Endotracheal Tubes and Supraglottic Airways Flashcards Preview

Anesthesia Equipment Exam 1 > Endotracheal Tubes and Supraglottic Airways > Flashcards

Flashcards in Endotracheal Tubes and Supraglottic Airways Deck (24)
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What is the major difference between supraglottic and subglottic airways?

1. Supraglottic does not go through the vocal cords
2. Subglottic: goes through the vocal cords


Supraglottic Airway/LMA

1. Less invasive airway- non irritating to bronchial tree, less anesthetic required
2. relatively quick and easy to insert
3. requires no special equipment for insertion
4. less coughing on emergence
5. if removed inflated, secretions come out with LMA
6. Less chance of kinking, but may be more likely to dislodge
7. Can avoid mask ventilation



1. Aspiration protection (GERD, full stomach, lap)
2. More "secure" airway, less like to dislodge
3. Ability to positive pressure ventilate at higher peak pressures
4. Used if post operative ventilation required (obese, lung disease)
5. Protects against laryngospasm with ETT in place


Sizes of ETT

1. Based on internal diameter (ID)
-2.5 (mm) to 9.0 (mm)
2. Adults: 7.0-9 mm
3. Children: age divided by 4 + 4
-compare diameter of ETT to pinky size
-depth= ETT X3


Premature infant size ETT vs adult size?

1. Premature infants= 2.5 mm ID
2. 2-years of age= 4.5 mm ID
3. Adults= 6.5-7.0 mm ID


ETT Poiseuille's Law

R= 8 X N X L/ pi r ^4

n= viscosity


Microlaryngoscopy Tube (MLT)

-small diameter, longer ETT to facilitate the view of airway
-size 5.0-6.0 mm
-OTO cases normally use this


Depth of ETT

- usually 22-26 depth


Cuffed ETTs: low volume, high volume?

-low volume, high pressure
-high volume, low pressure


Nasal RAE insertion tips

-place ETT in warm saline container
-mix Afrin with 2% lidocaine jelly
-dilate nasal passage with nasal trumpets lubricated with above solution
-use McGill forceps to guide tube, but often with external laryngeal manipulation, ETT will directly & naturally want to go through vocal cords


Laryngectomy/Tracheal Stoma ETTs

-"J tube"
-placed through stoma
-can be done awake or asleep
-a regular tube can be used, but these are much more convenient


Supraglottic Airway: Laryngeal Mask Airway (LMA)

-Dr. Archie Brain
-essentially a big oral airway that fills entire pharynx
-LMA is trade marked
-ASA difficult airway algorithm stresses early insertion of LMA in the event of difficult mask
-reusable, no bells and whistles.
-no latex
-some single use LMA
-cuff pressure should be less than 60 cm H2O
- if controlled ventilation used, peak inspiratory pressure should be kept below 20 cm H2O


Insertion technique for LMA: cuff inflation volume

-cuff inflated to leak of less than 20 cm H2O
max cuff volume for size 4-5= 30-40 ml


Proseal LMA (esophageal drain)

-Has 4 main parts: cuff, inflation line with pilot balloon, airway tube, and drain tube.
-size 4 for adult women and 5 for most adult men
-smaller and shorter than LMA-Class, wire reinforced which makes it more flexible
- accessory vent under drainage tube prevents secretions from pooling
-allows liquids and gases to escape from the stomach, which reduces risk of gastric insufflation and pulmonary aspiration
-when inserting patient's head should be in sniffing position
-associated with higher leak pressures
-peak inspiratory pressure should be kept below 30 cmH20


LMA supreme

-fixation tabs
-bite block
-do not need muscle relaxant with these
-single use, built in drain tube and works to protect airway from epiglottic obstruction
-gentle curve to allow for easier insertion and more stable placement


What supraglottic can you intubate through?

-LMA Fastrach
-has metal handle attached to it


LMA C Trach

-weights less than 8 ounces and is totally wireless
-30 minutes of uninterrupted viewing
-has dedicated Et tube with atraumatic tip
-two fiberoptic bundles emerge at the distal end of the airway tube under the modified epiglottic elevating bar, which optimizes the light source and enables image transmission to the viewer while protecting the airway tube from obstruction.
-lifts epiglottis out of the way
-ET can pass through it



-accurate and natural positioning
-positions itself over the laryngeal framework, providing a reliable perilaryngeal seal without the need for inflatable cuff
-integrated bite block and belly suction
-theres a line on i-gel that tells you how deep to place it


Complications of Supraglottic Airways

-sore throat, trauma from insertion
-nerve injury including hypoglossal nerve- vocal cord paralysis (reported as temporary), excessive high cuff pressures, use of nitrous oxide
-gastric distention and aspiration
-nitrous can work its way into cuff*


Ring, Adair, Elwin (RAE) ETTs

-can bend to whatever way you need them to
-heat them up and they will stay that way
-when surgeons working on the face can adjust how tubing falls
-can use metal stylet in oral BUT NEVER nasal*


Standard Insertion of LMA-Classic

1. midline or slightly diagonal approach with cuff fully deflated
2. Head should be extended and neck flexed (sniffing)
3. jaw can be pulled down by assistant. the tube portion is grasped and the index finger pressing on the point where the tube joins the mask
4. It is pressed upward against the hard palate
5. if mask feels like tip is flipping over on itself, remove and restart


LMA- Unique

-single use
-same insertion as LMA-classic
-protection against infection


LMA- Flexible

-wire reinforced tube that is longer and narrower than LMA-CLassic
-single use or reusable is also available
-can be bent in any angle without kinking
-allows for positioning away from surgical field
-less likely to become displaced
-designed for surgical procedures: head, neck, and upper torso
-NO bite block***
-NOT for MRI


LMA Fastrach

-can intubate through this (large enough for 9.0 ET to be placed through it)
-tip is slightly curved to prevent traumatic insertion
- latex free
-size 3-5
-for insertion does not require placing fingers into the patient's mouth
-muscle relaxants not needed for insertion
-NOT for MRI*