airway management techniques

Question 1

what are indications for a LMA?

Answer 1

• use instead of mask
• facilitate ventilation, intubation with difficult airway
• ventilate for flexible bronchoscopy
• avoidance of airway manipulation (with RAD)

Question 2

what are contraindications for LMA use?

Answer 2

• pharyngeal pathology, obstruction
• full stomach, fasting not confirmed, GERD
• low pulmonary compliance (PIP > 30 cmH2O)
• irritable airway (COPD, emphysema) with increased PIP
• leaks at 20 cmH2O
• grossly or morbidly obese (while lying supine, if tip of stomach is over line of trachea; but still used sometimes)
• more than 14 wks pregnant
• multiple or massive injuries (potential to code, intubate)
• acute abdomen, lap chole (need NMB)
• thoracic injury (decreased compliance)
• any delayed gastric emptying (opioid therapy)
• pts. who are not profoundly unconscious (maximize airway, intubate)

Question 3

what are the advantages of LMA when compared to mask?

Answer 3

• allows hands free, less fatigue
• better seal, esp. with beard or no teeth
• allows operating (ENT, esp. nose and eys)
• easier to maintain airway
• protects against nasal secretions (not gastric!)
• less facial nerve and eye injury (place gauze under mask straps)
• less OR pollution
• no neck manipulation

Question 4

what are disadvantages of LMA when compared to mask?

Answer 4

• more invasive
• airway trauma potential
• different skill
• deeper anesthesia required
• TMJ must be mobile
• N2O can diffuse into cuff
• contraindications: laryngeal pathology, obstruction

Question 5

what are potential complication with a LMA?

Answer 5

• aspiration (2: 10,000)
• sore throat (10%)
• hypoglossal nerve injury
• tongue cyanosis
• vocal cord paralysis (poor insertion technique; over-inflation of cuff)

Question 6

describe insertion technique for LMAs

Answer 6

• choose appropriate size
• deflate cuff, lubricate back side of cuff
• anesthesia (propofol 2.5-3.0 mg/kg) or local anesthesia or SLN block
• press mask against the hard palate (the black line should be pointing directly cephalad)
• press LMA into pharynx along the curve of the palate using the index finger
• grasp the LMA with the opposite hand and withdraw the inserting finger
• press downward on the LMA until resistance is met
• inflate cuff with appropriate amount of air and visualize the LMA displace out slightly

Question 7

what are the common sizes of LMAs for adult males and females?

Answer 7

adult female: 4

adult male: 5

Question 8

where should the tip of the LMA be?

Answer 8

over the esophagus

Question 9

what is the appropriate LMA size for a 30-50 kg (small) adult and appropriate max volume to inflate cuff?

Answer 9

• LMA size 3
• max volume 20 cc
• largest ETT mm: 6.0 cuffed

Question 10

what is the appropriate LMA size for a 50-70 kg adult and its max cuff volume? what’s the largest ETT size that can be used with the LMA?

Answer 10

• LMA size 4
• 30 cc
• 6.0 cuffed ETT

Question 11

what is the appropriate LMA size for a 70-100 kg adults and max cuff volume? what is the largest ETT size that can be used?

Answer 11

• LMA size 5
• 40 cc
• 7.0 ETT cuffed

Question 12

what size LMA is used for adult pts. > 100kg, what is the max cuff volume and what is the largest ETT size that can be used?

Answer 12

• LMA size 6
• 50 cc
• 7.0 cuffed ETT

Question 13

what are ways to intubate through a LMA

Answer 13

• use fiberoptic to visualize cords (need to have ETT threaded on before inserting)
• blindly insert smaller ETT (6.0) through LMA
• use intubating LMA (Fastrach) to insert larger ETT (not to be left in place)
• inserting intubating stylet

Question 14

describe Fastrach LMAs

Answer 14

• advanced LMA for tracheal intubation
• handle allows one hand insertion, removal
• comes in sizes 3, 4, 5 with max air 20cc, 30cc, and 40 cc respectively

Question 15

describe ProSeal LMAs

Answer 15

• has a separate lumen through which a gastric tube can be inserted to evacuate contents from the stomach
• allows for positive pressure ventilation (studies show higher airway leak pressure)
• studies show that PIP are lower with the ProSeal b/c it has a smaller leak
• can use higher PIP with better seal and lower leak
• if air is introduced to stomach, has a way to get out

Question 16

describe ventilation with the LMA

Answer 16

• spontaneous ventilation: assisted ventilation to maintain EtCO2 (beware with opioids and inhalation agents which can cause shallow breathing and allow CO2 build up; EtCO2 may read low d/t shallow expiration)
• CPAP- 3 cm pressure: reduces work of breathing
• pressure support with CPAP: lower EtCO2, slower RR, lower WOB, lower esophageal pressure, higher expired TV
• no difference in SaO2, MAP, HR with LMA ventilation

Question 17

how should LMAs be cleaned and sterilized?

