vitals review

What is the primary source of heat production in the body?

Metabolism.

What increases heat production?

Hormones, muscle movement/exercise, epinephrine, norepinephrine, thyroid hormone, and shivering.

How does exercise increase body heat?

Muscle movement increases metabolism, which increases heat production.

How does shivering increase body heat?

Muscle tremors increase metabolic activity and produce heat.

How do epinephrine and norepinephrine affect heat production?

They rapidly alter metabolism when additional heat is needed, increasing heat production.

How does thyroid hormone affect heat production?

It increases metabolism and therefore increases heat production over a longer period.

What controls body temperature?

The thermoregulatory center in the hypothalamus.

How does the hypothalamus regulate temperature?

It compares information from warm and cold receptors with its set point, then causes the body to produce/conserve heat or increase heat loss.

What is the primary site of heat loss?

The skin.

What are the other sources of heat loss?

Evaporation of sweat, warming/humidifying inspired air, and elimination of urine and feces.

What are the 4 mechanisms that transfer body heat to the environment?

Radiation, convection, evaporation, and conduction.

What is radiation?

Heat transfer from one surface to another WITHOUT direct physical contact.

Radiation example

Your body loses heat to a cold window or cold surroundings without touching them.

What is conduction?

Heat transfer between objects that ARE in direct physical contact.

Conduction example

A patient loses heat by lying directly on a cold surface.

What is convection?

Heat transfer caused by movement of air or fluid around the body.

Convection example

A fan blows across the skin and carries warm air away from the body.

What is evaporation?

Heat loss when liquid changes into vapor.

Evaporation example

Sweat evaporates from the skin and removes body heat.

Radiation vs conduction

Radiation = NO touching. Conduction = DIRECT touching.

Convection vs evaporation

Convection = moving AIR/fluid carries heat away. Evaporation = LIQUID changes to vapor and removes heat.

What are arteriovenous shunts?

Connections between arterioles and venules near the skin that can open to promote heat loss or close to conserve heat.

What happens to arteriovenous shunts when the body needs to lose heat?

They open so more heat can be transferred to the skin and environment.

What happens to arteriovenous shunts when the body needs to conserve heat?

They close to retain heat.

What controls opening and closing of arteriovenous shunts?

The sympathetic nervous system.

What factors affect body temperature?

Circadian rhythm, age, biologic sex, physical activity, state of health, and environmental temperature.

How does circadian rhythm affect temperature?

Temperature is generally lowest in the early morning and highest in the late afternoon/early evening.

When does body temperature normally peak?

Approximately 3–6 PM.

How does physical activity affect temperature?

Physical activity increases metabolism and heat production, increasing temperature.

How does age affect temperature?

Very young and very old people are more sensitive to environmental temperature changes; older adults may also have a lower baseline temperature.

How does environmental temperature affect body temperature?

Extreme cold increases heat loss; prolonged extreme heat can increase body temperature.

How does biologic sex affect temperature?

Hormonal changes can cause greater temperature fluctuations in women.

What is a fever (pyrexia)?

An increased body temperature caused by an UPWARD change in the hypothalamic set point.

What is a pyrogen?

A substance that causes the hypothalamic temperature set point to rise and produces fever.

What does the body do when the hypothalamic set point rises during a fever?

It initially tries to PRODUCE and CONSERVE heat through responses such as shivering and vasoconstriction.

Why might someone shiver even though they have a fever?

The hypothalamic set point has risen, so the person's current temperature is below the new set point and the body tries to generate heat.

What is hyperthermia?

Abnormally high body temperature in which the hypothalamic set point has NOT changed and heat-control mechanisms cannot compensate.

Fever vs hyperthermia

Fever = hypothalamic set point INCREASES. Hyperthermia = set point DOES NOT change.

What is hypothermia?

Core body temperature below 35°C (95°F).

What happens to metabolism during hypothermia?

Metabolism decreases.

How can hypothermia affect pulse and respirations?

Pulse and respirations can decrease as metabolism slows.

What factors affect PULSE?

Age, biologic sex, physical activity, body temperature, stress, medications, and health/disease conditions.

How does age affect pulse?

Pulse is generally faster in infants/children and decreases toward adult rates with age.

How does exercise affect pulse?

Exercise increases pulse to meet increased oxygen and metabolic demands.

How does fever affect pulse?

Fever generally INCREASES pulse because metabolism increases.

How does hypothermia affect pulse?

Hypothermia generally DECREASES pulse because metabolism slows.

How does stress affect pulse?

Pain, fear, and anxiety activate the sympathetic nervous system and can increase pulse.

