Support of the Airway and Ventilation Flashcards
Describe the primary assessment and resuscitation of airway and breathing.
SUPPORT OF THE AIRWAY AND VENTILATION
PRIMARY ASSESSMENT AND RESUS
- Primary assessment
- rapid physiological examination
- aim: identify immediately life-threatening emergencies
- treat problems as they are identified, then re-assess + continue primary assessment
- A
- ? patent/ airway obstruction
- ? stridor
- self-ventilation where possible
- O2 - encourage but do not force
- keep calm - parental involvement, do not inspect airway
- Mx
- Trauma
- Immobilise C-spine as appropriate
- consider <<c>> - simultaneously control major haemorrhage </c>
- O2
- airway opening manoeuvres (head tilt chin lift, jaw thrust) - if obstruction/ altered consciousness
- suction +/- foreign body removal
- airway adjuncts e.g. oropharyngeal/ nasopharyngeal airway, LMA, i-gel (if obstruction persists)
- I+V
- Trauma
- B
- LOOK, LISTEN, FEEL for breath (10 secs)
- LOOK:
- skin colour
- symmetrical movement of chest
- WOB / resp distress, depression or arrest
- Chest injury –> ? tension/ open PTX, haemothorax, flail segment
- LISTEN:
- BS (auscultate) - wheeze/ crackles –> ? asthma, bronchiolitis, pneumonia, heart failure, inhaled foreign body
- stridor
- lateralised ventilatory deficit –> ?haemoPTX, inhaled foreign body, consolidation, collapse, effusion
- FEEL: expansion, percussion
- Mx
- RR, Sats, capnometry (intubated)
- high-flow O2 (resp distress, high RR)
- BVM (resp arrest or depression)
- supraglottic airway (i.e. pharyngeal - nasopharyngeal, oropharyngeal = guedel, LMA/ i-gel)
- I+V / surgical airway
- may need to loosen cervical collar if it impairs airway access
- check position with auscultation + capnometry
- Consider failed intubation algorithm (see image)
- early in severe trauma (even if airway not compromised)
- BEWARE coughing, vomiting, bucking –> raised ICP (will need GA - perform neuro assessment BEFORE)
- OGT/ NGT - decompress the stomach
- Specific conditions:
- PTX? –> needle decompression + chest drain
- Massive haemothorax –> chest drain + blood products (simultaneous)
- Sedative / paralysing drugs –> reversal agent
- Acute severe asthma –> inhaled/ IV b-agonists, steroids, aminophylline, magnesium
Describe the secondary assessment of airway and breathing.
AIRWAY AND BREATHING
SECONDARY ASSESSMENT
- Thorough physical examination
- airway, neck, chest incl. the back of the chest
- swelling? bruising? wounds?
- SYMMETRY
- chest movement
- air entry
- Ix as appropriate
What should you do at any time the patient deteriorates?
Stop! Breathe!
Return to PRIMARY ASSESSMENT
Cycle back through ABCDEFG
RESUSCITATION of life-threatening problems as identified
SECONDARY ASSESSMENT
EMERGENCY Mx
What is bucking?
BUCKING
- violent expiratory contraction of skeletal muscles
- reflex response to chemical or physical irritation e.g. insertion of ETT, inhalation of concentrated vapours
What are the responsibilities of the team members at the head of the bed? Who usually performs this role?
TEAM ASPECTS OF AIRWAY MANAGEMENT
HEAD OF THE BED
- anaesthetist of paeds intesivist
- a skilled assistant (help with drugs and equipment if intubation needed)
- Role
- manage airway
- protect C-spine
- coordinate rolling manoeuvres during secondary survey / transfer e.g. to imaging/ ICU
- identify scalp lacerations (sig. blood loss in children)
What is the difference b/w LMA and i-gel?
Both are supraglottic airways (sit above the glottis).
- LMA = laryngeal mask airway
- inflatable cuff
- reusableor or disposable (newer)
- +/- channel for suctioning gastric contents
- i-gel
- non-inflatable cuff
- disposable
- considered easier to use by many
- channel for suctioning gastric contents
What are the two types of pharyngeal airways?
