5) LMA and Supraglottic Devices

indications for supraglottic device use

alternative to face mask

difficult airways

establish clear airway during resuscitation when ETT can’t be used

when was LMS invented and by whom?

1981 by Dr. Archie Brain

why was the LMA invented?

form a seal around the laryngeal that’s more secure and convenient than a face mask

3 main components of the LMA

airway tube, mask, inflation line

reusable LMAs are made of…

silicone

single use LMAs are made of…

PVC

the curved tube in an LMA is angled at…

30 degrees

the ________ orients the LMA to the midline

black longitudinal line

what’s the purpose of the 2 flexible vertical bars at the entry of the tube?

prevent obstruction by the epiglottis

where does the tip of the LMA go?

upper esophageal sphincter

where do the sides of the LMA face?

pyriform fossae

where do the upper borders of the LMA face?

base of tongue

how many times can a classic LMA can be used?

max 40 times

how many times can a LMA unique be used?

once

what kind of LMA?

classic

what kind of LMA?

unique

3 benefits of using LMA Supreme

improved glottic seal

built in bite block

gastric tube

higher PPV threshold

max peak airway pressure when using LMA Supreme…

30 cmH2O

what kind of LMA?

supreme

4 benefits of using LMA ProSeal

fits better to curve of oropharynx, better seal

built in bite

gastric tube

higher PPV threshold

what kind of LMA?

proseal

what size gastric tube can be used with LMA ProSeal?

</= 16 french

what’s the potential benefit of the LMA Protector being constructed of silicone?

less sore throat

the LMA Protector has similar features to the LMA ________.

unique features include…

supreme

no epiglottic bars → intubating conduit

colored pilot balloon indicates cuff pressure

what kind of LMA?

protector

what kind of LMA?

flexible

Flexible LMA provides better protection from…

blood and secretions above the trachea

Flexible LMA does not offer resistance to…

occlusion by biting

Flexible LMA features a ________ that allows the tube to be bent without ________

wire-reinforced tube, dislodgment of LMA

LMA-Fastrach is also known as…

iLMA

what was LMA-Fastrach (iLMA) designed for?

one-hand use to facilitate blind intubation

what LMA has its own special insertion technique and endotracheal tube?

LMA-fastrach (iLMA)

what tube can’t be used in routine cases and why?

LMA-fastrach causes increased pharynx pressure if used long-term

contraindications to LMA/SGD use in patients with…

high risk for aspiration

fixed pulmonary compliance → requires higher peak airway pressures

inability to provide medical history

does LMA prevent aspiration?

no

what’s the overall incidence of aspiration in general anesthesia?

1-6 in 10,000 cases

what’s the overall incidence of aspiration with LMA?

2 in 10,000 cases

what LMAs allow for max 20 cmH₂O of peak airway pressure?

classic, unique, flexible

what LMAs allow for max 30 cmH₂O of peak airway pressure?

proseal, supreme

what surgical environments would you avoid using LMA?

bed turned 180

patient paralyzed

robotic

LMA size 1: patient size and max cuff volume

<5kg, 4mL

LMA size 1.5: patient size and max cuff volume

5-10kg, 7mL

LMA size 2: patient size and max cuff volume

10-20kg, 10mL

LMA size 2.5: patient size and max cuff volume

20-30kg, 14mL

LMA size 3: patient size and max cuff volume

30-50kg, 20mL

LMA size 4: patient size and max cuff volume

50-70kg, 30mL

LMA size 5: patient size and max cuff volume

70-100kg, 40mL

LMA size 6: patient size and max cuff volume

>100kg, 50mL

what side of the LMA should you lubricate and where will this slide along?

posterior, hard palate

where should you avoid placing lube on an LMA and why?

anterior side, could trigger laryngospasm

advance LMA until definite resistance is felt at the base of the…

hypopharynx

if re-inflated the LMA cuff once inside patient, should you hold the tube or let go?

do not hold tube while reinflating cuff

where to avoid suctioning with LMA and why?

below LMA, cuff forms seal with upper pharynx

do not manipulate LMA with a patient in what phase of anesthesia?

stage 2

when to take out the LMA?

patient shows return of airway reflexes

what to do if LMA does not seal, leaks, or does not seat properly

withdraw it and attempt to place again (don’t keep adding adding air)

what are the limited situations where a muscle relaxant is used with LMA?

facilitate placement

prevent dislodgment

facilitate surgical access

open globe cases

what’s the best patient position for use of LMA?

supine

when using LMA, what are tidal volumes limited to?

8mL/kg

what to do if you can’t get good volumes with the limited peak airway pressure?

convert to ETT

if a case is >3 hrs, what should you consider using?

tube with gastric suctioning ability

if using N₂O, what do you have to check and adjust, and why?

cuff pressure to prevent mucosal damage

when to use a Combitube?

can’t intubate or ventilate

in a blind intubation, ____ of the time, the Combitube will end up in the esophagus

95%

what’s the biggest benefit of Combitube?

achieve ventilation with esophageal or tracheal placement

what kind of LMA?

combitube

Combitube size for 4-6 ft patient

37 french

Combitube size for >6 ft patient

41 french

Combitube size for pediatric patients

none

the proximal cuff of the Combitube seals…

oro and nasopharynx

the distal cuff of the Combitube seals…

upper esophagus

the distal cuff of the Combitube takes ____ of air and is ________ in color

10mL, white

the proximal cuff of the Combitube takes ____ of air and is ________ in color

85mL for 37 french

100mL for 41 french

blue

what depth to insert Combitube?

upper incisors between 2 black guidelines

what should your left hand do when doing a blind intubation with Combitube?

elevate chin

what color connector on the Combitube corresponds to the trachea?

clear

what color connector on the Combitube corresponds to the esophagus?

blue

if unable to ventilate thru either lumen of Combitube, what’s likely happening?

too deep, oropharyngeal balloon is obstructing trachea

how long can a Combitube be left in?

8 hours

max peak airway pressure for Combitube?

50 cmH2O

what kind of supraglottic device?

king laryngeal tube

how many pilot balloons does the king laryngeal tube have?

1 balloon for 2 cuffs

how much air to put in an adult king laryngeal tube?

60mL

how much air to put in a pediatric king laryngeal tube?

35mL

king laryngeal tube sizing is based on…

weight and height

when using the king laryngeal tube, the proximal cuff should lie in the ________ and the distal cuff should lie in the ________

hypopharynx, esophagus

the king laryngeal tube can pretty much never be placed where?

trachea

what 2 things does the Portex Soft-Seal LMA minimize?

trauma and N2O permeation

does the Portex Soft-Seal have epiglottis bars? what does this facilitate?

no, fiberoptic and tube insertion

what kind of LMA?

portex soft seal

what kind of LMA?

ambu aura40

what kind of LMA?

ambu auraonce

what’s the benefits of Ambu Aura40 and Auraonce?

L shaped bend and reinforced tip

what’s the difference between Ambu Aura40 and Auraonce?

how many times you can use it

what kind of LMA?

igel

what’s the benefits of i-Gel LMA?

easy to place

built in bite block

gastric tube

what’s unique about the i-Gel?

no cuff to inflate

what kind of LMA?

fastrach

what LMAs have a built in bite block and gastric channel?

supreme, proseal, igel, protector