Vital Signs and Body Temperature

• Vital signs indicate a person's health condition
  • Pulse
  • Temperature
  • Blood pressure
  • Respiratory rate
  • Pulse oximetry (for respiratory problems)
• Anthropometric measurements include:
  • Height
  • Weight
  • Body mass index
  • Head circumference (for children)
• Vital signs are taken every visit to establish a baseline for comparison

Body Temperature

• Regulated by the hypothalamus in the brain
• Limited variation (1-2 degrees Fahrenheit) due to physical activity or external temperature
• Maintained by balance of heat production and heat loss
• Physical activity increases body temperature
  • Hypothalamus senses this
  • Sweat glands increase sweat production
  • Evaporation cools the body
• Core temp 97-99 degrees F
• Average of 98.6
• Fatal Temperature: 109.4

Heat Production

• Muscle activity (voluntary and involuntary)
• Cell metabolism (breakdown of food)
• Stress (anger, fear)

Heat Loss

• Perspiration (evaporation of sweat)
• Exhalation (water vapor and heat)
• Urine and stools
• Mechanisms of heat loss include:
  • Radiation (heat radiating from the body)
  • Conduction (direct transfer of heat, e.g., sitting on a cold chair)
  • Convection (heat loss through air current)

Factors Affecting Body Temperature

• Age: Children have higher temperatures due to activity and less established regulation; elderly have lower temperatures due to less activity and metabolism
• Diurnal variation: Lowest in the morning upon waking
• Emotional state: Stress increases temperature
• Cold and hot weather: Limited effect (1-2 degrees Fahrenheit variation)
• Physical activity/exercise: Increases temperature
• Pregnancy: Slightly higher due to increased metabolism and hormones

Fever

• Febrile: Patient with a fever
• Afebrile: Patient without a fever
• Pyrogen: Substance causing fever, resets the hypothalamus to increase body temperature to fight microorganisms
• Stages of fever include
  • Onset (gradual or sudden)
  • Feeling cold and shivering
  • Increased respiratory rate
• Types of fever include
  • Sustained: Temperature is elevated consistently with minimal fluctuations
  • Intermittent: Temperature returns to normal or below normal between spikes
  • Remittent: Temperature fluctuates but remains above normal
• Symptoms: Increased heart rate and respiratory rate, headache, flushed skin, thirst, loss of appetite, malaise (weakness and fatigue)
• Subsiding stage: Fever decreases gradually or suddenly (crisis with sweating)

Temperature Measurement Sites

• Oral (mouth)
• Axilla (armpit)
• Rectum
  • Rich in blood supply
  • Closed cavities (minimal air currents)
  • Axilla: Add 1 degree Fahrenheit to reading
  • Rectum: Subtract 1 degree Fahrenheit to reading
• Tympanic (ear)
• Temporal artery (forehead)
• Oral temperature: Thermometer placed under the tongue, patient closes mouth
• Axillary temperature: Mainly for toddlers and preschoolers, add one degree to the reading
• Tympanic temperature: Aim probe towards eardrum, straighten ear canal
  • Children over 3/adults: Pull ear backward and upward
  • Children under 3: Pull ear backward and downward Temporal artery temperature:
  • Scan slowly across forehead
  • Hold switch during measurement
  • Forehead: Subtract 1 degree Fahrenheit

Thermometer Types

• Mercury thermometers (no longer used due to mercury's toxicity)
• Chemical thermometers (least accurate)
• Digital thermometers (most commonly used)
  • Blue probe: Oral or axillary
  • Red probe: Rectal
  • Use disposable plastic cover
  • Clean probe with alcohol wipe
• Tympanic thermometers
  • Measures heat radiating from eardrum
  • Cone-shaped cover
  • Clean probe regularly

Temporal Artery Thermometers

• Scan button needs pressing and holding while moving the probe
• Computer calculates and adjusts for heat lost to air current (ambient temperature)
• Alternative site: Behind ear (mastoid process) if forehead is sweating, less accurate
• Care of thermometers: Clean with alcohol wipe, avoid water and extreme temperatures

Pulse Measurement

• Radial pulse is often used in the lab
• Apical pulse is useful in children or when needing an accurate count
• Apical Pulse
  • Count in young children and when needing an accurate count
  • Use stethoscope at the apex of the heart
• Count is the heat beating during each minute
• Brachial Pulse
  • Can be used during cardiac arrest of infants
• Caused by heart contraction pumping blood into arteries, arteries expand and recoil
• Highest Rate newborns (120-160) then to 60-100 beats per minute

Factors Affecting Pulse Rate

• Age: Children have higher pulse rates
• Gender: Females have faster pulse rates
• Exercise: Increases pulse rate
• Emotional status: Stress increases pulse rate
• Metabolism: Increased metabolism increases pulse rate
• Fever: Increases heart rate and respiratory rate

Pulse Locations

• Temporal (forehead/front of ear)
• Carotid (neck): Best for adults in cardiac arrest
• Apical (chest): Apex of the heart in 5th intercoastal space with the midclavicular line
• Brachial (inner elbow), Tracheal (inner aspect of area)
• Radial (base of thumb)
• Ulnar (base of little finger): Evaluates circulation to the hand
• Femoral (upper thigh): Detect pulse in children/infants, evaluate blood flow to lower extremities
• Popliteal (behind knee): Used with bilateral amputees
• Posterior tibial (behind medial malleolus)
• Dorsalis pedis (top of foot, between first and second metatarsal bones): Circulation in the foot, especially in diabetics
• Pulse is assessed by palpation (feeling the pulse, not applying too much pressure)
• When commenting about the pulse: Make sure that the pulse is regular

