Anaesthesia, 2008, 63, pages 364–369
doi:10.1111/j.1365-2044.2007.05353.x
.....................................................................................................................................................................................................................
Unanticipated difficult airway management in anaesthetised
patients: a prospective study of the effect of mannequin
training on management strategies and skill retention
P. M. Kuduvalli,1 A. Jervis,3 S. Q. M. Tighe2 and N. M. Robin2
1 Research Fellow – Simulation ⁄ Education and Specialist Registrar – Anaesthesia, Department of Anaesthesia, Aintree
University Hospital NHS Foundation Trust, Longmoor Lane, Liverpool, Merseyside L9 7AL, UK
2 Consultant Anaesthetist, 3 Resuscitation Training Officer, Countess of Chester Hospital NHS Foundation Trust,
Liverpool Road, Chester, Cheshire CH2 1UL, UK
Summary
This prospective study on a medium-fidelity simulator (SimMan, Laerdal Medical Corporation,
Wappingers Falls, NY, USA) examined the management of unanticipated difficult airway by 21
anaesthetists and the effect of training in this context. There were two scenarios investigated:
‘cannot intubate, can ventilate’(CI) and ‘cannot intubate, cannot ventilate’(CICV). Following
initial evaluation, volunteers underwent training in the ‘Difficult Airway Society’ (DAS) algorithms
and associated technical skills. At 6–8 weeks and 6–8 months, performance was compared with the
initial evaluation. There was a more structured approach following training (p < 0.05), which was
sustained at 6–8 months, but only for the CICV scenario (p < 0.01). In CI, use of standard
and intubating laryngeal mask airway increased following training (p = 0.021). This was sustained
over time (p = 0.01). In both scenarios there was a reduced incidence of equipment misuse
(p < 0.0005), which was sustained over time (p < 0.0001). We conclude that simulation-based
training significantly improves performance for at least 6–8 weeks. Training should be repeated at
intervals of 6 months or less.
. ......................................................................................................
Correspondence to: Dr P. M. Kuduvalli
E-mail: [email protected]
Accepted: 22 September 2007
Problems with intubation remain the most common
cause of anaesthetic death, according to data from the UK
medical defence organisations [1, 2]. The Confidential
Enquiry into Maternal and Child Health (CEMACH)
2000–03 highlighted the increasing contribution of failed
airway management to anaesthetic mortality [3].
In 2004, the Difficult Airway Society (DAS) developed
national guidelines for management of unanticipated
difficult intubation in the adult non-obstetric patient
[4]. It has subsequently been suggested that formal
training should be provided at 6-month intervals by
every anaesthetic department to implement these guidelines and reduce anaesthetic related mortality [5].
Although the effect of training on some individual
technical skills has been reported [6, 7], the effect of
training on the overall management of difficult airway
scenarios has not been formally assessed and the optimum
interval for retraining has not been evaluated. This
prospective, controlled study was therefore designed to
364
measure the effect of training on compliance with
national guidelines for the management of unanticipated
failed intubation and ⁄ or ventilation. It also assessed the
effect of formal training on performance over time.
Methods
Following ethics committee approval, we invited all the
anaesthetists from the Countess of Chester Hospital to
participate. This was entirely voluntary and confidentiality of individual performance was assured.
The evaluations were carried out using a programmed
medium fidelity simulator (SimMan Universal Patient
Simulator, Laerdal Medical Corporation, Wappingers
Falls, NY, USA) in a mock operating theatre in the
Resuscitation Training Centre. Monitoring included
SpO2, FÉCO2, ECG and non-invasive blood pressure.
