lecture 2: airway management Flashcards
indications for intubation
V - ventilation (increase in PaCo2)
O - oxygenation (low in PaO2)
P - protection (paralysis/sedation, lack of drive)
S - secretion management (normal secretion reflexes impaired)
types of surgeries requiring intubation
- need for controlled invasive ventilation
- lung isolation required
- unusual positioning
- long duration
- airway access
- patient paralysis
- high risk for resuscitation
- possible use of high pressures
- prolonged post-op incubation
- gas exchange like to be impaired
difficult assumes
experienced person; optimal mm relaxation; sniff position; external laryngeal pressure; different blades
airway assessment includes:
- mouth open/close
- head up and down/side to side
- mallampati score
- dentition
- visual inspection (gaiter, displaced trachea, obstruction)
difficult BVM (MOANS)
M - mask seal
O - obesity or obstruction
A - age
N - no teeth
S - stiff lungs
assessing difficult laryngoscopy / intubation (LEMON)
L - look externally
E - evaluate 3-3-2
M - mallampati score IV
O - obstruction
N - neck mobility
mouth opening
inter-incisor distance normally 4-6cm (>3 fingers)
thyromental distance
mentum to upper border of thyroid cartilage normally ~7cm (>3 fingers), under 6cm predicts issue
hymenal distance
head and neck are in neutral position, space between
3-3-2
mouth opening, thyromental, b/w base of tongue and larynx
atlanto-occipital joint
C1 articulates with skull
normal extension ROM is 35degrees
mallampati score
class I - see soft palate, fauces, uvula, tonsillar pillars
class II - see soft palate, fauces, and uvula
class III - see soft palate and base of uvula
class IV - cannot even see soft palate
anatomy for possibly difficult intubation
- length of upper incisors and overriding maxillary teeth (overbite)
- inter incisor (b/w front teeth) distance <3cm (two finger tips)
- thyromental distance <7cm (3 fingers)
- neck extension <35 degrees
- sternomental distance <12.5cm
- narrow palate
- mallampati score class III or IV
- stiff joint syndrome
flow rate for BVM? how know enough?
o2 source at 15LPM, reservoir bag should be 1/2 full
if fully deflates at end inspiration means room air may be getting entrained as flow of o2 not enough
purpose of sniffing position
- lifting occiput narrows PA and LA axis
- lifting chin into sniff position aligns PA/LA/OA
- flexes lower c-spine and extends upper c-spines
what is the purpose of troop pillow
all in one positioning device for high BMI patients to align 3 axis into sniffing position
what is jaw thrust
one/two hand; placing index and middle fingers behind the jaw angle to physically push the posterior aspects of the mandible upwards while the thumbs push down on the chin to open the mouth
- doesn’t manipulate c-spine
complications and contraindications for NPA
complications
- epistaxis
- submucosal tunneling
- avulsion of the turbinates
- pressure ulcers
contraindications
- nasal fractures
- known nasal airway occlusion
- coagulopathy
- cerebrospinal fluid rhinorrhea
- known / suspected basilar skull fracture
- adenoid hypertrophy
- prior transphenoidal hypophysectomy
risk factors for difficulty mask ventilation
- BMI >/= 30 kg/m2
- beard
- hx snoring/OSA
- > /= 55 years
- mallampati III or IV
- limited mandibular protrusion test
- airways masses/tumours
- male
- edentulous state (w/out teeth)
- neck radiation changes
signs of inadequate ventilation: visual
- chest movement
- breath sounds
- condensation on mask
- cyanosis
- gastric air entry or dilation of abdomen
signs of inadequate ventilation: monitors
- EtCO2 absent or inadequate
- exhaled flow/spirometry measurements absent or inadequate
- decreasing or inadequate SpO2
- hemodynamic changes associated with hypoxemia/hypercarbia (hypertension, tachycardia, arrhythmia)
general uses of supraglottic airway devices (SAD)
[temporary, rescue, conduit, resuscitation, minimally invasive surgeries)
- temporary airway management during anesthesia
- airway rescue after failed intubation and mask ventilation
- as a conduit for tracheal intubation
- during cardiopulmonary resuscitation in and out of hospital
- short, minimally invasive surgeries
SAD use in __ procedures
- radiology / MRI
- radiation therapy
- catheterization procedures
- diagnostic and invasive endobronchial procedural
- ophthalmologic procedures
- tonsillectomy and adenoidectomy
- awake craniotomies
- short surgical procedures (i.e. biopsies, resections)
- surgical procedures that use a nerve block and don’t require patient be under GA
LMA considerations (RODS)
Restriction
- increased airway resistance and restricted mouth opening
Obstruction/Obesity
- +/- redundant tissue, higher PIP requirements cause leaks
Disrupted/Distorted anatomy
- deviation from midline makes seating harder, mouth not stable/pt not supine affect seating
Short thyromental distance
- position of tongue causes difficulties
LMA contraindications
- morbidly obese
- not in supine (i.e. prone, lateral)
- full stomach
- GERD
- intestinal obstruction
- reduced pulmonary compliance require high ventilation pressures
- certain oral / periglottic pathologies (abscess/tumour)
- situations when airway can’t be readily accessed when dislodged
- hyper reactive airways (ex. asthmatic)
how much to inflate LMA?
