Anestesia pediatrica. Mitos, dogmas y evidencia.

ANESTESIA
PEDIATRICA

MITOS, DOGMAS Y EVIDENCIAS.

DR. LUIS VERA LINARES
LIMA 2011

email: drluisveralinares@gmail.com

SOBRE EVALUAR UN
MITO...

• PROBAR LA VALIDEZ SOBRE EL MITO
DANES DE QUE EL ALCOHOL PUEDE SER
ABSORBIDO A TRAVES DE LOS PIES:
ESTUDIO EXPERIMENTAL DE TIPO
ABIERTO.

RESEARCH

CHRISTMAS 2010: RESEARCH
Testing the validity of the Danish urban myth that alcohol can
be absorbed through feet: open labelled self experimental
study
Christian Stevns Hansen, doctor Louise Holmsgaard Færch, doctor Peter Lommer Kristensen, doctor and
research fellow

Endocrinology Section, Department ABSTRACT in vodka; the Peace On Earth (Percutaneous Ethanol
of Cardiology and Endocrinology, Objective To determine the validity of the Danish urban Absorption Could Evoke Ongoing Nationwide
Hillerød Hospital, Dyrehavevej 29,
DK-3400 Hillerød, Denmark myth that it is possible to get drunk by submerging feet in Euphoria And Random Tender Hugs) study. The
Correspondence to: P L Kristensen alcohol. results could have great implications, by freeing
pelk@hih.regionh.dk Design Open labelled, self experimental study, with no human resources for other, relevant, activities.
Cite this as: BMJ 2010;341:c6812
control group.
doi:10.1136/bmj.c6812 Setting Office of a Danish hospital. METHODS
Participants Three adults, median age 32 (range 31-35), The Peace on Earth study was open labelled and self
free of chronic skin and liver disease and non-dependent experimental, with no control group. It evaluated the
on alcohol and psychoactive drugs. effect of submerging feet in 2100 mL of vodka (three bot-
Main outcome measures The primary end point was the tles’ worth) on the concentration of plasma ethanol. Sec-
concentration of plasma ethanol (detection limit ondary end points were intoxication related symptoms.
2.2 mmol/L (10 mg/100 mL)), measured every 30 minutes Three healthy adults (all authors, CSH, LHF, and
for three hours while feet were submerged in a washing- PLK) agreed to participate. None had any chronic skin
up bowl containing the contents of three 700 mL bottles of or liver disease or was dependent on alcohol or psy-
vodka. The secondary outcome was self assessment of choactive drugs. None was members of local Alcoholics
intoxication related symptoms (self confidence, urge to Anonymous communities or had been implicated in
speak, and number of spontaneous hugs), scored on a serious incidents or socially embarrassing events related
scale of 0 to 10. to alcohol during the week before the experiment.
Results Plasma ethanol concentrations were below the
detection limit of 2.2 mmol/L (10 mg/100 mL) throughout Study protocol
the experiment. No significant changes were observed in The participants abstained from consuming alcohol
the intoxication related symptoms, although self 24 hours before the experiment. The evening before
confidence and urge to speak increased slightly at the the experiment they rubbed their feet with a loofah to
start of the study, probably due to the setup. remove skin debris. On the day of the experiment, a
Conclusion Our results suggest that feet are impenetrable baseline blood sample was taken through a venous
to the alcohol component of vodka. We therefore conclude line. The participants then submerged their feet in a
that the Danish urban myth of being able to get drunk by washing-up bowl containing the contents of three
submerging feet in alcoholic beverages is just that; a myth. 700 mL bottles of vodka (Karloff vodka; M R tefánika,
The implications of the study are many though. Cífer, Slovakia, 37.5% by volume). Before each blood
sample was taken the venous catheter and cannula
INTRODUCTION were flushed with saline by a trained study nurse.
According to Danish urban folklore, it is possible to Plasma ethanol concentrations were determined
become drunk by submerging feet in alcoholic bev- every 30 minutes for three hours. Blood samples
erages. Furthermore, claims exist of urine becoming were taken to the laboratory for immediate analysis
red when feet are submerged in beetroot juice. Because by the study nurse. Plasma ethanol concentrations,
the transcutaneous transport of alcohol to the circula- measured as soon as possible in case of rapid and
tion may have widespread implications, such urban potentially fatal increases, were determined using a
myths need to be investigated in a scientific setting. photometric method, with a detection limit of

• HANSEN ET AL. BMJ 2010; 341:C6812.
• POBLACION DE ESTUDIO: 3 MDS.
• METODO: PIES INMERSOS EN VODKA
DURANTE 3 HORAS.
• RESULTADOS: NIVELES DE ETANOL,
SINTOMAS SUBJETIVOS.

SINTOMAS DE INTOXICACION

• HANSEN. BMJ 2010

CONCLUSIONES

• NUESTROS RESULTADOS SUGIEREN QUE LOS
PIES SON IMPENETRABLES AL COMPONENTE
ALCOHOLICO DEL VODKA Y EN TANTO
CONCLUIMOS QUE ESTE MITO DANES ES TAN
SOLO ESO... UN MITO

OBJETIVOS DE ESTA
CONFERENCIA

• EVALUAR ALGUNOS MITOS Y
CREENCIAS ACTUALES DE LA
PRACTICA ANESTESICA PEDIATRICA.

OBJETIVOS DE ESTA CONFERENCIA

• USAR LA EVIDENCIA ACTUAL PARA DAR
SOPORTE O RECHAZAR ALGUNAS
PRACTICAS EN ANESTESIA PEDIATRICA:
• VIA AEREA

• AGENTES INHALADOS

• OTRAS DROGAS

• MISCELANEAS

• “CREER A CIEGAS ES PELIGROSO” - LUYIA

DOGMAS SOBRE
VIA AEREA EN
PEDIATRIA

DOGMAS SOBRE
VIA AEREA EN
PEDIATRIA

• LA PARTE MAS ESTRECHA DE
LA VIA AEREA EN NIÑOS ESTA
A NIVEL DEL CARTILAGO
CRICOIDES.

DOGMAS SOBRE
VIA AEREA EN
PEDIATRIA

• LA PARTE MAS ESTRECHA DE
LA VIA AEREA EN NIÑOS ESTA
A NIVEL DEL CARTILAGO
CRICOIDES.

• EL DIAMETRO DEL DEDO
MEÑIQUE PREDICE DE
FORMA MUY PRECISA EL
TAMAÑO DEL TUBO
ENDOTRAQUEAL.

DOGMAS SOBRE
VIA AEREA EN
PEDIATRIA

• LA PARTE MAS ESTRECHA DE • LA PRESION DEL CARTILAGO
LA VIA AEREA EN NIÑOS ESTA CRICOIDES ES UN
A NIVEL DEL CARTILAGO COMPONENTE IMPORTANTE
CRICOIDES. EN LA INDUCCION DE
SECUENCIA RAPIDA.
MEÑIQUE PREDICE DE
FORMA MUY PRECISA EL
TAMAÑO DEL TUBO
ENDOTRAQUEAL.

DOGMAS SOBRE
VIA AEREA EN
PEDIATRIA

• LA PARTE MAS ESTRECHA DE • LA PRESION DEL CARTILAGO
LA VIA AEREA EN NIÑOS ESTA CRICOIDES ES UN
A NIVEL DEL CARTILAGO COMPONENTE IMPORTANTE
CRICOIDES. EN LA INDUCCION DE
SECUENCIA RAPIDA.
MEÑIQUE PREDICE DE • LOS TUBOS
FORMA MUY PRECISA EL ENDOTRAQUEALES CON
TAMAÑO DEL TUBO CUFF SON SEGUROS/
ENDOTRAQUEAL. PELIGROSOS EN NIÑOS.

