Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
Endotracheal intubation is an advanced 
airway skill that is essential in the resuscitation and 
management of critically ill patients, and for the 
facilitation of general anesthesia when controlled 
ventilation is required. Successful endotracheal 
intubation requires not only the technical skills of 
laryngoscopy, which are learned by repeated 
supervised practice, but also an understanding of the 
indications for intubation, how to evaluate a patient’s 
airway, and what instruments, medications and 
devices must be available to the practitioner. As with 
any other procedural skill, recognition and treatment 
of potential complications is necessary.   
Before learning to perform endotracheal 
intubation, it is essential to learn effective bag-mask 
ventilation. It is important to keep in mind that 
patients do not die from lack of intubation, they die 
from 
a 
lack 
of 
VENTILATION 
and 
OXYGENATION, both of which can be provided by 
bag-mask ventilation.  
 
Bag-Valve-Mask Ventilation 
To 
perform 
bag-valve-mask 
(BVM) 
ventilation, it is important to start with an 
appropriately sized device. Ambu bags typically 
come in adult, pediatric and neonatal sizes. The 
corresponding volumes associated with those 
devices are approximately 1500 mL, 630 mL and 220 
mL, respectively. It is also important to choose an 
appropriately sized face mask, one that completely 
covers the mouth and the nose of the patient, and 
with which the provider is able to create a seal that 
allows effective ventilation. Most suppliers of face 
masks provide three adult sizes (small, medium and 
large) and three pediatric sizes (neonatal, infant and 
pediatric). 
 
Ambu-bag with various sizes of masks. The pressure of the 
inflatable portion of the mask can be changed by inflating with 
a syringe at the port (Red arrow.)  
 
The most common technique for effective 
BVM ventilation is the “EC” clamp technique. 
Unless a cervical spine injury is suspected, the head 
is gently tilted back while the jaw is lifted.  
 
One handed “EC” technique for bag-mask ventilation: The 
“C,” formed by the thumb and index fingers, presses the mask 
downwards while the “E,” formed by the 3rd, 4th and 5th 
fingers, pulls the body of the mandible upwards.  
 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
Two handed “EC” technique for bag-mask ventilation. An 
assistant manually ventilates the patient.  
 
A breath is administered over 1 second, 
which should produce a visual chest rise. If the chest 
does not rise, airway obstruction should be 
suspected. This obstruction may be relieved by 
repositioning, or if this is unsuccessful, it may be 
necessary to place an oral airway.  It is mandatory to 
use an appropriately sized oral airway. One that is too 
small can push the tongue backwards, worsening 
airway obstruction, while one that is too large can 
occlude the glottic opening. The easiest way to 
choose the appropriate size for an oral airway is to 
place the airway next to the patient’s face. With the 
flange at the level of the patient’s mouth, the 
posterior part should reach the angle of the patient’s 
mandible  
 
Oral airway in place. This is a rigid tube which  extends beyond 
the base of the tongue and raises the soft palate away from the 
oropharynx. When it is in place, the bag-valve mask can be used 
more effectively to ventilate the patient. 
 
 
Various sizes of oral airway are available and should be fitted 
to the patient as below:  
 
 
How to choose an oral airway. When the flange is at the level 
of the patient’s lips, the tip will reach the angle of the mandible.  
 
It should be noted that an oral airway will not 
be tolerated in a conscious patient. Its placement can 
provoke gagging and vomiting which may lead to 
aspiration. If the patient is conscious a nasal airway 
will be better tolerated and will relieve soft tissue 
airway obstruction by lifting the patient’s soft palate 
and tongue. 
 
 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
www.vumc.org/global-surgical-atlas 
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
 
Nasal airway in place. This is a soft tube which extends beyond 
the soft palate into the oropharynx or hypopharynx. When it is 
in place, the bag-valve mask can be used more effectively to 
ventilate the patient. 
 
If you are unable to ventilate using the one-
handed EC clamp technique (with or without an oral 
or nasopharyngeal airway), using a two-handed EC 
technique (with an assistant squeezing the bag) may 
improve your ability to effectively ventilate. If all of 
these techniques fail, plans should be made for an 
advanced airway, such as a laryngeal mask airway or 
endotracheal intubation.  
 