Answer 17

• wash in 10% sodium bicarbonate solution
• detergent: Endozime
• steam autoclave only (deflate cuff prior) to a temp of 275 degrees F (135 C); don’t want cuff to inflate and burst
• avoid: germicides, disinfectants, gluteraldehyde, ethylene oxide, phenol-based cleaners, iodine-containing cleaners, ,or quaternary ammonium compounds (all can be absorbed)

Question 18

describe the esophageal-tracheal combitube

Answer 18

• alternative emergency airway
• allows ventilation whether the tip enters the esophagus or the trachea (usually goes to esophagus)
• only 1% of times goes into trachea
• two balloons, one 100cc in the oropharynx and one smaller 15cc near the tip
• two lumens- one straight used if tip in trachea; one with side perforations used if tip in the esophagus

Question 19

describe fiberoptic intubation

Answer 19

• indirect visualization using a flexible fiberoptic bronchoscope
• considered the Gold Standard for management of expected difficult airway (although not frequently used)

Question 20

what are clinical indications for fiberoptic intubation?

Answer 20

• airway tumors
• infections
• cervical spine fractures, instability
• cervical spine fixation (immobility; down syndrome; cant extend neck)
• very limited TMJ mobility
• conscious intubation
• difficult intubation

Question 21

what should pt. be pretreated with prior to fiberoptic intubations?

Answer 21

-glycopyrrolate and neosinephrine (nasal vasoconstriction) to decrease oral secretions and nasal bleeding

Question 22

describe an awake, oral fiberoptic procedure

Answer 22

• nebulize lidocaine 4% (gets above and below cords)
• cetacaine spray to posterior pharynx
• lidocaine gel oral prep (gargle and spit out)
• insert special oropharyngeal airway to prevent biting (protects tubes)
• lubricated ETT inserted 4-5 cm into airway
• fiberoptic scope is threaded into ETT
• *view: uvula, epiglottis and vocal cords
• advance scope into mid trachea (have propofol ready and hooked up, push when carina is seen, give before threading ETT)
• thread ETT over scope tip

Question 23

describe nasal fiberoptic intubation

Answer 23

• causes less gagging
• patient cannot bite the scope
• insert warmed (more pliable), lubricated ETT into vasoconstricted (neosinephrine, afrin, manually stretch), anesthetized nasal passage
• suction oropharynx
• insert scope through ETT, straight shot, into glottis
• thread ETT over the scope
• be careful of epistaxis

Question 24

describe an asleep fiberoptic intubation

Answer 24

• must interrupt to ventilate patient
• results when a failed intubation occurs unexpected
• can maintain cricoid pressure
• compared to awake pts., these have greater chance of tongue and epiglottis blocking cords

Question 25

describe a glidescope

Answer 25

- video laryngoscope - digital camera in the blade tip - 60 degree curvature - can be used with patient in neutral cervical position - stylet needed (make sure stylet angle matches angle of glidescope) * indirect method of visualization of vocal cords

Question 26

how does glottic view with glidescope use in pts. with cervical collar compare to direct laryngoscopy with a Mac?

Answer 26

- 93% pts. had an improved view with the glidescope - average time to intubation: 38 sec. - no complication, including dental trauma

Question 27

describe technique for glidescope use

Answer 27

- look into the mouth as you insert midline into mouth - look at the monitor as you lift up to see the epiglottis and glottic opening (may lift as the Mac or use to directly lift epiglottis) - look into mouth as you guide the tube with the stylet toward the tip of the scope - look back at the monitor to complete the insertion of the ETT into the glottic opening

Question 28

describe the bullard laryngocope

Answer 28

- rigid laryngoscope with fiberoptic capability - can view cords without sniffing position - indicated for cervical immobility or instability - suction channel used for suctioning, insufflating O2, or injecting local anesthesia - light source can be laryngoscope handle or fiberoptic light source

Question 29

describe insertion technique for the bullard laryngoscope

Answer 29

- load ETT onto stylet - prepare pt. with antisialagogue - blade inserted midline with handle parallel to pts. body - slide blade down into laryngopharynx as the handle comes to vertical - lower the blade to pick up the epiglottis to visualize the cords - slide the ETT off the stylet into the trachea

Question 30

describe light wand technique

Answer 30

-lighted stylet which transilluminates the neck -used for routine and difficult intubations technique: -insert stylet into ETT -bend ETT proximal to cuff to 90 degree angle -induction of anesthesia -pull tongue forward -insert ETT with light wand stylet -visualize light as it advances down trachea *if dims or disappears, the ETT has entered the esophagus *once light is below cricoid cartilage, stylet withdrawn to allow insertion of the ETT into the trachea

Question 31

describe retrograde intubation

Answer 31

- insertion of a guide wire through the crciothyroid membrane, through the mouth over which the ETT is inserted * most common complication is bleeding

Question 32

describe technique for retrograde intubation

Answer 32

- topical anesthesia to oropharynx, larynx, and trachea - needle (18g) attached to syringe containing lidocaine 2% inserted through cricothyroid membrane - aspirate air to confirm placement - guide wire is threaded into the pharynx back into mouth and retrieved (once passed through mouth, hook something at neck to prevent from pulling out) - a guide is passed over wire, through the cords - ETT passed over guide; can use fiberoptic scope

Question 33

describe jet ventilation

Answer 33

- temporary oxygenation - 14g or larger IV catheter inserted through the cricothyroid membrane (12 g better) - oxygen source to deliver flow at 30 psi and 15 L/min - ventilate 6-8 breaths/min - I:E 1:4, long expiratory phase to allow emptying * may need to employ airway techniques, positioning or jaw thrust to allow exhalation (verify emptying to avoid barotrauma)

Question 34

describe cricothyrotomy

Answer 34

- the cricothyroid membrane is surgically cut and an ETT is placed into the trachea * risks higher than a cricothyroid puncture