ANATOMIA DE LA VIA AEREA EN PEDIATRIA:
TRABAJO INICIAL

• “EN EL INFANTE... EL ANILLO CRICOIDEO PUEDE SER MAS PEQUEÑO
QUE LA GLOTIS O QUE EL DIAMETRO INTERNO DE LA TRAQUEA”

• “EN INFANTES Y NIÑOS, BAYEUX, USANDO CADAVERES Y
SECCIONES ANATOMICAS, ENCONTRO QUE LA CIRCUNFERENCIA
DEL ANILLO CRICOIDEO ERA MAS ESTRECHA QUE EL DE LA
TRAQUEA O QUE EL DE LA GLOTIS”.

• (BAYEUX PRESS MED. 1897: ECKENHOFF, ANESTHESIOLOGY 1951)

Anesthesiology 2003; 98:41–5 © 2003 American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc.

DevelopmentalAnesthesiology 2003; 98:41–5 Laryngeal Dimensions in Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc.
Changes of © 2003 American

Unparalyzed, Sedated Children
Developmental Changes of Laryngeal Dimensions in
Ronald S. Litman, D.O.,* Eric E. Weissend, M.D.,† Dean Shibata, M.D.,‡ Per-Lennart Westesson, M.D., Ph.D., D.D.S.§
Unparalyzed, Sedated Children
Background: Knowledge of the influence Litman, D.O.,* Eric E. Weissend, M.D.,† Dean Shibata, M.D.,‡ Per-Lennart Westesson, M.D., Ph.D., D.D.S.§
Ronald S. of age on laryngeal bony framework of the larynx throughout childhood.1–3
dimensions is essential for all practitioners whose interest is These studies determined that the larynx is conically
the pediatric airway. Early cadaver studies documented that the
larynx is conically shaped, with the apex of the cone caudally
shaped, with the apex of the “cone” caudally positioned
positioned at the nondistensible cricoid cartilage. These dimen- at the nondistensible cricoid cartilage. These dimensions the larynx throughout childhood.1–3
Background: Knowledge of the influence of age on laryngeal bony framework of
dimensions isassumes a more all practitioners whose interest is larynx assumes a cylin-
sions change during childhood, as the larynx essential for change during childhood as the These studies determined that the larynx is conically
cylindrical shape. The authors the pediatric airway. Early cadaver studies documented that the
analyzed laryngeal dimensions drical, rather than a conical shape.4shaped, with the apex of the “cone” caudally positioned
It is unknown if this
during development to determine if thisis conically shaped, with relationship continuescaudally in unparalyzed children in
larynx relationship continues the apex of the cone to exist
in unparalyzed children in whom laryngeal muscles are toni-
positioned at the nondistensible cricoid cartilage. These dimen- at the nondistensible cricoid cartilage. These dimensions
whom laryngeal muscles demonstrate tonic activity.5
cally active. The authors determined the relationships between
sions change during childhood, as the larynx assumes a more change during childhood as the larynx assumes a cylin-
the vocal cord, sub–vocal cord, and cricoid ring dimensions and Therefore, we undertook this study to determine the influ- 4
ence of age on laryngeal dimensions.drical, rather than a conical shape. It is unknown if this
cylindrical shape. The authors analyzed laryngeal dimensions
the influence of age on these relationships.
during development to determine if this relationship continues
Most specifically, we
Methods: Infants and children undergoing magnetic reso- were interested in the relationshipsrelationship continues to exist in unparalyzed children in
in unparalyzed children in whom laryngeal muscles are toni- between vocal cord,
nance imaging with propofol sedation had determinations of whom laryngeal muscles demonstrate tonic activity.5
sub–vocal cord, and cricoid ring dimensions, and how
the transverse and anterior–posterior (AP) dimensions of determined the relationships between
cally active. The authors the
these relationships change as children grow. Wewe undertook this study to determine the influ-
larynx at the most cephalad level of the cord, sub–vocal cord, and cricoid ring dimensions and
the vocal larynx (vocal cords) Therefore, hypothe-
sized that these relationships change during development
and the most caudad level (cricoid).influence of age on addi- relationships.
the Most patients had an these ence of age on laryngeal dimensions. Most specifically, we
tional measurement (sub–vocal cord) at a level between children undergoing magnetic reso- management.
Methods: Infants and the and may influence clinical airway were interested in the relationships between vocal cord,
vocal cords and the cricoid ring. Relationships were obtained sedation had determinations of
nance imaging with propofol
by plotting age against laryngeal dimensions and the ratio of
sub–vocal cord, and cricoid ring dimensions, and how
the transverse and anterior–posterior (AP) dimensions of the
laryngeal dimensions at different levelsat the most cephalad level of the larynx (vocal cords)
larynx within the larynx.
these relationships change as children grow. We hypothe-
Materials and Methods
Results: The authors measured transverse and AP laryngeal
and the most caudad level (cricoid). Most patients had an addi- sized that these relationships change during development
dimensions in 99 children, aged 2 months–13 yr. The relation-
tional measurement (sub–vocal cord) Research Subjects’ Review Board of the Universityclinical airway management.
ship between the transverse and AP dimensions at all levels of The at a level between the and may influence
the larynx did not change during development. Transverse and ring. Relationships(Rochester, New York) approved this
vocal cords and the cricoid of Rochester were obtained
by plotting at allagainstof the
AP dimensions increased linearly with age age levels laryngeal dimensions and the ratio of
study, and written informed consent was obtained from
larynx. In all children studied, the narrowest portion at different levels within the larynx.
laryngeal dimensions of the all parents of children in the study. Children who were
Results: The authors measured transverse and AP laryngeal
larynx was the transverse dimension at the level of the vocal Materials and Methods
cords. Transverse dimensions dimensions in 99 in a caudad
old enough to understand that they were participating in
increased linearly children, aged 2 months–13 yr. The relation-
direction through the larynx (Pship between the dimensions andaAP dimensions at all their assent. Children aged 0 –14 yr
< 0.001), while AP transverse research study gave
levels of The Research Subjects’ Review Board of the University
did not change relative to laryngeal level. The shape of the who presentedTransverse and magnetic resonance(Rochester, New York) approved this
the larynx did not change during development.
for an elective of Rochester im-
AP dimensions increased linearly with age with deep sedation were eligible to partici- informed consent was obtained from
aging scan at all levels of the
cricoid ring did not change throughout childhood.
Conclusions: In sedated, unparalyzed children, the narrowest study, and written
studied, pate.narrowest portion of the
larynx. In all children level)
portions of the larynx are the glottic opening (vocal cord the Consecutive children were all parents of children in the study. Children who were
enrolled within the
and the immediate sub–vocal cord level,was there is no change
limits of investigator-related and clinical situations. Ex-
larynx and the transverse dimension at the level of the vocal
old enough to understand that they were participating in
clusion criteria included obvious anatomical deformities
in the relationships of these cords. Transverse dimensions increased linearly in a caudad
dimensions relative to cricoid
dimensions throughout childhood.direction through the larynx (P < 0.001), while neck, or any other condition the investi- their assent. Children aged 0 –14 yr
of the head or AP dimensions a research study gave
did not change relative to laryngeal level. would cause abnormal laryngeal anatomy. an elective magnetic resonance im-
gators felt The shape of the who presented for
Children who received airway management withwith deep sedation were eligible to partici-
cricoid ring did during child-throughout childhood.
THE development and growth of the larynx not change aging scan either a
Conclusions: Ina century.1
hood has been a subject of interest for over sedated, unparalyzed children, airway or endotracheal tube were also children were enrolled within the
laryngeal mask the narrowest pate. Consecutive
portions of the larynx are the glottic opening (vocal cord level)
excluded.
Knowledge of the influence of the age of the child on limits of investigator-related and clinical situations. Ex-
and the immediate sub–vocal cord The study there is no changechildren who were deeply
level, and was performed in
laryngeal dimensions is essential for all practitioners clusion criteria included obvious anatomical deformities
in the relationships of these dimensions relative ␮g cricoid · minϪ1 propofol. Most
sedated with 200 to · kgϪ1
whose interest is the pediatric airway. throughout childhood.
dimensions Early studies in of the head or neck, or any other condition the investi-
cadaver specimens documented the cartilaginous and children did not previously have an indwelling intrave-
nous catheter and therefore initially received would cause abnormal laryngeal anatomy.
gators felt a mask
anesthetic with sevoflurane and Children who received airway management with either a
THE development and growth of the larynx during child- nitrous oxide, both of

