W3 (1) Flashcards
What are the key numbers to know about oxygen?
Maximum pressure on the manometer when giving a breath (20)
Minimum pressure of oxygen in the tank prior to an anesthetic event (500psi)
Oxygen flowrates
Tidal Volume
(TV): The amount of air that passes into or out of the lungs in a single breath
Based on body weight
Tidal Volume = 5 mls/lb. (10 – 15 ml/kg)
TV = 5 x weight (lbs)
Respiratory Minute Volume
(aka Minute Ventillation): The total amount of air that moves into and out of the lungs in 1 minute
Minute Volume = Tidal volume x RR
What are the Oxygen flowrates at Cscc
Partial Rebreathing system:
- Induction – 3 L/min
- Maintenance Range
- 10-20 L/lb/min
- Minimum of 500 ml/min
- Recovery – 3 L/min
Non-rebreathing system:
- Induction – 3 L/min
- Maintenance Range
- 1.5-2 x (Minute ventilation)
- 1.5-2 x (TV x RR) (units = ml/min)
- Recovery – 3 L/min
What are the rules of the rebreathing bag?
Rebreathing bag size = TV x 5 (mls)
Always round up
What are the components of the anesthesia machine
- Compressed gas supply
- Anesthesia vaporizer
- Breathing circuit
- Scavenging system
Function of inhalation anestetic machines
- deliver volatile anesthetic gases
- delivery is via a carrier gas (oxygen, oxygen / nitrous oxide)
- controlled flow rate of delivery
- container in which liquid anesthetic is placed (vaporizer)
- carrier gas passes over volatile liquid and vapors carried to patient
- move exhaled gases away from patient
- scavenging system
- carbon dioxide absorbing / removing system
Pop-off valve related morbidity and mortality
- Left closed, excessive pressure build in the anesthetic system. In the short term the patient is unable to ventilate which increases PaCO2 and decrease PaO2.
- As pressure builds, pulmonary barotrauma develops; in the extreme, lungs rupture and collapse as pneumothorax develops.
- Hypoxic brain damage, including blindness, can result. Pneumothorax requires chest aspiration and possible chest tube placement. Pyothorax could develop.
- The cost of extended hospitalization and the mental anguish associated the patient’s disease and potential death is incalculable.
Shutting down the oxygen system
- Oxygen tank valve closed
- Pop Off Valve Open
- Oxygen flush valve depressed
- Pressure Manometer at zero
- Tank Pressure Gauge at zero
Pressure checking the anesthesia machine
- Oxygen tank valve open
- Pop off Valve closed
- Occlude opening of Y piece
- Oxygen flush valve depressed OR Open Flow meter
- Pressure Manometer at 20 cmH20
- Watch for Manometer pressure to be maintained
- Open Pop Off Valve
- Assure Manometer pressure is 0 cm H20
- Release opening of Y piece
Non-Rebreathing circuits
Patients Less than 15 lbs.
- Non-Rebreathing circuits are designed to deliver oxygen and anesthetic gases with less resistance to breathing in small patients under 15 lbs. (7 kg)
- These circuits do not use a soda lime canister
- Use specially designed circuits and a higher fresh gas flow to remove carbon dioxide
Mechanical Dead space
- Dead space in the breathing circuit is the space where inhalation and exhalation coincide
- Since the patient breathes in and out of the same tube, they could inhale exhaled gas (containing CO2)
How to switch from Rebreathing to Non-rebreating system
- Removes the CO2 absorber
- Removes the flutter valves
- Removes the manometer
- Removes the y-piece
- Ensure oxygen flow is off
- Disconnect the rebreathing circut at the fresh gas hose
- Attach the fresh gas hose to the non-rebreathing circuit
Will have a different pop-off valve and scavenger connection
What are the pertenant parts of the Respiratory system for inhalant anesthesia
- Trachea
- Bronchi
- Bronchioles
- Alveoli
What are the different gas delivery methods
- Mask
- Chamber
- Endotracheal tube
