Sellick's maneuver




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Editorial
SellickÕs Maneuver: To Do or Not Do
1
Andranik Ovassapian, MD*The introduction of cricoid pressure (CP) by Sellickin 1961 “to control
regurgitation until intubation with a cuffed endotracheal tube was com-
M. Ramez Salem, MD†pleted” was met with an enthusiastic reception worldwide and rapidly
became an integral component of the rapid sequence induction/intubation
technique (RSII). The maneuver consisted of “occlusion of the upper
esophagus by backward pressure on the cricoid ring against the bodies of
1
cervical vertebrae to prevent gastric contents from reaching the pharynx.”
1
Sellickprovided evidence that extension of the neck and application of CP
obliterated the esophageal lumen at the level of the 5th cervical vertebra, as
seen in a previously placed soft latex tube distended with contrast media
to a pressure of 100 cm H2O. He also confirmed the value of CP in
preventing saline (run into the esophagus from a height of 100 cm H2O)
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from reaching the pharynx in a patient undergoing gastroesophagectomy.
1,2
Sellickemphasized that the lungs can be ventilated by intermittent
positive pressure and that CP can prevent inflation of the stomach during
positive pressure ventilation. References to CP were found in the literature
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more than 230 yr ago.In a letter from Dr. W. Cullen to Lord Cathcart
dated August 8, 1774, concerning the recovery of persons “drowned and
seemingly dead,” the use of CP by Dr. Monro was referred to as a means
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of preventing gastric distension during inflation of the lungs.
Before Sellick described CP, several techniques were used in patients at
risk of aspiration of gastric contents: awake intubation, induced hyperven-
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tilation with carbon dioxide during inhaled induction,and RSII per-
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formed with the patient in a 40° head-up tilt.The rationale behind the
head-up tilt was that gastric contents could not reach the laryngeal level
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even if contents were moved up into the esophagus.The RSII with CP was
extended not only to emergency surgical and obstetrical procedures and
the critical care setting, but also to elective procedures in patients at risk of
aspiration of gastric contents. The plethora of manuscripts, correspon-
dence, and reviews on CP is a testimony to its relevance to anesthetic
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practice and continuing interest to clinicians.
In the last 2 decades, clinicians have questioned the efficacy of CP and
7,8
therefore the necessity of the maneuver.Some suggested abandoning it
on the following grounds: (a) Its effectiveness has been demonstrated only
9-11
in cadavers,and therefore its efficacy lacks scientific validation. (b) It
8,12
induces relaxation of the lower esophageal sphincter.(c) There have
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From the *Department of Anesthesia andbeen reports of regurgitation of gastric contents and aspiration despite CP.
Critical Care, Airway Study and Training
(d) The esophagus is not exactly posterior to the cricoid, and thus the
Center, University of Chicago; and †Depart-14
maneuver is unreliable in producing midline esophageal compression.(e) It
ment of Anesthesiology, Advocate Illinois
15
Masonic Medical Center, Department of An-is associated with nausea/vomiting and also with esophageal rupture.(f) It
esthesiology, University of Illinois College of15-18
makes tracheal intubation and mask ventilation difficult or impossible.
Medicine, Chicago, Illinois.
Because of ethical considerations, a controlled study of the efficacy of CP is
Accepted for publication June 18, 2009.
not feasible. Even if such a study were conducted, it would probably yield
Address correspondence and reprint re-
quests to Andranik Ovassapian, MD, Depart-little information, given the low incidence of pulmonary aspiration. The
ment of Anesthesia and Critical Care, Airwaycompelling evidence supporting the effectiveness of CP comes from studies
Study and Training Center, University of Chi-
that unequivocally demonstrate its efficacy in preventing gastric inflation in
cago, 5841 South Maryland Ave., Chicago, IL19-21
60637. Address e-mail to aovassap@dacc.anesthetized children and adults.It is inconceivable that a maneuver
uchicago.edu.effective in preventing gastric inflation during manual ventilation would not
Copyright © 2009 International Anesthe-be effective in preventing esophageal contents from reaching the pharynx.
sia Research Society22
The study by Rice et al.in the current issue sheds new light on the
DOI: 10.1213/ANE.0b013e3181b763c0
efficacy of CP. In 24 awake volunteers, magnetic resonance imaging was
1360Vol. 109, No. 5, November 2009



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performed with and without CP in sniffing, neutral,prevented regurgitation at a pressure of 40 mm Hg.
and extended head positions. Without CP, the diam-Accordingly, the current recommendation is to apply
eter of the postcricoid hypopharynx was 7.3 
 1.9 mm.10 N when a patient is awake, and increase the force to
15
The anteroposterior thickness of the anterolateral wall30 N once the patient loses consciousness.Evidence
(2.6 
 1.0 mm) and posterior wall (3.5 
 1.2 mm)is mounting regarding improper application of CP by
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added up to 6.1 mm. Because the anteroposterioranesthesia personnel.In one survey, 48% of partici-
diameter of the postcricoid hypopharynx with CPpants did not apply CP properly. Conversely, anesthe-
measured only 4.7 
 1.4 mm, the authors inferred thatsia personnel can be trained to perform the correct
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the lumen of the alimentary tract posterior to the cricoidmaneuver by practicing on weighing scales.With
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cartilage was indeed compressed.This finding clearlyproper training, the correct force applied is reproduc-
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demonstrates the efficacy of CP. Furthermore, magneticible within a range of 2 N.
