Indian Pediatr 2014;51:
Point of Care Ultrasonography for Position of
tip of Endotracheal Tube in Neonates
Ankur Sethi, *Archana Nimbalkar, Dipen Patel, Amit Kungwani and
From Departments of Pediatrics and *Physiology, Pramukhswami Medical
College, Karamsad, Anand, Gujarat.
Correspondence to: Dr Somashekhar Nimbalkar, Department of
Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat,
India. 388 325.
Received: April 03, 2013;
Initial review: May 30, 2013;
Accepted: October 09, 2013.
Objective: To compare ultrasonography with chest radiograph to
detect the level of endotracheal tube tip in intubated neonates.
Setting: Neonatal care unit of a teaching
Participants: 53 neonates selected by convenience
Intervention: Ultrasonography of chest was done
with probe of 5 to 8 MHz using high parasternal view. The distance of
the endotracheal tube tip to the arch of aorta on ultrasonography was
compared with level of endotracheal tube tip in radiograph.
Primary Outcome: Distance of endotracheal tube
tip from the upper border of the arch of aorta on ultrasonography.
Results: Endotracheal tube tip was visualised on
ultrasonography within 0.5 - 1.0 cm distance from upper border of arch
of aorta in 48 out of 53 neonates. This corresponded with the normal
position of endotracheal tip in radiograph at T2 to T3. In 5 neonates,
endotracheal tube tip was not visualized on ultrasonography and in all
these newborns it was at higher level in radiograph.
Conclusions: Distance of endotracheal tip to arch
of aorta as measured on ultrasonography is helpful in early
identification of the level of endotracheal tube tip.
Keywords: Arch of aorta, Endotracheal intubation, Ultrasound.
monitor and chest radiography has been used to identify correct
intubation . Clinical findings such as direct visualisation of
passage of tube through glottis, rising heart rate, improving oxygen
saturation and improvement in colour suggest tracheal intubation but are
prone to errors [2-5]. ETCO2
measurement in preterm and term neonates has been recommended to confirm
tracheal intubation [6-8]. However, ETCO2
measurement does not inform the healthcare personnel about the depth of
ET insertion. Chest radiograph is considered as a gold standard
investigation for determining level of the ET tip but has radiation
hazard [9,10], involves handling of the neonate, and has high turnaround
Endotracheal intubation is a common procedure in
neonatal intensive care unit (NICU) and in delivery room. Correct
placement in trachea and correct level of endotracheal tube (ET) tip is
of paramount importance in emergency as well as elective conditions.
Clinical methods, end-tidal carbon-di-oxide (ETCO
There is evidence in adult literature [12,13] about
the use of ultrasonography (US) for confirming ET tip but it has not
been studied adequately in neonatal and pediatric population. This study
attempts to evaluate role of US for determining the level of ET tip in
relation with arch of aorta in neonates.
We conducted this prospective observational study
between August 2011 and September 2012 at 550 bedded tertiary-care rural
teaching hospital and medical college in Western India. The study was
approved by the Institutional human research ethics committee.
All neonates intubated in NICU irrespective of their
gestational age, birth weight and diagnosis were eligible for inclusion
in the study. Neonates intubated in delivery room and in emergency room
were excluded. After intubation, ET tube was secured (based on ET length
formula of weight in kg + 6 cm, lip to tip) and confirmed with clinical
signs and oxygen saturation (SPO2)
monitoring. The time of ET insertion was noted and simultaneous calls to
radiography technician and US machine were sent. End points were
confirmation of ET tip position by radiograph and distance of ET tip to
arch of aorta by US. Turnaround times for both the modalities were
noted. Head was kept in sniffing position during both procedures.
Sonosite MicroMaxx portable US machine with probe of
5 to 8 MHz frequency was used to identify the ET tip level. All the US
were performed by a single investigator, who was trained in tube
localization and related anatomy for a period of 2 weeks by a
radiologist prior to initiation of study. Pre-warmed gel was applied on
the probe and kept on baby using high parasternal view. Arch of aorta
was visualized and subsequently ET tip was identified after producing a
gentle motion of less than 0.5 cm ensuring that the ET was not
displaced. Distance of the ET tip from superior border of aortic arch
was measured and noted. The videos were recorded and stored in flashcard
of US machine. These videos were later transferred to the computer for
storage and subsequent analysis. Time taken to confirm ET position by US
after intubation was noted.
