NBCRNA Core Modules Supplemental Part 2
Airway Management
Instrumentation &
Techniques
Amy Sheppard, CRNA, MSNA

Getting your credits
❖ NBCRNA Core Module #1: Airway
❖ Series of 3 Airway lectures online: INCLUDED in
conference fee
❖ CRNA Today is a recognized vendor for NBCRNA &
Prior Approve by the AANA

Getting your credits
❖ FIRST – Visit and Register at CRNAToday.com
❖ Enroll in the Airway: NBCRNA Core Module #1….At check out utilize your Coupon
Code “1FL” followed by your AANA number. NO Leading zero. Click Update
❖ Online lecture
❖ Can be viewed on-demand….
❖ 3 attempts to pass Post Test
❖ To get Class A Credit- A Post Test grade of 80% is required
❖ 3 Attempts
❖ Certificate is only available after passing
❖ All records submitted to the AANA monthly

Objectives
❖ The Learner will demonstrate the appropriate steps in assessing an
airway to develop the appropriate patient-specific plan that ensures
safe management of the airway and facilitates continuity of care
❖ The Learner will identify the indications and contraindications
associated with the use of airway equipment.
❖ The Learner will understand the associated malpractice claims
arising from the management of the airway, using a closed claims
analysis.
❖ The Learner will identify the complications associated with airway
equipment

History of Airway
Management
Morton Inhaler
Dräger “Pulmonator”
Alfred Kirstein
Autoscope
1943 1941
Murphy Endotracheal Tube
“Airway Management”
A broad term used to describe the tools, techniques and procedures
used to support and control oxygenation and ventilation as well as
delivery of anesthetics.

Getting started
❖ What factors need to be considered?
• NPO status
• Risk of aspiration
• Patient factors
• Surgeon factors
• Type and length of surgery
• Regional anesthesia
• Provider competencies

Preoperative Fasting
Guidelines
❖ 2017: ASA updated recommendations for pre-operative
fasting1
• 2 hours clear liquids
• 4 hours breast milk
• 6 hours solid foods, infant formula & non-human milk
• 8 hours fried or fatty foods

Preoperative Fasting
Guidelines
❖ Gum, smokeless tobacco, hard
candy2
• Not specifically addressed
by the ASA guidelines
• European Society of
Anaesthesiology
guidelines do NOT
recommend delaying
anesthesia

Aspiration Prophylaxis
❖ Overall incidence of aspiration remains very low
❖ Incidence of anesthesia related fatal aspiration was only
1:350,000 (.0003%)3
❖ In the NAP4 study, aspiration was responsible for 50% anesthetic
deaths.3
❖ Risk of aspiration is greater with higher patient Physical Status
(ASA status) and emergency surgery3

Aspiration Prophylaxis
❖ The intended goal of aspiration prophylaxis is to
decrease gastric volume and pH.
❖ Sodium Citrate, Metoclopramide, Ranitidine (or other H2
antagonist)
The ASA guidelines do NOT recommend routine
prophylaxis1

Aspiration Prophylaxis
❖ Full stomach
❖ Diabetic gastroparesis
❖ Symptomatic GERD
❖ Pregnancy
❖ Emergency surgery
❖ ESRD
❖ GI obstruction
❖ Hiatal hernia
❖ Active N/V
❖ NG tube
❖ Morbid obesity
Indications: 4, 5

Aspiration Prophylaxis in
Pregnancy
Updated report from ASA task force on Obstetric Anesthesia & the
Society for Obstetric Anesthesia and Perinatology6
For clear liquids: “The uncomplicated patient undergoing elective surgery (e.g.
scheduled C/S, post partum tubal ligation) may have moderate amounts of clear
liquids before induction of anesthesia.”
For solids: “The patient undergoing elective surgery (e.g. scheduled C/S, post
partum tubal ligation) should undergo a fasting period of 6-8 hours depending on
the type of food ingested (e.g. fat content).”
Before surgical procedures (e.g., cesarean delivery or post- partum tubal
ligation) “The clinician should consider the timely administration of nonparticulate
antacids, H2 antagonists, and/or metoclopramide for aspiration prophylaxis.”
After 20 weeks gestation, extra caution should be exercised with the unprotected
airway to prevent aspiration29