Volunteers were assisted by an experienced Operating
Department Practitioner and had a difficult airway trolley
2008 The Authors
Journal compilation 2008 The Association of Anaesthetists of Great Britain and Ireland
Æ
Anaesthesia, 2008, 63, pages 364–369
P. M. Kuduvalli et al.
Unanticipated difficult airway management
. ....................................................................................................................................................................................................................
stocked with equipment as defined by the Difficult Airway
Society [8]. Equipment comprised facemasks; oropharyngeal airways in three sizes; nasopharyngeal airways in three
sizes; laryngeal mask airways (LMA) – standard LMA
(LMA ClassicTM, Intravent Orthofix, Berkshire, UK),
intubating LMA (ILMATM, The Laryngeal Mask Company, Bucks, UK) sets and Proseal LMA (PLMATM,
Laryngeal Mask Company, Henly-On-Thames, UK) – in
a range of sizes; tracheal tubes (standard, reinforced and
microlaryngeal) in a range of sizes; two working laryngoscope handles; Macintosh blades sizes 3 and 4; alternative
blades – straight and McCoy; a tracheal tube introducer ⁄ gum-elastic bougie; a malleable stylet; Magill
forceps; flexible fibreoptic laryngoscope with a portable
light source; Aintree Intubation Catheter (AIC, Cook
Critical Care, Bloomington, IN, USA); cricothyroid
cannulae (Ravussin jet ventilation catheters, VBM Medizintechnik, GmbH, Sulz a.N., Germany); high pressure
jet ventilation system (Manujet III, VBM Medizintechnik
GmbH); surgical cricothyroidotomy kits for the four-step
technique (Scalpel with number 20 blade, tracheal hook,
6 ⁄ 7 mm tracheal and tracheostomy tubes) and wireguided technique (cuffed Melker emergency cricothyroidotomy catheter set, Cook, Bloomington, IN, USA).
There were two hypothetical clinical scenarios of
‘cannot intubate, can ventilate’ (CI) and ‘cannot intubate,
cannot ventilate’ (CICV) (Appendix 1). Each volunteer
was required to deal with both scenarios sequentially in
real time.
Standard settings on the mannequin included application of maximum tongue oedema to ensure a Grade 4
view on laryngoscopy according to Cormack & Lehane
[9]. Additional pharyngeal obstruction and bilateral lung
resistance was added for the CICV scenario. If oxygen
delivery was interrupted for 20 s or longer, SpO2 was
reduced by a value of 3% every 5 s until first effective
ventilation of the mannequin. SpO2 was restored to 90%
20 s after restoration of ventilation. Time to first effective
ventilation was defined as the time from picking up a
particular piece of equipment to at least two effective
breaths witnessed as FÉCO2 traces on the monitor. For the
jet ventilation technique, adequate ventilation was
defined by the appearance of lung filling on the computer
animation. Oxygen desaturation was defined as SpO2 of
90% or lower.
Volunteers were asked about previous anaesthetic
experience, difficult airway exposure and training. A
single observer carried out all of the evaluations. Management of the scenarios was scored against an ‘ideal’
management plan which was derived from the DAS
guidelines [3] (Appendix 2). Any deviation was recorded
and the participant was redirected to the correct pathway
after 60 s. Shortly after the evaluation (Group A),
2008 The Authors
Journal compilation 2008 The Association of Anaesthetists of Great Britain and Ireland
volunteers underwent a half day of formal training which
focused on the DAS guidelines ⁄ algorithms and included
individual ‘hands on’ training in the following technical
skills: intubation through a standard LMA and ILMA,
both with and without the aid of a fibreoptic laryngoscope; cricothyroid puncture and jet ventilation using the
Manujet system; surgical cricothyroidotomy. Volunteers
were given copies of their initial assessment, reflecting
individual learning points and correction of technical
errors. Following training, the same volunteers were
reassessed using the same scenarios within 6–8 weeks
(Group B) and again at 6–8 months (Group C).
Statistical analysis
Power calculations based on previous data from a
mannequin-based study [10] indicated that a minimum
number of 15 volunteers in each group (95% CI with 5%
a error and 80% power with 20% b error) would be
required to detect a 30% improvement in performance
following formal training.
The performance prior to training was compared with
that at 6–8 weeks and at 6–8 months.
Nonparametric data were analysed using Fisher’s exact,
Kruskal–Wallis and Mann–Whitney U tests. Parametric
data were analysed using Student’s t-test.