size - 1 x 10
4 - 1 x 10 = 30mls
features of LMA proseal and supreme
- bite blocks
- gastric drain tube
- can be used as introducer for an ETT or fiberoptic bronchoscopy
4 advantages of OPA / NPA
- little training required
- no special equipment necessary
- inexpensive
- can be quickly placed
disadvantages of OPA / NPA
- doesn’t guarantee airway patency
- may worsen obstruction
- poorly tolerated by awake patient
- doesn’t prevent aspiration
- short term use
- doesn’t facilitate +’ve pressure ventilation
advantages of double lumen airway (combitube) placement
- less skill than bag-valve-mask or intubation
- no special equipment necessary
- protection against aspiration
- facilitates +’ve pressure ventilation
disadvantages of double lumen airway (combitube) placement
- difficulty distinguishing tracheal vs esophageal insertion
- short term use
- aspiration during removal
- cannot suction in esophageal position
- only one size (adult)
- potential for esophageal injury
4 advantages of LMA
- easy to insert
- no special equipment necessary
- can intubate without removing LMA
- avoids laryngeal and tracheal trauma
3 disadvantages of LMA
- short term use
- aspiration not avoided
- cannot provide high ventilation pressures
equipment for intubation
- ONT suction equipment + inline suction
- BVM
- intubation equipment (ETT’s, laryngoscope, blades, stylet, lubrication)
- placement confirmation methods (ETCO2 line, stethoscope)
steps for ETT preparation
- select right type
- select right size
- select half size up/down
- check cuff integrity
- insert stylet
- shape ETT (</= 35 degrees)
- keep tube as clean as possible
- lubricate distal end
Direct Laryngoscopy Technique
- induce and pre-ox patient
- introduce laryngoscope from right side, displace tongue left
- look for epiglottis
- readjust (pull back) laryngoscope so tip of blade fits in to vallecula
- use lifting action moving blade caudally and anteriorly, line up OA/PA/LA
- keep attempt <30 seconds
- view glottis and vocal chords
- insert ETT proper distance from right of mouth, turn CTC and insert tip past chords to black line
- inflate cuff
- confirm placement (etCO2, auscultation)
- secure ETT (tapes, flannels, sutures)
Cormack Lehane classification
grade I
- full view of glottis
grade II
- partial view of glottis or only arytenoids
grade III
- only epiglottis visible
grade IV
- neither glottis nor epiglottis visible
BURP
backwards, upwards, rightwards pressure
- optimize view of larynx and vocal cords in pt with anterior larynx/cormack-lehane grade II-IV
- intubator applies pressure while obtaining view of larynx, then assistant mimics pressure and holds until ETT has passed through cords
rapid sequence intubation (RSI) / crash induction definition
the rapid and nearly simultaneous infusion of a neuromuscular blocking agent and anesthetic agent to facilitate intubation, while decreasing the risks of aspiration, combativeness and potential damage to the patient
indications for rapid sequence intubation (RSI) / crash induction
- recent meal or unknown time of last meal <6hours, emergency situation
- delayed stomach emptying (opioids, alcohol, diabetic gastroparesis)
- bowel obstruction
- GERD
- pregnancy
- early (<48hrs) postpartum
- GI bleeds
- previous gastric surgery
- hiatus hernia
- preoperative nausea/vomiting
- pain
sequence of rapid sequence intubation (RSI) / crash induction
- pre-ox (DO NOT BAG, spontaneous breathing)
- IV administration of hypnotic (propofol)
- immediate administration of rapid-onset neuromuscular blocking drug
- application of cricoid pressure
- avoidance of ventilation via mask
- tracheal intubation
- release of cricoid pressure after confirmation of placement of ETT
indirect laryngoscopy
- glidescope
- storz c-mac
- airtraq
- McGrath
- bullard
GlideScope
- video laryngoscope, indirectly view, midline insertion, doesn’t displace tongue, don’t lift to expose epiglottis just watch screen
- best to use rigid stylet, has proprietary version
- GVL, Cobalt, Ranger
Storz C-MAC
- can be used for in/direct laryngoscopy and bronchoscopy
blades: Mac 3, Mac 4, hyperangulated
AirTraq
- no hyperextension of neck required allowing intubation in any position, easy to learn/use
McGrath laryngoscope
- one handed use with no cables, battery operated, disposable blades (Mac 3/4)
- same technique as direct laryngoscopy
Bullard laryngoscope
