The Definitive Guide to Vital Signs and Medical Assisting

Written by: 
Daymar College

Medical error is the third leading cause of deaths in the US, according to a study published in the BMJ. Based on an analysis of prior research, the Johns Hopkins study estimates that more than 250,000 Americans die each year from medical errors. Taking vital signs is the first line of defense when a patient enters a doctor’s office or medical facility to prevent medical errors.

Vital signs give the medical assistant and attending physician a guide to a patients’ health offering clues along with symptoms for possible health issues and treatment options. Vital signs include body temperature, heart rate, blood pressure, respiration rate and oxygen saturation. The vital signs are usually taken at the beginning of each patient appointment, so the physician can compare them to previous readings and to help with future diagnoses. The medical assistant should become familiar with normal ranges of vitals based on the age group of the patient. The medical assistant should also make sure that the equipment to measure vital signs is in good working order and will give an accurate reading.

Vital Sign: Body Temperature

A contact temperature range must be kept for the body to function properly. The body uses perspiration to cool down when needed. Body temperature should not only be taken if a patient has a fever, but a baseline should be set for future appointments to catch abnormalities. The medical assistant must also become familiar with proper procedure to take body temperature during a patient’s appointment, how the body regulates temperature with heat production, heat loss, body temperature conditions and body temperature influencers. The normal human body temperature ranges from 97 degrees to 99 degrees Fahrenheit.

There are five places on the body that a medical assistant can take the body’s temperature, they include the mouth, axilla, rectum, ear and forehead. The part of the body is chosen based on age, condition, and state of consciousness.

  • Oral Assessment – temperature is taken by placing the thermometer under the tongue in the mouth.
  • Axillary Assessment – temperature is taken by placing the thermometer in the armpit of the patient.
  • Rectal Assessment – the rectal method is typically used on infants and young children.
  • Aural Assessment – temperature is taken by placing the thermometer in the ear and can typically be used on young children and uncooperative patients.
  • Forehead Assessment – temperature is taken by placing a temporal artery thermometer on the forehead.

Heat is produced in the body when nutrients are broken down in the cells. Heat can be produced by contraction of the muscles, during digestion, when shivering, from fever or strong emotion.  Heat is lost from the body in urine, feces, water vapor from the lungs and perspiration. When moisture is released, the body cools to normal temperatures as managed by the hypothalamus. There are four different types of heat loss, they include:

  • Radiation – the transfer of heat in electromagnetic waves generated by the thermal motion of charged particles in matter.
  • Conduction – the transfer of heat from one object to another through direct contact.
  • Convection – the transfer of heat through cool air currents that cause the body to lose heat.
  • Evaporation – losing heat through the conversion of water to gas, for example the evaporation of sweat.

High temperatures in the body can indicate disease or illness. Lower temperatures are usually caused by the environment.

  • Fever - a body temperature greater than 100.4 degrees.
  • Low Grade Fever – a body temperature between 99 degrees and 100.4 degrees.
  • Hyperpyrexia - A body temperature greater than 105.8 degrees. A body temperature greater than 109.4 degrees is fatal.
  • Hypothermia – a body temperature less than 97 degrees Fahrenheit. The body usually can’t survive with a temperature lower than 93.2 degrees.
  • Basal Body Temperature – the lowest temperature attained by the body during rest.
  • Core Temperature – the temperature in deep structures of the body including the liver. Rectal temperature is the standard measurement used to establish core temperature.

The medical assistant should consider the following factors while taking a patient’s body temperature.

  • Age – infants and children tend to have higher temperatures whereas the elderly can have lower temperature.
  • Diurnal Variations – body metabolism and muscle contraction can slow down during sleep causing the body temperature to be the lowest in the morning.
  • Emotional States – strong emotion can cause the body temperature to increase.
  • Environment – cold weather or hot weather destinations can cause the body temperature to be slightly lower or higher than average.
  • Exercise – vigorous activity can cause increase muscle contraction raising the body’s temperature.
  • Pregnancy – during pregnancy cell metabolism increases and can raise the body temperature.