dotracheal tube based on the size of the cricoid ring may
not prevent mucosal damage to the larynx cephalad to

between tra-
EVALUACION POR RMN DE LA VIA AEREA
the cricoid ring in unparalyzed children. On the other
hand, these more cephalad portions of the larynx consist
bottom) di-
ic area, and
PEDIATRICA
of yielding structures that distend with placement of a
relatively larger endotracheal tube. The cricoid ring is
nearly in a unyielding and prone to development of edema and
he box is the
th and 75th scarring in response to excessive mucosal pressures.
nd 95th per-
1st and 99th
nes are the
• A: CUERDAS
ildren, the
VOCALES

•
portion of

not attempt
B: NIVEL
of respira-
ge in spon-
SUBGLOTICO

•
dimensions
an average
cords dur-
C: NIVEL
ossible that
tured” in a
SUBGLOTICO

•
ion. If this
bjects, the
n would be
ANILLO
xplanation CRICOIDEO
ropofol on
esses vocal Fig. 4. Representative sample of axial magnetic resonance im-
aging slices through the vocal cords (A), subglottic levels (B and
cle) and vo- C), and cricoid ring (D). Transverse diameters increase in a
y8 and may caudad direction.

Litman, Anesthesiology 2003

EVALUACION POR RMN DE LA VIA AREA
44
PEDIATRICA LITMAN ET AL.

have influenced vocal cord positions in the children we
studied.
In 1951, Eckenhoff4 published a seminal article on
characteristics of the infant larynx and their influence on
endotracheal anesthesia. This article was one of the first
to emphasize that the cricoid cartilage is functionally the
narrowest point of the upper respiratory tract of the
child. Eckenhoff described the cricoid plate as “inclined
posteriorly at its superior aspect, so that the larynx is
funnel shaped with the narrowest point of the funnel at
the laryngeal exit.” This narrowest point is described as
Respirando espontaneamente
possibly smaller than more cephalad portions of the
trachea. Eckenhoff Sedado as the child grows, the
stated that
cricoid plate becomes vertical, and the larynx becomes
Niños sin paralisis
more cylindrical shaped. He derived this information
from Bayeux,1 who used moulages and anatomic sec-
tions of 15 children, aged 4 months to 14 yr. Bayeux
documented that the circumference of the cricoid ring
was narrower than that of the trachea or the glottis. Our
results do not allow us to make direct comparisons with
the findings of Eckenhoff and Bayeux since we measured
dimensions in the tonically active larynx.
The clinical importance of our findings is speculative.
On one hand, our results indicate that choosing an en-
dotracheal tube based on the size of the cricoid ring may
not prevent mucosal damage to the larynx cephalad to
the cricoid ring in unparalyzed children. On the other
hand, these more cephalad portions of the larynx consist
Fig. 3. Box plots demonstrating the relationship between tra-
cheal transverse (top) and anterior–posterior (A-P; bottom) di- of yielding structures that distendAnesthesiology 2003
Litman, with placement of a
ameters at the levels of the vocal cords, subglottic area, and relatively larger endotracheal tube. The cricoid ring is
cricoid ring. Transverse diameters increased linearly in a unyielding and prone to development of edema and
caudad direction (P < 0.001). The middle line of the box is the

Pediatric Anesthesiology
Section Editor; Peter J. Davis

Pediatric Laryngeal Dimensions: An Age-Based Analysis
Priti G. Dalal, MD, FRCA* BACKGROUND: In children, the cricoid is considered the narrowest portion of the
“funnel-shaped” airway. Growth and development lead to a transition to the more
David Murray, MD† cylindrical adult airway. A number of airway decisions in pediatric airway practice
are based on this transition from the pediatric to the adult airway. Our primary aim
in this study was to measure airway dimensions in children of various ages. The
Anna H. Messner, MD‡ measures of the glottis and cricoid regions were used to determine whether a
transition from the funnel-shaped pediatric airway to the cylindrical adult airway
Angela Feng, MDʈ could be identified based on images obtained from video bronchoscopy.
METHODS: One hundred thirty-five children (ASA physical status 1 or 2) aged 6 mo to
John McAllister, MD¶ 13 yr were enrolled for measurement of laryngeal dimensions, including cross-
sectional area (G-CSA), anteroposterior and transverse diameters at the level of the
David Molter, MD# glottis and the cricoid (C-CSA), using the video bronchoscopic technique under
general anesthesia.
RESULTS: Of the 135 children enrolled in the study, seven patients were excluded
from the analysis mainly because of poor image quality. Of the 128 children studied
(79 boys and 49 girls), mean values (Ϯstandard deviation) for the demographic
data were age 5.9 (Ϯ3.3) yr, height 113.5 (Ϯ22.2) cm and weight 23.5 (Ϯ13) kg.
Overall, the mean C-CSA was larger than the G-CSA (48.9 Ϯ 15.5 mm2 vs 30 Ϯ 16.5
mm2, respectively). This relationship was maintained throughout the study popu-
lation starting from 6 mo of age (P Ͻ 0.001, r ϭ 0.45, power ϭ 1). The mean ratio
for C-CSA: G-CSA was 2.1 Ϯ 1.2. There was a positive correlation between G- and
the C-CSA versus age (r ϭ 0.36, P Ͻ 0.001; r ϭ 0.27, P ϭ 0.001, respectively), height
(r ϭ 0.34, P Ͻ 0.001; r ϭ 0.29, P Ͻ 0.001, respectively), and weight (r ϭ 0.35, P Ͻ
0.001; r ϭ 0.25, P ϭ 0.003, respectively). No significant gender differences in the
mean values of the studied variables were observed.
CONCLUSION: In this study of infants and children, the glottis rather than cricoid was
the narrowest portion of the pediatric airway. Similar to adults, the pediatric
airway is more cylindrical than funnel shaped based on these video bronchoscopic
images. Further studies are needed to determine whether these static airway
measurements in anesthetized and paralyzed children reflect the dynamic charac-
teristics of the glottis and cricoid in children.
(Anesth Analg 2009;108:1475–9)

T he pediatric laryngeal and cricoid relationship has
been described as “funnel-shaped” with the apex of
of postmortem airway measurements, forms the ana-
tomical basis for a number of pediatric airway man-
the funnel at the level of the cricoid.1 This funnel- agement decisions.1–3 Recent clinical studies conducted
shaped airway description, based on a limited number using different measurement techniques measured
airway dimensions using two different techniques

MIDIENDO LAS DIMENSIONES LARINGEAS POR
VIDEO BRONCOSCOPIA...

Figure 1. Measuring laryngeal dimen-
sions. The catheter tip touching the
graph paper (a), the glottis (b), and
cricoid (c) regions.

