Airway Management Flashcards
When confirming correct placement of an endotracheal tube, verifying the presence
of sustained exhaled carbon dioxide requires all the following EXCEPT:
a) CO2 rises with expiration and falls with inspiration
b) Consistent square waveform
c) Consistent or increasing amplitude of the capnogram over 7 breaths
d) Peak amplitude more than 7.5mmHg above baseline
e) Capnogram is clinically appropriate
Preventing unrecognised oesophageal intubation: a consensus guideline from the Project for Universal Management of Airways and international airway societies
Suggests b) is most correct answer
Verifying the presence of sustained exhaled carbon dioxide requires all the following criteria to be met (Fig. 2; [93]):
- Amplitude rises during exhalation and falls during inspiration.
- Consistent or increasing amplitude over at least seven breaths [74, 91].
- Peak amplitude more than 1 kPa (7.5 mmHg) above baseline [74, 94].
- Reading is clinically appropriate.
The intrinsic muscles of the larynx do NOT include:
a) Cricothyroid
b) Suprahyoid
c) Transverse arytenoid
d) Cricoarytenoid
b) Suprahyoid
Suprahyoid muscles are extrinsic muscles of the larynx that attach outside the laryngeal framework and assist in swallowing and other movements. Not in anatomy for anaesthetists!
The intrinsic muscles of the larynx have a threefold func-
tion: they open the cords in inspiration, they close the cords and the laryngeal inlet during deglutition, and they alter the tension of the cords during speech.
They comprise the posterior and lateral cricoarytenoids,
the interarytenoids and the aryepiglottic, the thyroarytenoid, the thyroepiglottic, the vocalis and the cricothyroid muscles.
Anatomy for Anaesthetists
The breathing system shown in the accompanying picture is an example of
Mapleson:
a) A
b) B
c) C
d) D
e) F
c
The tooth most commonly damaged during direct laryngoscopy is the:
a) Right maxillary central incisor
b) Left maxillary lateral incisor
c) Left maxillary Central incisor
d) Right maxillary lateral incisor
c) Left maxillary Central incisor
BJA education article - 2016 and Aagbi
Left max central incisor most common from blade (fulcrum) 32%
Right max central - 19%
Right third molar if posterior injury
Periodontitis and cvs risk link
Reminder to link poor dentition with other risk factors - meth/smoking/poor diet/autoimmune conditions and their anaesthetic impact
1:4500 risk (Rcoa)
In a can’t intubate, can’t oxygenate (CICO) scenario when using a 14G cannula
and a Rapid-O2 oxygen delivery device, the initial rescue breath should be:
a) 2 seconds, 10L O2
b) 4 seconds, 10L O2
c) 2 secs 15L
d) 4 secs 15L
d) 4 secs 15L
Initial breath 4 seconds @ 15L (rate is 250ml/s i.e. total delivered in 4 seconds = 1L)
If no improvement in SpO2 after 30 seconds give another 2 second breath
Subsequent breaths once sats fall by 5% from maximum Spo2 achieved with initial jet ventilation breath = 2 secs (I.e. 500ml)
In this ultrasound image, the cricothyroid membrane is at the position marked
A
B
C
D
E
C
The following supraglottic airway devices allow direct intubation EXCEPT for the:
a) Classic
b) iGel
c) Auragain
d) Supreme
e) Proseal
Classic has the internal bands that need cutting ?I think its classic.
iGel clearly used for direct intubation.
I can’t see anything about “direct intubation” with the supreme but can find via bougie and aintree exchange.
Auragain allows: The Ambu® AuraGain™ (Ambu A/S, Ballerup, Denmark) is a new anatomically curved, single-use supraglottic airway device launched in June 2014, that features an integrated gastric access port and direct intubation capability using a standard endotracheal tube ideally guided by a flexible videoscope.