Aspiration Prophylaxis
Strategies for reducing aspiration risk3
Reducing gastric
volume
Preoperative fasting, nasogastric aspiration, pro
kinetic premedication
Avoidance of general
anesthesia
Is regional anesthesia an option?
Reducing pH of gastric
contents
Antacids, H2 antagonists, proton pump inhibitors
Airway protection
Tracheal intubation, 2nd generation supra-glottic
airway devices
Prevent regurgitation Rapid sequence induction
Extubation
Extubate only after awake and airway reflexes have
returned

Cricoid Pressure & Preventing
Aspiration
Is it time to LET GO of cricoid pressure?

Cricoid Pressure & Preventing
Aspiration
❖ Does cricoid pressure (CP) reduce the risk of aspiration?
• Evidence to support that CP is effective is based almost exclusively on cadaver studies and
case reports of regurgitation occurring after CP has been released. There is no evidence for or
against the use of CP and there are no published randomized controlled trials comparing the
incident of regurgitation on induction, with or without the use of CP. Additionally, CP has been
shown to decrease LES tone thus potentially increasing the risk of aspiration.3
❖ Is cricoid pressure properly applied?
• Who is applying the CP? Have they been trained? Do YOU even know how to properly apply?
❖ Does properly applied cricoid pressure actually compress the esophagus?
• The esophagus is laterally displaced relative to the midline of the vertebral body in 49%-53% of
subjects without cricoid pressure being applied. When CP was applied, lateral displacement
increased by 53%- 91%.7
❖ Does cricoid pressure increase or decrease the quality of the laryngeal view?
• Numerous articles have been published with contradictory results. However, it has been found
that application of > 40N of force can compromise airway patency and cause difficulty with
tracheal intubation.7
❖ Is CP harmful?
• Difficult laryngoscopy, esophageal rupture, cricoid fracture8
❖ Are there any contraindications to use of CP?
• Trauma to anterior neck, unstable C-spine, obstructing mass, active vomiting8

Cricoid Pressure & Preventing
Aspiration
Is it time to LET GO of cricoid pressure?
Cochrane Anaesthesia, Critical and Emergency Care Group9
There is currently NO information available from published RCTs
(randomized controlled trials) on clinically relevant outcome measures
with respect to the application of cricoid pressure during RSI.

Cricoid Pressure & Preventing
Aspiration
To correctly apply cricoid pressure,
30 - 40N (3 - 4 Kg)
of force should be applied downward onto the cricoid cartilage.10
If you are going to do it, you should at least do it correctly.

Just how good is your
cricoid?
Investigator
Ok, please proceed with the application of
cricoid pressure to the test fixture

Just how good is your
cricoid?
Participant
OK!

Just how good is your
cricoid?
Investigator
Are you applying cricoid pressure to the test
fixture?

Just how good is your
cricoid?
Participant
Yes, of course

Just how good is your
cricoid?
Investigator
Something must be wrong. We’re not
registering any pressure? You are pressing
down on the cricoid, right?

Just how good is your
cricoid?
Participant
Oh no, I would never do that. I always
“squeeze” the sides of the throat. Pushing down
would obstruct the view of the person
intubating.

Just how good is your
cricoid?
Investigator
And how long have you been applying cricoid
pressure in this manner?

Just how good is your
cricoid?
Participant
For 38 years!