- eyepiece; C-MAC has video adjunct for this
flexible fiberoptic intubation
- topicalize structures as visualized
- 1-2% lidocaine below cords
- otrivin (vasoconstricts)
indications for fiberoptic Bronch
- when mouth opening or neck mobility limited
- for awake intubations and difficult airway/inability to mask ventilate
- c-spine injuries
specialty tube in OR
- reinforced/armoured
- preformed oral/nasal
- laser
- endotrol
- double-lumen tubes R vs. L
- univent
- bronchial blocker aka Fogarty catheter / Aintree
- tracks, laryngectomy
Nasal (RAE) vs Oral (RAE)
nasal:
- right angle, curve towards head
- oral surgery; mandibular fracture
- magill forceps to guide nasotracheal tube
- check nares for patency, otrivin, soak ETT in warm saline
oral:
- right angle, curve towards feet
- facilitates redirecting the tube away from the surgical field above the neck
- ophthalmology; ENT; facial surgeries
process for blind nasotracheal intubation
- topical anaesthetic to nares/nasopharynx (spray/gel anesthetic and vasoconstricting spray)
- lubrication
- insert tube with upwards motion with gentle pressure
- when tip reaches posterior nasopharynx towards glottis, listen for breathing through tube, advance through glottic opening on inspiration
- if blind insertion not successful, use magill forceps to guide ETT through vocal cords with direct laryngoscopy or bronchoscope
Laser Tubes
material: PVC (flammable) core wrapped in two layers, one metallic foil (SS) protecting actual tube from laser light, and outer non-reflective layer
- pilot balloon contains blue dye granules which dissolve when filled with water/saline… the dyed water has 2 purposes: indicator of cuff burst; fire prevention/fire extinguisher
double lumen tubes (DLTs) and bronchial blockers indications
thoracic surgeries to ventilate one lung
- prevent contamination or spillage
- infection
- hemorrhage
- unilateral bronchopulmonary lavage
- control of the distribution of ventilation and/or PEEP
- bronchopleural fistula
- unilateral lung cyst or bullous disease
- severe hypoxemia d/t asymmetric lung disease
- enhance surgical exposure
- pneumonectomy / lobectomy / wedge resection
- thoracic aneurysm repair
- esophageal resection
- anterior mediastinal exploration with hilarious extension
- lung transplantation
- procedures on the thoracic spine
DLT - most used, size M/F, ideal features
left sided DLT for endobronchial intubation in one-lung anesthesia
M - 39/41
F - 35/37
should pass through airway easily, cause no trauma, align well w/ intended bronchus, forms a good seal with both tracheal + bronchial cuffs
sequence for confirmation of DLT placement (left)
- inflate bronchial cuff slowly with 0.5-1ml of air (small cuff)
- initial ventilation through the bronchial lumen should produce LL ventilation
- a malpositioned tube could result in either the RL or both lungs being ventilated
- confirmation of ventilation of the LL indicates the at the bronchial lumen has entered the left main bronchus
- next, the tracheal cuff is inflation
- ventilation through the tracheal lumen should produce only RL ventilation, indicating that the tracheal lumen is above the carina
- fiberoptic visualization confirms or aids in correct tube positioning
bronchial blockers
- single lumen ETT to allow lung isolation (i.e. Univent., Ardnt)
- useful if post-op ventilation required bc eliminates need to exchange DLT back to single-lumen tube
- indicated when DLT difficult/impossible d/t difficult airway
- confirmation/placement should include fiberoptic bronchoscopy
advantages of double lumen tubes
- suctioning and drainage of blood, pus, secretions (protection against contralateral lung contamination or flooding with any fluid)
- secure damaged (or operated) airways
- lesser risk of intraoperative displacement
- easier to correct position under FOB guidance (w/ pt in lateral position)
- less interference w/ surgical manipulation
- conversion from two to one lung ventilation (vice versa)
- CPAP to correct intraoperative hypoxemia
- differential lung ventilation (if different lung compliance), re-ventilation of the excluded lung at the end of surgery
- possibility of “blind” insertion (if FOB not available)
disadvantages of double lumen tubes
- difficulties to place in pts with abnormal airways after lung surgery (e.g. post-pneumnectomy), in children (<120cm)
- laryngeal and trachea-bronchial injuries, sore throat