Results
Demographics (Table 1)
Twenty-one volunteers consented to participate and
underwent the initial assessment (Group A). Nineteen
anaesthetists underwent training and reassessment at 6–
8 weeks (Group B) and 15 were assessed at 6–8 months
(Group C). There were no significant differences in
anaesthetic or airway experience between the three
assessment periods.
Table 1 Demographics of volunteers: Group A (pretraining),
Group B (6–8 weeks), Group C (6–8 months after training).
Groups
SHOs
SpRs
NCCGs
Consultants
Median years experience
Past ALS airway training; n (%)
Past ‘CI’ experience; n (%)
Past ‘CICV’ experience; n (%)
Past airway complications; n (%)
A (n = 21)
B (n = 19)
C (n = 15)
8
3
2
8
9
21
14
4
17
7
3
2
7
9
19
12
3
16
5
3
1
6
9
15
10
3
12
(100)
(66.6)
(19)
(81)
(100)
(63.1)
(15.7)
(84.3)
(100)
(66.6)
(20)
(80)
SHOs, Senior House Officers; SpRs, Specialist Registrars; NCCGs, NonConsultant Career Grades.
365
Æ
P. M. Kuduvalli et al.
Unanticipated difficult airway management
Anaesthesia, 2008, 63, pages 364–369
. ....................................................................................................................................................................................................................
Table 2 Outcome measures: Group A (pretraining), Group B (6–8 weeks), Group C (6–8 months after training).
Groups
A (n = 21)
B (n = 19)
C (n = 15)
CI scenario
Mean time in seconds to LMA insertion (SD)
Number attempting intubation (%)
Success rate for attempted intubation (%)
Number intubated (%)
Median no. of episodes of desaturation [range]
Mean duration in seconds of desaturation (SD)
Median lowest oxygen saturation [range]
Median no. of deviations from DAS [range]
13.2 (12.48)
13 (62%)
46%
6 (28.6)
1 [0–7]
16 (15.1)
85 [73–90]
3 [0–6]
12.52 (13.07)
18 (95%)*
44%
8 (42.1)
2 [0–4]
21.4 (23.8)
79 [65–89]
2 [0–6]*
27.26 (8.18)*
15 (100%)*
47%
7 (46.7)
2 [1–3]
26.9 (17.4)
82 [63–88]
2 [0–6]
CICV scenario
Correct cannula insertion technique (%)
Correct adjustment of Manujet (%)
No. achieving successful cannula insertion (%)
Mean time in seconds to cannula insertion (SD)
Mean time to effective jet ventilation (SD)
Number achieving surgical airway (%)
Correct confirmation of airway placement (%)
Median no. of episodes desaturation [range]
Mean duration in seconds of desaturation (SD)
Median lowest oxygen saturation [range]
Median no. of deviations from DAS [range]
11 (55%)
4 (20%)
4 (20%)
24.22 (14.4)
38.5 (12.58)
19 (90%)
15 ⁄ 19 (78%)
1 [0–2]
216 (69)
23 [0–72]
4 [0–7]
17 (89%)*
19 (100%)**
18 (95%)**
16.52 (8.68)*
19.72 (16.56)
19 (100%)
19 ⁄ 19 (100%)
2 [0–2]
132 (48)†
41 [6–62]*
0 [0–2]**
15 (100%)*
12 (80%)**
14 (94%)**
21.6 (5.53)
35.85 (43.43)
14 (93%)
13 ⁄ 14 (93%)
2 [0–2]
238 (165)
40 [0–68]
1 [0–7]**
2 (10%)**
2 (10%)
3 (20%)**
3 (20%)
Complications (both scenarios)
Number using equipment incorrectly (%)
Misplacement
17 (81%)
6 (28%)
*p < 0.05 when compared with Group A, **p < 0.01 when compared with Group A, †p < 0.05 when compared with Group C.