Airway Assessment

Airway
Assessment
No single test has been devised that can
predict a difficult airway 100% of the time;
especially when tests are done by
themselves.
Evaluating the Airway

Modified Mallampati
Classification
• Originally described in 1983, Mallampati is an easy to perform, commonly used airway assessment
tool. As a stand alone tool however, it is insufficient to predict the difficult airway.11
• In a meta analysis of over 177,000 patients, only 35% of patients with a difficult intubation were
identified as Mallampati III or IV.11
• May be useful clinically when used in combination with other airway predictors11
• To properly perform, the neck should be neutral (not extended) and the patient should not phonate4

LEMON
Test15 Evaluation
Look externally
Are there any physical
attributes that stand out?
Evaluate 3-3-2 3-3-2 rule
Mallampati
Obstruction/Obesity
Facial trauma, edema,
foreign body, obesity, large
breasts?
Neck mobility RA? Radiation? Burns?
*Adapted with permission from The Difficult Airway Site (TheAirwaySite.com) &
Walls RM & Murphy, MF:Manual of Emergency Airway Management, 4th ed
Philadelphia, Lippincott, Williams and Wilkins, 2012

El-Ganzouri Multivariate Risk
Index
Abdel Raouf Sayed Ahmed El-Ganzouri, M.D.
Test 12, 13 Score
Mouth Opening 0 - 1
Mallampati 0 - 2
TM Distance 0 - 2
Neck Movement 0 - 2
Hx difficult intubation 0 - 2
Ability to prognath 0 - 1
Weight 0 - 2
TOTAL 0 - 12
A score ≥ 4 indicates potential difficulty when performing direct laryngoscopy

Documenting EGRI
A score ≥ 4 indicates potential difficulty when performing direct laryngoscopy
0 1 2
Mouth Opening ≥ 4 cm < 4 cm
Mallampati 1 2 3, 4
TM Distance > 6.5 cm 6 - 6.5 cm < 6 cm
Neck Movement > 90 80 - 90 < 80
Hx difficult intubation No Questionable Yes
Ability to prognath Yes No
Weight < 90 kg 90 - 110 kg > 110 kg
Total =_______

Deciding How to Manage the
Airway
vs
vs
vs
vs
vs

Positioning
7-9cm
“Sniffing Position”: Neck flexion and head extension14

Positioning
Ideally, the external auditory meatus should be in horizontal alignment
with the sternal notch.
Positioning of the obese patient14

Capnography
❖ Continuously monitor ETC02 during controlled or assisted ventilation
and any anesthesia or sedation technique requiring artificial airway
support. During moderate or deep sedation, continuously monitor
for the presence of expired C02.16

Preoxygenation
❖ Optimal is 3 mins Vt, but 8 Vc
may be acceptable.4
❖ ET O2 should be > 90% to
maximize apnea time.4
❖ What’s the purpose?
Denitrogenation: increase
the time a patients will stay
oxygenated during apnea

Mask Ventilation
❖ Indications: preoxygenation, short
duration anesthetic, bridge to
definitive airway4
❖ Relative contraindication: full
stomach, facial trauma, unstable c-
spine4
❖ Complications: hyper/hypo
ventilation, aspiration4
Ideally, peak inspiratory pressure should be kept less than 20cm H2O4

Prediction of Difficult Mask
Ventilation
*Adapted with permission from The Difficult Airway Site (TheAirwaySite.com) & Walls RM & Murphy, MF:Manual of
Emergency Airway Management, 4th ed Philadelphia, Lippincott, Williams and Wilkins, 2012
MOANS15
Difficult Mask Ventilation Mnemonic
Mask Seal Beard? Jowls?
Obese
Age > 55 y/o
No Teeth Is the patient edentulous
Stiff/Snoring Stiff neck/jaw? Sleep apnea?