resonance imaging showed compression of the post-Cricoid force greater than 40 N can compromise
cricoid hypopharynx during CP regardless of theairway patency and cause difficulty with tracheal
position of the cricoid cartilage (midline or lateralintubation.6,15,16 CP may displace the esophagus,14
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displacement) relative to the vertebral body.make ventilation with a facemask or with an LMA
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Unlike “the cervical esophagus,” Rice et al.ob-6,17
more difficult,interfere with LMA placement and
served that the postcricoid hypopharynx moved with6,16,18
advancement of a tracheal tube,and alter laryn-
the cricoid ring as an anatomic unit, an anatomicalgeal visualization by a flexible bronchoscope.16Other
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relationship that has been described previously.
investigators have found that CP does not increase the
Although they distinguished between the postcricoid32,33
rate of failed intubation.Releasing CP is certainly
hypopharynx, the part of the alimentary tract com-justified if the glottic view remains distorted or mask
pressed by CP, and the esophagus, they referred to the
ventilation and tracheal intubation become difficult.
postcricoid hypopharynx as the “cricopharyngeus.”
Contrary to Sellick’s recommendations, the current
The question remains: Is the postcricoid hypopharynx
teaching is to avoid manual ventilation of the lungs
a part of the esophagus or a separate entity? Clinicians
before intubation during RSII to prevent gastric dis-
have regarded the cricopharyngeus as a major com-
tension, a potential cause for regurgitation. The effec-
ponent of the upper esophageal sphincter. Its muscle
tiveness of CP in preventing gastric insufflation was
tone creates a sphincteric pressure (mean 38 mm Hg,15
first recognized in 1974.Subsequent studies con-
in awake subjects) that prevents esophageal contents
firmed that CP prevents gastric distension even when
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from reaching the pharynx (second line of defense).
inflation pressures as high as 60 cm H2O are used,
Sphincter pressure increases slightly during inspiration15-17
provided the airway remains clear.Thus, manual
preventing air entry into the esophagus but markedly
25inflation of the lungs need not be withheld before
decreases with neuromuscular blockade.Although
intubation during RSII. In patients with insufficient
distinct from the remainder of the cervical esophagus,
oxygen reserve, or when consumption is high or when
one can argue that the postcricoid hypopharynx (the
a nondepolarizing muscle relaxant with a slow onset
cricopharyngeus) is the upper esophagus.
is used, manual ventilation during CP application is
It has been suggested that pulmonary aspiration
necessary.
despite CP may reflect concomitant reflex relaxation
8
of the lower esophageal sphincter,which is not
attenuated by prior administration of metoclopra-
12SUMMARY
mide.This suggestion is unlikely for several reasons:
CP substitutes for the loss of tone in the cricopharyn-
(a) The purpose of CP is to prevent gastric contents
from reaching the pharynx, not to prevent gastro-geus, nature’s normal defense mechanism. The findings
esophageal reflux. (b) In a study of healthy volunteers,of Rice et al. lend strong support to the efficacy of
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gastroesophageal reflux did not occur during CP.(c)Sellick’s maneuver in occluding the alimentary tract
The incidence of pulmonary aspiration, with the use ofposterior to the cricoid cartilage. There is strong evidence
a laryngeal mask airway (LMA), which is also knownthat gastric insufflation can be prevented by CP, and
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to decrease lower esophageal sphincter tone,is notthat mask ventilation can be applied safely during
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higher than that associated with tracheal intubation.RSII. On the other hand, there are circumstances in
Sellick recommended that CP should be appliedwhich CP or RSII is undesirable or contraindicated.
“lightly” first, then with “firm” pressure exerted whenThese situations should be respected and other alter-
consciousness is lost. Based on studies of cricoid forcenative management strategies sought. In the clinical
to prevent material from reaching the pharynx, 40 Nsetting, the decision to use CP should be a balance
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(10 N  1.0 kg) was recommended.Studies showedbetween the potential benefits that have been demon-
that 34 and 30 N occluded a manometry catheterstrated repeatedly, and rare potential complications
behind the cricoid cartilage in all patients at a pressurethat are likely a result of improper application of the
24,293431
greater than 30 and 25 mm Hg, respectively.In atechniquebut that can easily be taught.It is our
cadaver study, 20 N prevented the regurgitation ofduty as clinicians to make Sellick’s great contribution
esophageal fluid at a pressure of 25 mm Hg, and 30 Na safe practice.
Vol. 109, No. 5, November 2009© 2009 International Anesthesia Research Society1361