Outcome measures (Table 2)
For the CI scenario there was a significant increase in the
time taken to insert an LMA or ILMA 6–8 months after
training (p < 0.05, Group A vs C). There was a significant increase in the proportion of anaesthetists who
attempted tracheal intubation via an LMA or ILMA after
training (predominantly via ILMA, p = 0.021, Group A
vs B), which was sustained at 6–8 months (p = 0.011,
Group A vs C). The actual success rate remained constant
at 44–47%. There were more successful intubations after
training, but differences were not significant. There were
no significant differences in either the number or duration
of oxygen desaturation episodes. However, there was a
significant reduction in the number of deviations from the
DAS guidelines 6–8 weeks after training (p < 0.05,
Group A vs B). At 6–8 months, this difference was not
significant.
For the CICV scenario there was a significant and
sustained improvement in most technical skills involving cricothyroid cannulation (p < 0.05, Group A vs
Groups B and C), but the initial improvement in time
to effective jet ventilation was not maintained at 6–
8 months. There was a 90% success rate for achievement
of a surgical airway before training. There was a
nonsignificant reduction in the mean duration of oxygen
desaturation following initial training. By 6–8 months,
366
this time increased significantly (p = 0.029, Group B vs
C). The median lowest oxygen saturation was significantly higher following initial training (Table 2)
(p < 0.05, Group A vs B) but this difference was not
significant at 6–8 months.
There was a significant reduction in the number of
deviations from DAS guidelines (p < 0.001, Group A vs
B) which was sustained over time (p < 0.01, Group A vs
C). In both scenarios there was a significant reduction in
the improper use of equipment (p < 0.0005, Group A vs
B), which was sustained over time (p < 0.0001, Group A
vs C).
Discussion
Although rare, airway disasters occur regularly and
unexpectedly, causing the majority of anaesthetic related
mortality [1–4]. As a result, some UK anaesthetic
departments provide regular workshop training in airway
management techniques to improve subsequent performance and patient outcome [5].
The Difficult Airway Society has published evidencebased guidelines and a structured approach for the
management of difficult intubation and ventilation [4],
but the effect of these guidelines on individual performance and patient outcome has not been assessed.
2008 The Authors
Journal compilation 2008 The Association of Anaesthetists of Great Britain and Ireland
Æ
Anaesthesia, 2008, 63, pages 364–369
P. M. Kuduvalli et al.
Unanticipated difficult airway management
. ....................................................................................................................................................................................................................
Training in individual airway skills has been shown to
improve performance [6, 7], both initially and over time,
and it has been recommended that workshop training
should be repeated at intervals of 6 months [5], as skill
retention fades over time, particularly for skills that are
rarely used [7]. However, this recommended interval was
not based on any published evidence [5].
We describe a prospective case-control interventional
study of strategies practised in a district general hospital
for the management of unanticipated difficult intubation ⁄ ventilation and the effects of formal training on
performance, both initially and over time. To our
knowledge, this is the only prospective study with
primary emphasis on a structured approach to airway
management and adherence to national guidelines.
Although all of the airway equipment recommended
by DAS [8] was provided, we chose to limit choice to
evaluate performance more objectively. Volunteers were
trained to concentrate on maintaining oxygenation as the
first priority. For CI, manual ventilation, followed by
LMA placement and fibreoptic intubation through the
LMA was the suggested order of intervention, with
the ILMA as an alternative. After 20 min, volunteers
could suggest reversal of the muscle relaxant and awake
fibreoptic intubation. For CICV, we expected volunteers
to reverse hypoxia rapidly with cannula cricothyroidotomy and jet ventilation. We then added regurgitation
and imminent aspiration to the scenario to encourage
surgical cricothyroidotomy. These sequences were in
accordance with DAS guidelines [4], although they were
more didactic.
