131 Mock Final Flashcards
What is the point in the respiratory track where inspired gas reaches body temperature, ambient pressure, saturated (BTPS) conditions?
Isothermic saturation boundary
What factors cause the isothermic saturation boundary (ISB) to shift farther down into the airways?
Decreased ambient temperature
Increased tidal volume (VT)
Endotracheal intubation
What is the primary goal of humidity therapy?
Maintain normal physiologic conditions
Indications for warming inspired gases include all of the following except:
Reducing upper airway inflammation or swelling
What can the inhalation of dry gases do?
Increase viscosity of secretions
Impair mucociliary motility
Increase airway irritability
What inspired conditions should be maintained when delivering medical gases to the nose or mouth?
50% relative humidity (RH) at 20° to 22° C
What inspired conditions should be maintained when delivering medical gases to the hypopharynx, as when administering oxygen by nasal catheter?
95% RH at 29° to 32° C
What device adds molecular water to gas?
Humidifier
What is the most important factor determining a humidifier’s performance?
Temperature
Gas leaving an unheated humidifier at 10° C and 100% relative humidity (absolute humidity = 9.4 mg/L) would provide what relative humidity at body temperature?
About 20%
What is the simplest way to increase the humidity output of a humidifier?
Increase the temperature of either the water or the gas.
What types of humidifiers are used in clinical practice?
Heat-moisture exchanger
Passover humidifier
Bubble humidifier
What is the goal of using an unheated bubble humidifier with oronasal oxygen delivery systems?
Raise the humidity of the gas to ambient levels
Why should you NOT heat the reservoirs of a bubble humidifier used with an oronasal oxygen delivery system?
Condensate will obstruct the delivery tubing
What is used to protect against obstructed or kinked tubing in simple bubble humidifiers?
Pressure relief valve
When checking an oxygen delivery system that incorporates a bubble humidifier running at 6 L/min, you occlude the delivery tubing, and the humidifier pressure relief immediately pops off. What does this indicate?
Normal, leak-free system
A design that increases surface area and enhances evaporation by incorporating an absorbent material partially submerged in a water reservoir that is surrounded by a heating element best describes what type of humidifier?
Wick
What are types of heat-moisture exchangers (HMEs)?
Simple condenser
Hygroscopic condenser
Hydrophobic condenser
A heat-moisture exchangers has an efficiency rating of 80%. What does this mean?
Of the exhaled water vapor, 80% returns to the patient on inspiration
According to the National Institute of Standards and Technology of the U.S. Department of Commerce, a gas cylinder that is color-coded brown and green should contain which of the following?
Helium
Oxygen
The gauge on an E cylinder of O2 reads 800 psig. About how long would the contents of this cylinder last, until completely empty, at a flow of 3 L/min?
1 hour 20 minutes
What do the components of a liquid O2 bulk storage tank include?
Inner and outer steel shells, separated by a vacuum
Safety system that vents O2 if warming occurs
Vaporizer system that converts liquid O2 to gas
Pressure-reducing valves to lower pressure to 50 psig
What are specific clinical objectives of oxygen (O2) therapy?
Decrease the symptoms caused by chronic hypoxemia
Decrease the workload hypoxemia imposes on the heart and lungs
Correct documented arterial hypoxemia
What are signs and symptoms are associated with the presence of hypoxemia?
Tachypnea
Tachycardia
Cyanosis