Oral & Nasal Airways
Oral4 Nasal4
❖ Indications: airway obstruction, facilitate mask
ventilation, facilitate suctioning
❖ Relative contraindication: intact gag reflex
❖ Complications: dental damage, soft tissue
damage, bleeding, lingual nerve palsy
❖ Proper sizing: Corner of mouth to earlobe
❖ Indications: airway obstruction, facilitate
mask ventilation, facilitate suctioning
❖ Relative contraindication: basilar skull
fracture, coagulopathy
❖ Complications: bleeding, soft tissue
damage
❖ Proper sizing: Nostril to earlobe

Supraglottic Airway
❖ Indication: facilitate oxygenation and ventilation, delivery
of anesthesia, conduit to intubation, bridge to extubation,
failed intubation (rescue device)17
❖ Relative Contraindications: Active GERD, obesity,
traumatic airway injury, intestinal obstruction, intoxication,
restricted mouth opening, deformed airway anatomy17
❖ Complications: Inadequate ventilation, airway injury, sore
throat, tongue edema, frenulum injury, aspiration17
Cuff pressure should be <60 cm H2O18

Supraglottic Airways (SGA)
❖ 1st generation: LMA Classic and
other manufacturers of laryngeal
masks19
• Simple, low pressure
• Easy to place
❖ 2nd generation: i-gel, LMA ProSeal,
LMA Supreme19
• Additional design features to reduce
aspiration risk, allow for higher seal
pressure to facilitate controlled ventilation,
and may also have integrated bite block.

Prediction of Difficult SGA
Placement
RODS15
Difficult SGA Placement Mnemonic
Restricted Mouth opening
Obstruction
Distorted Airway
Stiff lungs/neck
*Adapted with permission from The Difficult Airway Site (TheAirwaySite.com) & Walls RM & Murphy,
MF:Manual of Emergency Airway Management, 4th ed Philadelphia, Lippincott, Williams and Wilkins,
2012

LMA in the Prone Patient
❖ Review prone LMA insertion in 441
subjects in 1 RCT, 2 description
studies, 1 case series and 2 case
reports20
❖ Successful LMA placement: 100%
❖ Successful ventilation: 100%
❖ Risks: “Comparable to those when
LMA’s are used in the supine patient.”

Endotracheal Intubation
❖ Indications: General anesthesia, aspiration prevention,
respiratory failure, inadequate oxygenation/ventilation4
❖ Contraindications: Penetrating or blunt force trauma to
the upper airway anatomy, unstable c-spine4
❖ Complications: Sore throat, dental damage, soft tissue
damage, vocal cord damage4

Modified Cormack-Lehane
❖ The Cormack-Lehane classification, first described in 1984, is broadly used
to describe the laryngeal view obtained during laryngoscopy4
❖
4Yentis further defined this grading system in 1998 when he divided Grade 2 into 2A and 2B4

Direct Laryngoscopy
The goal of traditional direct laryngoscopy
is to obtain direct line of sight with the
glottic opening. To accomplish this task,
the rigid laryngoscope is used to align the
oral, pharyngeal and laryngeal axes.
In the overall patient population, clinicians are unable to visualize the
vocal cords when performing direct laryngoscopy up to 7.5% of
patients21

Video Laryngoscopy

Predictors of Difficult Video
Laryngoscopy
❖ Usual clinical indicators of difficult direct laryngoscopy
& intubation do not appear to predict difficult video
laryngoscopy.22
❖ In a study of 6,278 subjects, patients were divided into
2 groups base on their EGRI score21
• ≥ 7 and patient received awake FOB
• ≤ 6 and patients were intubated via video
laryngoscope
❖ 6 patients received awake FOB based on protocol, 1
patients received awake FOB based on presence of
large neck tumor and another an awake tracheostomy
for the same reason (even though their score was less
than 7). All other patient were intubated via video
laryngoscope.
❖ The incidence of C/L grade III was only 0.14% when
performing VL. Grade IV was not encountered. All
patients in the study were successfully intubated.

