Module 2 - Oxygenation and Vital Signs Flashcards
What is the difference between hypoxemia and hypoxia?
Hypoxemia is a condition where the partial pressure of oxygen is lower than normal ( <80 mmHg), indicating an inadequate supply of oxygen in the arterial blood.
Hypoxia involves a reduction in oxygen supply at the tissue level, rather than the partial pressure of oxygen in the arteries.
True or false? A patient who has hypoxemia will also have hypoxia
False. Hypoxia and hypoxemia often go hand in hand, but patients can compensate for low PaO2 by increasing oxygen supply - ^^ cardiac output (^ HR), lowering tissue O2 consumption
True or false? A patient who has hypoxia will also have hypoxemia?
False. If a patient has adequate partial pressure of oxygen in the arteries, but the tissues are unable to use it, or delivery to the tissues is diminished, they may be hypoxic but not hypoxemic.
What is one situation where oxygen supplementation would NOT improve hypoxia?
If the cause for the hypoxia is related to cardiac function (ie. decreased cardiac output, anemia)
What is oxygen supply?
Oxygen that we are breathing in through our lungs and traveling through the circulatory system to tissues
What is oxygen demand?
The amount of oxygen needed by cells to maintain homeostasis, driven partially by metabolic needs
What is oxygenation?
Process of taking oxygen from the environment and delivering it to cells
What is ventilation?
The process of moving air into the alveoli, involves inspiration and expiration
What is respiration?
The exchange of CO2 and O2 at the alveoli and capillaries (external) and at the capillaries and tissues (internal)
What are the 2 types of respiration?
Internal and external
What processes does oxygenation rely on?
Ventilation, external and internal respiration, circulatory system
What factors influence ventilation?
Intact thoracic cavity wall, patent airway, functioning muscles, lungs clear of debris/fluid/obstructions
What are some of the muscles of inspiration?
Main: External intercostals, diaphragm
Accessory: sternocleidomastoid, pectoralis minor
What are some of the muscles of expiration?
Main: Internal intercostals, diaphragm
Accessory: abdominals, quadratus lumborum
What happens if the thoracic cavity is no longer intact?
Will not be able to maintain negative pressure needed to move air into lungs
What types of receptors control ventilation? What area of the brain controls ventilation rate?
Chemoreceptors that monitor for PaCO2 and PaO2 and send signals to the medulla to modify RR and depth
What is PEEP and how does it help improve external respiration?
Positive end expiry pressure (such as a cough, deep breathing, pursed lip breathing). Improves external respiration by increasing the pressure difference and allowing more air to be inhaled
Which type of respiration requires lots of ventilated + intact alveoli, and capillaries close to the alveolar wall?
External respiration
Which type of respiration requires adequate flow of oxygenated blood to cells, diffusion of O2, and the presence of glucose or fatty acids?
Internal respiration
What is the role of glucose or fatty acids in internal respiration?
Primarily provide an energy source for cells to participate in gas exchange
External respiration is the exchange of gases between ______ and ______.
A) atmosphere, blood
B) skin, air
C) atmosphere, skin
D) skin, blood
A is correct
A patient is experiencing difficulty breathing due to a foreign body in the airway. This patient is experiencing difficulty with:
A) internal respiration
B) ventilation
C) external respiration
D) oxygenation
B is correct –> when there’s a foreign body in the airway, this is an issue with the process of getting air in/out of our lungs.
A patient with asthma is having an asthma attack. The patient’s alveoli are collapsing. This patient is experiencing difficulty with:
A) internal respiration
B) ventilation
C) oxygenation
D) external respiration
D is correct –> when the alveoli are involved, it’s usually external respiration.
oxygenation is technically correct as well, but the acute problem causing the issues with oxygenation are the alveoli collapsing
How do we know if pt has good kidney oxygenation?
If we aren’t seeing any issues with urination
How do we know if pt has good cardiac oxygenation?
If the skin colour is normal
How do we know if pt has good neurological oxygenation?