Proseal can’t find anything
Supraglottic airway devices as conduits for tracheal intubation
There are a number of SGAs that allow direct passage of an adult-sized ETT, including the LMA Fastrach™, the LMA Classic Excel™, the LMA cTrach™ (LMA™ North America, Inc., San Diego, CA, USA), the Air-Q™ (Mercury Medical®, Clearwater, FL, USA), the Ambu® Aura-i™, the Ambu® AuraOnce™ (Ambu Inc. Glen Burnie, MD, USA), the i-gel™ (Intersurgical Ltd., Liverpool, NY, USA), and the Elisha airway device (Elisha Medical Technologies, Ltd., Katzrin, Israel).4-9 An adult ETT can be placed directly into the trachea via these SGAs, either blindly or with bronchoscopic guidance. However, these SGAs designed for intubation may not be readily available in the operating room,10 and many anesthesiologists are not familiar with using them as stand-alone airways or intubating devices.
https://link.springer.com/article/10.1007/s12630-012-9714-8 (its old from 2012 but lists classic as a no.
There are other SGAs in which passage of an adult full-sized ETT into the trachea may be problematic, including the LMA Classic™, the LMA-Unique™, the double lumen SGAs (i.e., the LMA ProSeal™ and LMA Supreme™), and other SGAs. While they do not permit direct ETT intubation, these SGAs are readily available in the operating room and are commonly used as a stand-alone airway device. The small internal diameter (ID) of the airway lumen in these SGAs prevents an adult full-sized ETT (7.0 mm or larger) from passing through. In addition, the length of the ETT may be too short to reach mid-trachea (Fig. 1). This increases the risk of vocal cord compression and dislodging when the SGA is removed.1-3,11,12 In this case, the use of introducers or catheters is necessary to achieve tracheal intubation. In this article, we review the use of the following devices: 1) an Aintree Intubation Catheter, 2) a guidewire catheter, 3) a gum elastic bougie, and 4) a small ETT.
Many extraglottic airway devices allow the direct passage of an adult-sized tracheal tube, but this is not possible with the LMA-Supreme(TM) . We evaluated the feasibility of using the LMA-Supreme(TM) as a conduit for intubation in patients with known difficult airways.
CJA 2012 - supreme requires use of guidewire/AIC/fibrescope
The main difference between a size 5 microlaryngeal tube (MLT) and a standard size 5 endotracheal tube is that the size 5 MLT:
A. Smaller cuff
B. Longer length
C. Larger external diameter
Longer length
Different cuff size/ length: The MLT® has a cuff size/ length that would be typical for an adult-sized ‘standard’ ETT. A ‘standard’ pediatric 5.0 enndotracheal tube has a smaller cuff made for a pediatric-sized trachea (see picture below).
Distance of cuff from tube tip: In an MLT® the cuff is further away from the tube tip which is acceptable as the adult trachea is obviously longer than the pediatric one (see picture below).
When using an endotracheal tube in an adult, the highest recommended cuff pressure to avoid mucosal ischaemia is
a. 10cmH2O
b. 20
c. 30
d. 40
e. 50
AT
REPEAT
C. 30cmH2O
(c.f. 60cmH20 for same question but for LMA cuff pressure)
References (a bit old now):
“Guidelines1,2 recommend a cuff pressure of 20 to 30 cm H2O. Inflation of the cuff in excess of 30 cm H2O damages the tracheal mucosa by compromising capillary perfusion. When pressures are greater than 50 cm H2O, total obstruction of tracheal blood flow occurs.3 In rare instances, massive overinflation of the cuff may lead to acute complications such as tracheal bleeding or rupture.4 “
- from Cuff Pressure of Endotracheal Tubes After Changes in Body Position in Critically Ill Patients Treated With Mechanical Ventilation by Lizy et al 2014
Whereby:
1 American Thoracic Society; Infectious Diseases Society of America. Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia. Am J Respir Crit Care Med. 2005; 171(4):388–416.
2 Lorente L, Blot S, Rello J. Evidence on measures for the prevention of ventilator-associated pneumonia. Eur Respir J. 2007;30(6):1193–1207.
The sensor on a NIM (Nerve Integrity Monitor) endotracheal tube used for thyroid surgery directly records
a. Electromyography of internal laryngeal muscles
b. Recurrent laryngeal nerve action potential
c. Movement of the vocal cords on the endotracheal tube
d. Pressure of the vocal cords on the endotracheal tube
e. Recurrent laryngeal nerve action potential
AT - REPEAT
a. Electromyography of internal laryngeal muscles
True - the NIM-EMG tube tests RLN function via EMG of the muscles
wiki:
Notably, the only muscle capable of separating the vocal cords for normal breathing is the posterior cricoarytenoid. If this muscle is incapacitated on both sides, the inability to pull the vocal folds apart (abduct) will cause difficulty breathing. Bilateral injury to the recurrent laryngeal nerve would cause this condition. It is also worth noting that all muscles are innervated by the recurrent laryngeal branch of the vagus except the cricothyroid muscle, which is innervated by the external laryngeal branch of the superior laryngeal nerve (a branch of the vagus).