The oxygen saturation data were artificial and directly
proportional to time without effective ventilation. Oxygen saturation was reduced manually during the simulation according to a protocol to stimulate a sense of realism
from the declining pitch of the oximeter and to approximate the real physiological relationship between the
duration of obstruction and oxygenation. The oxygen
saturation data should be interpreted in this context. In
addition, the simulation differed from the real clinical
situation in several other respects. In particular, the
anatomical characteristics of the SimMan made some of
the airway manoeuvres more difficult than usual and the
degree of obstruction to ventilation may have been
unrealistic. Nevertheless, the same difficulties were experienced by all volunteers in each assessment period and
represented the worst case scenario. It would not have
been ethically acceptable to conduct this study in clinical
practice, or on cadavers in the UK, so that simulation was
the only option. Our results should therefore be interpreted cautiously when transposing to the clinical context.
There were no differences in the volunteers’ relevant
airway experience between the three assessment periods.
2008 The Authors
Journal compilation 2008 The Association of Anaesthetists of Great Britain and Ireland
Seventeen (81%) volunteers had no previous experience
of CICV, confirming the opinion expressed by Chambers [11], in which he expressed doubt that he was alone
in never having encountered CICV in 25 years of
practice. However, the frequency of this life-threatening
event in the experience of nearly a fifth of the
anaesthetists we surveyed does perhaps justify particular
training emphasis.
In the CI scenario, the significant increase in time to
insert an LMA at 6–8 months is difficult to account for
and is probably artefactual. Significantly more candidates
attempted tracheal intubation via the LMA or ILMA
after training and this difference was sustained over
time. Because the success rate per attempt was similar,
more successful tracheal intubations were therefore
performed after training, although this increase was
not statistically significant. This was not at the expense
of increased duration or episodes of hypoxia, which
were not significantly different between assessments.
However, hypoxic indices were not reduced by training, as might have been expected. This was probably
because of the ease of hypoxia prevention in this
scenario with manual ventilation, reversal of muscle
relaxant and awakening, without tracheal intubation.
Nevertheless, these results suggest that training may
prevent patients having delayed or abandoned surgery
when CI is experienced.
In the CICV scenario, there was a significant,
substantial improvement in the technique and success of
cricothyroid cannulation, which was sustained over time.
In addition, there was a significant improvement in the
speed of insertion early after training, but this was not
maintained at 6–8 months. Use of the Manujet jet
ventilator was particularly poor initially, with significant
sustained improvements after training, although there was
a nonsignificant decline at 6–8 months. Volunteers were
surprisingly competent at surgical cricothyroidotomy
before training and resorted to this technique early after
failed jet ventilation. Most volunteers had experienced
previous training on Advanced Life Support courses,
which included jet ventilation and surgical cricothyroidotomy. However, the jet ventilation technique taught on
such courses is generally low pressure, low flow [12], not
high pressure high flow, as currently recommended [4].
This explains the poor utilisation of the Manujet system,
but not the poor cannula insertion technique, which may
therefore require more frequent reinforcement. Surgical cricothyroidotomy skill seems to be retained well.
However, jet ventilation via a cricothyroid cannula is a
very effective, safe and rapid means of restoring oxygenation if the correct technique is used [4]. Incorrect use is
not only ineffective, but can also be life threatening [4]. It
is of great concern that only 20% of volunteers could
367
Æ
P. M. Kuduvalli et al.
Unanticipated difficult airway management
Anaesthesia, 2008, 63, pages 364–369
. ....................................................................................................................................................................................................................
initially use this technique effectively despite 38% being
consultants. However, training substantially improved
performance, which was sustained over time, making this
technique subsequently more available to these practitioners and their patients, without necessarily having to
resort to the more invasive technique of surgical cricothyroidotomy.
Misplacement and improper use of equipment were the
only complications that could be noted on the SimMan.
Our study showed a considerable significant reduction in
the overall incidence of equipment misuse in the early
post-training phase, from 81% to 10%, which increased to
20% 6–8 months later. These results are better than those
of Jeffrey et al. [7], who reported a rate of complications
or equipment misuse of 16% after training, 50% at
4 months and 80% at 8 months.