Regional anesthesia and the difficult
airway
❖ Regional anesthesia is recommended in patients with
potentially difficult airways who present for surgery23
❖ However incidents may occur after the initiation of
regional anesthesia that would “force” the clinician to
manage the airway. These incidents may include
hemorrhage, high/total spinal, anaphylaxis, failed
block23
❖ A successful regional anesthetic may help avoid the
need to directly manage a difficult airway, it does not
prevent it23
Even when utilizing regional anesthesia, an airway management
strategy should always be discussed with the patient and planned in
advance23

Apneic Oxygenation
❖ 15 L/min
❖ May prolong the time patient
maintain adequate oxygen
saturation during
laryngoscopy/intubation
Use of high-flow nasal cannula oxygen therapy can
prevent desaturation during tracheal intubation24

ETT Cuff Pressure
❖ Complications associated with excessive ETT cuff
pressure can include25
• Sore throat
• Recurrent laryngeal nerve palsy
• Mucosal ischemia
• Tracheal ulceration
• Tracheal stenosis
• Trachea-esophageal fistula
• Death
❖ Studies have shown an inability to accurately identify ETT cuff pressure by palpating the
pilot balloon.
❖ No correlation between years in practice or number of intubations performed and the
ability to properly inflate the ETT cuff or detect over inflation.
❖ Current evidence suggests that a minimum volume of air to obviate air flow past the cuff,
up to a maximum pressure of less than 25cm H20, is safest to minimize complications
from high ETT cuff pressures.

Closed claims and the airway
Originally 223 cases (1989-1997) from the records of St. Paul Fire and Marine
Insurance Company. Reviewed by 8 CRNA researchers
Updated recently looking at 245 claims (2003-2012 ) provided by CNA insurance
company. Reviewed by 15 CRNA researchers
AANA Foundation Closed Claims Analysis26

Closed claims and the airway
❖ Years of experience do not appear to be a factor in terms of frequency of
occurrence of adverse events.
❖ 69.8% of adverse events occurred in hospitals
❖ 68.2% of the events are confirmed to have occurred during the intra-anesthesia
period but only 38.8% of the events became apparent to the provider during the
intra-anesthesia period.
❖ 45.5% of negative outcomes were preventable
❖ In 32.7%, anesthesia management was deemed to have been inappropriate
❖ Respiratory events are responsible for the most common negative outcomes
(31.8%).
❖ When there was a failure to meet AANA Practice Standards for Nurse Anesthetists,
breach of standard #5 (includes continuous monitoring of oxygenation and
ventilation) occurred 2nd most often behind breach of standard #4
AANA Foundation Closed Claims Analysis26

Closed claims and the airway
❖ Established in 1985 in an attempt to improve patient
safety and prevent anesthesia related injuries
❖ At the time, 11% of total dollars paid for anesthesia
related patient injuries while Anesthesiologist accounted
for only 3% of total physicians insured
❖ Data is derived from lawsuits regardless of the litigation
outcome
ASA Closed Claims Database27

Closed claims and the airway
❖ Respiratory system issues accounted for 17% of all
claims
❖ The most common respiratory events leading to
anesthesia claims were difficult intubation, inadequate
oxygenation or ventilation and pulmonary aspiration
❖ Claims arising from esophageal intubation have largely
disappeared with the adoption of capnography
ASA Closed Claims Database27
(1990-2007)

Closed claims and the airway
Respiratory events leading to claims27
(1990-2007)

Closed claims and the airway
Claims related to the difficult airway27
(1990-2007)

Closed claims and the airway
Lessons Learned27
❖ During airway emergencies, persistent intubation
attempts were associated with death or permanent
brain damage
❖ The LMA was not an effective rescue device in some
claims in which multiple, prolonged intubation
attempts had been made
❖ Surgical airway should be instituted early in the
management of the difficult airway

Closed claims and the airway
❖ NAP4: National Audit Project of the
Royal College of Anesthetist and the
Difficult Airway Society28
❖ Not a closed claims per se.
Evaluated cases from 309 NHS
hospitals in the UK over a year
(2008-2009)
❖ Designed to evaluate what types of
airway devices are used during
anesthesia, how often complications
resulting in serious harm occur and
to see how this information be used
to reduce the incidence of these
events and complications.

