using the laryngeal mask airway norman l. goody, md

Using the Laryngeal Mask Airway

Norman L. Goody, MD

Objective Using the LMA LMA and the Difficul

t Airway LMA and Pediatric A

nesthesia LMA and OB Anesth

esia Advantages of Usin

g the LMA

Disadvantages of the LMA

Complications Arising from Use of the LMA

Contraindications to Using the LMA

History of the LMAdevelopment began in 1981 at Royal London H

ospital by Dr. Archie Brain

modification of the Goldman Dental Mask

available commercially in UK since 1988 and in the US since 1992

now used in >50% of general anesthetics in some centers in UK (and probably US, too- especially ambulatory surgery)

Characteristics of the LMA Latex free, medical-grade silicone Aperture bars Sizes

#1 <6.5 kg 2-5 ml

#2 6.5-25 kg 7-10 ml

#2 1/2 20-30 kg 14 ml

#3 25-70 kg 15-20ml

#4 70+ kg 25-30ml

Using the LMA Preparation of the LMA

• Check patency of cuff• Lubricate POSTERIOR surface only• Surgilube v. lidocaine jelly

Induction Insertion of the LMA

• Common Problems• Cricoid Pressure

Securing the LMA

Using the LMA Maintenance of Anesthesia Removal of the LMA Cleaning, Sterilization and Re-use

Determining Life Span of LMA intended for 40-50 uses, but highly over-manufact

ured• tube remains translucent• aperture bars remain intact• cuff deflates correctly• no valve leakage• cuff remains symmetric• pilot balloon retains shape• connector remains tight/ not broken

THE LMA IS NOT DISPOSABLE

LMA and the Difficult Airway Awake Intubation Difficult MASK Airway Blind Intubation Failed Intubation Fiberoptic Bronchoscopy and the LMA Emergent Intubation by an Unskilled Pr

ovider

LMA and Pediatric Anesthesia DL&B tracheal stenosis difficult airway

Accuracy of End-tidal CO2 in Pediatrics using LMA

22 children, mechanically ventilated to a stable ETCO2ventilation via the LMA

mean ETCO2 and PaCO2 obtained were 37.7 +/- 3.3 and 41.9 +/- 9.09, respectively

ventilation via ETTmean ETCO2 and PaCO2 obtained were 35.2 +/- 2.9 and 39.2 +/-

5.25, respectively

LMA ETCO2 is as accurate an indicator of PaCO2 as when ventilated via ETT

Anesth Analg Feb;82 (2) :247-50

LMA and OB AnesthesiaQuestionnaire to 250 anesthesiologists in the UK

LMA was available in 91.4% of obstetric units

72% were in favor of using LMA for failed intubation with inadequate ventilation via face mask

24 had experience with LMA in such a situation, 8 of which stated that LMA had proved to be a “lifesaver”

Authors believed that we should use LMA before cricothyroidotomy for failed intubation/ventilation

Can J Anaesth Gataure, et al. 1995 Feb;42(2):130-3

Advantages of Using the LMAMeta-analysis comparing advantages of the LMA

over the tracheal tube or face mask

Reviewed 858 LMA publications identified to December 1994, of which 52 met criteria for analysis

32 different issues were tested

Can J Anaesth Brimacombe 1995 Nov;42(11):1017-23

Advantages of LMA over ETT increased speed and ease of placement by i

nexperienced personnel increased speed of placement by anesthetis

ts improved hemodynamic stability at induction

and during emergence minimal increase in intraocular pressure foll

owing insertionCan J Anaesth Brimacombe 1995 Nov;42(11):1017-23

Advantages of LMA over ETT reduced anesthetic requirements for airway

tolerance lower frequency of coughing during emerge

nce improved oxygen saturation during emerge

nce lower incidence of sore throats in adults


Advantages of LMA over Face Mask

easier placement by inexperienced personnel

improved oxygen saturation less hand fatigue improved operating conditions during mi

nor pediatric otological surgery


Additional Advantages of Using the LMA

leaves provider’s hands free patient can produce effective cough allows spontaneous ventilation even malpositioned can adequately vent

ilate

Disadvantages of LMA over the ETT

lower seal pressure higher frequency of gastric insufflation


Disadvantages of LMA over the FM

esophageal reflux more likely



Full Stomach• Non-fasted• 34+ week pregnant• trauma• acute abdomen• thoracic injury• opiate premedication• autonomic neuropath

y

• patient unable to follow instructions

• any condition known to delay gastric emptying


Full Stomach Patients with a history of GE reflux


Full Stomach Patients with a history of GE reflux Patients with low pulmonary compliance

needing positive pressure ventilation


Aspiration

Passive Regurgitation and the LMA

Study looked at gastric regurgitation during GA in different positions with the LMA15 minutes before induction, patients swallowed a 75 mg meth

ylene blue capsule.

supine, Trendelenburg and lithotomy positions

post-op, LMA and oropharynx were inspected for bluish discoloration

No blue dye was detected in the supine group but it was observed in one patient in each of the other two groups

Anaesthesia Strong, et al. 1995 Dec;50(12):1053-5

Passive Regurgitation: LMA v. ETT

Study at UT Dallas comparing incidence of reflux for spontaneously breathing anesthetized patients with either an ETT or LMA by continuous measurement of hypopharyngeal pH

“Continuous monitoring...failed to detect evidence of pharyngeal regurgitation.”

Anesth Anal Joshi, et al. 1996 Feb;82(2):254-7


Aspiration Coughing

ComplicationsIncidence of airway complications following GA using eith

er ETT or LMA

Significantly greater incidence of coughing PRIOR to extubation, AT extubation and AFTER extubation in the ETT group than in the LMA group

No airway complications were seen in either group

JR Soc Med Denny, et al. 1993 Sep;86(9):521-2


Aspiration Coughing Sore Throat

Sore Throatincidence of sore throat looked at in 327 patients wh

o had GA

mild/moderate soreness • 7% of patients with LMA• 10% who had FM and oral airway• 47% of had ETT

24 hours later, 3% of intubated group still c/o severe soreness, while NONE of the other patients had any c/o

Other Uses for the LMA Bronchoscopy “Big MAC” Oral Surgery Head and Neck Surgery Professional Singers Laparoscopic Surgery?

Conclusions Many advantages over ETT and FM Useful in many areas of anesthesia car

e Especially useful in outpatient anesthesi

a Safe when used appropriately

Take Home Message routinely test the cuff before use avoid lubricating the anterior surface of the mask only insert the LMA when an adequate depth of

anesthesia has been obtained maintain an adequate anesthetic depth througho

ut surgery avoid disturbing the patient during emergence keep the cuff inflated until the patient is awake

using the laryngeal mask airway norman l. goody, md

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