Our training programme significantly reduced the
number of deviations from DAS guidelines [4] in both
scenarios, suggesting that training results in a more
structured approach. This was sustained for 6 months
for CICV, but not for CI. This may be partly because
management of CI involves more alternatives, in a less
critical situation, compared with CICV.
It would have been ideal if the study had a control
group that had not undergone training, to account for any
simulator learning effect. However, there were no further
significant improvements in performance noted at 6–
8 months compared with the initial re-evaluation and
most skills had deteriorated slightly, indicating that any
direct simulator learning effect is relatively unimportant,
compared with the effect of training.
We conclude that simulation-based airway training
significantly improves early performance. Adherence to
the DAS guideline process was sustained for 6–8 months
for CICV, but only for 6–8 weeks for the CI scenario.
Improvements in most technical skills were maintained at
6 months, although there were some indications of
deterioration. Long-term retention of both technical
and decision-making skills requires frequent reinforcement. Our conclusions support recent recommendations
to provide regular ‘in house’ workshops at intervals of
6 months or less [5].
Acknowledgements
We would like to thank the following: the anaesthetists
from the Department of Anaesthesia at The Countess of
Chester Hospital for their participation; Mr Keith Jarman,
Senior Theatre Practitioner and Ms Ana-Marie Davies,
Theatre Practitioner, for their assistance; Freelance Surgical Ltd. for provision of disposable airway equipment;
and Laerdal Medical Corporation for provision of
disposables for the mannequin.
368
References
1 Utting JE. Pitfalls in anaesthetic practice. British Journal of
Anaesthesia 1987; 59: 877–90.
2 Gannon K. Mortality associated with anaesthesia. A case
review study. Anaesthesia 1991; 46: 962–6.
3 Confidential Enquiry into Maternal and Child Health. Why
Mothers Die 2000–02. The Sixth Report of the Confidential
Enquiries into Maternal Death in the United Kingdom.
London: RCOG Press, 2004.
4 Henderson JJ, Popat MT, Latto IP, Pearce AC, Difficult
Airway Society. Difficult Airway Society Guidelines for
management of the unanticipated difficult intubation.
Anaesthesia 2004; 59: 675–94.
5 Cook TM. Still time to organise training in airway management in the UK. Anaesthesia 2006; 61: 727–30.
6 Wong DT, Prabhu AJ, Coloma M, Imasogie N, Chung FF.
What is the minimum training required for successful
cricothyroidotomy? A study in mannequins. Anesthesiology
2003; 98: 349–53.
7 Jeffrey SD, Lochhead V, Pryn A. Skill retention following
cricothyroid puncture training using the Melker Airway Kit.
Annual Meeting of The Difficult Airway Society 2006:
Scientific Programme and Abstracts: 31.
8 The Difficult Airway Society. http://www.das.uk.com/
equipmentlistjuly2005.htm [accessed 14 August 2007].
9 Cormack RS, Lehane J. Difficult tracheal intubation in
obstetrics. Anaesthesia 1984; 39: 1105–11.
10 Sulaiman L, Tighe SQM, Nelson RA. Surgical vs wireguided cricothyroidotomy: a randomised crossover study of
cuffed and uncuffed tracheal tube insertion. Anaesthesia
2006; 61: 565.
11 Chambers WA. Difficult airways – difficult decisions:
Guidelines for publication? Anaesthesia 2004; 59:
631–3.
12 American College of Surgeons Committee on Trauma.
Advanced Trauma Life Support for Doctors, 7th edn. Chicago:
American College of Surgeons, 2004.
Appendix 1
Scenario 1: Cannot intubate (CI) scenario during
routine induction of anaesthesia in an adult
non-obstetric patient
A 55-year-old man, with a body mass index of 30 and
ASA 1, has no factors suggestive of a difficult airway on preoperative assessment. He is undergoing anaesthesia for a
lumbar discectomy, for incipient cord compression. He
will be ventilated prone with a cuffed tracheal tube. In the
presence of full monitoring, anaesthesia is induced with
intravenous propofol 200 mg, fentanyl 50 lg and atracurium 50 mg. Facemask ventilation is straightforward.