- difficulties in selecting proper size
- damage to tracheal and/or bronchial cuffs (during intubation)
advantages of endobronchial blockers
- suitrable for pts with difficult airways, abnormal anatomy (i.e. porcine trachea)
- in pts/surgeries requiring nasal intubation
- failure to pass a DLT
- lesser risk of laryngeal injuries and postoperative sore throat or hoarseness
- less risk of tracheal cuff damage during intubation
- CPAP to correct intraoperative hypoxemia
- postoperative ventilation through the standard single lumen tube (no need to re-intubate the pt)
disadvantages of endobronchial blockers
- small suction channel doesn’t allow drainage of fluid
- more frequent intraoperative displacement or loss of seal
- difficulties in repositioning
- no differential lung ventilation
- absolute requirements for fiberoptic guidance
surgical airway options
- needle cricothyroidotomy (CTN) + transtracheal jet ventilator
- surgical cricothyrotomy
- retrograde intubation
needle cricothyroidotomy (CTN)
- 14-16 gauge angiocatheter + syringe with saline
- o2 only, no co2 removal or spont resps d/t narrow orifice
- temporary (max 10 min)
process:
1. puncture cricothyroid membrane and aspirate back; look for air bubbles in saline for lung placement
2. remove needle, leave catheter
3. attache o2 source (high pressure jet)
portex cricothyroidotomy kit vs angiocath
- this kit has a mini-trach like tube that can be secured with ties and act as a semi-permanent airway; can be connected to bag or vent circuit
- technique is truly for emergency purposes; utilizing the plastic catheter/sheath of a large IV (14g) to access the trachea and deliver o2; ventilation not ideal; no 15mm connector, no securement methods, only jet ventilation
surgical cricothyrotomy
small ETT (#5) inserted, or can introduce progressively larger dilators and eventually small cuff less trach; must follow needle cricothyroidotomy to ensure larger diameter for ventilation
need tracheostomy in <24hrs ideally
retrograde intubation procedure
- insert needle
- pass retrograde guidewire/catheter
- remove needle
- pull both ends tight
- pass larger integrate guide (use suction port of FOB)
- withdraw retrograde guide
- pass ETT over FOB
airway exchange catheters
- ideal for changing to new ETT or extubation in pts with hx of difficult intubation
- can use some types of o2 insufflation, low flow o2 and jet ventilation
- can also bougie, consider length of ETT
ridged bronchoscopy indications
- foreign body retrieval
- removal of blood clots (i.e. hemoptysis/trauma)
- relieving airway obstruction (i.e. stenosis)
- placement of tracheal/bronchial stents
- laser treatment
- debridement
4 ways to ventilate during rigid bronchoscopy
- jet (venturi) ventilation (most common)
- intermittent volume ventilation (w/ ventilator circuit but ++ leak)
- continuous insufflation (slow inflation)
- spontaneous ventilation (conscious sedation)
instruments for rigid bronchoscopy
- forceps
- biopsy needles
- balloon dilators
- ruler
oxygen insufflation catheters
- method to deliver low flow o2 during apnea and mitigate hypoxia
- most commonly achieved with suction catheters attached to o2
can be provided with: exchange catheter, bougie, specialized catheter with ETT or rigid Bronch w/out obstructing full view of airway
surgeries in supine position
lying on back to access
- thoracic
- pericardial
- peritoneal
- abdominal
- head/neck
- extremities
surgeries in prone position
lying on chest/abdomen to access
- spine
- back
induce supine and intubate then prone; proning pillows with hole for nose/mouth
surgeries in fowlers position + angle
angles between 45-90
- shoulder
- ear and nose
- craniotomy
surgeries in semi fowlers
angles between 15-45 degrees, most frequently 30
- shoulder
- nasal
- cranial
- abdominoplasty
- breast reconstruction
- may be used for induction then pt positioned for procedures
surgeries for lateral decubitus
down arm either placed on arm board or rested on procedure table; nondependent arm supported on pillows or special holders, head and neck maintained neutral
- lung
- aorta
- kidney (head of the bed lower than rest of body in this position)
- hip
surgeries for lithotomy position
pt supine with legs bent and elevated (pressure on abdomen can reduce FRC/cause atelectasis) and increase venous return to heart
- birth/vaginal access