Closed claims and the airway
❖ NAP 4 Highlights28
• Poor airway assessment
• Poor planning: Plan vs Strategy
• Failure to plan for Failure
• Failed use of awake FOI
• Repeated intubation attempts
• Supraglottic devices were used inappropriately
• High failure rate of needle cricothyroidotomy
• Aspiration was the single most common cause of death
Poor judgment,
as determined by both the reporters and the reviewers,
repeatedly appeared to be the most common cause of events

The Takeaway
❖ Chose the right tool for the right patient (proper
preparation, strategy)
❖ Learn from other’s mistakes (closed claims)

References
1. Practice Guidelines for Preoperative Fasting & the use of pharmacologic agents to reduce the risk of pulmonary aspiration: Application to healthy
patients undergoing elective procedures. An Updated Report by the American Society of Anesthesiologists Task Force on Preoperative Fasting and the
Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration. Anesthesiology. 2017;126(3):376-393.
2. Smith I, Kranke P, Murat I, et al. Perioperative fasting in adults and children. European Journal of Anaesthesiology. 2011;28(8):556-569.
doi:10.1097/eja.0b013e3283495ba1.
3. Robinson M, Davidson A. Aspiration under anesthesia: Risk assessment and decision making. Continuing Education in Anaesthesia Critical Care and Pain.
2014;14(4):171-175.
4. Miller RM et al.,eds. Miller's Anesthesia. 8th ed. Philadelphia: Saunders; 2015: 1652-1680.
5. Butterworth JF, Mackey DC, Wasnick JD, eds. Morgan & Mikhail’s Clinical Anesthesiology. 5th ed. McGraw Hill Companies. New York: 2013: 769.
6. Practice Guidelines for Obstetric Anesthesia. An Updated Report by the American Society of Anesthesiologists Task Force on Obstetric Anesthesia.
Anesthesiology. 2016;124:00-00.
7. Bhatia N, Bhagat H, Sen I. Cricoid pressure: Where do we stand? J Anaesthesiol Clin Pharmacol Journal of Anaesthesiology Clinical Pharmacology.
2014;30(1):3. doi:10.4103/0970-9185.125683.
8. Stewart JC, Bhananker S, Ramaiah R. Rapid-sequence intubation and cricoid pressure. International Journal Critical Illness and Injury Science.
2014;4(1):42–49.
9. Algie CM, Mahar RK, Tan HB, Wilson G, Mahar PD, Wasiak J. Effectiveness and risks of cricoid pressure during rapid sequence induction for
endotracheal intubation. Cochrane Database of Systematic Reviews. 2015. doi:10.1002/14651858.cd011656.
10. Lefave M, Harrell B, Wright M. Analysis of Cricoid Pressure Force and Technique Among Anesthesiologists, Nurse Anesthetists, and Registered Nurses.
Journal of PeriAnesthesia Nursing. 2016;31(3):237-244.
11. Lundstrom LH, Vester-Andersen M, Moller AM, Charuluxananan S, L'hermite J, Wetterslev J. Poor prognostic value of the modified Mallampati score: a
meta-analysis involving 177 088 patients. British Journal of Anaesthesia. 2011;107(5):659-667.
12. El-Ganzouri AR, Mccarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD. Preoperative Airway Assessment. Anesthesia & Analgesia. 1996;82(6):1197-1204.
doi:10.1213/00000539-199606000-00017.
13. Corso RM, Cattano D, Buccioli M, Carretta E, Maitan S. Post analysis simulated correlation of the El-Ganzouri airway difficulty score with difficult
airway. Brazilian Journal of Anesthesiology (English Edition). 2016;66(3):298-303. doi:10.1016/j.bjane.2014.09.003.
14. El-Orbany M, Woehlc H, Salem M. Head and neck position for direct laryngoscopy. Anesthesia and Analgesia. 2011;133:103-109.
doi:10.1213/ane.0b013e31821c7e9c.
15. Walls RM, Murphy MF. Manual of Emergency Airway Management, 4th Ed Philadelphia: Lippincott Williams and Wilkins; 2012.

