airway management techniques Flashcards
what are indications for a LMA?
- use instead of mask
- facilitate ventilation, intubation with difficult airway
- ventilate for flexible bronchoscopy
- avoidance of airway manipulation (with RAD)
what are contraindications for LMA use?
- 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)
what are the advantages of LMA when compared to mask?
- 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
what are disadvantages of LMA when compared to mask?
- more invasive
- airway trauma potential
- different skill
- deeper anesthesia required
- TMJ must be mobile
- N2O can diffuse into cuff
- contraindications: laryngeal pathology, obstruction
what are potential complication with a LMA?
- aspiration (2: 10,000)
- sore throat (10%)
- hypoglossal nerve injury
- tongue cyanosis
- vocal cord paralysis (poor insertion technique; over-inflation of cuff)
describe insertion technique for LMAs
- 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
what are the common sizes of LMAs for adult males and females?
adult female: 4
adult male: 5
where should the tip of the LMA be?
over the esophagus
what is the appropriate LMA size for a 30-50 kg (small) adult and appropriate max volume to inflate cuff?
- LMA size 3
- max volume 20 cc
- largest ETT mm: 6.0 cuffed
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?
- LMA size 4
- 30 cc
- 6.0 cuffed ETT
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?
- LMA size 5
- 40 cc
- 7.0 ETT cuffed
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?
- LMA size 6
- 50 cc
- 7.0 cuffed ETT
what are ways to intubate through a LMA
- 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
describe Fastrach LMAs
- 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
describe ProSeal LMAs
- 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
describe ventilation with the LMA
- 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
how should LMAs be cleaned and sterilized?
- 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)
describe the esophageal-tracheal combitube
- 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
describe fiberoptic intubation
- indirect visualization using a flexible fiberoptic bronchoscope
- considered the Gold Standard for management of expected difficult airway (although not frequently used)
what are clinical indications for fiberoptic intubation?
- airway tumors
- infections
- cervical spine fractures, instability
- cervical spine fixation (immobility; down syndrome; cant extend neck)
- very limited TMJ mobility
- conscious intubation
- difficult intubation
what should pt. be pretreated with prior to fiberoptic intubations?
-glycopyrrolate and neosinephrine (nasal vasoconstriction) to decrease oral secretions and nasal bleeding
describe an awake, oral fiberoptic procedure
- 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
describe nasal fiberoptic intubation
- 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
describe an asleep fiberoptic intubation
- 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
describe a glidescope
- 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
how does glottic view with glidescope use in pts. with cervical collar compare to direct laryngoscopy with a Mac?
- 93% pts. had an improved view with the glidescope
- average time to intubation: 38 sec.
- no complication, including dental trauma
describe technique for glidescope use
- 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
describe the bullard laryngocope
- 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
describe insertion technique for the bullard laryngoscope
- 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
describe light wand technique
-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
describe retrograde intubation
- insertion of a guide wire through the crciothyroid membrane, through the mouth over which the ETT is inserted
- most common complication is bleeding
describe technique for retrograde intubation
- 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
describe jet ventilation
- 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)
describe cricothyrotomy
- the cricothyroid membrane is surgically cut and an ETT is placed into the trachea
- risks higher than a cricothyroid puncture
