Chapter 10: Respiration and Artificial Ventilation
Topics
● Physiology and Pathophysiology
● Respiration
● Positive Pressure Ventilation
● Oxygen Therapy
● Special Considerations
● Assisting with Advanced Airway Devices
Physiology and Pathophysiology
Physiology and Pathophysiology-Mechanisms of Breathing
● Ventilation is the process of moving air into (inhalation) and out of (exhalation) the chest
● Inhalation is an active process
○ Chest muscles expand and the diaphragm contracts
○ The size of the chest increases
○ Negative pressure pulls air into lungs
● Exhalation is a passive process
○ Chest muscles and the diaphragm relax
○ The size of the chest decreases
○ Positive pressure pushes air out of the lungs
● Tidal volume is the amount of air moved in one breath
● Minute volume is the amount of air moved into and put out of the lungs per minute
● Ventilation is designed to move air to and from the alveoli for gas exchange
○ Not all of the air breathed reaches the alveoli
○ Some air occupies dead space
● Alveolar ventilation refers to the amount of air that actually reaches the alveoli
○ It can be altered by changes in rate or volume
○ It depends heavily on tidal volume, but is affected by very fast or very slow rates
Physiology and Pathophysiology-Physiology of Respiration
● Alveoli from the ends of the bronchiole tubes
○ Bunches of sacs are inflated and ventilated as air moves in and out
○ Each alveolus is a bubble-like structure
● Pulmonary capillaries bring blood close to the sacs
● Thin alveoli and capillary walls allow for gas exchange
○ Oxygen in the alveoli moves into the blood
○ Carbon dioxide in the blood moves into the alveoli
● Diffusion is movement of gases from an area of high concentration to an area of low
concentration
● Pulmonary respiration is diffusion of oxygen and carbon dioxide between the alveoli and
the circulating blood
● Cellular respiration is diffusion or oxygen and carbon dioxide between the cells and the
circulating blood
, ● In order for pulmonary and cellular respiration to occur, the respiratory and circular
systems work in conjunction
○ This is sometimes called the cardiopulmonary system
○ It may also be called a ventilation-perfusion (V/Q) match
● When either the respiratory or circular system fails, the process of respiration is defeated
Physiology and Pathophysiology-Cariopulmonary Pathophysiology
● Mechanical failures of the cardiopulmonary system limit the ability of the chest to create
pressure changes
○ Stab wounds allow air into the cavity and make it impossible to create negative
pressure
○ Loss of nervous control makes it impossible to innerate respiratory muscles
○ Painful chest wall injuries limit chest wall movement
○ Airway problems like bronchoconstriction limit air flow
● Interrupted gas exchange impairs the ability to diffuse oxygen and carbon dioxide
○ Low oxygen levels in outside air limit the amount of oxygen that can be inhaled
○ Diffusion problems caused by alveoli that do not work properly limit the ability to
exchange gases
● Circulation issues prevent blood from carrying enough oxygen to the cells of the body
○ Significant blood loss reduces the amount of blood circulated to the alveoli
○ Insufficient hemoglobin or hemoglobin that is not working properly limits the
transport of oxygen
Respiration
Respiration-Adequate and Inadequate Breathing
● Brain and body cells need a steady supply of oxygen to maintain function
○ Hypoxia is a low level of oxygen function
○ Hypercapnia is a high level of carbon dioxide
● Assess the cardiopulmonary system by evaluating how well it is oxygenating and
removing carbon dioxide
● When the cardiopulmonary system fails, the body compensates for hypoxia and
hypercapnia
○ Chemoreceptors stimulate the respiratory system to breathe more rapidly
○ Respiratory rate and heart rate increase and blood vessels constrict
● Respiratory distress
○ Compensation is working
○ The patient has normal mental status, skin color, and oximetry readings
● Respiratory failure (inadequate breathing)
○ Compensation is not working
○ Metabolic needs of the body are not met
● Respiratory failure is a precursor to respiratory arrest
● Inadequate breathing occurs when a challenge is too great for body’s compensatory
mechanisms
○ Rate of breathing, depth of breathing, or both fall outside of normal ranges