Table 1. Results of the Linear Regression Analysis for Laryngeal
Dimensions Versus Age, Height, and Weight, Respectively,
in 128 Patients
Age Height Weight
G-CSA r ϭ 0.36
P Ͻ 0.001
r ϭ 0.34
P Ͻ 0.001
r ϭ 0.35
P Ͻ 0.001
Dalal, Anesth Anag 2009
G-AP r ϭ 0.38 r ϭ 0.36 r ϭ 0.39
P Ͻ 0.001 P Ͻ 0.001 P Ͻ 0.001
G-trans r ϭ 0.24 r ϭ 0.22 r ϭ 0.17
P ϭ 0.005 P ϭ 0.009 P ϭ 0.047
C-CSA r ϭ 0.27 r ϭ 0.29 r ϭ 0.25

C-AP r ϭ 0.13 r ϭ 0.12 r ϭ 0.12
P ϭ 0.129 P ϭ 0.167 P ϭ 0.14
C-trans r ϭ 0.13 r ϭ 0.19 r ϭ 0.12
P ϭ 0.117 P ϭ 0.03 P ϭ 0.18
DIAGRAMA DE DISPERSION DE LAS SECCIONES study population
Cricoid:glottic CSA
ments in the
r ϭ 0.18
P ϭ 0.04
r ϭ 0.11
P ϭ 0.18
r ϭ 0.14
P ϭ 0.11
Figure 3. Box and whiskers plo

CRUZADAS DE AREA GLOTICA Y CRICOIDEA ϭ cricoid anteropo
anteroposterior diameter; G-tra
G-CSA ϭ glottic cross-sectional area; G-AP ϭ glottic anteroposterior diameter; G-trans ϭ glottic
eter; C-AP
transverse diameter; C-CSA ϭ cricoid crosssectional area; C-AP ϭ cricoid anteroposterior diam-
eter; C-Trans ϭ cricoid transverse diameter. cricoid transverse diameter.

gender differences analyses,
metric data) and the Mann
(nonparametric data) were
differences in values of each
male and female children.
considered as significant.

RESULTS
Overall, 135 patients were
these, seven patients were e
mainly because of poor im
children studied (79 boys a
(Ϯsd) for the demographic d
height 113.5 (Ϯ22.2) cm, and
Figure 2. Scatterplot with regression line and confidence
interval lines for the cross-sectional areas (CSA) versus age. relationship between C-CS
C-CSA ϭ cricoid cross-sectional area; G-CSA ϭ glottic given by the equation C-C
cross-sectional area. G-CSA), r ϭ 0.45, P Ͻ 0.001

Vol. 108, No. 5, May 2009 © 2009 International

Dalal, Anesth Analg 2009

MITO O REALIDAD
LA TRAQUEA PEDIATRICA Y EL DEDO
MEÑIQUE

• ¿PREDICE EL DIAMETRO
DEL DEDO MEÑIQUE
LA TALLA DEL TUBO
ENDOTRAQUEAL?

QUE NOS DICEN LOS LIBROS?

• “OTRO METODO NO COMPROBADO
CIENTIFICAMENTE , CLINICAMENTE
UTIL USADO POR ALGUNOS
ANESTESIOLOGOS ES COMPARAR EL
DIAMETRO EXTERNO DEL TUBO ET
CON EL DEL DEDO MEÑIQUE”

THE ‘BEST FIT’ ENDOTRACHEAL
TUBE IN CHILDREN
- Comparison of Four Formulae -

TURKISTANI A*, ABDULLAH KM***, DELVI B**
AND A L -M AZROUA KA ****

Abstract
Background: Uncuffed endotracheal tubes are still being recommended by most pediatric
anesthetists at our Institutes. Different algorithms and formulae have been proposed to choose the
best-fitting size of the tracheal tube. The most widely accepted is related to the age of the child
[inner diameter [ID] in mm = (age in yr/4) +4; the second is a body, length-related formula (ID in
mm = 2 + height in cm/30); the third, a multivariate formula (ID in mm = 2.44 + age in yr 0.1 +
height in cm 0.02 + weight in kg 0.016]5; the fourth, the width of the 5th fingernail is used for
ID prediction of the ETT (ID in mm = maximum width of the 5th fingernail).
The primary endpoint of this prospective study was to compare the size of the ‘best fit’
tracheal tube with the size predicted using each of the above mentioned formulae.
Patients and Methods: With Institutional Ethics Committee approval and parental consent,
27 boys, 23 girls, ASA I-III, 2-10 years, scheduled for different surgical procedures requiring
general anesthesia and endotracheal intubation, were enrolled in the study. The size of ‘best
fit’ endotracheal tubes in those children were compared. The internal diameter considered the
‘best fit’ by the attending pediatric anesthesiologist was compared to age-based, length-based,
multivariate-based and 5th fingernail width-based formulae. For all tests, P < 0.05 was considered
to be statistically significant.
Results: The mean (SD) IDs for the ‘best fit’, age-based, length-based, multivariate and 5th
fingernail techniques were 5.31 (0.691), 5.54 (0.622), 5.82 (0.572), 5.71 (0.67) and 5.43 (0.821)
mm, respectively.
Conclusions: The age-based and 5th fingernail width-based predictions of ETT size are more
accurate than length-based and multivariate-based formulae in terms of mean value and case
matching.
Key Words: pediatric, endotracheal tube, age, length, multivariate, 5th fingernail, formula

From College of Medicine, King Saud University, Riyadh 11461, P.O. Box: 2925, Riyadh, S.A.
* MD, Assoc. Prof. of Anaesthesia. ** MD, Assist. Prof. of Anaesth. **** MD, FAAP, Assoc. Prof. Ped. Otolaryngology.
From King Abdul-Aziz Medical City, Riyadh 11426, P.O. Box: 22490, Riyadh, S.A.
*** MD, Arab Board, Consultant Cardiac Anaesthetist.
Address for correspondence: Dr. Khaled M Abdullah, Consultant Cardiac Anaesthetist, King Abdul-Aziz Medical City.
E-mail kmabdalla67@hotmail.com

383 M.E.J. ANESTH 20 (3), 2009

height in cm 0.02 + weight in kg 0.016]5; the fourth, the width of the 5th fingernail is used for
ID prediction of the ETT (ID in mm = maximum width of the 5th fingernail).
The primary endpoint of this prospective study was to compare the size of the ‘best fit’
tracheal tube with the size predicted using each of the above mentioned formulae.
Patients and Methods: With Institutional Ethics Committee approval and parental consent,
27 boys, 23 girls, ASA I-III, 2-10 years, scheduled for different surgical procedures requiring
general anesthesia and endotracheal intubation, were enrolled in the study. The size of ‘best
fit’ endotracheal tubes in those children were compared. The internal diameter considered the
‘best fit’ by the attending pediatric anesthesiologist was compared to age-based, length-based,
multivariate-based and 5th fingernail width-based formulae. For all tests, P < 0.05 was considered
to be statistically significant.
Results: The mean (SD) IDs for the ‘best fit’, age-based, length-based, multivariate and 5th
fingernail techniques were 5.31 (0.691), 5.54 (0.622), 5.82 (0.572), 5.71 (0.67) and 5.43 (0.821)
mm, respectively.
Conclusions: The age-based and 5th fingernail width-based predictions of ETT size are more
accurate than length-based and multivariate-based formulae in terms of mean value and case
matching.
Key Words: pediatric, endotracheal tube, age, length, multivariate, 5th fingernail, formula

From College of Medicine, King Saud University, Riyadh 11461, P.O. Box: 2925, Riyadh, S.A.
* MD, Assoc. Prof. of Anaesthesia. ** MD, Assist. Prof. of Anaesth. **** MD, FAAP, Assoc. Prof. Ped. Otolaryngology.
From King Abdul-Aziz Medical City, Riyadh 11426, P.O. Box: 22490, Riyadh, S.A.
*** MD, Arab Board, Consultant Cardiac Anaesthetist.
Address for correspondence: Dr. Khaled M Abdullah, Consultant Cardiac Anaesthetist, King Abdul-Aziz Medical City.
E-mail kmabdalla67@hotmail.com