Bedside portable 100 mA radiograph machine (GE) was
used for chest radiographs. Radiographs were taken by technician in
antero-posterior view in the NICU. Films were collected and checked for
correct placement by the investigators in the NICU. Time taken
immediately after intubation and visualization of ET tip on radiograph
was noted. US and Radiograph findings were compared for position of the
tip of ET and the time taken to obtain the results of the procedures.
Corrective measures regarding the length of ET tube were taken only
after confirming from radiograph.
From August 2011 to September 2012, 310 intubations
were performed in neonates in the hospital. Out of these, 123
intubations were done in emergency room and 56 intubations were
performed in delivery area. Out of 131 intubations in NICU, 53 (34
males) were studied (depending on availability of AS). Forty-eight were
emergency and 5 (9%) were elective intubations; 50 (94%) were first time
intubations and three were repeat intubations. Mean (SD) gestational age
was 36.1 (2.85) weeks; mean (SD) birth weight was 2.067 kg (0.653), and
mean (SD) age at intubation was 3.89 (5.45) days.
On radiograph, ET tip was in correct position in 48
neonates and at higher position in 5 neonates. Ultrasonography was able
to identify ET tip in 48 (90.6%) neonates. In all these cases, after
gentle motion of the ET, the ET tips were visualized above the upper
border of the arch of aorta within the range of 0.5 cm to 1.0 cm. In the
five neonates where ET tip was not visualised on US, the radiograph
showed ET tip lying at or above the first thoracic vertebra. Ultrasound
had sensitivity of 91% for visualization of ET tip with positive
predictive value of 100%. As there were no true negative cases in US for
ET tip identification, specificity could not be measured. There was no
case of esophageal intubation or over insertion of ET in the right main
Mean (SD) time taken to confirm ET tip position on US
was 19.3 (7.9) minutes and on radiograph was 47.3 (9.0) minutes.
We investigated the use of ultrasonography
concurrently with clinical signs for confirmation of tracheal intubation
and found it to be potentially useful tool to locate the ET tip in
There are few studies of ET localization in newborn
and pediatric population. Slovis, et al.  used 5-8 MHz probe
in neonates and encountered no difficulty in identifying ET tip and
related anatomical structures. They also correlated the distance from ET
tip to aortic arch and concluded that the ET tip more than 1 cm above
aortic arch was optimum. Lingle  also used arch of aorta as a
landmark during US with 5 MHz probe and ET tip was considered in low
position if the tip was located below the superior margin of arch of
aorta and high position if the tip is located above the superior border
of manubrium sternum assessed by shadow from the tin foil. Kerrey, et
al.  found limited usefulness of US in detection of tracheal
intubation by examining movements of both the diaphragms during positive
pressure ventilation. Galicinao, et al.  successfully
confirmed tracheal intubation using both curvilinear and linear probes
of US through cricithyroid membrane in pediatric and neonatal
population. Razzaq  proposed potential benefit of using sliding lung
sign (movement of pleural line on both side of anterior chest using US
with high-frequency linear transducer) with certain limitations like
difficulty in interpretation in pneumothorax and in spontaneously
breathing intubated patients.
In our study, we were able to get the results of the
US earlier than radiography. This difference was because of time
required for the technician to come in NICU from radiology department,
arrange the radiograph machine, keeping the plate in optimum position
under the newborn’s chest, wearing the radio protective grown,
transporting the plate to the radiology department, printing process of
radiography and again transporting back to NICU for reading.
Malpositioned tube could cause complications like hemorrhage, mismatched
ventilation and hypoxia. Time saved in locating ET tip could be of
significance in sick neonates.
The limitation of the study was not checking for
inter-observer variability between various operators. There was no
esophageal intubation in this study; we were therefore not able to
comment on the use of US in esophageal intubation.
We conclude that visualization of ET tip and its
distance of 0.5 to 1.0 cm from upper border of arch of aorta by US
performed by trained personnel, using 5-8 MHz probe, suggests normal
Contributors: AS: designed the study,
analyzed the data, wrote the paper, and performed the ultrasonography
examinations; AN; designed the study, wrote the paper, and assisted in
the ultrasonography examinations DP: analyzed the data, drafted the
paper, and assisted in ultrasonography examinations; AK: interpreted the
data and wrote the paper and approved the final manuscript; SN:
conceived the study, designed the study and revised it critically for
important intellectual content and script. He will be the guarantor. All
authors approved the final manuscript.
Competing interest: None; Funding:
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