Laryngeal Mask Airway 
A laryngeal mask airway (LMA) is more 
invasive than an oral or nasopharyngeal airway, but 
less invasive and easier to perform than endotracheal 
intubation. LMAs are available in multiple sizes 
based on the weight of the patient. They can be used 
as airway rescue devices or as the primary airway in 
patients requiring general anesthesia who are not 
paralyzed and remain spontaneously ventilating. The 
inflatable portion of the LMA produces a seal around 
the glottic opening and allows ventilation to be 
achieved. As with the oral airway, the LMA will not 
be tolerated in the conscious patient and will not 
protect against aspiration of gastric contents in a 
patient with a full stomach. Lubricating the posterior 
surface of the mask and tip of the LMA will facilitate 
insertion. The LMA is inserted gently until resistance 
is encountered, at which point the entry port can be 
connected to an Ambu bag or breathing circuit. 
 
The laryngeal mask airway is designed to fit in the 
hypopharynx, with the pointed tip in the opening of the 
esophagus, and direct air into the larynx across the vocal cords. 
It is inserted along the posterior oropharynx and then directed 
downwards to its position. It is inserted  with the inflatable 
portion partially inflated, pressure can be added to improve the 
seal if necessary.  
 
 
Table: sizes of laryngeal mask airways, their appropriate 
weight patients, and amounts of air to fill their balloons.  
 
 
Laryngeal mask in place, having been inserted by sliding along 
the soft palate and posterior oro- and hypopharynx. 
 
Endotracheal intubation 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License  
 
Endotracheal Intubation 
Indications 
for 
endotracheal 
intubation 
include relief of airway obstruction (if this cannot be 
achieved 
using 
the 
previously 
mentioned 
techniques), airway protection, failure of ventilation 
and/or oxygenation, an expected clinical course that 
requires intubation (eg. evidence of airway injury 
after fire exposure) as well as general anesthesia 
when controlled ventilation is needed. Preparation is 
vital to successful intubation. A checklist for steps to 
take in preparation for endotracheal intubation is a 
useful tool.  
 
A  checklist of steps prior to intubation 
 
In addition to the other equipment and 
medications listed, it is important to have an 
appropriately sized endotracheal tube (ETT) as well 
as laryngoscope. It is best to choose which size ETT 
you think will be used based on the patient’s age as 
well as an ETT one size larger and one size smaller 
than your estimated size. It is also best practice to 
have a variety of laryngoscope blades (Macintosh 
and Miller) available.  
 
Table: Formulas for selecting the correct size of endotracheal 
tubes 
 
 
A laryngoscope with a lighted Miller blade. This blade is 
designed to retract the epiglottis directly. Memory trick: The 
scope handle and MiLLer blade together are shaped like the 
letter “L.”  
 
 
A laryngoscope with a lighted Macintosh blade. This blade is 
designed to retract the epiglottis indirectly, when its tip is 
placed in the vallecula, the space between the base of the tongue 
and the epiglottis. This maneuver is shown further in the 
diagrams below. Memory trick: The blade of the MaCintosh is 
shaped like the letter “C” 
 
Positioning the patient before attempting 
endotracheal intubation will greatly improve your 
chances of success. The ideal positioning is the 
“sniffing position.” The goal of this position is to 
align the patient’s head and neck in such a way as to 
allow direct visualization of the vocal cords. This is 
especially important in obese patients. Using folded 
blankets to create a “ramp” behind the patient’s back 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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will allow you to successfully position obese patients 
in the sniffing position. 
 
The “sniffing position” to improve visualization of vocal cords 
during direct laryngoscopy 
 
 
In obese patients, the excess tissue of the chest and abdomen 
make accessing the airway more difficult.  
 
 
When this problem exists, the “sniffing position” can be 
supplemented by using folded blankets to create a “ramp.” This 
position allows gravity to pull the tissue of the patient’s neck 
and upper chest towards the patient’s feet and out of your way.  
 
Whenever possible, prior to attempting 
endotracheal intubation, the patient should be pre-
oxygenated. This involves the administration of 
100% oxygen for 3 to 5 minutes, with a good mask 
seal, while the patient is spontaneously breathing. 
This will fill the functional residual capacity (FRC) 
of the patient’s lungs with a high concentration of 
oxygen and prolong the period of apnea before 
oxygen desaturation occurs. This can be critical in 
patients who are difficult to intubate, or must be 
allowed to emerge from the effects of the induction 
drug because they cannot be intubated.  
 
