Exam 2- Breathing System I (6/26/23) Flashcards
What are the six functions/definitions of the breathing system per Dr. Erickson?
- Receives gas mixture from the machine
- Delivers gas to the patient
- Removes CO2
- Provides heating and humidification of the gas mixture
- Allows spontaneous, assisted, or controlled respiration
- Provides gas sampling, measures airway pressure, and monitors the volume
What are the six desirable characteristics of a breathing circuit per Dr. Erickson?
- Low resistance to gas flow
- Minimal rebreathing
- Removal of CO2 at rate of production
- Rapid changes in delivered gas when required
- Warmed humidification of inspired gas
- Safe disposal of waste gases
Name and Describe the four classifications of breathing circuits.
- Open - No reservoir bag and no rebreathing (nasal cannula)
- Semi-Open - Reservoir bag but no rebreathing d/t FGF > minute ventilation.
- Semi-Closed - Reservoir bag w/ partial rebreathing
- Closed- Reservoir bag and complete rebreathing, FGF equivalent to patient uptake
When would you want a closed breathing circuit?
- Conserve patient’s temperature
- Trying to be economical and not waste any gas
- Trying to perform low flow anesthesia
Name the components of the breathing system.
- Facemask, LMA, ETT
- Y-piece with mask/ tube connectors
- Breathing tube (corrugated tubing)
- Respiratory Valves (unidirectional)
- Fresh gas inflow site
- APL (Pop-off) Valve leading to scavenger
- CO2 absorption canister
- Reservoir Bag
The facemask needs to fit between the _____________ and in the groove between the ___________ and alveolar ridge.
- interpupillary line
- mental process
The facemask will connect to the Y-piece/connector, how big is the female connection?
- 22 mm
A fitting that joins together 2 or more components.
- Connectors/ Adapters
What are the benefits of connectors and adaptors?
- Extends the distance b/w patient and breathing system
- Change the angle of the connection
- Allow more flexibility/ less kinking (The accordion will give you the most flexibility)
What are the disadvantages of connectors and adaptors?
- Increased resistance
- Increased dead space
- Additional locations for disconnections
How long is the breathing tubing?
What is the internal volume of the breathing tubing?
- 1 meter in length
- 400-500 mL for each meter in length
Describe the flow in the corrugated breathing tubing.
- Turbulent Flow
True/False: Breathing tubes connected together to increase tube length will increase dead space.
- False
- Longer tubes do not create deadspace
- Dead space is only from Y-piece to patient
Pressure check the circuit before use. What value should this be?
- 30 cm H2O
With a normal tidal volume. How much air is in the anatomical deadspace?
- 150 mL
That is why we deliver at least 300 mL of tidal volume in simulation for adequate ventilation.
What directs respiratory gas flow in the correct direction?
- Unidirectional valves
These unidirectional valves must open widely with very little pressure. Low resistance, high competence. Open/Close rapidly with no backflow.
The inspiratory valve opens on ___________.
The inspiratory valve close on _________.
What does the inspiratory valve prevent?
- The inspiratory valve opens on inspiration.
- The inspiratory valve close on exhalation.
- Prevents backflow of exhaled gas
The expiratory valve opens on ___________.
The expiratory valve close on _________.
What does the expiratory valve prevent?
- The expiratory valve opens on exhalation.
- The expiratory valve close on inspiration.
- Prevents rebreathing
Proper valve placement and functioning prevents any part of the circle system from contributing to _________.
- Apparatus Dead Space
What composes the apparatus dead space?
- Distal limb of Y-connector
- Tube/mask/LMA
The unidirectional valves are located near what parts of the breathing system?
- CO2 absorber canister
- Fresh gas inflow site
- APL Valve
What are the requirements of unidirectional valves?
- Arrows/ Directional words
- Hydrophobic - needs to repel water/moisture
- Must open and close appropriately
- Clear dome - need to visualize if valves are working
- Must be placed between patient and reservoir bag
How much volume is in a traditional reservoir bag?
- 3 L
Can range from 0.5 to 6 L
All reservoir bags must have _____ mm female connector on the neck.
- 22 mm
Anesthesia reservoir bags must adhere to pressure standards, which mandate a minimum pressure of approximately _____ cm H2O and a maximum pressure of approximately ____ cm H2O when the bag is filled to four times its stated capacity.
- 30 cm H2O (minimum)
- 60 cm H2O (maximum)
Although most bags adhere to these standards, some latex-free bags have exceeded the upper pressure limit.
Which unidirectional valve is more likely to be stuck? Inspiratory or Expiratory?
- The expiratory valve is more vulnerable because it is subject to greater moisture exposure.
Miller pg. 605
What are the functions of the reservoir/breathing bag?
(1) Reservoir for anesthetic gases/oxygen
(2) A means of delivering manual ventilation or assisting spontaneous breathing
(3) Serving as a visual or tactile means of monitoring a patient’s spontaneous breathing efforts
(4) Partially protecting the patient from excessive positive pressure in the breathing system.
What is another name for the Gas Inflow site?
- Fresh gas inlet