PHARYNGEAL AIRWAYS
- Oropharyngeal (guedel)
- Nasopharyngeal
When and why are Guedel (oropharyngeal) airways used?
OROPHARYNGEAL AIRWAY
GUEDEL
WHEN & WHY
- Unconscious or obtunded
- short-term
- to create a patent airway channel b/w the tongue and the posterior pharyngeal wall
- first intervention if manual airway opening manoeuvres fail
- stabilisation of ETT
- NOT if gag reflex present (vomiting)
- remove as the pt becomes more conscious
How do you size oropharyngeal and nasopharyngeal airways?
SIZING
PHARYNGEAL AIRWAYS
- Oropharyngeal (guedel)
- centre of the incisors to the angle of the mandible
- Nasopharyngeal
- lateral edge of the nostril to the tragus of the ear
- diameter - just fits into the nostril w/o blanching
- can use shortened ETT with a large safety pin if too wide
When are nasopharyngeal airways contraindicated?
Base of skull fractures (anterior)
How do you calculate the approximate inflation volume of an LMA?
LMA
Approximate inflation volume (ml) =
(LMA size x 10) - 10
What benefit do i-gel and LMA confer over BVM?
i-gel & LMA Vs. BVM
- lower risk of aspiration as less gastric distension
- however seal is less effective than an ETT
How long should intubation take? What should be done if it is not achieved in this time frame?
INTUBATION
- no longer than 30 secs
- failure or desaturating –> re-ventilate w/ BVM before re-attempting
- O2 sats should not fall during intubation
Describe the different types of laryngoscopes. Is there any benefit of one over another?
LARYNGOSCOPES
- Use the type that gives the best view of the vocal cords
- Fibreoptic light guide - green bands in handle and blade show compatibility
- Use size appropriate for age
- Can intubate with a laryngoscope that is too long but now w/ one that is too short
- Straight or curved blade
- Straight-bladed
- e.g. Miller, Robertshaw
- lift the epiglottis and uncover vocal cords
- Curved-bladed
- e.g. Macintosh
- move the epiglottis by lifting from in front
- tip of the blade in the vallecula (mucosal pocket)
- less vagal stimulation as vallecula innervated by glossopharyngeal nerve (but pt shoudl ve anaethetised so shouldn’t matter)
Should cuffed or uncuffed tracheal tubes be used?
ETT
- traditionally uncuffed - lower risk of mucosal airway damage
- can also used cuffed
- may be easier to ventilate if non-compliant (stiff) lungs e.g. severe bronchiolitis
- counterbalance risk of airway damage with failure to ventilate properly
What size of tube (diameter and length) should be used in children? Should there be air leak?
ETT size
- Uncuffed
- choose a size that gives a relatively gas tight fit
- air leak audible when inflation is continued to pressures slightly above max normal inflation pressure
- prevents damage to mucosa at level of cricoid ring & oedema following extubation
- Cuffed
- do not overinflate cuff
- monitor cuff pressure - same reason
- INTERNAL DIAMETER
- > 1 yo, uncuffed : internal diameter (mm) = (age/4) + 4
- cuffed: (age/4) + 3.5
- 1 year: size 4.5
- 6 months: size 4
- neonates < 3kg: uncuffed 3.0 or 3.5
- pre-term: even smaller
- LENGTH (cm) - use NON-SHORTENED, predicted length helpful to gauge length at lips, still do clinical check for placement
- ORAL: (age/2) +12
- NASAL: (age/2) +15
If tracheal suction is needed after intubation, what size of tracheal catheter should be used? What is the risk of using a suction catheter that is too large?
Tracheal suction after intubation
- To remove bronchial secretions or aspirated fluids
- Size = 2 x internal diameter of ETT
- e.g. ETT 3mm –> suction catheter French gauge 6
- Ifsuction catheter is too large then instead of suctioning the ETT contents, the ETT is occluded and suction pressure is transmitted to lungs –> atelectasis
What checks should be performed immediately after intubation and when taking over for an intubated patient?