If patient is alert, oriented x4
What does oxygen supply depend on?
Cardiac output and arterial oxygen content
What does cardiac output depend on?
Stroke volume and heart rate
What does arterial oxygen content depend on?
Arterial oxygen saturation and oxygen transport
What does arterial oxygen saturation depend on?
Adequate ventilation and oxygenation (SpO2/O2 sat)
V/Q matching and internal respiration play a big role.
What does oxygen transportation depend on?
Adequate respiration (internal + external) - VQ matching and diffusion
2 factors that contribute to ventilation:
Work of breathing + respiratory rate
What is the most common way to measure arterial oxygen content?
Arterial blood gas (ABG)
What is the difference between PaO2 and SpO2?
PaO2 is a measure of the partial pressure of all the oxygen in the arteries, while SpO2 measures how many hemoglobin molecules are bound to oxygen (basically oxygen content vs saturation)
At what PaO2 is a person considered hypoxic?
<60 mmHg
What conditions must be met for oxygen to be released at the tissues?
Sufficient blood volume, red blood cells, and hemoglobin
What conditions would make it unfavourable for hemoglobin to release oxygen?
Hypothermic, acidic blood pH, high CO2 content
If you were measuring arterial oxygen saturation, which method would you use?
A) ABG
B) Red blood cell count
C) Pulse oximeter
D) sphygmomanometer
C is correct - pulse oximeter uses a laser to measure O2 saturation bc O2 bound to hemoglobin absorbs and emits light of different frequencies
ABG would be performed if we wanted to measure the total arterial oxygen content (bound and unbound O2). It’s more invasive than SpO2 and is usually only done if SpO2 is low.
What does a V/Q mismatch mean?
Ventilation/Perfusion (or external respiration) mismatch means that there is no longer balance between the two activities. Either we are seeing a challenge with getting O2 into the lungs and CO2 out, or we are seeing a challenge with blood flow through the capillaries, or with the membrane between the capillaries and alveoli
What conditions could cause a V/Q mismatch to occur?
Damage to the thoracic wall, weak chest wall muscles, loss of patent airway (as in asthma), thickening of alveolar membrane (as in pneumonia, COPD)
What is the difference between tidal volume and vital capacity?
Tidal volume refers to the amount of air that can be breathed in or out during one respiratory cycle while vital capacity is the maximum amount of gas that can be forcefully exhaled after a forceful inhalation
Essentially normal breathing vs deep breathing
How can nurses measure ventilation?
Counting respiratory rate, examining work of breathing
Also by taking PCO2 from the ABG
What is a normal PCO2? What is considered low PCO2? What is considered high PCO2?
Between 35-45 mmHg
Low is <35 mmHg
High is >45 mmHg
Arterial oxygen content provides information that indicates:
A) enough oxygen has reached the alveolar/capillary bed
B) enough oxygen has reached the cells
C) quality of gas exchange between the atmosphere and lungs
D) quality of blood supply to the alveolar/capillary membrane
C is correct –> it tells us how much O2 is in the blood, which is a measure of the quality of the gas exchange taking place
B is incorrect because it’s not telling us how much O2 has reached the cells, just that we have adequate or inadequate O2 to reach the tissues.
Nurses assess work of breathing to indicate effective:
A) ventilation
B) O2 saturations
C) oxygen content in arterial blood
D) oxygen transport
A is correct –> WOB is a component of ventilation (along with respiratory rate)
Does sepsis increase or decrease our oxygen consumption?
Increase - sepsis is an infection, and to fight an infection, or bodies require increased oxygen
When administering anaesthesia or drugs, what do nurses have to consider (with respect to oxygen consumption)?
Oxygen consumption typically decreases with anaesthesia or neuromuscular blocking drugs, so nurses have to consider a patient’s O2 status and potentially adjust to avoid hyperoxygenation
Are anxiety/irritability/small changes to level of consciousness signs or early or late stage hypoxia?
Early stage. Late stage hypoxia is indicated by general combativeness and aggression.
Why would you see increased respiratory rate or heart rate in a hypoxic person?