Vital Sign: Heart Rate

The pulse can be checked to see how well the heart is working or in an emergency to see if the heart is pumping enough blood. Pulse can help diagnose symptoms of illness and disease. A medical assistant can check for blood flow after an injury or when a blood vessel may be blocked.

The pulse is created by the heart contracting and forcing blood into the heart’s aorta. The aorta must expand because it already has blood and must make room for the new blood. This creates a pulse wave through the walls of the arterial system. The heart rate is measured by counting the number of pulses or beats per minute (bpm). There are many different pulse sites and pulse rate influencers. The medical assistant must also be familiar with how to assess readings of the patient’s heart rate.​

  • Radial Pulse – the most common place to measure the pulse is from the inside of the wrist just below the thumb.
  • Apical Pulse – measurement with a stethoscope just over the apex of the heart.
  • Brachial Pulse – pulse taken on the inside of the elbow.
  • Ulnar Pulse – pulse taken on the little finger side of the wrist and can be used to measure circulation in the hands.
  • Temporal Pulse – measurement on the front of the ear just about eye level.
  • Carotid – the best place to find a pulse quickly at the side of the neck.
  • Femoral Pulse – pulse taken in the middle of the groin and can be used to measure circulation in the lower legs.
  • Popliteal Pulse – pulse taken at the back of the knee.
  • Posterior Tibial Pulse – pulse taken on the inner ankle and can be used to measure circulation in the feet.
  • Dorsalis Pedis Pulse – pulse taken on the upper surface of the foot, also used to measure circulation to the foot.

Pulse rate can vary based on different factors. The medical assistant should consider the following factors when assessing pulse rate including age, gender, physical activity, emotional state, metabolism, fever, air temperature, body size and medications taken.

  • Age – as age increases, the pulse rate gradually decreases.
  • Gender – women tend to have slightly quicker pulses than men.
  • Physical Activity – can increase pulse rate temporarily.
  • Emotional States – can also temporarily increase pulse rate
  • Metabolism – an increased body metabolism can increase the pulse rate
  • Air Temperature – when temperatures increase outside, the body compensates by pumping a little more blood.
  • Body Size – those that are obese may have a higher pulse rate.
  • Medications – may increase or decrease the pulse rate depending on side effects. Beta blockers are a common medicine to reduce heart rate.

A pulse rate assessment is used to establish the patient’s baseline pulse and re-assess after a procedure, while taking medication or to assess the heart for disease. Pulse should be taken by the medical assistant with moderate pressure using the three middle fingers. Excessive pressure can cause the pulse to close off and little pressure may not be enough to detect a pulse.

Pulse Rate – the number of heart beats that occur in 1 minute. The normal resting pulse rate, in an adult, ranges from 60 to 100 beats per minute.

  • Tachycardia – abnormally fast heart rate of more than 100 beats per minute. May be an indicator of hemorrhaging or heart disease.
  • Bradycardia – abnormally slow heart rate, less than 60 beats per minute.

Pulse Rhythm – pulse rhythm indicates the time interval between heart beats. A normal rhythm is a consistent time interval between heart beats.

  • Dysrhythmia – unequal or irregular intervals between heart beats.
  • Apical-Radial Pulse – taking the measurements at the heart and on the inside of the wrist at the same time to determine symmetry. A pulse deficiency exists if they are out of balance. This may indicate that not all of the heart beats are reaching the peripheral arteries.

Pulse Volume – the strength of the heartbeat. If the amount of blood pumped into the aorta is consistent, the patient will have a strong pulse.

Vital Sign: Blood Pressure

Blood pressure (BP) is a measurement of the pressure exerted by the blood on the walls of the arteries. The blood pressure is taken on every visit to establish a baseline for future visits.