Anaesthesia: Nerve Integrity Monitor tubes for thyroid surgery (2014)
Recurrent laryngeal nerve function should be monitored during thyroid surgery [1], either by direct observation of vocal cord function during surgery [2], which can be difficult, or by electromyography (EMG), during which electrodes are placed adjacent to the vocal cords to detect motion when the laryngeal nerves are stimulated. Electrodes can be secured to the outside of a tracheal tube so that they come into contact with the vocal cords during intubation [3]. Indeed, electrodes have been embedded into the material of the tracheal tube (Medtronic Nerve Integrity Monitor (NIM) Standard Reinforced EMG Endotracheal Tube, Medtronic Xomed Inc., Jacksonville, FL, USA), albeit leading to an increase in bulk and external diameter in comparison with equivalent internal diameter tubes (Fig. 2). The size and rigidity of the NIM tubes mandate oral tracheal intubation rather than nasal intubation, which itself is further inhibited by the positioning of cable attachments for the electrodes along the tube’s length.
http://smpp.northwestern.edu/bmec66/weightlifting/emgback.html
An electromyography (EMG) is a measurement of the electrical activity in muscles as a by product of contraction. An EMG is the summation of action potentials from the muscle fibers under the electrodes placed on the skin. The more muscles that fire, the greater the amount of action potentials recorded and the greater the EMG reading.
http://www.shanahq.com/main/content/reliable-technique-make-nim-tube-work-preview
The specialized endotracheal tubes (ETT), such as Xomed and TriVantage Nerve Integrity Monitoring (NIM) ETTs (Medtronic Xomed Inc., Jacksonville, FL USA) allow for RLN identification through continuous intraoperative EMG monitoring of the laryngeal muscles.
https://www.aana.com/newsandjournal/Documents/jcourse1_0410_p151-160_rev2.pdf
The Medtronic NIM electromyographic (EMG) endotracheal tube (Medtronic Xomed) is constructed of a flexible silicone elastomer and has a distal inflatable cuff.
The tube is fitted with 4 stainless steel wire electrodes (2 pairs) that are embedded in the silicone of the main shaft distance, slightly superior to the cuff. The electrodes are designed to make contact with the patient’s vocal cords to facilitate EMG monitoring of the RLN when connected to a multichannel EMG monitoring device. If monitoring correctly, the EMG monitor should show a consistent sound signal and an action potential tracing.
J Anaesthesiol Clin Pharmacol: The neural integrity monitor electromyogram tracheal tube: Anesthetic considerations (2013)
When attempting to identify LNs, a stimulating electrical current of 0.5-2.0 mA is used by the surgeon. This current is administered via a sterile probe, which is placed directly on the anatomical site in question. Additionally, return electrodes are positioned in the skin above the sternum.
When a LN is located, an electrical signal is subsequently generated by the motion of the vocal cords. An audibly recognizable “machine gun click” is then produced from the device’s associated monitor. This sound has a set frequency of 4 times/s (4 Hz). Simultaneously, an oscilloscope-like screen displays an identifiable sinusoidal response.
