associated with a decrease in BP. True or false?

False.

How does elasticity of vessel walls affect BP?

Increasing rigidity (usually with age) is associated with increase in BP

What measures BP?

Stethoscope and sphygmomanometer

Why must the aneroid gauge be recalibrated at least once a year and must rest at zero?

Because it is subject to drift

Width of rubber bladder should equal ______% of circumference of person’s arm; length of bladder should equal ______% of this circumference.

40; 80-100

During arm pressure procedure, how should the patient be oriented?

Person may be sitting or lying, with bare arm supported at heart level; feet must be flat on floor if sitting (crossing legs increase BP)

In arm pressure procedure, palpate the

Brachial artery; center it around 1 in above the brachial artery evenly. Then palpate either the radial or brachial artery and start procedure

When should you stop inflating the cuff?

Until artery pulsation is obliterated, and then beyond 20-30 mm Hg. This is to avoid missing an auscultatory gap, when Korotkoff sounds disappears during auscultation

For all age-groups, is now used to define diastolic pressure.

Fifth Korotkoff sound; silence

What should you detect a variance greater than 10 to 12 mm Hg between phases IV and V?

Record both phases along with systolic reading

What errors lead to high BP readings?

• Taken when physiologically active (following activity or emotionally liable)

• Narrow cuff size/applied too loose

• Reinflating during procedure

What errors lead to low BP readings?

• Decreased inflation

• Too large cuff size

Examiner observer error leading to high/low readings

• Position of arm/leg

• Improper cuff size

• Deflating cuff too quickly

Take serial measurements of pulse and blood pressure in the following situations:

 You suspect volume depletion.

 Person is known to have hypertension or taking antihypertensive medications.

 Person reports fainting or syncope.

 Position changed from supine to standing, normally slight decrease (less than 10 mm Hg) in systolic pressure may occur.

Orthostatic hypotension

Steep drop in BP (SP drops greater than 20 mm Hg; DP drops greater than 10 mm Hg) when standing from a lying/sitting position

When do orthostatic changes occur?

With prolonged bed rest, older age, hypovolemia, and some medications.

When is thigh BP measured?

When BP measured at arm is excessively high, compare it with thigh pressure to check for coarctation of aorta (congenital form of narrowing).

Where is coarctation of the aorta typically seen?

Adolescents and young adults

Normally, thigh pressure is higher than arm. True or false?

True.

Where is cuff centered for thigh pressure procedure?

Low third of thigh, centered over popliteal artery on back of knee. Auscultate popliteal artery for reading.