Pulse Characteristics

• Regularity: Duration between beats is consistent
• Rhythm: Number of beats per minute
• Volume: Strength of the pulse (bounding = strong, threading = weak and fast)
• Normal pulse rate: 60-100 beats per minute (average 76)
• Tachycardia: Fast pulse rate (>100 bpm)
• Bradycardia: Slow pulse rate (<60 bpm), during sleep or in athletes
• Arrhythmia/dysrhythmia: Irregular rhythm
• Pulse deficit: Difference between apical and radial pulse rates, taken at the same time
• Pulse volume/strength indicates blood flow to the circulatory system

Respiration

• Purpose is gas exchange (oxygen in, carbon dioxide out)
• Trachea leads to bronchi, which branch into bronchioles, ending in alveoli (air sacs)
• Respiratory cycle: Inhalation (breathing in) and exhalation (breathing out)

Inhalation Process

• Diaphragm and intercostal muscles contract
• Diaphragm straightens
• Ribs pulled upwards
• Increases chest cavity volume
• Creates negative pressure, drawing air into lungs

Exhalation Process

• Diaphragm and intercostal muscles relax
• Chest cavity volume decreases
• Creates positive pressure, pushing air out of lungs
• External respiration: Gas exchange in lungs (oxygen from alveoli to blood, carbon dioxide from blood to alveoli)
• Internal respiration: Gas exchange at cellular level (oxygen to cells, carbon dioxide from cells to blood)
• Respiratory control center: Medulla oblongata in the brainstem

Respiratory Rate

• Normal: 12-20 breaths per minute
• Respiratory rate is about 1/4 the heart rate
• Tachypnea: Fast respiration (>20 breaths per minute)
• Bradypnea: Slow respiration (<12 breaths per minute)

Factors Affecting Respiratory Rate

• Age: Children have faster rates
• Physical exercise: Increases rate
• Emotional status: Stress increases rate
• Fever: Increases rate
• Medications: Can increase or decrease rate
• Rhythm (regularity) and depth (volume of air) of respiration should be noted

Respiratory Terms

• Eupnea: Normal respiration (12-20 bpm, even and regular, normal depth)
• Hyperpnea: Increased rate and depth, during exercise, fever, or pain
• Hyperventilation: Faster and deeper breathing, anxiety/panic attacks
• Hypopnea: Slower rate and shallower depth, during sleep (sleep disorder)
• Apnea: Absence of respiration (sleep apnea)
• Dyspnea: Difficult breathing/shortness of breath (lung conditions like asthma)
• Orthopnea: Difficult breathing when lying flat

Cyanosis

• Bluish coloration of skin/mucous membranes due to deficient oxygenation
• Observe lips, under tongue, nail beds
• Evident in lung and heart diseases
• Cyanosis: Blue coloration of the skin, reduction in oxygen supply of the tissue

Oximetry

• Measures oxygen saturation (SpO2) in the blood
• Normal: 95-99%
• Reduction in the oxygen supply of the tissue
• Can lead to headache, confusion and difficulty breathing
• Can lead to tissues can be damaged and die

Hemoglobin

• Carries oxygen in red blood cells
• Hypoxemia: Decreased oxygen saturation in the blood
• Hypoxia: Drop in oxygen delivered to tissues and cells

Oximeter

• Device with two arms applied to the finger
• Measures SpO2, monitors respiratory conditions and tolerance for surgery/anesthesia

Factors Affecting Oximetry

• Probe positioning (alignment of arms)
• Pediatric oximeter in patients w very small fingers
• Alternative site earlobe in patients w large fingers
• Dark nail polish and Cold temperatures will impede it's ability/circulation
• Patient movement (neurological conditions)
• Note: Dark skin does not affect the transmission of infrared rays -The best tissues that will be affected is the brain, heart, and liver

Blood Pressure

• Force exerted by blood against blood vessel walls
• Expressed as systolic/diastolic in millimeters of mercury (mmHg)
• Systolic: Pressure during heart contraction (highest pressure)
• Diastolic: Pressure during heart relaxation (lowest pressure)
• Normal Blood Pressure: Less than 120/80 mmHg

Blood Pressure Classifications

• Elevated: Systolic between 120-129 and diastolic less than 80
• Hypertension Stage 1: Systolic between 130-139 or diastolic between 80-89
• Hypertension Stage 2: Systolic at least 140 or diastolic at least 90
• Hypotension: Blood pressure below 90/60 mmHg
• Pulse Pressure: Difference between systolic and diastolic
• Monitor medications

Factors Affecting Blood Pressure

• Age: Increases with age
• Diurnal Variation: lower at night
• Emotional state: Stress increases the BP
• Exercise: Increases BP
• Body position/Medications -minimal effect

Blood Pressure Measurement

• Equipment: Sphygmomanometer (cuff, manometer, pressure bulb with valve) and stethoscope
• Proper measurement: Use correct cuff size, position cuff correctly over brachial artery
• Korotkoff sounds: Heart sounds heard while taking blood pressure, indicate systolic and diastolic pressures.

Prevention of Errors with Blood Pressure

• Use correct cuff size
• Ensure cuff encircles 80-100% of the arm
• Do not put BP over cloths
• Feet on floor
• Have the patient be resting
• Make sure you use the diaphragm of the stethoscope in the corect position
• Gentle pressure on Brachial artery
• Slow release of air -about 2-3 mmHg per second
• Start in the left arm then after visits only take vitals from left arm to have a similar baseline with other readings
• Put it on the radial pulse to take the punctuation