Primary Assessment Study Guide for the EMT Test

Airway

Airway refers to the passage through which air enters and leaves the lungs; this includes the mouth, nose, throat, and trachea. Assessment of the airway is one of the earliest steps in the primary assessment. EMTs assess the patient’s airway for patency, meaning it is open and free from obstruction. If the patient is speaking without difficulty, this is a good indicator that their airway is clear. However, if a patient is choking or unresponsive, the EMT must immediately provide intervention to ensure the airway is clear before proceeding with their assessment.

Respiratory System Anatomy

The respiratory system is divided into two sections, the upper airway and the lower airway. All the structures of both sections play a role in breathing and gas exchange.

Upper Airway

The upper airway is made up of the mouth, or oral cavity, nose, tongue, jaw, larynx, and pharynx. The main function of the upper airway is to serve as a passage for air to be inhaled and exhaled out of the lungs. The upper airway also humidifies and heats the air.

Here are some terms to know:

• respiratory system—body system responsible for breathing and exchanging gases (bringing oxygen into the body and removing carbon dioxide from the body)

• nasopharynx—upper part of the throat behind the nose; connects the nasal passages to the throat

• trachea—windpipe; tube that carries air from the throat to the lungs

Lower Airway

The lower airway consists of the trachea and the lungs. The trachea divides into the right and left mainstem bronchi. The bronchi branch into the right and left lung. The lungs are further divided into lobes. The left lung consists of two lobes, the upper and lower. The right lung is composed of the upper, middle, and lower lobes. Each lobe is made up of millions of alveoli, which are tiny air sacs where gas exchange occurs.

Here are some terms to know:

• thyroid cartilage—large angular cartilage in front of the neck; forms the Adam’s apple and protects the vocal cords

• cricoid cartilage—ring-shaped cartilage just below the thyroid cartilage; forms the lower part of the larynx

• cricothyroid membrane—soft tissue between the thyroid cartilage and the cricoid cartilage

• alveoli—tiny air sacs in the lungs where oxygen and carbon dioxide are exchanged

Differences in Child and Adult Airways

There are several differences between a child’s airway and an adult’s. Overall, a child’s upper and lower airways, which include the nose, mouth, and trachea, are smaller and more flexible than an adult’s. Smaller structures may mean an airway obstruction occurs easier in a child than an adult. Although a child’s tongue is also smaller, proportionally, it takes up more space.

Obstruction of Airway

An airway obstruction can be caused by mucus plugs that block the flow of air into the lungs or by the swelling of the tissues of the airway. More commonly, obstruction of the airway is caused by a foreign body that blocks the flow of air into the lungs. Food is a common foreign body. In young children, everything from toys to coins can become lodged in the airway. Signs of an airway obstruction include wheezing, stridor, and a weak cough. Signs of a complete obstruction include cyanosis, inability to speak, and loss of consciousness.

Here are some terms to know:

• mild airway obstruction—occurs when the airway is partially blocked; patient can still breathe, speak, and cough

• severe airway obstruction—complete or nearly complete blockage of the airway; patient cannot speak, breathe, or cough; requires immediate intervention

• stridor—noisy, high-pitched sound heard during breathing, usually indicating some type of upper airway obstruction

Breathing

Assessing a patient’s breathing is one of the first steps in providing care. When performing a respiratory assessment, several factors must be considered. Questions in this area on the EMT test concern everything related to the process of breathing. You’ll need to know the parts of the body that make breathing possible and how each one functions. You need to be able to use techniques and equipment appropriately during an emergency, when it is necessary to make breathing possible or more easily achieved. Here are the most important things you need to study. Be sure you thoroughly understand each topic and seek further information in your textbook about specific procedures. Also, know the meaning and significance of all of the terms listed. First, here’s a little background on the respiratory system.

Adequate versus Abnormal Breathing

There are several factors to consider when determining adequate breathing. Respiratory rate should be assessed to determine if it is abnormally high or low. The patient’s “work of breathing” should also be evaluated, including whether the breathing is labored. The depth of breathing and the patient’s level of consciousness also needs to be assessed.

Here are some terms to know:

• work of breathing—the effort a person has to exert to breathe

• retractions—the pulling in of the skin and muscles of the chest; indicate breathing difficulty

• agonal gasps—irregular, ineffective breaths that occur during respiratory failure; they are not true respirations and are usually a sign of impending arrest

• Cheyne-Stokes—abnormal breathing pattern where the patient’s breaths gradually become deeper and faster, then become slow and briefly stop before repeating

• apnea—absence of breathing

• ataxic respirations—irregular, unpredictable breathing pattern with varying rate and depth

Respiratory System Physiology

The physiology of the respiratory system includes respiration and ventilation. The processes of both respiration and ventilation are involuntary, which means they are done reflexively, without the person thinking about it. It’s important to understand the difference between ventilation, oxygenation, and respiration.

Ventilation

Ventilation, in simple terms, refers to breathing. It involves the act of inhaling air in and exhaling air out of the lungs. Ventilation requires structures, such as the diaphragm and intercostal muscles, to work together and contract, allowing for inhalation. During exhalation, the muscles relax. If ventilation is inadequate, oxygenation will also be insufficient, and the need for ventilatory assistance should be assessed.

Here are some terms to know:

• inhalation—bringing air into the lungs

• exhalation—bringing air out of the lungs

• partial pressure—the pressure exerted by a single gas within a gas mixture (oxygen or carbon dioxide in the blood)

• dyspnea—difficulty breathing

How Ventilation Works

Ventilation is accomplished through the respiratory system. The respiratory system is made up of organs and tissues that aid in the inhalation of oxygen and exhalation of gaseous wastes, called carbon dioxide. The lungs are the organs that accomplish the function of this exchange of air. The air enters the lungs via the nose and mouth, and then it is carried to and from the lungs by the trachea. The alveoli and bronchi aid in the gas exchange and air passage process. Intercostal muscles and the diaphragm assist in the inhalation and exhalation work.