How can medications affect pulse?

Depending on the medication, they can increase or decrease heart rate.

What does sympathetic stimulation do to pulse?

INCREASES heart rate.

What does parasympathetic stimulation do to pulse?

DECREASES heart rate.

What nerve is associated with parasympathetic slowing of the heart?

The vagus nerve.

What factors affect RESPIRATIONS?

Age, exercise, pain, anxiety, smoking, body position, medications, neurologic injury, and hemoglobin function.

How does age affect respirations?

Infants and children normally breathe faster; respiratory rate decreases toward the adult range with age.

How does exercise affect respirations?

Increases respiratory rate and depth because the body needs more oxygen and produces more CO₂.

How does fever affect respirations?

Increased metabolism increases oxygen demand and CO₂ production, so respirations usually increase.

How does anxiety affect respirations?

Anxiety can increase respiratory rate and depth.

How can pain affect respirations?

Pain may increase respiratory rate, but chest/thoracic pain may cause shallow breathing because deep breaths hurt.

How do opioids affect respirations?

They can depress the respiratory center, decreasing respiratory rate and depth.

How does body position affect respirations?

An upright position generally allows greater lung expansion than lying flat.

What is the strongest normal respiratory stimulus emphasized in the slides?

Increased carbon dioxide (CO₂).

What factors affect BLOOD PRESSURE?

Age, biologic sex, race, circadian rhythm, food intake, exercise, weight, emotional state, body position, and medications.

How does age affect blood pressure?

BP generally increases with age as arteries become less elastic and peripheral resistance increases.

How does exercise affect blood pressure?

Systolic BP increases during exercise.

How do emotions affect blood pressure?

Fear, anger, excitement, and pain can temporarily increase BP.

How does body weight affect blood pressure?

BP tends to be higher in people with obesity.

How does food intake affect blood pressure?

BP may increase after eating.

How does circadian rhythm affect blood pressure?

BP is generally lowest on arising, rises during the day, and decreases again during sleep.

How does body position affect blood pressure?

BP can change when moving between lying, sitting, and standing positions.

How can medications affect blood pressure?

Some medications increase BP while others decrease it.

What happens to BP if cardiac output increases?

BP tends to increase.

What happens to BP if peripheral resistance increases?

BP tends to increase.

What does sympathetic stimulation generally do to BP?

It can increase heart rate/cardiovascular activity and increase BP.

What does the renin–angiotensin–aldosterone system do to BP?

It raises blood pressure.

FEVER + VITAL SIGNS pattern

Fever → metabolism ↑ → pulse ↑ and respirations ↑.

EXERCISE + VITAL SIGNS pattern

Exercise → heat production ↑, pulse ↑, respirations ↑, and systolic BP ↑.

STRESS + VITAL SIGNS pattern

Stress/anxiety → sympathetic stimulation → pulse ↑, respirations may ↑, and BP may ↑.

HYPOTHERMIA + VITAL SIGNS pattern

Hypothermia → metabolism ↓ → pulse and respirations may ↓.

What should you think when you see RADIATION?

NO CONTACT.

What should you think when you see CONDUCTION?

DIRECT CONTACT.

What should you think when you see CONVECTION?

MOVING AIR/FLUID.

What should you think when you see EVAPORATION?

LIQUID → VAPOR.

What should you think when you see SYMPATHETIC?

Fight-or-flight → heart rate goes UP.

What should you think when you see PARASYMPATHETIC?

Rest-and-digest → heart rate goes DOWN.

What should you think when you see FEVER?

Hypothalamic set point goes UP.

What should you think when you see HYPERTHERMIA?

Body overheats WITHOUT changing the hypothalamic set point.

What does TPR BP stand for?

Temperature, Pulse, Respirations, Blood Pressure.

What are the 4 main vital signs?

Temperature (T), Pulse (P), Respirations (R), and Blood Pressure (BP).

Newborn temperature range

97.2–99.9°F (36.2–37.7°C)

Infant temperature range

96–99.7°F (35.6–37.6°C)

Toddler temperature range

96–99°F (35.6–37.2°C)

Child temperature range

96–99°F (35.6–37.2°C)

Adolescent temperature range

96.4–99.5°F (35.8–37.5°C)

Adult temperature range

96.4–99.5°F (35.8–37.5°C)

Newborn pulse range

95–170 beats/min

Infant pulse range

85–170 beats/min

Toddler pulse range

70–150 beats/min

Child pulse range

65–130 beats/min

Adolescent pulse range

60–115 beats/min

Adult pulse range

60–100 beats/min

Newborn respiratory rate

30–60 breaths/min