  • Systolic Pressure – measurement of the blood pushed out of the heart into the aorta and pulmonary aorta that is exerting pressure on the walls of the arteries.
  • Diastolic Pressure – measurement when the heart relaxes between contractions.

The equipment needed to measure manual blood pressure includes a stethoscope and a sphygmomanometer. The numerator is the systolic pressure and the denominator is the diastolic pressure. A standard unit for measuring blood pressure is millimeters of mercury (mm Hg). A normal blood pressure reading is 110/70.

  • Prehypertension – blood pressure reading of 120/80
  • Hypertension – high blood pressure; excessive pressure on the walls of the arteries and a reading higher than 140/90.
  • Hypotension – low blood pressure; reduced pressure on the walls of the arteries and a reading lower than 95/60.

The pulse pressure is the difference between systolic and diastolic pressure. A pulse pressure between 30 and 50 mm Hg is in the normal range.

A medical assistant should consider certain factors that can increase or decrease blood pressure when checking vital signs. These factors include age, gender, diurnal variations, emotional states, exercise, body position and medication taken.

  • Age – as age increases, blood pressure gradually increases.
  • Gender – women usually have a lower blood pressure than men of the same age. After menopause, the blood pressure can become higher in women.
  • Diurnal Variations – in the morning the blood pressure is lower. Blood pressure rises with the metabolism and activity throughout the day.
  • Emotional States – strong emotions can increase blood pressure.
  • Exercise – physical activity can temporarily increase blood pressure.
  • Body Position – blood pressure can be different when a patient is sitting versus lying and standing.
  • Medication – some side effects of medications may include an increase or decrease of blood pressure.

Vital Sign: Respiration Rate

The purpose of respiration is to exchange oxygen and carbon dioxide. The assessment should be done without the patients’ knowledge as they may change the rate it they know they are being tested. During inhalation the lungs expand with oxygen from the atmosphere. As the lungs exhale carbon dioxide is removed from the body. A normal healthy adult will breathe in and out 12 to 20 times per minute.

  • Tachypnea - An abnormal respiration rate higher than 20 breathes per minute.
  • Bradypnea - reparation rate under 12 breathes per minute.

Many factors can affect the normal respiration rate in healthy adults, they include age, physical activity, emotional state, fever and medications taken.

  • Age – as age increases, the respiratory rate decreases.
  • Emotional State – strong emotions can temporarily increase respiration rates.
  • Fever – the lungs will increase respiratory rate in order to expel excess heat.
  • Medications – some side effects of medicines include the increase and decrease of respiration rates.

The respiration rhythm should be even and regular with equal pauses between inhaling and exhaling. The respiration depth is described as normal, deep or shallow based on the movement of the chest. Normal depth is described as the baseline respiration depth. Deep respiration involves an increased amount of air inhaled whereas shallow respiration involves a slow exchange of oxygen and carbon dioxide.

  • Hyperpnea – an abnormal increase in the rate and depth of respiration. Can be caused simply by exercise but can also be a sign of problems if at rest.
  • Hyperventilation – abnormally fast and deep breathing, typically associated with acute anxiety and may be supplemented by dizziness and weakness.
  • Hypopnea – an abnormal decrease in rate and depth approximately half of baseline respiration rate. Hypopnea can be found primarily with sleep disorders.

The patient’s color can tip off a medical assistant to problems while taking vital signs.

  • Hypoxia – a reduction in oxygen supply to the tissue
  • Cyanosis – a bluish discoloration of the skin and mucous membranes.

There are different types of abnormalities caused by physical activity or disorders of the body function, they include apnea, dyspnea, orthopnea, platypnea, trepopnea, Biot’s respiration, Cheyne-Stokes respiration, and Kussmaul breathing.