Functional Residual Capacity (Red circle) can be conceived as 
the air remaining inside a patient’s lungs at the end of a normal 
respiratory cycle. In an adult male, this can be as much as 2-
2.5L. Preoxygenation fills this space with 100% oxygen, 
allowing more time without breathing before the oxygen level 
starts to drop.  
 
A 70 kg adult man has an FRC of 
approximately 2.5 L, and consumes 250 mL of 
oxygen each minute while producing 200 mL of 
CO2. Theoretically you should have 8 - 10 minutes 
(2,500 divided by 250) to control this patient’s 
airway but in reality it is 3 to 4 minutes. It is 
important to have that time available should 
difficulties with intubation arise. 
After pre-oxygenation, induction drugs with 
or without paralytics are administered. While 
patients can be intubated without paralysis, use of 
depolarizing or non-depolarizing muscle relaxants 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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will make laryngoscopy and intubation significantly 
easier, especially in adult patients.  
 
Table: commonly used sedation agents for intubation and some 
of their side effects 
 
 
Table: commonly used paralytics and their duration of onset. 
Recall that during the time of onset, the patient may not be able 
to breathe but may not be paralyzed enough to intubate, so a 
shorter onset is almost always preferable.  
 
After administration of an induction drug, the 
practitioner should ensure that the patient is 
unconscious before giving a paralytic or attempting 
intubation. This can be evaluated by gently brushing 
the eyelash with a finger; if no response is elicited 
you should proceed with intubation. Unless the 
patient is undergoing a rapid-sequence induction (see 
below), it is important to verify that you can provide 
effective bag-mask-ventilation before proceeding 
with paralysis. If it is not possible to ventilate, the 
patient can be allowed to emerge from the effect of 
the induction agent and other options for airway 
control can be considered.  
If ventilation is possible, when the patient is 
adequately paralyzed the laryngoscope is gently 
inserted into the right side of the patient’s mouth, and 
the tongue is swept to the left. As the laryngoscope 
is advanced, the epiglottis will be visualized. When 
using a Macintosh blade, the tip is inserted anterior 
to the epiglottis in the vallecula; if using a Miller 
blade the tip will actually lift the epiglottis. By 
exerting pressure in the same direction as the handle 
the laryngoscope blade will lift the epiglottis and soft 
tissues to allow visualization of the vocal cords at 
which point the endotracheal tube can be inserted 
into the trachea. It is important while elevating the 
tongue and mandible that there be NO pressure on 
the upper teeth, as this can dislodge a tooth and create 
a foreign body obstruction in an unconscious patient. 
 
The laryngoscope is held gently in the left hand so that the tube 
can be inserted with the right hand. 
 
 
The Macintosh laryngoscope is inserted on the right side of the 
patient’s mouth so that the tongue can be swept towards the 
patient’s left and the tube can be inserted along the right side 
of the scope.  
 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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As the blade of the scope is inserted farther into the throat, be 
careful to apply force in the direction shown by the upper 
arrow, raising the tongue and mandible in an anterior and 
inferior direction. If you “pry” the scope by rotating the tip 
upwards, the upper part of the blade will press on the upper 
incisors and loosen, damage, or dislodge one or more upper 
teeth. 
 
 
View of the vocal cords and trachea with the Macintosh 
laryngoscope in proper position. The tip of the blade is in the 
vallecula, between the base of the tongue and the epiglottis. 
Pressure in the right direction, as shown above, raises up the 
epiglottis and exposes the vocal cords. The Miller 
laryngoscope, in contrast, passes below the epiglottis and 
raises it directly.,  
 
 
While applying traction in the right direction, and visualizing 
the cords, the operator then passes the tip of the endotracheal 
tube between the vocal cords. Note that a stylet, a thin stiff piece 
of metal, is inside the endotracheal tube to prevent it from 
flexing. Note also that the blade is close to the upper incisors: 
carelessness here, due to attention on the vocal cords only, 
could cause dental trauma.  
 