Kate
A 54-year-old has a laryngeal mask airway inserted for a surgical procedure. The
following day it is noted that the tongue is deviated to the right. The most likely site
of nerve injury is the right:
a) Hypoglossal
REPEAT
Hypoglossal (deviates to the affected side)
Nerve injuries : (pressure neuropraxia)
Lingual nerve injury (most common)
RLN (most serious)
Hypoglossal
Glossopharyngeal
Inferior alveolar
Infra orbital
Usually self resolve except for RLN
Kate For driving pressure guided ventilation, driving pressure is the:
a) Pplat-peep
b) Peak pressure-peep
c) Other formulas
Pplat-PEEP
driving pressure is defined as distending pressure above the applied Peep Required to generate Vt
- key variable for optimisation when performing mechanical ventilation in ARDS
- also Vt/CRS (Ratio of Tidal volume to static resp system compliance)
23.1 You are planning to extubate a patient following airway surgery. The patient has FAILED the cuff-leak test when
a. <110ml leak with cuff deflated
b. >110ml leak with cuff deflated
c. Audible leak with cuff deflated
d. No audible leak with cuff deflated
e. No audible leak with cuff pressure <30cm H2O
a. <110ml leak with cuff deflated
approach is to use 110 mL or 10% of tidal volume as the cut-off
https://litfl.com/cuff-leak-test/
20.1
a. Arndt blocker
b. Cohen blocker
c. Microlaryngeal tube
d. Husaker tuber
e. Parker Flex-tip tube
B Cohen Blocker
23.1 Causes of exhaled carbon dioxide detection following oesophageal intubation include
all of the following EXCEPT
a. Massive bronchopleural fistula.
b. Carbonated drink.
c. Vigorous bag valve masking previously.
d. Previous gastric insufflation with CO2 for endoscopy.
e. Tracheoesophageal fistula.
A Massive bronchopleural fistula.
Nick Chrimes 2022 - Journal of Anaesthesia
‘Preventing unrecognised oesophageal intubation: a consensus guideline from the Project for Universal Management of Airways and international airway societies’
Causes of exhaled carbon dioxide detection despite oesophageal intubation
No alveolar ventilation occurring
-Prior ingestion of carbonated beverages or antacids
-Gastric insufflation of CO2 for upper gastrointestinal endoscopy
-Prolonged ventilation with facemask or poorly positioned supraglottic airway before attempting tracheal intubation
-Bystander rescue breaths
Some alveolar ventilation potentially occurring
-Tracheo-oesophageal fistula with tube tip proximal to fistula
-Proximal oesophageal intubation with uncuffed tube in a paediatric patient
22.1 A straight laryngoscope blade is likely to be more useful than the Macintosh blade when
performing direct laryngoscopy in patients with all of the following EXCEPT
A. Prominent maxillary Incisors
B. Undergoing manual inline stabilisation
C. Large Tongue
D. Floppy Epiglottis
E. Retrognathia
Not actually remembered answers
B undergoing manual inline stabilisation (posterior column problem, all others are anterior column issues)
https://www.anzca.edu.au/getattachment/9ef4cd97-2f02-47fe-a63a-9f74fa7c68ac/PS56BP-Guideline-on-equipment-to-manage-difficult-airways-Background-Paper
Straight laryngoscope blades:
These may be considered for patients with anterior column problems including:
- prominent maxillary incisors
- retrognathia
- large tongue and
- large floppy epiglottis
The Miller straight blade with its low profile produces a higher pressure on the submandibular tissues with the same force (pressure = force/area), and can be used to lift the epiglottis directly 75 to facilitate intubation.
There is evidence to support better success rates with straight blades as a rescue device when the Macintosh blade has failed. However, comparative studies of straight blades and videolaryngoscopy are lacking. As the paraglossal technique
for straight laryngoscope blades is different from Macintosh blades, training and ongoing volume of practice is recommended for optimal use. It should be
recognised that while straight blades provide better laryngoscopic views, the incidence of difficult intubation due to the narrower field of vision is increased .
McCoy (CLM) laryngoscope blades
When “McCoy” laryngoscope blades are in their flexed position, they apply pressure at the base of the tongue lifting the epiglottis anteriorly and are therefore, suitable for posterior column problems (e.g. manual inline stabilisation of head and neck) where the mandible and submandibular tissues are normal.
However, the effect of this levering action of McCoy blades has not been shown to consistently improve laryngeal view. When compared to Glidescope TM videolaryngoscopes, McCoy laryngoscope blades resulted in longer tracheal intubation times in bariatric patients.