Increasing discrepancy between uncuffed ETT OD and sub- in the use of racemic epinephrine for postext
glottic diameter in proportion as a function of subglottic tic edema, the rate of successful extubation
diameter indicates that the narrowest part of the pediatric tracheotomy between intubations with cu
PERIOPERATIVE MEDICINE larynx must lie above the cricoid ring level even among par- cuffed ETTs.16 –18
alyzed patients (fig. 3). In summary, previous established formu
Although ultrasonography is an operator-dependent poorly predicted pediatric ETT size. In con
technique, it is relatively simple to learn. A total of approxi- upper airway diameter measured by ultraso
mately 15 procedures are required for operators to obtain good predictor of correct cuffed and uncuff
reliable and reproducible measurements.11 Another concern pediatric patients.
about ultrasonic measurements is that age-dependent physi-
ologic calcification of the larynx creates an acoustic shadow. References
However, as calcification begins to occur in the laryngeal 1. Browning DH, Graves SA: Incidence o
endotracheal tubes in children. J Pediatr
cartilage during the third decade of life, ultrasonography can
2. Oshodi A, Dysart K, Cook A, Rodriguez
be applied with few problems in pediatrics.20 TH, Miller TL: Airway injury resulting f
Fig. 1. Photograph and illustration of ultrasonography ofsizeneck to be selected from measurement of
Optimal ETT the could measure subglottic diameter. Patient consent was obtained intubation: Possible prevent
dotracheal
21 diatr Crit Care Med 2010 Apr 1. [Epub a
for use of this photograph. the tracheal diameter on chest radiography. A good corre-
lation in tracheal diameter between computed tomography 3. Roy WL: Intraoperative aspiration in a p
Can Anaesth Soc J 1985; 32:639 – 41
as determined by ultrasonography, better predicts optimal indicatesof the true vocal folds as paired hyperechoic linear struc-
and chest radiography ization that the latter could give a
ETT size than existing methods. representative measurement of that moved with respiration and swallowing4. Sherman JM, Nelson H: Decreased incid
tures tracheal diameter.22 A length before pa-
stenosis using an “appropriate-sized” end
tients were paralyzed. The probe was then moved caudally to Pediatr Pulmonol 1989; 6:183
of approximately 70% (uncuffed) or 60% (cuffed) of the neonates.
Materials and Methods visualize the cricoid arch (i.e., round hypoechoic structure with
5. Dillier CM, Trachsel D, Baulig W, Gys
hyperechoic as Determined by air-column diameter was Laryngeal damage due to an u
edges). The transverse
This study was approved by the Review Board2. Human Exper- Tube Size the lower edge of the cricoid cartilage afterWeiss M:
Table for Endotracheal
measured at patients
and inappropriately designed cuffed p
iments at Kyoto Prefectural UniversityUltrasonography for Pediatric Patients
of Medicine (Kyoto, Japan).
were paralyzed, and was considered tracheal diameter. These mea- a 13-month-old child. Can J Anae
tube in
Written informed consent was obtained from custodial adults. We
surements were Outer Diameter, mm or positive end-ex- Pediatric formulas for the anesth
performed without ventilation
enrolled a total of 192 patients aged 1Inner 6 yr, split intomm
mo to Diameter, devel-
6. Cole F:
piratory pressure to minimize fluctuation in tracheal diameter.Child 1957; 94:672–3
Dis
opment and validation phases. Each patient was scheduled for sur-
3.0 4.3
The ultrasonographer had considerable experience7. Motoyama EK: Endotracheal intubation.
performing
gery requiring general endotracheal anesthesia. Those with condi-
3.5 4.9
laryngeal ultrasonography before the starting this investigation. Infants and Children. St Louis
thesia for
tions known or suspected to predispose them4.0 laryngeal or
to 5.6 269 –75.
Typically, the ultrasound measurements took approximately 30 s.
tracheal pathology were excluded. General anesthesia was induced
4.5 6.2
The trachea was then intubated using direct laryngos- Wears RL, Broselow J, Zarits
8. Luten RC,
by inhalation of sevoflurane or intravenous administration of thio-
5.0 copy. Size of the initial 6.9 was selected as follows: T, Bailey A, Vally R, Brown R, Ros
tube Lee
(1)
pental. Vecuronium was given to all patients for muscle relaxation.
5.5 7.5 formulas: ID (inner diameter)endotracheal tube and emergen
based
Our primary endpoint was a regression of outer ETT uncuffed tubes, with the Cole pediatrics. Ann Emerg Med 1992; 21:90
diameter against subglottic diameter as determined by ultra- in mm ϭ 0.25 ϫ (age in years) ϩ 4; (2) cuffed ETTs in
sonography. In a pilot study, the SD of subglottic diameter children aged 2 yr or older, with the Motoyama formulas: ID
Shibasaki et al. Anesthesiology, V 113 • No 4 • Oct
was 2.9 mm, the correlation coefficient between ETT outer in mm ϭ 0.25 ϫ (age in years) ϩ 3.5; (3) cuffed ETTs in
diameter (OD) and subglottic diameter was 0.7. The slope children younger than 2 yr, with the Khine formulas: ID in
estimate obtained from regression equation was 0.5. Assum- mm ϭ 0.25 ϫ (age in years) ϩ 3.0.
ing a true regression slope of 0.5, a total of 19 subjects were If there was resistance to ETT passage into the trachea, or
required to reject the null hypothesis that this slope equals there was no audible leak when the lungs were inflated to a
zero with 90% power at an ␣ level of 0.01.13 Our primary pressure of 20 –30 cm H2O, the tube was exchanged with one

PERIOPERATIVE MEDICINE Anesthesiology 2010; 113:819 –24
Copyright © 2010, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins

Prediction of Pediatric Endotracheal Tube Size
by Ultrasonography
Masayuki Shibasaki, M.D.,* Yasufumi Nakajima, M.D., Ph.D.,† Sachiyo Ishii, M.D.,*
Fumihiro Shimizu, M.D.,* Nobuaki Shime, M.D., Ph.D.,‡ Daniel I. Sessler, M.D.§

