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Questions and Answers
What is the definition of relative humidity?
What is the definition of relative humidity?
- The total amount of water vapor in the air at any temperature.
- The absolute moisture content in milligrams per liter.
- The amount of water vapor present in relation to the air pressure.
- A ratio of the amount of water in a gas compared to its capacity at a specific temperature. (correct)
What occurs at the isothermic saturation boundary (ISB)?
What occurs at the isothermic saturation boundary (ISB)?
- Temperature and humidity levels remain constant during inspiration.
- Humidity levels drop significantly as air moves deeper into the lungs.
- The inspired air is fully saturated at body temperature. (correct)
- Airway bypass leads to a higher humidity deficit.
Which factor does NOT shift the ISB deeper into the lungs?
Which factor does NOT shift the ISB deeper into the lungs?
- Breathing through the mouth.
- Breathing cold, dry air.
- Upper airway bypass.
- Increased humidity in inspired air. (correct)
What is the purpose of humidity therapy?
What is the purpose of humidity therapy?
What happens to the temperature and humidity levels during inspiration above the ISB?
What happens to the temperature and humidity levels during inspiration above the ISB?
What is a common function of the nose in the respiratory system?
What is a common function of the nose in the respiratory system?
When the inspired air is fully saturated, how much water does 1 liter hold at body temperature?
When the inspired air is fully saturated, how much water does 1 liter hold at body temperature?
Which humidifier type is common for oronasal oxygen delivery systems?
Which humidifier type is common for oronasal oxygen delivery systems?
What is the primary purpose of a humidifier?
What is the primary purpose of a humidifier?
What risk accompanies breathing dry gas through an endotracheal tube?
What risk accompanies breathing dry gas through an endotracheal tube?
What is the term for the difference between the inspired air and the body’s humidity needs?
What is the term for the difference between the inspired air and the body’s humidity needs?
Which principle affects humidifier performance the most?
Which principle affects humidifier performance the most?
What is the expected change in humidity levels when using a bubble humidifier at flow rates higher than 10 lpm?
What is the expected change in humidity levels when using a bubble humidifier at flow rates higher than 10 lpm?
When expressed as a percentage, how is humidity deficit calculated?
When expressed as a percentage, how is humidity deficit calculated?
What is the purpose of a hydrophobic membrane in gas humidification?
What is the purpose of a hydrophobic membrane in gas humidification?
Which aerosol device generally produces the highest output without heating?
Which aerosol device generally produces the highest output without heating?
What can cause decreased air entrainment and increased FiO2 in a nebulizer setup?
What can cause decreased air entrainment and increased FiO2 in a nebulizer setup?
In what way is an impeller nebulizer commonly used?
In what way is an impeller nebulizer commonly used?
What is a potential risk when using aerosol therapy in infants?
What is a potential risk when using aerosol therapy in infants?
What is the primary function of a device known as an 'artificial nose' in respiratory therapy?
What is the primary function of a device known as an 'artificial nose' in respiratory therapy?
How does a piezoelectric transducer in an ultrasonic nebulizer work?
How does a piezoelectric transducer in an ultrasonic nebulizer work?
What might cause inadequate aerosol output from an aerosol device?
What might cause inadequate aerosol output from an aerosol device?
What size range do 90% of aerosol particles produced by ultrasonic nebulizers fall within?
What size range do 90% of aerosol particles produced by ultrasonic nebulizers fall within?
Why is it important to monitor the condition of a nebulizer during use?
Why is it important to monitor the condition of a nebulizer during use?
What should be done if bronchospasm occurs during aerosol therapy?
What should be done if bronchospasm occurs during aerosol therapy?
What characteristic is necessary for effective high-density mist delivery?
What characteristic is necessary for effective high-density mist delivery?
What is one effect of using hypertonic saline in respiratory therapy?
What is one effect of using hypertonic saline in respiratory therapy?
Which statement about the use of liquid particles in aerosol therapy is true?
Which statement about the use of liquid particles in aerosol therapy is true?
Study Notes
Humidity & The Respiratory System
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Absolute Humidity: Amount of water vapor in a given volume of air. Measured in mg/L.
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Relative Humidity (RH): Ratio of the amount of water vapor in air to the maximum amount it can hold at a given temperature, expressed as a percentage.
- Formula: RH = (Absolute Humidity / Capacity) x 100
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Humidification: Process of adding water vapor to inspired gas.
- Objectives: Compensate for water loss during dry gas delivery or upper airway bypass, maintain normal physiologic conditions in lower airways.
Humidification in the Respiratory Tract
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Normal Humidification: Air passing through the nose, pharynx, trachea, and bronchial tree becomes warmed and humidified.
- At the isothermic saturation boundary (ISB), about 5 cm below the carina, inspired air achieves Body Temperature and Pressure Saturated (BTPS), reaching 100% RH at 37 degrees Celsius.
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Factors Shifting ISB:
- Mouth Breathing
- Cold, Dry Air
- Bypassing Upper Airway
- High Minute Ventilation
Humidity Deficit
- Humidity Deficit: Difference between the inspired air's water content and what the body needs.
- Can be expressed in mg/L or as a percentage.
- Formula: (Humidity deficit / 44 mg/L) x 100
Clinical Applications of Humidification
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Primary Indications:
- Humidify dry medical gases
- Overcome humidity deficit caused by upper airway bypass
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Secondary Indications:
- Managing hypothermia
- Treating bronchospasm caused by cold air
Hazards of Dry Gas Delivery
- Bypassing the Upper Airway: Increased risk of breathing dry gas, especially through an endotracheal tube.
- Dry gas can damage tracheal epithelium within minutes.
Principles of Humidification
- Humidifier Function: Devices that add molecular water to a gas.
- Key factors: Temperature, surface area, contact time.
- Humidifiers with higher temperatures produce more water vapor.
Types of Nebulizers
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Bubble Humidifiers:
- Low flow: Provides about 25% body humidity.
- High flow: Effectiveness decreases, limited at flows > 10 lpm.
-
Passover Humidifiers:
- Direct gas over water.
- Types: Simple, wick, membrane.
- Can deliver 100% body humidity.
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Heat Moisture Exchangers (HMEs):
- Artificial nose.
- Uses exhaled heat and moisture to humidify inspired gas.
- Short-term humidification (up to 48 hours).
Aerosol Therapy
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Aerosol: Liquid particles suspended in a gas.
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Clinical Uses:
- Mobilize respiratory secretions
- Prevent/Relieve bronchospasm
- Hydrate airway for tracheostomy patients
- Induce cough for sputum collection
Types of Nebulizers
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Large Volume Jet Nebulizers:
- Most common.
- High velocity gas through a jet orifice creates aerosol.
- Utilizes Bernoulli principle (entrainment of room air).
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Impeller Nebulizers:
- Spinning disk.
- Less effective for clinical aerosol generation.
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Ultrasonic Nebulizers:
- High frequency vibrations create aerosol.
- Produces fine particle size.
Aerosol Delivery Devices
- Masks: Used for aerosol administration.
- Face Tents: Used for aerosol administration.
- Tracheostomy Devices: Used for aerosol administration.
- Mist Tents: Used for aerosol administration.
Complications of Aerosol Therapy
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Overhydration:
- Risk highest in infants, small children, and patients with fluid/electrolyte imbalances.
- Daily water gain for adults: 200 ml.
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Bronchospasm:
- Stop therapy, administer O2, bronchodilator.
- May need to provide bronchodilators at specific intervals if aerosol treatment is continued.
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Other Complications:
- Swelling of secretions
- Cross-contamination/infection
- Environmental safety
- Inadequate aerosol output
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Description
Explore the crucial relationship between humidity and the respiratory system in this quiz. Learn about absolute and relative humidity, the process of humidification, and how air is conditioned in the respiratory tract. Test your knowledge of concepts such as the isothermic saturation boundary and factors affecting humidification.