Recommendations concerning Straight and McCoy laryngoscope blades:
Page 15 PG56(A)BP Difficult airway equipment BP 2021
Advanced equipment, such as videolaryngoscopy and the common availability of flexible bronchoscopes and intubation guides/bougies, may prove to be better alternatives to difficult airway management. While evidence is currently lacking, it is recommended that Straight and McCoy laryngoscope blades are not required in DATs unless operators have been trained in their use and have ongoing volume of practice (Weak recommendation for, level of evidence
moderate quality)
22.2 The sensor on a NIM (Nerve Integrity Monitor) endotracheal tube used for thyroid surgery directly records
a. Electromyography of internal laryngeal muscles
b. Recurrent laryngeal nerve action potential
c. Movement of the vocal cords on the endotracheal tube
d. Pressure of the vocal cords on the endotracheal tube
e. Recurrent laryngeal nerve action potential
a. Electromyography of internal laryngeal muscles
N22.2 The piece of airway equipment shown is a
a. bullard laryngoscope
b. CMAC video stylet
c. lightwand
d. flexible bougie
CMAC video stylet
see image for alternative equipment images
21.1 The equipment shown in the picture is a (airway device shown)
a) Arndt bronchial blocker
b) Cohen bronchial
blocker
c) Microlaryngoscopy tube
d) Hunsaker tube
e) Parker flex ETT
Hunsaker Mon-jet ventilation tube for microlarnygeal surgery
Description:
-Laser-safe
-fluoroplastic
-self-centring catheter
Uses:
-subglottic ventilation during microlaryngeal surgery
Components:
- proximal end for attaching to jet insufflation system
-proximal end allows passage of stylet to aid insertion
-Side port at proximal end for monitopring airway pressure and ETCO2
-Outer diameter 4.3mm for maintaining good surgical access
-Green basket to keep the centre port at its tip away from tracheal mucosa and avoiding potential damage from jet ventilation
21.2 The Vortex Approach to airway management does all of the following EXCEPT
a) At least 1 attempt by the most experienced clinician
b) Maximum 3 attempts at each lifeline (unless gamechanger)
c) CICO status escalates with unsuccessful best effort at any lifeline
d) Trigger for initiating CICO Rescue is SpO2 <90%
d) Trigger for initiating CICO Rescue is SpO2 <90%
- According to the Vortex Approach the trigger for initiating CICO Rescue is the inability to confirm adequate alveolar oxygen delivery following best efforts at all three upper airway lifelines.
Trigger for Initiating CICO Rescue VORTEX APPROACH
The trigger for initiating CICO Rescue is the inability to confirm adequate alveolar oxygen delivery following best efforts at all three upper airway lifelines.
Note that this trigger is independent of the oxygen saturations since, even in the unusual situation where the oxygen saturations remain high following best efforts at all three lifelines, the inability to confirm alveolar oxygen delivery means that eventual desaturation is inevitable.
Rather than being a deterrent to its performance, recognition of the need for CICO Rescue while the oxygen saturations remain high should be viewed as advantageous – providing increased time to perform this confronting procedure in a more controlled manner, thereby increasing the chance of success.
Conversely, a critically low oxygen saturation is not in itself a trigger to initiate CICO Rescue if best efforts at all three lifelines have not yet been completed.
While legitimate opportunities to enter the Green Zone in a timely fashion via the familiar upper airway lifelines remain, these should be given priority, as they are more likely to be successful than resorting to an unfamiliar and more traumatic technique.
Oxygen saturations are therefore not a relevant consideration in deciding the trigger for CICO Rescue – this is always “the inability to confirm adequate alveolar oxygen delivery following best efforts at all three upper airway lifelines”.
They are, however, a relevant consideration in making the context dependent decision of what constitutes a best effort at each lifeline in a particular situation.
This is because the oxygen saturations impact on how much time it is reasonable to invest in optimising each of the upper airway lifelines before declaring a best effort.
When the oxygen saturations are critically low it might be reasonable to have only one attempt at each lifeline before declaring a best effort, even though this means leaving some potential optimisation interventions untried.
This is because the incremental benefit of repeated attempts to optimise a lifeline that has already failed is typically low relative to untried alternative lifelines.
Thus the time expended on such low yield interventions cannot be justified when the patient is already critically hypoxaemic and alternatives (including CICO Rescue) with a substantially higher likelihood of success remain.
