Term
What are the goals of oxygen therapy (4)?
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Definition
*Treatment or prevention of hypoxemia
*Decrease work of breathing
*Decrease myocardial work
*Provide sufficient amount of oxygen in the inspired air |
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Term
| What are the four types of hypoxia? |
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Definition
*Anemic
*Hypoxemic
*Hypoperfusion or Stagnant
*Histotoxic |
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Term
| What are the causes of anemic hypoxia? |
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Definition
*Hemoglobin deficiency
*Inability of hemoglobin to combine effectively with oxygen |
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Term
| What lab values are normal in Anemic Hypoxia? |
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Definition
*Alveolar oxygen tension (PAO2)
*Arterial oxygen tension (PaO2) |
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Term
| What lab values are reduced or abnormal in anemic hypoxemia? |
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Definition
*Arterial oxygen content (CaO2)
*Mixed venous oxygen content (CvO2)
*Venous oxygen tension (PvO2) |
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Term
| What are examples of anemic hypoxia? |
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Definition
*Carbon Monoxide poisoning
*Methemoglobinemia |
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Term
| What is the treatment for anemic hypoxia? |
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Definition
*Can include 100% O2
*Blood transfusion or replacement may be needed
*Hyperbaric chamber effective for CO poisoning |
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Term
| What are the causes of hypoxemic hypoxia |
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Definition
| *Associated with conditions causing abnormally low PaO2 levels or oxygenation |
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Term
| What are examples of causes of hypoxemic hypoxia? |
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Definition
*High Altitude
*Hypoventilation
*Decreased FiO2
*Ventilation-perfusion mismatches
*Diffusion impairments |
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Term
| What causes of hypoxemic hypoxia can be effectively treated by oxygen administration? |
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Definition
*Ascent to high altitudes
*hypoventilation
*Diffusion impairments
*Ventilation-perfusion mismatch |
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Term
| What causes of hypoxemic hypoxia are NOT effectively treated by oxygen? |
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Definition
*Absolute intrapulmonary shunting
*Intracardiac disease
*Hypoventilation and subsequent hypercarbia or hypercapnia |
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Term
| What is the cause of hypoperfusion or stagnant hypoxia? |
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Definition
| *Occurs due to greatly decreased cardiac output |
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Term
| What values are reduced with hypoperfusion/stagnant hypoxia? |
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Definition
*Mixed venous oxygen content
*Venous pO2 |
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Term
| What clinical values are normal with hypoperfusion/stagnant hypoxia? |
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Definition
*Alveolar oxygen tension (PAO2)
*Arterial oxygen tension (PaO2)
*Arterial oxygen content (CaO2) |
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Term
| What are examples of causes of hypoperfusion/stagnant hypoxia? |
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Definition
*Cardiac arrest
*Septic shock
*MI
*CHF
*Cardiovascular collapse |
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Term
| What is the treatment for hypoperfusion/stagnant hypoxia? |
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Definition
*MUST treat the cause of the hypoperfusion
*Treatment with oxygen therapyu alone is generally ineffective. |
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Term
| What are the causes of histotoxic hypoxia? |
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Definition
*The amount of oxygen delivered to the tissues is adequate.
*The cells are able to utilize the oxygen due to an aberration in cellular chemistry |
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Term
| What are examples of histotoxic hypoxia? |
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Definition
*Cellular derangement in the oxidative phosphorylation
*Cyanide poisoning |
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Term
| What clinical values are elevated with histotoxic hypoxia? |
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Definition
*Venous oxygen tension (PvO2)
*Mixed venous oxygen content (CvO2) |
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Term
| What values are normal with histotoxic hypoxia? |
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Definition
*Alveolar oxygen tension (PAO2)
*Arterial oxygen tension (PaO2)
*Alveolar oxygen content (CAO2) |
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Term
| What is the treatment for histotoxic hypoxia? |
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Definition
*Must treat at the cellular level.