Direct laryngoscopy reveals a Grade 4 Cormack and
Lehane view. The volunteer is asked to demonstrate how
they would proceed to intubate the trachea, using any of
the available equipment.
2008 The Authors
Journal compilation 2008 The Association of Anaesthetists of Great Britain and Ireland
Æ
Anaesthesia, 2008, 63, pages 364–369
P. M. Kuduvalli et al.
Unanticipated difficult airway management
. ....................................................................................................................................................................................................................
Scenario 2: Cannot intubate and cannot ventilate
(CICV) scenario in an adult non-obstetric patient
This scenario is identical to scenario 1, except that
following administration of induction agents and muscle
relaxant, facemask ventilation is impossible. Use of airway
adjuncts such as Guedel’s airway and nasopharyngeal
airway fail to improve the situation. Direct laryngoscopy
reveals a Grade 4 view and the patient’s oxygen saturation
falls rapidly. The volunteer is asked to demonstrate how
he or she will manage this situation.
After needle cricothyroidotomy and jet ventilation
have been attempted, the volunteer is informed that the
patient has started to regurgitate, in order to assess his ⁄ her
ability to establish a surgical airway. If a surgical technique
is selected first, the volunteer is informed that there will
be a delay of a few minutes to assemble the equipment, in
order to assess cannula cricothyroidotomy skills.
Appendix 2: ‘Ideal’ management plans
Cannot intubate scenario
Call for help.
Plan A
• optimise head ⁄ neck position;
• correct laryngoscope technique and vector;
• external laryngeal manipulation;
• ensure vocal cords open and immobile;
• introducer (Gum Elastic Bougie) and ⁄ or alternative
laryngoscope;
• maximum of four attempts, maintaining ventilation
with 100% oxygen and volatile anaesthesia.
Plan B (when Plan A fails to achieve intubation)
• insert LMA, PLMA or ILMA;
• maximum up to two attempts at insertion; use of
alternative LMA device;
• ventilate with 100% oxygen and volatile anaesthesia
between attempts;
• ventilate with 100% oxygen via successfully inserted
LMA ⁄ PLMA ⁄ ILMA;
• confirm ventilation, oxygenation, anaesthesia, CVS
stability and muscle relaxation;
2008 The Authors
Journal compilation 2008 The Association of Anaesthetists of Great Britain and Ireland
• fibreoptic intubation (FOI) via LMA ⁄ PLMA (with or
without Aintree catheter) or intubation via ILMA: One
attempt;
• verify intubation with capnography and stethoscope;
continue ventilation.
Plan C (when Plan B fails to achieve intubation)
• when insertion of LMA ⁄ ILMA ⁄ PLMA fails, revert
to face mask, oxygenate and ventilate; reverse nondepolarising neuromuscular blocking drug;
• when intubation via LMA fails, ventilate via LMA;
reverse non-depolarising neuromuscular blocking drug;
• plan for an awake FOI.
Cannot intubate, cannot ventilate scenario
Call for help.
Insertion of LMA
• oxygenation and ventilation;
• maximum of two attempts at insertion.
Cannula cricothyroidotomy
• insert Ravussin cannula through cricothyroid membrane;
• confirm correct cannula placement by air aspiration;
• assistant’s hand to maintain position of cannula;
• adjust Manujet pressure setting and attach ventilation
system to cannula;
• commence cautious jet ventilation;
• confirm ventilation of lungs and exhalation through
upper airway.
Surgical cricothyroidotomy (when ventilation fails or any
other complication develops)
• preparation of necessary equipment.
• four-step technique: (i) identification of cricothyroid
membrane; (ii) stab incision and blunt dilation;
(iii) caudal traction on cricoid cartilage with tracheal
hook; (iv) insertion of cuffed tracheal ⁄ tracheostomy
tube and inflation of cuff
• ventilation with low pressure source;
• verification of tube position and ventilation of lungs
(as above).
369