HR increases in an attempt to circulate more oxygen to the tissues in distress, and RR increases in an attempt to get more oxygen in.
What are some differences between early and late stage hypoxia?
- changes to level of consciousness (irritable in early stage, combative at late stage)
- shortness of breath on exertion in early stage, SOB at rest in late stage
- pausing for breath while speaking at late stage
- cyanosis or hypotension at late stage, generally no changes to skin colour at early stage
A nurse is caring for a patient with COPD and knows hypoxia may occur with respiratory diseases. What are some signs of mild hypoxia? Select all that apply
A) lethargy
B) dyspnea upon exertion
C) cyanosis
D) SaO2 of 93%
A, B, D are correct
Cyanosis is usually only in late stages
A nurse is caring for a patient with asthma. What method should the nurse use to determine the patient’s oxygen saturation?
A) arterial blood gas
B) pulse oximetry
C) respiration rate
D) chest x ray
B is correct –> pulse ox is the least invasive, easiest method of measuring O2 sat. If we need more info, we can do an ABG
RR won’t tell us about O2 sat, but would tell us about ventilation, and oxygenation status. Chest xrays are usually only done if we suspect an issue within the lungs/chest cavity.
What is one way we can measure CO2 in ventilation?
Capnography
_____ is a sensation of breathlessness in a recumbent position that can be relieved by sitting upright, typically experienced in COPD or heart failure
Orthopnea
_____ is a general sensation of shortness of breath regardless of position, experienced in respiratory and/or cardiac diseases
Dyspnea
_____ _____ _____ is a sensation of shortness of breath that wakes someone up and can be relieved by sitting up. Usually experienced in heart failure
Paroxysmal nocturnal dyspnea
What is the difference between a productive and unproductive cough?
Productive coughs produce a lot of mucous, while unproductive coughs do not
What is meant by a strong cough?
A cough that is easily able to clear mucous from the system.
What is sputum and what can it tell us about a patient’s condition?
Sputum includes any lung secretions, and can give indicators of a patient’s status based on the colour and consistency.
What do fine crackles indicate? What do coarse crackles indicate?
Both types of crackles indicate fluid in the lungs, but fine crackles indicate a thinner fluid in the alveoli and coarse indicate a thicker fluid or fluid in the bronchi/trachea.
What causes a wheezing sound?
Air passing through a narrowed airway, like in asthma
What does stridor indicate?
An obstructed trachea - this needs immediate medical attention
If the alveoli are collapsing, what breath sound would we hear?
Decreased/diminished breath sounds, eventually none at all.
Accessory muscle use, tripod position, and subcostal indrawing are examples of ______ work of breathing.
Severe
What are two main signs associated with severe hypoxia?
Cyanosis and clubbing
What is one of the first interventions if we notice poor breathing sounds or oxygenation?
Chest X-ray! It’s pretty non-invasive and can give us info about fluid in lungs, collapsed lung, other chest wall structures
What are the steps of the ICOUGH protocol?
I = incentive spirometry every hour or so to measure how forcefully they breathe
C = coughing/breathing techniques
O = oral care
U = understand ICOUGH
G = get out of bed (ambulate)
H = head of bed elevation
What amount of O2 is a nurse allowed to administer?
2 L/min via nasal prongs. Anything else has to come from physician
What criteria must be met to administer supplemental O2?
Increased WOB, low O2 sat, high RR, signs of hypoxia
A nurse should be most concerned by which breath sounds?
A) coarse crackles with cough + short of breath
B) asthma attack with wheezing
C) stridorous breath sounds
D) use of rescue inhaler every day
C is correct –> stridor always indicates some type of upper respiratory tract distress, which needs immediate medical attention
If a nurse is assessing someone with atelectasis (collapsed alveoli), what sound would they expect to hear?
A) diminished breath sounds
B) stridor
C) wheezes
D) crackles
A is correct –> when the alveoli collapse, we are not experiencing adequate gas exchange, which leads to diminished breath sounds