Once the endotracheal tube is inserted to an 
appropriate depth (21 cm at the teeth in most adult 
women; 23 cm at the teeth in most adult men), the 
balloon should be inflated (3 – 5 mL of air injected 
through the pilot balloon) and the tube should be 
connected to the breathing circuit or Ambu bag and 
ventilation verified. As esophageal intubation is 
possible, even when the vocal cords are well 
visualized, it is important to verify endotracheal 
placement using multiple techniques, including 
visualization of chest rise, positive auscultation of 
breath sounds, fogging of the tube, and whenever 
possible, detection of end-tidal CO2 (capnography). 
If while auscultating, you hear breath sounds over the 
stomach but not in the chest, you have an esophageal 
intubation. Remove the endotracheal tube, mask 
ventilate, and consider repositioning the patient prior 
to your next attempt. If you hear breath sounds on the 
right, but not on the left you may have a right-
mainstem intubation. Withdraw the tube slowly 
while checking breath sounds. 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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Capnography uses a sensor that is connected in-line to the 
ventilator tubing, just proximal to the endotracheal tube, to 
detect carbon dioxide. A rise and fall of CO2 with respiration, 
as shown here (Red arrow) confirms that the endotracheal tube 
is within the trachea.  
 
Rapid Sequence Induction 
Patients who are at elevated risk for 
aspiration of gastric contents (recent meal, delayed 
gastric emptying, trauma, pregnancy) should 
undergo a rapid sequence induction (RSI) when 
endotracheal intubation is necessary. While the steps 
are similar to those described above, the patient 
should 
NOT 
be 
ventilated 
after 
loss 
of 
consciousness, but instead short-acting paralytics 
should be used (succinylcholine or rocuronium) and 
an assistant will need to place gentle pressure over 
the cricoid cartilage (Sellick’s maneuver) in an 
attempt to occlude the esophagus and prevent 
regurgitation of gastric contents. This cricoid 
pressure should be light (300-400g,) should begin as 
the patient loses consciousness, and should not be 
released 
until 
the 
practitioner 
has 
verified 
endotracheal placement of the tube.  
 
The Difficult Airway 
Patients who will be difficult to ventilate 
and/or intubate can often, but not always, be 
identified during a pre-intubation airway evaluation. 
Therefore, it is vital to know what steps to take when 
one encounters an anticipated or unanticipated 
difficult intubation. 
Whenever 
a 
difficult 
intubation 
is 
anticipated, it is always best to have all available 
airway equipment (including videolaryngoscopy or 
fiberoptic laryngoscopy if available) in the room. It 
is also wise to have a second operator who is skilled 
at intubation assist you, and whenever possible to 
have a surgeon who can provide a surgical airway 
present as well.  
A bougie (Eschmann stylet) can be useful 
when only the posterior part of the vocal cords or the 
arytenoid cartilages are visualized. This stylet has a 
small “hook” on the end which can pass under the 
epiglottis and allow entry into the trachea. If the 
stylet passes successfully into the trachea, the 
operator will normally feel it passing along the 
tracheal rings and then resistance to forward 
movement as the carina is encountered. At this point 
an ETT can be passed over the stylet to an 
appropriate depth and the stylet withdrawn. If 
tracheal rings are not felt and no resistance is 
encountered, this suggests esophageal placement. 
 
An intubating bougie with endotracheal tube loaded. The end 
on the left is passed through the vocal cords. As the tip passes 
over the tracheal rings, the operator feels this feedback and 
tracheal position is confirmed. The endotracheal tube is then 
advanced over the bougie into the trachea. Source: Baker JB et 
al, WestJEM 16:4;2015 
DOI: 10.5811/WESTJEM.2015.4.22857 
 
Videolaryngoscopy has become a widely 
available tool for patients who are difficult to 
intubate and has dramatically decreased the need for 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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awake fiberoptic intubations. The technique is 
similar to the technique described above. However, 
as a smaller mouth opening is needed to insert this 
unique videolaryngoscope blade,, many patients 
(especially those with anterior vocal cords) who are 
unable to be intubated with direct laryngoscopy will 
be able to be intubated using a videolaryngoscope. 
 
Intubation using a fiberoptic glidescope. Note that the 
anesthetist is holding the blade with her left hand and an 
endotracheal tube with a stylet in the right hand, watching the 
screen preparing to insert the tip of the tube between the vocal 
cords as seen on the screen (Red arrow.) 
 