ABSTRACT Conclusions: Measuring subglottic airway diameter with ul-
Background: Formulas based on age and height often fail to trasonography facilitates the selection of appropriately sized
reliably predict the proper endotracheal tube (ETT) size in ETTs in pediatric patients. This selection method better pre-
pediatric patients. We, thus, tested the hypothesis that sub- dicted optimal outer ETT diameter than standard age- and
glottic diameter, as determined by ultrasonography, better height-based formulas.
predicts optimal ETT size than existing methods.
Methods: A total of 192 patients, aged 1 month to 6 yr,
who were scheduled for surgery and undergoing general What We Already Know about This Topic
anesthesia were enrolled and divided into development ❖ The proper endotracheal tube size for children is poorly pre-
and validation phases. In the development group, the op- dicted by formulas relying on age and height.
timal ETT size was selected according to standard age-
What This Article Tells Us That Is New
based formulas for cuffed and uncuffed tubes. Tubes were
replaced as necessary until a good clinical fit was obtained. ❖ In 192 children aged 1 month to 6 yr, ultrasound measure-
ment of subglottic airway diameter better predicted appropri-
Via ultrasonography, the subglottic upper airway diame- ately sized endotracheal tube than traditional formulas using
ter was determined before tracheal intubation. We con- age and height.
structed a regression equation between the subglottic up-
per airway diameter and the outer diameter of the ETT
finally selected. In the validation group, ETT size was
selected after ultrasonography using this regression equa- I NTUBATION of pediatric patients with an endotracheal
tube (ETT) that is too small may result in insufficient
ventilation, poor reliability of end-tidal gas monitoring, leak-
tion. The primary outcome was the fraction of initial
cuffed and uncuffed tube sizes, as selected through the age of anesthetic gases into the operating room environment,
regression formula, that proved clinically optimal. and an enhanced risk of aspiration.1–3 In contrast, an ETT
Results: Subglottic upper airway diameter was highly corre- that is too large can cause upper airway damage (e.g., local
lated with outer ETT diameter deemed optimal on clinical ischemia, ulceration, scar formation) and the potential for
grounds. The rate of agreement between the predicted ETT subsequent subglottic stenosis.4,5
size based on ultrasonic measurement and the final ETT size Age-based formulas, such as those of Cole and Mo-
selected clinically was 98% for cuffed ETTs and 96% for toyama, have been used to estimate optimal ETT size for
uncuffed ETTs. more than half a century.6,7 Predictive formulas for ap-
propriate ETT size have also been based on patient weight
and height.8 –10 However, none of these systems work
* Instructor, ‡ Assistant Professor, Department of Anesthesiology
especially well. The result is that repeated laryngoscopies
and Intensive Care, Kyoto Prefectural University of Medicine, Kyoto, are often necessary to identify the appropriate tube for
Japan. † Assistant Professor, Department of Anesthesiology and In- individual patients.
tensive Care, Kyoto Prefectural University of Medicine, and Member,
OUTCOMES RESEARCH Consortium/Group. § Professor and Chair, Depart-
Recent reports suggest that the diameter of the subglottic

MITO O REALIDAD
PRESION CRICOIDEA

• ¿ES LA PRESION CRICOIDEA UN
COMPONENTE IMPORTANTE EN LA
INDUCCION DE SECUENCIA RAPIDA
EN NIÑOS?

DOCUMENTO DE SELLICK

• EN EL ENFERMO CRITICO, SE PUEDE PREFERIR LA INDUCCION
INHALADA.

• TAN PRONTO COMO SE PIERDA LA CONCIENCIA, UNA PRESION
FIRME DEBE SER APLICADA.

• DURANTE LA PRESION CRICOIDEA, LOS PULMONES PUEDEN SER
VENTILADOS.

• LA ANTIGUA INDUCCION INHALADA... CON LA CABEZA DIRIGIDA
HACIA ABAJO, TIENE ALGO QUE RECOMENDAR...

Editorial

Sellick’s Maneuver: To Do or Not Do

Andranik Ovassapian, MD* T he introduction of cricoid pressure (CP) by Sellick1 in 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
cervical vertebrae to prevent gastric contents from reaching the pharynx.”1
Sellick1 provided 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)
from reaching the pharynx in a patient undergoing gastroesophagectomy.2
Sellick1,2 emphasized 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
more than 230 yr ago.3 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
of preventing gastric distension during inflation of the lungs.3
Before Sellick described CP, several techniques were used in patients at
risk of aspiration of gastric contents: awake intubation, induced hyperven-
tilation with carbon dioxide during inhaled induction,4 and RSII per-
formed with the patient in a 40° head-up tilt.5 The rationale behind the
head-up tilt was that gastric contents could not reach the laryngeal level
even if contents were moved up into the esophagus.5 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
practice and continuing interest to clinicians.6
In the last 2 decades, clinicians have questioned the efficacy of CP and
therefore the necessity of the maneuver.7,8 Some suggested abandoning it
on the following grounds: (a) Its effectiveness has been demonstrated only
in cadavers,9 –11 and therefore its efficacy lacks scientific validation. (b) It
induces relaxation of the lower esophageal sphincter.8,12 (c) There have
From the *Department of Anesthesia and been reports of regurgitation of gastric contents and aspiration despite CP.13
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-
ment of Anesthesiology, Advocate Illinois maneuver is unreliable in producing midline esophageal compression.14 (e) It
Masonic Medical Center, Department of An- is associated with nausea/vomiting and also with esophageal rupture.15 (f) It
esthesiology, University of Illinois College of makes tracheal intubation and mask ventilation difficult or impossible.15–18
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, Airway compelling 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, IL
60637. Address e-mail to aovassap@dacc. anesthetized children and adults.19 –21 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 Society The study by Rice et al.22 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
1360 Vol. 109, No. 5, November 2009

Editorial

Sellick’s Maneuver: To Do or Not Do

Andranik Ovassapian, MD* T he introduction of cricoid pressure (CP) by Sellick1 in 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
cervical vertebrae to prevent gastric contents from reaching the pharynx.”1
Sellick1 provided 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)
from reaching the pharynx in a patient undergoing gastroesophagectomy.2
Sellick1,2 emphasized 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
more than 230 yr ago.3 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
of preventing gastric distension during inflation of the lungs.3
Before Sellick described CP, several techniques were used in patients at
risk of aspiration of gastric contents: awake intubation, induced hyperven-
tilation with carbon dioxide during inhaled induction,4 and RSII per-
formed with the patient in a 40° head-up tilt.5 The rationale behind the
head-up tilt was that gastric contents could not reach the laryngeal level
even if contents were moved up into the esophagus.5 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
practice and continuing interest to clinicians.6
In the last 2 decades, clinicians have questioned the efficacy of CP and
therefore the necessity of the maneuver.7,8 Some suggested abandoning it
on the following grounds: (a) Its effectiveness has been demonstrated only
in cadavers,9 –11 and therefore its efficacy lacks scientific validation. (b) It
induces relaxation of the lower esophageal sphincter.8,12 (c) There have
From the *Department of Anesthesia and been reports of regurgitation of gastric contents and aspiration despite CP.13
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-
ment of Anesthesiology, Advocate Illinois maneuver is unreliable in producing midline esophageal compression.14 (e) It
Masonic Medical Center, Department of An- is associated with nausea/vomiting and also with esophageal rupture.15 (f) It
esthesiology, University of Illinois College of makes tracheal intubation and mask ventilation difficult or impossible.15–18
Medicine, Chicago, Illinois.

PRESION CRICOIDEA

• FUE USADA POR PRIMERA VEZ EN 1774 POR MONRO,Y DESCRITA
POR CULLEN EN UNA CARTA DIRIGIDA A LORD CATHCART,
PRESIDENTE DEL COMITE POLICIAL DE ESCOCIA.

• CULLEN ABOGA QUE LA PRESION CRICOIDEA ES UN MEDIO PARA
PREVENIR LA INSUFLACION GASTRICA CUANDO SE DA
REANIMACION A “PERSONAS AHOGADAS O QUE PARECEN
MUERTAS”.

LA ISR CONTEMPORANEA EN ADULTOS

• PREOXIGENACION

• INYECCION RAPIDA DEL ANESTESICO Y RELAJANTE.

• PRESION CRICOIDEA.

• EVITAR LA VENTILACION MANUAL.

• INSERCION DEL TUBO ET, INFLADO DEL CUFF, CONFIRMACION DE
LA POSICION.

• LIBERACION DE LA PRESION CRICOIDEA.

ISR PEDIATRICA

• “... LAS CARACTERISTICAS CLAVES DE UNA ISR PEDIATRICA
MENCIONA UNA INDUCCION EFECTIVA DE UNA ANESTESIA
PROFUNDA, EVITAR LA PRESION CRICOIDEA Y LA CONFIRMACION
DE LA PARALISIS MUSCULAR COMPLETA...”.