  • Apnea – temporary absence of respiration.
  • Dyspnea – difficulty breathing and shortness of breath.
  • Orthopnea – occurs from a disorder of the heart and lungs including asthma, pneumonia or congestive heart failure.
  • Platypnea – shortness of breath that is relieved when lying down and worsens when sitting or standing. Due to either hepatopulmonary syndrome or anatomical cardiovascular defect.
  • Trepopnea – shortness of breath that is sensed while lying on one side of the body but not the other. Can result from disease in one lung or chronic congestive heart failure.
  • Biot’s Respiration – abnormal pattern of breathing characterized by groups of quick, shallow inspirations followed by regular or irregular periods of apnea.
  • heyne-Stokes Respiration – an abnormal pattern of breathing characterized by progressively deeper breathing followed by a gradual decrease that results in a temporary stop in breathing.
  • Kussmaul Breathing – a deep and labored breathing pattern often associated with severe metabolic acidosis, diabetic ketoacidosis and kidney failure.

Vital Sign: Pulse Oximetry

Pulse oximetry is often performed on patients complaining of respiratory problems. Pulse oximetry is the procedure used to measure the oxygen saturation of hemoglobin in arterial blood. Hemoglobin transports oxygen in the body. Taking a patients’ pulse oximetry helps the medical assistant and physician understand how much oxygen is being delivered to the tissues of the body. Pulse oximetry is typically used during or after surgery that uses sedation, to see how well lung medicines are working, to check a person’s ability to handle increased activity levels, to see if a ventilator is needed, or to check a patient that has sleep apnea. It can also be used when a patient has a heart attack, heart failure, anemia, lung cancer, asthma or pneumonia.

The Pulse Oximeter is the device used to measure and display the oxygen saturation of the blood. It is attached to the tip of the finger and transmits infrared light and red light through the patient’s tissues to a light detector on the other side of the probe. Hemoglobin that is bright red and rich in oxygen will absorb more of the infrared light emitted. A ratio determines the oxygen saturation of the patient’s hemoglobin or SpO2.

The pulse reading represents the percentage of hemoglobin saturated with oxygen. Every molecule of hemoglobin can carry four oxygen molecules. The more hemoglobin that is saturated with oxygen, the higher the oxygen saturation of the blood. A healthy oxygen saturation level is 95% to 99%.

  • Hypoxemia – oxygen saturation level lower than 95%
  • Hypoxia – a reduction in the oxygen supply to the tissues of the body that can lead to tissue damage and even death.

Conditions that can cause a decreased SpO2 rating include:

  • Chronic Obstructive Pulmonary Disease (COPD) - lung condition with an inability to exhale normally that can cause difficulty breathing.
  • Emphysema – lung damage that allows air to be trapped in the lungs.
  • Congestive Heart Failure – a chronic condition where the heart doesn’t pump blood as well as it should, causing shortness of breath at night, during exercise or while lying down.
  • Coronary Artery Disease – damage in the heart’s major blood vessels that can cause shortness of breath.

The medical assistant should know about the factors that can affect pulse oximetry, they include incorrect positioning of the probe, fingernail polish, poor peripheral blood flow, ambient light and patient movement.

  • Incorrect Positioning of the Probe – can be difficult with patients that have small or large fingers.
  • Fingernail Polish – a dark, opaque coating on the fingernail may result in low readings as a result of interference of the light penetration through the finger.
  • Poor Peripheral Blood Flow – may cause the pulse to be so weak that the oximeter cannot make a reading.
  • Ambient Light – if shining directly on the probe it can cause an inaccurate reading.
  • Patient Movement – motion affects the ability of the light to travel from one side of the pulse oximeter to the other. The medical assistant will ask that the patient remain still during the procedure.

Does the definitive guide to vital signs and medical assisting interest you? Want to become a medical assistant? The Medical Assisting program at Daymar College is designed to prepare current and future employees for the fast-paced changes encountered in the health care industry, and to help develop training, skills and attitudes necessary to excel in medical assisting. Contact us to learn more about a great opportunity to become a medical assistant.