For patients with severely limited mouth 
opening or other anatomic abnormalities that 
preclude both direct and video-laryngoscopy, the 
operator 
may 
choose 
to 
perform 
fiberoptic 
laryngoscopy, if available. This can be performed 
with the patient anesthetized (if mask ventilation is 
possible) or with the patient conscious. The awake 
patient may benefit from light sedation and local 
topicalization of the airway. Giving small doses of 
midazolam, an opioid and/or ketamine will provide 
you with a more cooperative patient, however, these 
medications should be slowly and carefully titrated 
such that the patient continues to breathe 
spontaneously. 
Draw 8-10 mL of 4% lignocaine into a 
syringe. Ask the patient to open his/her mouth and 
spray 4 to 5 mL of the solution onto and over the back 
of the tongue. If they are able to follow commands, 
ask them to gargle this solution prior to swallowing. 
Ask the patient to close his/her eyes and 
breathe deeply. Reassure them, and then gently 
introduce a well-lubricated laryngoscope (use 
lignocaine jelly if available) over the tongue until 
you see the tip of his epiglottis. Then spray a further 
1 to 1.5 mL of solution, through the scope itself, onto 
the epiglottis.  
When you see his vocal cords, spray the 
remaining 2–3 mL into the upper larynx and between 
the vocal cords.  
Optionally, you may wish to also use a 21 
gauge needle attached to a 3 mL syringe, containing 
4% lignocaine, to puncture the cricothyroid 
membrane. Upon aspiration of air inject the 
lignocaine. This will cause the patient to cough and 
will spread the lignocaine to the inferior surface of 
the vocal cords, the trachea and other areas of the 
glottic opening. 
 
Injecting lidocaine into the airway through the cricothyroid 
membrane, which is located immediately beneath the thyroid 
cartilage (“Adam’s apple.”) 
 
When his cords are widely abducted, pass the 
tracheal tube into his trachea and inflate the cuff. 
They may cough a little but will tolerate the tube. 
With his airway secured, you can, if necessary, 
induce the patient intravenously or by using 
inhalational agents. 
A similar sequence of steps can be 
undertaken for NASAL fiberoptic intubation, when 
mouth opening is severely limited or there is a 
surgical indication to have the patient intubated 
Airway Management and Endotracheal Intubation 
Gregory Sund, Rodger Barnette, Mark Newton 
 
OPEN MANUAL OF SURGERY IN RESOURCE-LIMITED SETTINGS 
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nasally. In this case, it is important to avoid 
traumatizing the nasal mucosa, which is fragile. Prior 
to inserting the fiberoptic scope, it is recommended 
that a topical vasoconstrictor such as oxymetazoline 
(Afrin) be sprayed into the nostril through which 
intubation will take place (usually the larger nostril). 
Also, 2% or 4% lidocaine can be sprayed into the 
nostril to improve patient tolerance to this procedure. 
Nasotracheal intubation can be performed with a 
regular oral endotracheal tube, however, if available, 
a nasal “RAE” endotracheal tube will be easier to 
position. 
For patients with large head and neck tumors 
or other severe airway conditions which will prevent 
even awake fiberoptic intubation, the only other 
option may be an awake tracheostomy.   
Finally, it is important to remember that 
patients with known or suspected cervical trauma 
should have their head and necks maintained in a 
neutral position, no matter which technique for 
intubation is chosen. This can be achieved by manual 
in-line stabilization (performed by an assistant) or by 
leaving the cervical collar in place, although this may 
make mouth opening difficult. See “Airway 
Management in Trauma.” 
 
Conclusion 
Endotracheal intubation is a life-saving skill, 
but one which requires technical ability obtained 
through 
supervised 
practice, 
a 
thorough 
understanding of the indications and complications 
of this procedure, and how to appropriately prepare 
for routine as well as difficult intubations. 
 
Note: all illustrations in this chapter are from Safe 
Anesthesia- A Training Manual Where Facilities are 
Limited by Lucille Bartholomeusz, 3rd Edition 2006 
(Updated and Revised by Jean Lees.) Used with kind 
permission 
from 
HealthBooks 
International. 
https://healthbooksinternational.org  
 
 
 
 
 
 
Gregory Sund, MD 
AIC Kijabe Hospital  
Kenya 
 
Rodger Barnette MD 
AIC Kijabe Hospital 
Kenya 
 
Mark Newton MD 
Vanderbilt University 
Nashville TN USA 
 