20.1 This type of tracheal tube is best described as a (picture of airway device shown)
a) Mini tracheostomy tube
b) South facing RAE
c) Laser tube
d) Laryngectomy tube
e) Fenestrated tracheostomy tube
laryngectomy tube
Rusch Larygoflex Reinforced Laryngectomy tube -
22.1 The manufacturer’s instructions for use of the i-gel supraglottic airway device recommend a minimum patient weight of
a. 1 kg
b. 2 kg
c. 3 kg
d. 5 kg
e. 10 kg
b. 2 kg
21.2 The size 5 i-gel® supraglottic airway is recommended for patients who weigh over
a) 50kg
b) 60kg
c) 70kg
d) 80kg
e) 90kg
e) 90kg
21.2 The equipment shown in the picture below is a
a) Parker flex tip
b) Hunsaker
c) Laryngectomy tube
d) NIM tube
e) Reinforced tube
NIM tube: Neural Integrity Monitor Electromyogram Tracheal Tube
20.1 According to the Australian and New Zealand Resuscitation Guidelines the immediate treatment for an adult conscious victim with a severe airway obstruction due to a foreign body inhalation is
a) a single back blow
b) two back blow
c) up to 5 blows to back, then up to 5 chest thrusts
d) up to 5 chest thrusts
e) sweep mouth
c) 5 back, 5 chest
4.1 Assess Severity
The simplest way to assess severity of a FBAO is to assess for effective cough.
4.2 Effective Cough (Mild Airway Obstruction)
The person with an effective cough should be given reassurance and encouragement to keep coughing to expel the foreign material. If the obstruction is not relieved the rescuer should call an ambulance.
4.3 Ineffective Cough (Severe Airway Obstruction) Conscious person
If the person is conscious send for an ambulance and perform up to five sharp, back blows with the heel of one hand in the middle of the back between the shoulder blades. Check to see if each back blow has relieved the airway obstruction. The aim is to relieve the obstruction with each blow rather than to give all five blows. An infant may be placed in a head downwards position prior to delivering back blows, i.e. across the rescuer’s lap [Class B; LOE IV].1,2
If back blows are unsuccessful the rescuer should perform up to five chest thrusts. To perform chest thrusts, identify the same compression point as for CPR and give up to five chest thrusts. These are similar to chest compressions but sharper and delivered at a slower rate. The infant should be placed in a head downwards and on their back across the rescuer’s thigh, while children and adults may be treated in the sitting or standing position [Class B; LOE IV].1,2
With each chest thrust, check to see whether the airway obstruction has been relieved. The aim is to relieve the obstruction rather than deliver all five chest thrusts. If the obstruction is still not relieved and the person remains responsive, continue alternating five back blows with five chest thrusts.
Unconscious person
If the person becomes unresponsive a finger sweep can be used if solid material is visible in the airway.1,2 [Class A; LOE IV] Call an ambulance and start CPR.
20.2 The equipment shown in the picture is a(n) (picture of an airway device shown)
Arndt bronchial blocker
- use with SLT
- 9fr, loop around scope for positioning
- suction to deflate lung
23.1 Patients with rheumatoid arthritis and the most common form of atlantoaxial instability have a widened atlantodental interval. This is measured between the
A. distance from posterior surface of dens to anterior surface of posterior arch of atlas
B. distance from anterior surface of dens to anterior surface of posterior arch of atlas
C. distance from posterior surface of dens to anterior surface of anterior arch of atlas
D. distance from posterior surface of dens to posterior surface of posterior arch of atlas
E. distance from anterior surface of dens to posterior surface of anterior arch of atlas
E. distance from anterior surface of dens to posterior surface of anterior arch of atlas
The atlantodental interval is used in the diagnosis of atlanto-occipital dissociation injuries and injuries of the atlas and axis.
The anterior atlantodental interval is the horizontal distance between the posterior cortex of the anterior arch of the atlas (C1) and the anterior cortex of the dens in the median (midsagittal) plane
Normal values for anterior atlantodental interval are:
radiographs:
adults:
males: <3 mm
females: <2.5 mm 1 (although most authors describe <3 mm ref)
children:
<5 mm ref
CT: adults: <2 mm
23.1 A Laser-Flex tube has a double cuff with two separate pilot balloons. The correct colours of the pilot balloons are that
a. Blue proximal cuff, clear distal cuff
b. Clear proximal cuff, blue distal cuff
c. Blue both
d. Clear both
b) Clear Proximal, Blue Distal
https://www.medtronic.com/content/dam/covidien/library/us/en/product/intubation-products/shiley-laser-oral-nasal-tracheal-tube-information-sheet.pdf
The commonest primary cause of death from anaesthesia airway events in the NAP4 report was
A. Barotrauma
B. Aspiration
C. Tracheostomy dislodged
D. Bleeding post-trache insertion
B. Aspiration
Aspiration was the single commonest cause of death in anaesthesia events.
