Can the Fluctuation Observed in the Endotracheal Tube With Compression Applied to the Epigastric Region be Used as a Confirmation Method for Endotracheal Intubation?
Phase: NA
Conditions: Intubation, Intratracheal
Sponsor: Duzce University

12.05.2021 
 
 
 
Can the fluctuation observed in the endotracheal tube with compression applied to the 
epigastric region be used as a confirmation method for endotracheal intubation? 
 
STUDY PROTOCOL 
 
 
 
This study was planned prospectively in the emergency department of a tertiary hospital. Ethics 
committee approval was obtained from the ethics committee of Düzce University (Date: 
18/01/2021, Decision no: 2021/05). The relatives of the participants included in the study were 
informed about the procedure and written informed consent was obtained. The procedure does 
not pose any additional risk to the routine procedure and the question "Can the tube position be 
confirmed by epigastric manual compression method in addition to the currently used 
confirmation methods?" was sought. 
Participants 
 
Patients admitted to the emergency department between 01/05/2021 and 30/05/2022, who 
were older than 18 years of age and who underwent ETE outside the hospital or within the 
first hour of arrival to the emergency department were included in the study. Patients in whom 
ETE was previously confirmed by USG or PETCO2, in whom elective intubation was 
decided, who were referred from another center, and who had known airway stenosis were 
excluded from the study. In the literature, it has been shown that >80% of ETE applications in 
the first attempt are successful [10,11]. This rate is 70% for out-of-hospital cardiac arrest 
cases [5]. In our clinic, an average of 300 ETE procedures are performed annually and the 
success rate is similar. