Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
34 Cards in this Set
- Front
- Back
|
What is Humidity?
|
Water in a gaseous state
Water vapor Molecular water Invisible moisture As soon as the water vapor becomes visible, it is aerosol |
|
|
Indications for humidification and warming of inspired gases
|
Administration of dried therapeutic medical gases NC > 4L/Min or Pt. preference
Overcome humidity deficit created when upper airway is bypassed Secondary Indications Hypothermia Bronchospasm brought on by cold air Cool humidity for upper airway swelling |
|
|
Humidity Compared to Aerosol
|
Humidity Therapy
Makes up for water loss when dry gas is delivered Makes up for water loss when upper airway bypassed Aerosol Therapy Uses water to make a visible mist to add to the airway May be used in thinning of secretions Also used for bypassed airway when OFF the vent |
|
|
Fully saturated inspired air (BTPS)
|
**********Holds 44 mg H2O per liter of gas (44mg/L) *********
********** Exerts 47 mm Hg of water vapor pressure ********* |
|
|
Relative Humidity
|
A % of the vapor capacity of a gas
The % water vapor gas is holding - compared to what it could hold Capacity = Water content when fully saturated Water content standard at various temperatures: can be found on tables - Equipment Book, pg. 99 You can directly measure RH using a Hygrometer |
|
|
Actual (absolute) Humidity
|
= the actual measurable content of water vapor in a gas = mg/L
|
|
|
Relative Humidity
|
The amount of water vapor in a gas expressed as a percentage of the capacity of that gas. In other words, it is the actual humidity expressed as a percentage. = %
|
|
|
Relative humidity
|
= (Actual (absolute) humidity / capacity (x100)
|
|
|
Actual humidity Calculation
If the TV weather person says: "Today it is 30 degrees Celsius with a relative humidity of 45% - what is th actual humidity? |
Actual humidity = Relative Humidity X Capacity
Actual humidity is the weight of the water vapor in a volume of gas - it is given in mg per Liter of gas mg/L .45 (RH) x 30.35 mg?L (capacity @ 30 celsius) (table) Actual Humidity = 13.66 mg/L |
|
|
Body humidity
|
The RH at body temperature
Expressed as a percentage We know that 44 mg/L is the capacity of water vapor at body temperature 37C What % of the ideal capacity (BTPS) is the gas supplying? BH = Absolute or actual Humidity / 44mg/L |
|
|
Humidity Deficit
|
Body Humidity - Actual Humidity
|
|
|
Most important respiratory gasses
|
O2
Carbon Dioxide |
|
|
O2
|
odorless
tasteless |
|
|
CO2
|
Colorless
Sour taste at high conentrations Found in very low concentrations in fresh air Asphyxiant |
|
|
Abnormal respiratory gas
|
Carbon Monoxide CO
Colorless Odorless tasteless results from incomplete combustion of carbon-containing compounds Heavier than air |
|
|
Respiratory Gas measurement
|
Arterial Blood Gas sampling
Pulse Oximetry Co-Oximetry - hemoglobin bound with carbon Monoxide |
|
|
Arterial Blood Gases
|
Gold standard for respiratory gas monitoring
Invasive Expensive Painful Difficult Excellent diagnostic tool Impractical in the prehospital setting |
|
|
SaO2 or SpO2?
|
SaO2 used for oxygen saturation readings derived from arterial blood gas analysis
SpO2 used for oxygen saturation readings from pulse oximetry. SpO2 and SaO2 are normally very close. |
|
|
Pulse Oximetry cannot tell you:
|
O2 content of the blood
Amount of O2 dissolved in plasma Respiratory rate or tidal volume (ventilation) Cardiac output or blood pressure. |
|
|
Isotonic
|
Isotonic solutions have equal osmotic pressure
|
|
|
Amplitude
|
The amplitude of a periodic variable is a measure of its change over a single period (such as time or spatial period).
|
|
|
Hygroscopy
|
Hygroscopy is the ability of a substance to attract and hold water molecules from the surrounding environment.
|
|
|
HME's - Heat Moisture Exchanger
|
AKA Artificial nose (**** NBRC***)
Humidity/warmth from lungs absorbed into hygroscopic filter on exhalation On inhalation humidity/warmth streamed back into lungs About 70-90% body humidity returned at 30-31C (equp pg. 122) Must be changed regularly Secretions Time 48 hours (**** NBRC *****) Short term usage <96 hrs. |
|
|
Administration of dry medical gases at flows greater than ____ L/m to the upper airway causes:
|
4L/min
causes immediate heat and water loss and if prolonged, causes structural damage to the epthelium |
|
|
indications for humidification therapy
|
humidifying dry medical gases
overcoming humidity deficit created when upper airway is bypassed managing hypothermia trating bronchospams caused by cold air. |
|
|
Clinical signs and symptoms of inadequate airway humidification
|
atelectasis
dry, nonproductive cough increased airway resistance increased work of breathing patient complaint of substernal pain and airway dryness thick, dehydrated secretions |
|
|
Aerosol Defined
|
Suspension of water in a particulate form (or mist) in gas
Nebulizers produce aerosolized gas Nebulizers are often referred to as aerosol generators Bland aerosols include: aerosols that consist of water, saline solutions, or similar substances that do not have important pharmacologic action. ******* called nebulizers or "aerosol generators" |
|
|
sedimentation
|
occurs when aerosol particles settle out of suspension and are deposited owing to gravity
|
|
|
vapor content
|
the amount of water present in the air.
Measured in mg/L water vapor content at body temp is 44mg/L, at room temperature it is less |
|
|
vapor pressure
|
water vapor pressure in the lungs exert 47 mmHg
|
|
|
Isothermic Saturation Boundry
|
The point at which inspired gases are fully 100% saturated and warmed to body temperature (44mg/L at 37 degrees Celcius
at or just below carina |
|
|
Hazards/Contraindications of Aerosol Therapy
|
Bronchospasm
Consideration of reactive airways water inhaled medications Overhydration (esp. infants) Electrolyte imbalances Excess NS = hypernatremia Infection Pseudomonas aeruginosa, Legionella pneumophila Aspiration of condensation Drain tubing/bag, change out every 24 hours Swelling of inspissaated secretions causing plugs Drug concentration Solute % may increase by jet/ultrasonic processing Gas overheating Noise: neonates (touch time) |
|
|
*** NBRC= Bypassed airway =
|
heated and humidified
|
|
|
Briggs Adaptor
|
Aka t-piece, T=tube, clear T
Attaches to ETT or Trach tube for weaning from ventilators Provide adequate exhalation reservoir for flow needs (6 inches per NBRC ******) |