Poor judgement was the likely root cause in many cases which included elements of poor assessment of risk (patient and operation) and failure to use airway devices or techniques that would offer increased protection against aspiration. Several major events occurred when there were clear indications for a rapid sequence induction but this was not performed.
The manufacturer guidelines suggest the smallest sized endotracheal tube that should be safely passed over an Aintree Intubation Catheter is (internal diameter) size
A. 4.0
B. 5.0
C. 6.0
D. 7.0
E. 8.0
Size 7.0
The Tube
The endotracheal tube has a length and diameter. The endotracheal tubes size (“give me a 6.0 tube”) refers to its internal diameter in millimeters (mm). The ETT will typically list both the inner diameter and outer diameter on the tube (for example, a 6.0 endotracheal tube will list both the internal diameter, ID 6.0, and outer diameter, OD 8.8).
21.1 A patient had prolonged surgery with a laryngeal mask airway in situ. The following day he reports a problem with his tongue. You examine him and see the following when he protrudes his tongue: The most likely cause of the abnormality is
a. R hypoglossal nerve injury
b. L hypoglossal
c. R glossopharyngeal
d. L glossopharyngeal
L hypoglossal
The hypoglossal nerve innervates all the extrinsic and intrinsic muscles of the tongue, except the palatoglossus which is innervated by the vagus nerve.
Injury to the hypoglossal nerve causes ipsilateral tongue deviation (pathognomonic), with dysarthria and dysphagia in severe cases. The tongue deviates towards the side that is affected due to the unopposed action of the contralateral genioglossus
The symptoms and signs of hypoglossal neurapraxia are often self-limiting and 43% of diagnosed patients achieve resolution within 6 weeks of surgery and an additional 40% are symptom free within 6 months after surgery
Nerves injured by SAD
- Lingual nerve (2ry to tube)
- Hypoglossal nerve (2ry to cuff)
- Recurrent laryngeal nerve (2ry to cuff)
Presenting symptoms and signs
Lingual nerve:
- loss of taste and sensation to tip of tongue
Hypoglossal nerve:
- dysphagia
- dysarthria
- tongue deviation in unilateral injury
Recurrent laryngeal nerve:
- altered voice
- rarely: stridor
Risk factors for injury:
- use of nitrous oxide-> over inflation
- selection of SAD that is too small-> over inflation
- LMA maximum inflation pressure 60cmH2O
20.2 The recommended maximum cuff pressure for insufflating a classic Laryngeal Mask is
a 15 cm H20
b 30 cm H20
c 40 cm H20
d 60cm H2O
d 60cm H2O
23.1 You are called to an airway emergency in the intensive care unit. A 40-year-old woman with morbid obesity and pneumonia had an elective percutaneous tracheostomy inserted eight hours previously. She is sedated, paralysed and ventilated. After being turned for pressure care, she desaturates and there is no clear CO2 trace on capnography.
The tracheostomy tube is still in the neck but you are concerned it has been displaced. Your immediate management should be to:
a. Reintubate from the mouth
b. Bronch via Trache
c. ?
a) reintubate from the mouth
? couldn’t find other recalled answers ? Will depend on the remembered answers ?
The key principles of the algorithm are:
1.Waveform capnography has a prominent role at an early stage in emergency management.
2.Oxygenation of the patient is prioritised.
3.Trials of ventilation via a potentially displaced tracheostomy tube to assess patency are avoided.
4.Suction is only attempted after removing a potentially blocked inner tube.
5.Oxygen is applied to both potential airways.
6.Simple methods to oxygenate and ventilate via the stoma are described.