• “... SE DEBE ABANDONAR LA PRESION CRICOIDEA EN TODOS LOS
PACIENTES CON EXCEPCION DE LOS PEDIATRICOS...”

¿POR QUE ESTA
CONTROVERSIA?

• NO HA SIDO LLEVADO A CABO UN ENSAYO CLINICO
RANDOMIZADO SOBRE ISR CLASICA.

• EL HECHO DE SER REALIZADO EN ADULTOS NO PUEDE SER
APLICADO A NIÑOS, DE TAL MODO QUE:

• LA PREOXIGENACION RARAMENTE ES ADECUADA.

• DESATURACION OCURRE MAS RAPIDAMENTE.

• LA APLICACION DE PRESION CRICOIDEA PUEDE HACER DEL
PROCEDIMIENTO DE INTUBACION UN PROCEDIMIENTO MAS
DIFICIL.

Pediatric Anesthesia 2010 20: 421–424 doi:10.1111/j.1460-9592.2010.03287.x

Complications during rapid sequence induction of
general anesthesia in children: a benchmark study
F R A N K J. GE N C O R E L LI M D * , R Y A N G. F I E L D S DO, MBA†
AND RONALD S. LITMAN DO‡
*Department of Anesthesiology, Hospital of the University of Pennsylvania School of Medicine,
Philadelphia, PA, USA, †Jersey Shore University Medical Center, Neptune, NJ, USA and
‡Department of Anesthesiology and Critical Care, The Children’s Hospital of Philadelphia,
Professor of Anesthesiology and Pediatrics, University of Pennsylvania School of Medicine, PA,
USA

Section Editor: Dr Andrew Davidson

Summary
Objectives: Determine incidence of complications such as difﬁcult or
failed intubation, hypoxemia, hypotension, and bradycardia in chil-
dren undergoing rapid sequence intubation (RSI) in a pediatric
anesthesia department in a tertiary care children’s hospital.
Aim: To establish a benchmark to be used by other institutions and
nonanesthesiologists performing RSI in children.
Background: RSI is being increasingly performed in the nonoperating
room setting by nonanesthesiologists. No published studies exist to
establish a benchmark of intubation success or failure and complica-
tions in this patient population.
Methods ⁄ Materials: Retrospective cohort analysis of children aged 3–
12 undergoing RSI from 2001 to 2006.
Results: One thousand seventy children underwent RSI from 2001 to
2006. Twenty (1.9%) developed moderate hypoxemia (SpO2 80–89%),
18 (1.7%) demonstrated severe hypoxemia (SpO < 80%), 5 (0.5%)

Professor of Anesthesiology and Pediatrics, University of Pennsylvania School of Medicine, PA,
USA

Section Editor: Dr Andrew Davidson

Summary
Objectives: Determine incidence of complications such as difficult or
failed intubation, hypoxemia, hypotension, and bradycardia in chil-
dren undergoing rapid sequence intubation (RSI) in a pediatric
anesthesia department in a tertiary care children’s hospital.
Aim: To establish a benchmark to be used by other institutions and
nonanesthesiologists performing RSI in children.
Background: RSI is being increasingly performed in the nonoperating
room setting by nonanesthesiologists. No published studies exist to
establish a benchmark of intubation success or failure and complica-
tions in this patient population.
Methods ⁄ Materials: Retrospective cohort analysis of children aged 3–
12 undergoing RSI from 2001 to 2006.
Results: One thousand seventy children underwent RSI from 2001 to
2006. Twenty (1.9%) developed moderate hypoxemia (SpO2 80–89%),
18 (1.7%) demonstrated severe hypoxemia (SpO2 < 80%), 5 (0.5%)
developed bradycardia (heart rate <60), and 8 (0.8%) developed
hypotension (systolic blood pressure <70 mmHg). One patient had
emesis of gastric contents but no evidence of pulmonary aspiration or
hypoxemia. Eighteen (1.7%) children were noted to be difficult to
intubate and required more than one intubation attempt. All were
eventually intubated without significant complications. Patients
between 10 and 19 kg had a higher incidence of severe hypoxemia
when compared with older children (P < 0.001). There was no
association between choice of muscle relaxant and any complication.
Conclusions: In our cohort of 1070 children who underwent RSI,
difficult intubation was encountered in 1.7% and transient oxy-
hemoglobin desaturation occurred in 3.6%. Severe hypoxemia was
more likely in children <20 kg. There were no children who could not
be intubated, and there were no long-term or permanent complica-
tions.

Correspondence to: Ronald S. Litman, DO, Department of Anesthesiology & Critical Care, The Children’s Hospital of Philadelphia, 34th St. &
Civic Center Blvd, Philadelphia, PA 19104, USA (email: Litmanr@email.chop.edu).

ISR PEDIATRICA3 Y
P E D IA T R I C R A P I D S E Q U E N C E IN D U C T I O N
42
DESATURACION
(a)

± (range)

•
SD

2.92 (3–12) 1070 ISR.
16.5 (10–180)

677
N (%)

(63.3)
• 1.7 % casos diﬁciles.

•
61 (5.7)
18 (1.7) 3.6 % de pacientes mostraron
21 (2.0)
262 (24.6) (b) desaturacion.
29 (2.7)

N (%)
• Pacientes entre 10 y 19 kg no
911
77
(85.1)
(7.2) demostraron hipoxemia moderada
64
10
(6.0)
(0.9)
comparado con los demas grupos.

•
nted in the
Pacientes entre 10 y 19 kg SI
uscle relaxant
Figure 1 demostraron hipoxemia mas
(a) Patients between 10 and 19 kg were not more likely to
demonstrate moderate hypoxemia (SpO2 80–89%) than patients
severa que los demas grupos
weighing 20 kg or greater (P = 0.19). (b) Patients between 10 and
ation 19 kg were more likely to demonstrate severe hypoxemia than
patients weighing 20 kg or greater (SpO2 < 80%) (P < 0.0001).
N (%)

20 (1.9)
were no further details. Of the 18 children who
18
5
(1.7)
(0.5) developed severe hypoxemia, there were accompa-
Gencorelli, Ped Anesth 2010
8 (0.8) nying comments on four. One was noted to be
18 (1.7)

EL ESTUDIO WARNER

• 63180 ANESTESIAS GENERALES EN NIÑOS MENORES DE 18 AÑOS.

• ASPIRACION PULMONAR EN 24 PACIENTES. (0.04%).

• NO HUBO MUERTES. SOLO 3 PACIENTES QUE REQUIRIERON IPPV
POR MAS DE 48 H.

• ASPIRACION OCURRIO MAYORMENTE EN EL MOMENTO DE
INDUCCION, A PESAR DEL USO DE LA PRESION CRICOIDEA.

• EN RIESGO: PACIENTES MENORES DE 3A CON CUADROS
OBSTRUCTIVOS INTESTINALES.

Warner X 5, Anesthesiology 1999

ISR MODIFICADA EN NIÑOS

• PREOXIGENAR DE LA MEJOR MANERA
POSIBLE.

• ASEGURAR UN PLANO PROFUNDO DE
ANESTESIA Y PARALISIS MUSCULAR
COMPLETA.

• VENTILACION CON PRESION POSITIVA
GENEROSA.

• NO APLICAR PRESION CRICOIDEA DE
RUTINA.

• PRESION CRICOIDEA EN CIRCUNSTANCIAS
ESPECIALES. EJ: DISTENSION ABDOMINAL
SEVERA.

MITO O REALIDAD
TUBOS ENDOTRAQUEALES EN PEDIATRIA: ¿CON
CUFF O SIN CUFF?

• EL USO DE TUBOS ET SIN CUFF,YA SEA DE BAJA O ALTA PRESION,
NO ESTA RECOMENDADO EN INFANTES Y NIÑOS MENORES DE 8
AÑOS DE EDAD.

