Ch 4 Flashcards
endotracheal tube?
a flexible tube, placed inside the trachea of an anesthetized patient, that is used to transfer anesthetic gases directly from the anesthetic machine into the patient’s lungs, bypassing the oral and nasal cavities, pharynx, and larynx
ET tubes are commonly used for patients undergoing general anesthesia because?
- they maintain an open airway
- decrease anatomic dead space
- allow precise administration of inhalant anesthetics and oxygen
- prevent pulmonary aspiration of stomach contents, blood and other material
- enable rapid response to respiratory emergencies
allow the anesthetist to accurately monitor and control patient respirations
What are the two basic types of ET tubes?
Murphy tubes and Cole tubes
Murphy tubes have?
beveled end, side opening (Murphy’s eye), and are cuffed or noncuffed
Cole tubes have?
no cuff or side hole but have an abrupt decrease in diameter near the patient end of the tube
Cole tubes are used specifically for?
species that have complete tracheal rings such as birds and some reptiles - this is to prevent damage to the trachea that would be caused by a cuffed tube
What are ET tubes made of?
- PVC (polyvinyl chloride)
- red rubber
- silicone
PVC tubes are?
transparent and somewhat stiffer than other types
Red rubber tubes are?
flexible and less traumatic but can kink or collapse, absorb disinfectant solutions, and tend to dry and crack after prolonged use
What are specialized rubber tubes?
spiral or anode tubes which contain a coil of metal or nylon embedded in the rubber designed to resist kinking or collapse from external pressure
Silicone tubes are?
expensive but combine strength with pliability r- resistant to collapse and less irritating to tissues
ET tubes come in ____ lengths.
standard
What is the scale on the side of the ET tube used for?
marks the distance from the patient end in centimeters
- used to estimate the appropriate distance to advance the tube
Tube size is most commonly expressed as the?
internal diameter (ID) in millimeters
ET tubes range in size from ___ to ___.
1 mm for exotic animals to 30 mm for mature large domestic animals
What are the endotracheal Tube parts?
patient end of tube, Murphy’s eye, the machine end, cuff or no cuff, pilot balloon, a valve and a tube tie
What does the Murphy’s eye do?
minimizes the risk of patient asphyxiation in the event that the end hole is blocked with mucous
What is asphyxiation?
act of cutting off the supply of oxygen supply; suffocation
The machine end of the ET tube does what?
protrudes from the mouth or nose and is connected to the breathing circuit of the anesthetic machine via the connector
What does the cuff do?
creates a seal between the tube and trachea
The cuff is connected via a small tube to a pilot balloon and a valve
What is the valve used for on the ET Tube?
used to inflate the cuff. The valve opens to permit air to enter or exit the cuff when a syringe is seated firmly into the valve opening and automatically closes when the syringe is removed.
What is the pilot balloon used for?
allows the anesthetist to monitor cuff inflation visually or manually
A cuffed tube is recommended for what reasons?
- the inflated cuff helps prevent leakage of air and gases around the tube
- minimizes the risk of aspiration of blood, saliva, vomitus, and other material into the lungs
- prevents the animal from breathing room air which could dilute anesthetic gases
ET tubes should be no longer than?
the distance between the most rostral aspect of the mouth and the thoracic inlet
What are the risks if the ET tube is too long?
- if the tube extends an excessive distance inside the trachea, the patient end may enter one main stem bronchus - only one lung will be infused with oxygen and anesthetic gas leading to hypoventilation, hypoxemia and difficulty keeping the patient anesthetized.
- if the tube extends beyond the rostral aspect of the mouth, it will increase mechanical dead space, resulting in hypoventilation (esp in small patients)
What is the guideline for ET Tubes?
if the tube is more than 2.5 cm longer than the distance between the most rostral aspect of the mouth and the thoracic inlet, it is too long and should be cut shorter or replaced with a shorter tube.