Here are some concepts to know:

• major components of the respiratory system

  • nose and nasal passages—filter, warm, and humidify air
  • mouth—airway
  • pharynx/throat—passageway for air to the larynx
  • larynx—protects the airway and produces sounds
  • trachea/windpipe—conducts air into the lungs
  • bronchi—two main tubes branching from the trachea to each lung
  • bronchioles—smaller branches within the lungs
  • alveoli—tiny air sacs where gas exchange occurs
  • diaphragm/intercostal muscles—help with breathing

• pathway and process of inhalation and exhalation—Inhalation and exhalation are the acts that cause breathing to occur. Inhalation occurs when the diaphragm contracts and moves downward, intercostal muscles lift the rib cage, the chest cavity expands, creating negative pressure, and air flows into the lungs. The pathway by which air flows into the lungs begins at the nose/mouth, then proceeds through the pharynx, larynx, trachea, bronchi, and alveoli. Exhalation occurs when the diaphragm relaxes and moves upward, the rib cage moves down and in, the chest cavity decreases in size, creating positive pressure, and air is pushed out of the lungs.

• potential impacts to ventilation with chest wall injury—Patients with a chest wall injury may take shallow breaths due to pain with breathing. Broken ribs or flail segments can prevent normal expansion of the chest wall. There is an increased risk of pneumothorax or lung collapse.

• intrathoracic pressure—pressure inside the chest cavity

Oxygenation

Oxygenation refers to the delivery of oxygen into the hemoglobin in the blood cells. Oxygen is needed for the organs and tissues of the body to function properly. Fresh atmospheric air, or inspired air is made up mostly of about 78% nitrogen and 21% oxygen, with a small amount of carbon dioxide (0.03%). Once air reaches the alveoli, oxygen passes into the blood and carbon dioxide passes from the blood into the lungs to be exhaled. Surfactant (see definition below) helps the alveoli stay open during breathing, which supports gas exchange.

Oxygenation can be disrupted due to various physiological states, as well as being at high altitudes and in places where the percentage of oxygen in the air is decreased, such as in a confined space. Signs of poor oxygenation include confusion, tachypnea, and cyanosis.

Here are some terms to know:

gas exchange—the movement of oxygen from the alveoli into the blood, and the movement of carbon dioxide from the blood into the alveoli to be exhaled.

• hypoxia—decreased oxygen to body tissue

• hypoxic drive—backup mechanism used by the body to control breathing, triggered by low blood oxygen levels.

• cyanosis—bluish coloring of the skin, lips, or nail beds

• tachypnea—fast breathing

Respiration

The cells in the body require oxygen and the removal of carbon dioxide. Respiration refers to gas exchange that occurs in the lungs. Oxygen is received through inhalation and carbon dioxide is removed through exhalation. Physiological processes, including diffusion, allow respiration to occur. Adequate ventilation is essential for proper respiration to take place. But even if ventilation is acceptable, it does not guarantee that gas exchange at the cellular level is sufficient.

Here are some terms to know:

• external respiration—exchange of gases between the lungs and blood

• surfactant—substance in the lungs that coats the inside of the alveoli; reduces surface tension, making breathing easier

• cellular respiration—process by which cells use oxygen to produce energy

Respiration Pathophysiology

Respiration is more complicated than it may seem. Various systems of the body work together for adequate respiration to occur, but it can be disrupted due to a variety of factors.

Nervous System Factors

The nervous system plays a role in respiration. Chemoreceptors in the nervous system monitor the pH of the spinal fluid, as well as the level of oxygen and carbon dioxide in the body. Based on those levels, the nervous system sends signals to the respiratory centers in the brain to change the respiratory rate or depth of breathing.

Ventilation/Perfusion Ratio and Mismatch

The ventilation and perfusion ratio refers to air flowing into the lungs and blood going to the lungs. The two variables should be matched. Insufficient gas exchange is often caused by a mismatch in the perfusion to ventilation ratio.

Pulmonary Ventilation Factors

Pulmonary factors that affect adequate ventilation can be intrinsic or extrinsic. Intrinsic factors may include allergic responses, lung infections, and the blockage of air flow in and out of the lungs, such as when the tongue is blocking the airway. Extrinsic factors can include blockage of the airway due to a foreign body or trauma to the chest or airway.

Here is a term to know:

• hypercapnia—too much carbon dioxide in the blood

Respiration Factors

Both internal and external conditions can affect respiration. External factors include altitude and the partial pressure of oxygen. Carbon monoxide in the environment can also affect proper respiration. Internal factors involve diseases and conditions that decrease the surface area of the portion of the lung involved in gas exchange. Examples include COPD, infection, and pulmonary edema.

Here is a term to know:

• intrapulmonary shunting—blood passes through the lungs without being properly oxygenated

Circulatory Compromise

Conditions that affect circulation also play a role in efficient respiration. Certain conditions can decrease oxygenation at the tissues. An interruption of blood flow to the tissues can be due to a pulmonary embolism, tension pneumothorax, or a variety of traumatic injuries. In other instances, cardiac problems may prevent the heart from effectively pumping oxygenated blood to the tissues and organs of the body.

Here are some terms to know:

• tension pneumothorax—when air builds up in the pleural space (between the lungs and chest wall) and cannot escape

• pulmonary embolism—blockage in a pulmonary artery in the lungs, usually caused by a blood clot traveling from the legs, reduces blood flow to the lungs and decreases oxygen levels in the blood