Bissonnette y Dalens, Ped Anesthesia 2002

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¿TUBOS ET CON CUFF O SIN CUFF
EN NIÑOS?

• HISTORICAMENTE, UNA ALTA INCIDENCIA DE
COMPLICACIONES EN VIA AEREA, NOTABLE EDEMA SUB
GLOTICO Y ESTENOSIS, CON EL USO DE LOS TUBOS ET
CON CUFF DE LATEX ROJO.

• LOS DATOS PICU (NEWTH,2004) SUGIEREN Q NO HAY
DIFERENCIAS EN CUANTO A COMPLICACIONES CON EL
USO DE TUBOS ET CON CUFF.

• LOS NUEVOS DISEÑOS DE LOS TUBOS ET HAN
PERMITIDO EL INCREMENTO EN EL USO DE MANERA
SEGURA DE LOS TUBOS ET CON CUFF.

Evidence-Based Positive Clinical Outcomes

Prospective Randomized Multi-Center Study

 24 centros hospitalarios en Europa: n = 2,249 patients
 Promedio de edad de pctes: 1.9 years (3.0mm-4.5mm tubos ET)
 Recambio de Tubo: 2.1% MICROCUFF, 29.9% Tubos sin cuff
 Estridor Post extubacion: 4.38% MICROCUFF, 4.69% Tubos sin cuff
 Pressure del cuff para sellar la traquea: 10.6 cm H2O

EL ESTUDIO WEISS METODOS

• TAMAÑO MUESTRAL GRANDE.

• RAMDOMIZADO DE FORMA ADECUADA.

• CIEGO.

• INCLUYO ESTRIDOR DE VARIAS CAUSAS.

• SOLO USO UN TIPO DE TUBO ET: MICROCUFF.

• USO INSUFLACION MINIMA DEL CUFF CON MEDICION DE PRESION
DE CUFF.

SOBRE TUBOS ET SIN CUFF...

Fuga en Via Presion sobre cricoides
Aerea

3.0mm 3.5mm 4.0mm

Tubo muy pequeño Tubo muy grande

- Ventilacion diﬁcil - Alto riesgo de estenosis subglotica

Diferencias de Sellado con Tubo ET sin Cuff

Fuga Texto
de Aire

Glotis

CrIcoides

Carina

Suominen P et al. Paediatric Anaesthesia, 2006.
Holzki J. Paediatric Anaesthesia, 1997.
Weiss and Gerber. Pediatric Anesthesia, 2006.


Fuga Texto
de Aire

Tubos Pequeños
Glotis

CrIcoides
Monitoreo Inadecuado

Carina



Fuga Texto
de Aire

Tubos Pequeños
Glotis

CrIcoides

Alto riesgo de aspiracion

Carina



Fuga Texto
de Aire

Tubos Pequeños
Glotis

CrIcoides


Dificultad para ventilacion
Carina



Fuga Texto
de Aire

Tubos Pequeños
Glotis

CrIcoides


Dificultad para ventilacion
Carina
Alto Flujo de gas fresco



Fuga Texto
de Aire

Tubos Pequeños Tubos Grandes
Glotis

CrIcoides
2.8 veces mas
Monitoreo Inadecuado posibilidades de desarrollar
eventos adversos.

Cause primaria (92%) de
trauma laringeo en un
Dificultad para ventilacion estudio con 65 pacientes.

Carina
Alto Flujo de gas fresco


Localización Ideal y Características de los Tubos
ET Pediatricos con Cuff

 Cortos, cuff cilíndrico localizado cerca de la punta del
tubo ET.
Glotis
 Localización del Cuff en la traquea, y no en la laringe
Posicion que es sensible a los cambios de presión del cuff.
Cricoides Adecuada
del cuff
 Marca de profundidad basada anatómicamente lo que
Traquea resulta en una correcta posición.
Media

 La punta debe situarse en la mitad de la traquea para
evitar la migración endobronquial.

Carina
 Debe tener un cuff de baja presión para reducir los
riesgos de trauma a la via aerea.

Muchos Tubos ET tienen diseños no adecuados para uso
pediatrico

 Posición del cuff muy alta, cuffs muy largos.
 Ausencia de marcas de profundidad.
 No tienen recomendaciones para la selección de tamaño.

Cuff position should avoid pressure-
sensitive vocal cords and cricoid ring

Weiss M et al, BJA 2004 Texto

The Solution:
KIMBERLY-CLARK* MICROCUFF* ET Tube

Finally, a cuffed ET tube specifically designed

Dullenkopf A et al. Pediatric Anesthesia, 2004.

The Solution:
KIMBERLY-CLARK* MICROCUFF* ET Tube

Confidence in a
Introducing a sealed airway
microthin
polyurethane cuff Superior seal at
ultra-low pressures

Short, distally-placed
cuff

Ensures correct placement,
avoiding repeated
intubations

Clinically verified,
anatomically correct vocal
cord depth mark

Finally, a cuffed ET tube specifically designed

Dullenkopf A et al. Pediatric Anesthesia, 2004.

Acta Anaesthesiol Scand 2005; 49: 232—237 Copyright # Acta Anaesthesiol Scand 2005
Printed in Denmark. All rights reserved
ACTA ANAESTHESIOLOGICA SCANDINAVICA
doi: 10.1111/j.1399-6576.2004.00599.x

Fit and seal characteristics of a new paediatric tracheal
tube with high volume—low pressure polyurethane cuff

A. DULLENKOPF, A. C. GERBER and M. WEISS
Department of Anaesthesia, University Children’s Hospital Zurich, Zurich, Switzerland

Background: To evaluate a new paediatric tracheal tube (4—20). In two patients postextubation croup required singular
(Microcuff, Weinheim, Germany) with an ultrathin high short-term therapy.
volume—low pressure polyurethane cuff. Conclusions: Microcuff paediatric tracheal tubes provided tra-
Methods: With approval of the Hospital Ethics Committee cheal sealing with cuff pressures considerably lower than
tracheas of children undergoing general anaesthesia were intub- usually accepted. The rate of tube exchange was very low
ated using a Microcuff tube. Tube sizes were selected accord- (1.6%), as was the rate of airway morbidity (croup requiring
ing to: internal diameter (mm) ¼ age/4 þ 3.5 in children aged therapy; 0.4%).
!2 years. In newborns (!3 kg) 1 year, ID 3.0-mm tubes, and in
children from 1 to 2 years, internal diameter 3.5-mm tubes were
used. Tubes were classified too large if no air leakage was Accepted for publication 1 October 2004
obtained at an airway pressure of 20 cm H2O with the cuff not
inflated. Sealing pressure was assessed by auscultation. Post- Key words: Children, paediatric; croup, sealing, tracheal;
extubation croup requiring therapy was noted. cuff, high volume-low pressure; morbidity; tracheal tube.
Results: Five-hundred children were studied. In eight children
the tubes were too large. Sealing pressure was 9.7 Æ 2.5 cm H2O # Acta Anaesthesiologica Scandinavica 49 (2005)

T HEuse of cuffed tracheal tubes is a controversial
topic in paediatric anaesthesia and intensive care
(1, 2). Whereas traditionally recommended for chil-
sized uncuffed tubes in order to avoid air leakage (4).
Oversized tracheal tubes in children are the main
cause of subglottic mucosal ischemia and ulceration
dren older than 8—10 years, during the past decade leading to subglottic stenosis (1, 10, 11).
several authors have argued for the use of cuffed The selection of cuffed tubes with a smaller internal

Anestesia pediatrica. Mitos, dogmas y evidencia.

Anestesia pediatrica. Mitos, dogmas y evidencia.

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