*Treatment with oxygen therapy alone is ineffective. |
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Term
| What physiological effects occur in the cardiovascular system due to hypoxia? |
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Definition
*Hypotension
*Bradycardia
*Arrhythmias
*Tachycardia- initially followed by profound bradycardia
*Sudden Hypertension
*Cyanosis |
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Term
| What effects does hypoxia have on the pulmonary system? |
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Definition
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Term
| What effect does hypoxia have on the central nervous system? |
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Definition
*Depressed Mentation
*Headache
*Paranoia
*Nausea
*Increased CSF Pressure
*Restlessness/Agitation |
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Term
| What is an adequate PaO2? |
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Definition
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Term
| What PaO2 rests on the steep end of the oxyhemoglobin dissociation curve? |
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Definition
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Term
| What occurs at the steep end of the oxyhemoglobin dissociation curve? |
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Definition
| *Small decrease in PaO2 results in large decreases in SaO2 |
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Term
| What occurs above the steep end of the curve? |
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Definition
| *Small increase in PaO2 results in only small increases in SaO2 |
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Term
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Definition
*Do not provide for all the patient's inspiratory volume
*Entrainment of room air essential to system
*FIO2 varies with amount of air entrained |
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Term
| What are examples of low flow oxygen systems? |
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Definition
*Nasal cannula
*simple masks
*Partial rebreathing systems |
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Term
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Definition
*Contains fixed air-oxygen entrainment ratios
*The device is able to meet the patient's inspired volume and flow needs
*No extraneous air is entrained
*Provide better control of FIO2 than low flow devices |
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Term
| What are examples of high flow systems? |
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Definition
*Air entrainment systems
*Anesthesia machine |
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Term
| What FIO2 can nasal cannula deliver? |
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Definition
| *between 24-50% depending on the patient's respiratory pattern and flow rate used |
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Term
| Where is the reservoir present with a person wearing a nasal cannula? |
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Definition
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Term
| How much does FIO2 increase per each liter per minute? |
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Definition
*2-5% increase in FIO2
*This increase varies as the patient's respiratory pattern increases |
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Term
| With nasal cannula, _________ tidal volume and amount of air entrained _______ FIO2. |
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Definition
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Term
| Decreased Tidal volume with less air entrained will __________ FIO2 delivered. |
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Definition
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Term
| With nasal cannula administration, tidal volume and FIO2 are _________ related |
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Definition
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Term
| As a general rule for each liter increase you can expect a ____% increase in FIO2 |
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Definition
*4%
-ex: 1LPM=24%
2LPM=28%
3LPM=32% |
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Term
| Flow rates greater than ____LPM will not significantly increase FIO2, but will dry mucous membranes and cause irritation. |
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Definition
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Term
| Where is the reservoir for a simple oxygen mask? |
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Definition
| *The reservoir is the mask itself, approx 100mL |
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Term
| What is needed when wearing a simple mask to ensure an accurate FIO2? |
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Definition
| *A regular respiratory pattern |
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Term
| How is room air entrained in an oxygen mask? |
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Definition
*Room air is entrained via side ports of mask
*Exhaled gases also exit via side ports |
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Term
| FIO2 levels between ______ can be achieved with 6-12 LPM flow with a simple oxygen mask |
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Definition
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Term
| What must flows be maintained at with a simple mask to avoid CO2 retention within the mask? |
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Definition
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Term
| What does the reservoir bag fill with in partial rebreathing masks during normal respirations? |
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Definition
*A mix of source and exhaled gases (Low in CO2 and high in O2)
*The first 1/3 of exhalation enters the reservoir bag along with the source gas (O2), remainder of exhalation exits the system via the side ports |
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Term
| What FIO2 range can be achieved with partial rebreathing systems? |
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Definition
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Term
| What should the flow rate be with partial rebreathing systems? |
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Definition
*High enough to prevent collapse of reservoir bag with inspiration
*6-10LPM |
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Term
| What are the constituents of a non rebreathing system? |
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Definition
*Large reservoir bag
*One way valve on side ports (Vented with simple mask)
*One way valve from bag to mask |
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Term
| Describe what happens on inspiration with a non-rebreathing mask |
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Definition
*Mask to bag valve open
*Gases flow in from reservoir bag only
*Side port valves closed
*No air entrained from outside |
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Term
| What happens on expiration with a non-rebreathing mask? |
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Definition
*Mask to bag valve closed
*Side port valves open for exhaled gases to excape |
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Term
| What FIO2 can be achieved and what does the flow rate need to be for a non-rebreather mask? |
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Definition
*In theory 100% FIO2- in fact, slightly less due to poor mask fit around pts face.
*Overall rate needs to be high enough to prevent reservoir collapse during inspiration. |
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Term
| What system is considered a rebreathing system? |
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Definition
*Used in anesthetic arena
*Considered a high flow system- entire inspiratory volume is supplied by the system
*FIO2 of 100 can be delivered |
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Term
| What are the components of a rebreathing system? |
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Definition
*Mask
*Reservoir System
*O2 source
*CO2 absorber |
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Term
| Describe an air entrainment system |
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Definition
*Volume and FIO2 of the gas mixture can be controlled
*Is a high flow system
*Utilizes a fixed Air:02 entrainment ratio (Bernoulli principle)
*Allows FIO2s of >0.95 to be delivered |
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Term
| What FIO2 and flow rates are needed for T-collar/T-bar? |
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Definition
*TC/TB can be connected to patients with ETT or Trachs to provide oxygen enriched inspired gas
*FIO2 between 0.35-1.0
*Flow rate of 10-15LPM |
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Term
| Where is the reservoir on a TB? |
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Definition
| *The little piece on end- 100mL reservoir/place for gas to be expelled-enough dead space so no rebreathing occurs. |
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Term
| What are the complications of oxygen therapy? |
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Definition
*Respiratory depression
*Atelectasis
*Circulatory depression
*Pulmonary oxygen toxicity
*Retrolental fibroplasia |
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Term
| What is the purpose for humidification? |
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Definition
*Prevent dryness and irritation of the mucosa and airways
*Essential to the normal functioning of the respiratory system |
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Term
| What are two categories for modes of humidification? |
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Definition
*Evaporation humidifier devices
*Aerosol Devices |
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Term
| What falls under the category of evaporation humidifier devices? |
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Definition
*Pass-over
*Bubble through
*Cascade humidifiers (Seen on ventilators in ICU) |
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Term
| What falls under the category of aerosol devices for humidification? |
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Definition
*Ultrasonic
*Jet humidifiers
*Babingotn devices |
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