Topics
● Physiology and Pathophysiology
● Respiration
● Positive Pressure Ventilation
● Oxygen Therapy
● Special Considerations
● Assisting with Advanced Airway Devices
Physiology and Pathophysiology
Physiology and Pathophysiology-Mechanisms of Breathing
● Ventilation is the process of moving air into (inhalation) and out of (exhalation) the chest
● Inhalation is an active process
○ Chest muscles expand and the diaphragm contracts
○ The size of the chest increases
○ Negative pressure pulls air into lungs
● Exhalation is a passive process
○ Chest muscles and the diaphragm relax
○ The size of the chest decreases
○ Positive pressure pushes air out of the lungs
● Tidal volume is the amount of air moved in one breath
● Minute volume is the amount of air moved into and put out of the lungs per minute
● Ventilation is designed to move air to and from the alveoli for gas exchange
○ Not all of the air breathed reaches the alveoli
○ Some air occupies dead space
● Alveolar ventilation refers to the amount of air that actually reaches the alveoli
○ It can be altered by changes in rate or volume
○ It depends heavily on tidal volume, but is affected by very fast or very slow rates
Physiology and Pathophysiology-Physiology of Respiration
● Alveoli from the ends of the bronchiole tubes
○ Bunches of sacs are inflated and ventilated as air moves in and out
○ Each alveolus is a bubble-like structure
● Pulmonary capillaries bring blood close to the sacs
● Thin alveoli and capillary walls allow for gas exchange
○ Oxygen in the alveoli moves into the blood
○ Carbon dioxide in the blood moves into the alveoli
● Diffusion is movement of gases from an area of high concentration to an area of low
concentration
● Pulmonary respiration is diffusion of oxygen and carbon dioxide between the alveoli and
the circulating blood
● Cellular respiration is diffusion or oxygen and carbon dioxide between the cells and the
circulating blood
, ● In order for pulmonary and cellular respiration to occur, the respiratory and circular
systems work in conjunction
○ This is sometimes called the cardiopulmonary system
○ It may also be called a ventilation-perfusion (V/Q) match
● When either the respiratory or circular system fails, the process of respiration is defeated
Physiology and Pathophysiology-Cariopulmonary Pathophysiology
● Mechanical failures of the cardiopulmonary system limit the ability of the chest to create
pressure changes
○ Stab wounds allow air into the cavity and make it impossible to create negative
pressure
○ Loss of nervous control makes it impossible to innerate respiratory muscles
○ Painful chest wall injuries limit chest wall movement
○ Airway problems like bronchoconstriction limit air flow
● Interrupted gas exchange impairs the ability to diffuse oxygen and carbon dioxide
○ Low oxygen levels in outside air limit the amount of oxygen that can be inhaled
○ Diffusion problems caused by alveoli that do not work properly limit the ability to
exchange gases
● Circulation issues prevent blood from carrying enough oxygen to the cells of the body
○ Significant blood loss reduces the amount of blood circulated to the alveoli
○ Insufficient hemoglobin or hemoglobin that is not working properly limits the
transport of oxygen
Respiration
Respiration-Adequate and Inadequate Breathing
● Brain and body cells need a steady supply of oxygen to maintain function
○ Hypoxia is a low level of oxygen function
○ Hypercapnia is a high level of carbon dioxide
● Assess the cardiopulmonary system by evaluating how well it is oxygenating and
removing carbon dioxide
● When the cardiopulmonary system fails, the body compensates for hypoxia and
hypercapnia
○ Chemoreceptors stimulate the respiratory system to breathe more rapidly
○ Respiratory rate and heart rate increase and blood vessels constrict
● Respiratory distress
○ Compensation is working
○ The patient has normal mental status, skin color, and oximetry readings
● Respiratory failure (inadequate breathing)
○ Compensation is not working
○ Metabolic needs of the body are not met
● Respiratory failure is a precursor to respiratory arrest
● Inadequate breathing occurs when a challenge is too great for body’s compensatory
mechanisms
○ Rate of breathing, depth of breathing, or both fall outside of normal ranges