MONITORING AN INTUBATED PATIENT
CHECKS TO BE PERFORMED AFTER INTUBATION & WHEN TAKING OVER
- Pulse oximeter
- assess oxygenation not ventilation
- sats drop SLOWLY if ETT in oesophagus
- not appropriate for rapidly checking correct ETT position
- Capnometer
- gold standard for checking correct intubation
- responds rapidly to falls in expired CO2
- no expired CO2 = oesophageal intubation
- sudden drop to 0 = equipment disconnection, ventilator failure, extubation
- gradual fall in ETCO2 = drop in CO (the lungs are still ventilated but CO2 washed out more slowly over several breaths) e.g.
- cardiac arrest
- inadequate cardiac compressions
- PE
- Auscultate
- both axillae
- NB in small pt’s BS sounds may transmit across the chest even if only one side is ventilated
- Asymmetrical –> ? endobronchial intubation
- stomach
- air entry –> ? oesophageal intubation
- both axillae
What are the limits of capnometry?
LIMITS OF CAPNOMETRY
- Low/ zero cardiac output states
- little or no expired CO2
- Endobronchial intubation
- not detected
- auscultate both axillae
- look for asymmetrical chest movement
- Uncuffed ETT that is too small
- large leak - especially if PEEP used
- expiration around the tube, not through it
- capnometer gives 0 or very low reading
Describe the assessment of potential airway and ventilator problems in an intubated patient. Use a mnemonic.
AIRWAY AND VENTILATOR PROBLEMS IN AN INTUBATED PATIENT
DOPE
-
D - Displaced ETT
- Endobroncial
- Signs
- asymmetrical chest movements
- unilateral BS
- SPO2 falling
- Mx: slight withdraw ETT –> re-auscultate
- Signs
- Oesophageal
- no ETCO2 on capnometry
- remove ETT, mask ventilate, re-intubate
- Endobroncial
-
O - Obstructed tube
- Kinked
- examine visible tube for kinks
- straighten and fix securely
- Blocked e.g. mucus, blood
- high index of suspicion esp. if small ETT and non-humidified gases used for ventilation
- thick mucus plugs at tube tip
- suction the tube
- not resolved –> remove, mask ventilate, re-intubate
- Kinked
-
P - PTX (Tension)
- Signs
- high peak ventilator pressure
- rapid fall in SPO2 & CO
- needle decompression
- Signs
-
E - Equipment problems
- Check for:
- breathing system disconnection
- leaks
- O2 supply failure / disconnection
- ventilator function
- deflated ETT cuff
- If problem not immediately obvious then hand ventilate whilst equipment checked
- Check for:
Describe the management of a blocked tracheostomy.
BLOCKED TRACHEOSTOMY Mx
- Stimulate
- Shout for help
- Head tilt chin lift (trache exposed and opens upper airway)
- O2 to face and trache
- Suction catheter - assess patency of trache
- NO PATENCY –> replace the tube (same size)
- easier if established trache
- care if newly created trache - until stoma track is established there is risk of creating a blind-ending false track during replacement
- NO –> half a size smaller
- NO –> thread a lubricated suction catheter through the smaller trache and try to guide into stoma
- NO –> remove trache
- LOOK, LISTEN, FEEL for breathing over tracheostomy (JUMP TO THIS STEP IF REPLACEMENT SUCCESSFUL AT ANY STAGE)
- BREATHING –> recovery position, continue to assess
- NO BREATHING –> 5 rescue breaths (ventilate)
- tube replacement successful –> BVM (attach self inflating bag) or mouth to trache
- unsuccessful but fully/ partially patent upper airway –> occlude stoma and BVM or mouth to mouth
- unsuccessful and no patent upper airway –> stoma ventilation
- ALL ELSE FAILS –> SURGICAL AIRWAY (CRICOTHYROIDOTOMY)
- IV cannula or purpose made cricothyroidotomy cannulae (less liable to kink than IV cannulae and have flange for suturing to neck)
- through cricothyroid membrane
- O2 1 L/ year of age/ min
- oxygenation but no ventilation
- To achive partial ventilation: can cut side hole in oxygen tubing or put Y-connector b/w cannula and O2 supply
- high failure rate - membrane hard to feel in young pts
- many ENT surgeons prefer an open tracheostomy
