CMA Chapter 4: Vital Signs

• Measurements taken at the first visit

  Recorded as baseline data and used as reference points for comparison during subsequent visits
• Placement of the scale is important for patient comfort during weight measurement
• An accurate weight is always required for pregnant patients, infants, children, and the elderly
• Height is measured in inches or centimeters, depending upon the physician's preference
• Weight monitoring may be required if the patient has been prescribed medications that must be carefully calculated according to body weight or for a patient who is attempting to gain or lose weight
• After the first office visit, the height is usually not taken; however, the vital signs and weight are taken and recorded for each adult patient at each visit to the medical office
• Height can be measured using the movable ruler on the back of most balance beam scales or a graph ruler mounted on a wall
• Body temperature reflects a balance between heat produced and heat lost by the body
• Vital signs, also known as cardinal signs, are measurements of bodily functions essential to maintaining life processes
• The body maintains a constant internal temperature of around 98.6 Fahrenheit (F) or 37.0° Celsius (C)
• Thermometers are used to measure body temperature using either the Fahrenheit or Celsius scale
• The hypothalamus in the brain regulates body temperature by initiating peripheral vasodilation to carry core heat to the body surface via the blood and increasing perspiration to cool the body by evaporation
• Rectal temperatures are usually 1°F higher than oral temperatures
• When recording body temperature, the method used must be indicated, such as oral, rectal, axillary, tympanic, or temporal artery
• Balance between heat produced and heat lost by the body


  Heat is produced during normal internal physical and chemical processes called metabolism and through muscle movement. Heat is normally lost through processes including respiration, elimination, and conduction through the skin
• Methods to measure body temperature

  • Oral
  • Rectal
  • Axillary
  • Tympanic
  • Temporal artery
• A patient with a temperature within normal limits is afebrile, while a patient with a temperature above normal is considered febrile (has a fever)
• Axillary temperatures are usually 1°F lower than oral temperatures
• Mechanisms of Heat Transfer

  • Radiation: Diffusion or dissemination of heat by electromagnetic waves
  • Convection: Dissemination of heat by motion between areas of unequal density
  • Evaporation: Conversion of liquid to vapor
  • Conduction: Transfer of heat during direct contact between two objects
• Regulation of body temperature

  The hypothalamus in the brain senses body temperature and initiates peripheral vasodilation to carry core heat to the body surface via the blood and increases perspiration to cool the body by evaporation. If the temperature is too low, vasoconstriction and shivering help maintain a normal core temperature
• Time of day

  Body temperature is usually lowest in the early morning before physical activity has begun
• Factors affecting body temperature

  • Age
  • Gender
  • Exercise
  • Time of day
  • Emotions
  • Disease process
• Gender

  Women usually have a slightly higher temperature than men, especially at the time of ovulation and during pregnancy
• Fever stages

  Onset may be abrupt or gradual. Course may range from a day to several weeks. Fever may be sustained, remittent, intermittent, or relapsing. Resolution may occur as a crisis or lysis
• Thermometers with a long, slender bulb are used for axillary or oral temperatures and are color-coded blue. Body heat expands the chemical in the bulb, which rises up the glass column and remains there until physically shaken back into the bulb. The Fahrenheit thermometer is calibrated with lines designating temperature in even degrees, with uneven numbers marked only with a longer line. The thermometer is read by noting the level of the mercury or nonmercury substance in the glass column
• Fever


  Usually results from a disease process such as a bacterial or viral infection. Pyrexia refers to a fever of 102°F or higher rectally or 101°F or higher orally. Hyperpyrexia, with a temperature of 105 to 106, is considered dangerous
• Temperature elevations and variations are often a sign of disease but are not diseases in themselves
• Age

  Children usually have a higher metabolism and body temperature than adults. The elderly usually have lower readings than younger adults. Temperatures of the very young and the elderly are easily affected by the environment
• Exercise


  Activity causes the body to burn more calories for energy, raising the body temperature
• Emotions


  Temperature tends to rise during times of stress and fall with depression
• Efforts to bring down a fever may be counterproductive as it is usually a natural response to disease. However, if the patient is uncomfortable or the temperature is abnormally high, it should be brought down to about 101°F
• Cleaning glass thermometers

  1. Place in a disposable clear plastic sheath before use

  2. Remove the sheath by pulling the thermometer out after use

  3. Dispose of the sheath in a biohazard container

  4. Sanitize and disinfect the thermometer according to office policy
• Types of Thermometers

  • Glass Thermometers
  • Electronic Thermometers
• Electronic thermometers have color-coded probes: blue for oral or axillary, red for rectal
• Mercury spill kit must be available in case of a mercury thermometer breakage
• A Fahrenheit (F) thermometer is scaled from 94°F to 108°F with each long line indicating 1 degree and each short line indicating 0.2 of a degree
• Rectal thermometers have a rounded or stubbed end and are usually color-coded red on the opposite flat end
• Most medical offices today do not use mercury-filled glass thermometers
• Some glass thermometers contain a nonmercury substance
• Mercury is a hazardous chemical if exposure occurs