References
16. Standards for Nurse Anesthesia Practice. American Association of Nurse Anesthetists website.
http://www.aana.com/resources2/professionalpractice/Pages/Scope-of-Nurse-Anesthesia-Practice.aspx. Updated 2013. Accessed June 12, 2016.
17. Michalek P, Donaldson W, Vobrubova E, Hakl M. Complications Associated with the Use of Supraglottic Airway Devices in Perioperative Medicine.
BioMed Research International. 2015;2015:1-13. doi:10.1155/2015/746560.
18. Kang J-E, Oh C-S, Choi JW, Son IS, Kim S-H. Postoperative Pharyngolaryngeal Adverse Events with Laryngeal Mask Airway (LMA Supreme) in
Laparoscopic Surgical Procedures with Cuff Pressure Limiting 25 : Prospective, Blind, and Randomised Study. The Scientific World Journal. 2014;2014:1-7.
doi:10.1155/2014/709801.
19. Cook T, Howes B. Supraglottic Airway devices: Recent Advances. Contin Educ Anaesth Crit Care Pain Continuing Education in Anaesthesia, Critical Care
& Pain. 2011;11(2):56-61. 10.1093/bjaceaccp/mkq058.
20. Whitacre W, Dieckmann L, Austin PN. An Update: Use of Laryngeal Mask Airway Devices in Patients in the Prone Position; AANA Journal. 2014:82(2).
21. Caldiroli D, Cortellazi P. A new difficult airway management algorithm based upon the El Ganzouri Risk Index and GlideScope videolaryngoscope. A
new look for intubation? Minerva Anestesiologica. 2011;77(10):1011-7.
22. Diaz-Gomez JL, Satyapirya A, Satyapriya SV et al. Standard clinical risk factors for difficult laryngoscopy are not independent predictors of intubation
success with the GlideScope. Journal of Clinical Anesthesia. 2011; 23(8):603-610 doi:10.1016/j.jclinane.2011.03.006.
23. Saxena, N. (2013). Airway management plan in patients with difficult airways having regional anesthesia. J Anaesthesiology Clin Pharmacol Journal of
Anaesthesiology Clinical Pharmacology. 2013:29(4):558 doi.org/10.4103/0970-9185.119106.
24. Weingart SD, Levitan RM. Preoxygenation and prevention of desaturation during emergency airway management. Annals of Emergency Medicine.
2012;59(3):165-175. doi:10.1016/j.annemergmed.2011.10.002.
25. Sultan P, Carvalho B, Rose BO, Cregg R. Endotracheal tube cuff pressure monitoring: a review of the evidence. Journal of Perioperative Practice.
2011:21(11).
26. Jordan LM, Quraishi. The AANA Foundation Malpractice Closed Claims Study: A Descriptive Analysis. AANA Journal. 2015;83(5); 318-323.
27. Metzner J, Posner KL, Lam MS, Domino KB. Closed claims’ analysis. Best Practice & Research Clinical Anaesthesiology. 2011;25(2)263-276.
doi:10.1016/j.bpa.2011.02.007.
28. Cook TM, Woodall N, Frerk C. Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of
Anaesthetists and the Difficult Airway Society. Part 1: Anaesthesia. British Journal of Anaesthesia. 2011;106(5):617–631. doi: 10.1093/bja/aer058.
29. Reitman E, Flood P. Anaesthetic considerations for non-obstetric surgery during pregnancy. British Journal of Anaesthesia. 2011;107(suppl 1):i72-I78.
doi:10.1093/bja/aer343.