7.A blocked or displaced tracheostomy tube is removed as soon as this is established and not as a ‘last resort’
BJA: Update on management of tracheostomy
https://www.bjaed.org/article/S2058-5349(19)30125-8/fulltext
https://www.tracheostomy.org.uk/storage/files/Patent%20Airway%20Algorithm.pdf
23.1 The difference between a size 5.0 microlaryngeal tube (MLT) and a standard size 5.0 endotracheal tube is that the size 5 MLT
A. Smaller cuff
B. Longer length
C. Larger external diameter
Longer length
Different cuff size/ length: The MLT® has a cuff size/ length that would be typical for an adult-sized ‘standard’ ETT. A ‘standard’ pediatric 5.0 enndotracheal tube has a smaller cuff made for a pediatric-sized trachea (see picture below).
Distance of cuff from tube tip: In an MLT® the cuff is further away from the tube tip which is acceptable as the adult trachea is obviously longer than the pediatric one (see picture below).
https://aam.ucsf.edu/microlaryngoscopy-tube-mlt%C2%AE
The most common cause of airway compromise after anterior cervical spine surgery is
A. Aspiration
B. RLN injury
C. Oedema
D. Phrenic nerve injury
E. Haematoma
C. Oedema
Blue book 2017
The aetiology of UAO differs from that of airway compromise seen after thyroid or carotid surgery.
Haematoma formation and cerebrospinal fluid leak are potential complications of CSS that usually present early in the postoperative period, whereas upper airway obstruction most commonly develops in the late postoperative period (days rather than hours).
UAO occurs because of prevertebral tissue swelling that evolves late in the postoperative course.
The danger is that the onset can be insidious in a ward environment, leading to late recognition and limited availability of practitioners with airway expertise12.
Development of prevertebral oedema has been implicated in several near misses and deaths, which became the sentinel events that stimulated creation of departmental protocols to safely manage these patients postoperatively
20.1 You are urgently called to assist a colleague in a neighbouring theatre who has been having difficulty with intubation of a large adult male. They have managed to pass a double lumen tube airway exchange catheter. If the tip of the catheter is at the level of the carina, the approximate length outside of the mouth will be
a.31 cm
b.40 cm
c.45 cm
d.58 cm
e.75 cm
Answer : e. 75cm
DLT exchange catheter is 100cm long (AEC, extra firm with soft tip)
Mouth to carina ~28cm
Outside of mouth ~72cm
Aintree Catheter 56cm
outside of mouth 31cm
22.2 The electrolyte abnormality most associated with an increased risk of laryngospasm is
a. Hypokalaemia
b. Hyponatraemia
c. Hypocalcaemia
d. Hypercalcaemia
e. Hypernatraemia
c. Hypocalcaemia
Laryngospasm is a rare, but serious and potentially lethal, complication of hypocalcemia in adults. In every adult presenting with acute dyspnea and stridor, the possibility of hypocalcemia should be considered. Hypocalcemia should be treated promptly.
The technique of airway pressure release ventilation
a. Has a prolonged expiratory time
b. Augments cardiac output in hypovolaemic patients
c. Results in reduced mean airway pressures
none of the remembered options
Airway pressure release ventilation (APRV) is an open-lung mode of invasive mechanical ventilation mode, in which spontaneous breathing is encouraged.
APRV uses longer inspiratory times; this results in increased mean airway pressures, which aim to improve oxygenation.
Brief releases at a lower pressure facilitate carbon dioxide clearance.
The terminology and methods of initiation, titration, and weaning are distinct from other modes of mechanical ventilation.
The use of APRV is increasing in the UK despite a current paucity of high-quality evidence
high intrathoracic pressure decreases the transmural left ventricular pressure, reducing the work of contraction and increasing cardiac output. In the context of hypoxaemia, a mode of mechanical ventilation that improves arterial oxygenation will improve myocardial oxygen delivery, myocardial function and cardiac output. As APRV is a spontaneous breathing mode, in addition to the benefits of spontaneous ventilation, reduced doses of sedative drugs can often be used, with subsequent reduction of requirement for vasoactive drugs and improvement in haemodynamic state.
Airway pressure release ventilation (APRV) is an open-lung mode of invasive mechanical ventilation mode, in which spontaneous breathing is encouraged. APRV uses longer inspiratory times; this results in increased mean airway pressures, which aim to improve oxygenation
https://www.bjaed.org/article/S2058-5349(19)30178-7/fulltext
https://derangedphysiology.com/main/required-reading/respiratory-medicine-and-ventilation/Chapter%20518/airway-pressure-release-ventilation-aprv-ards
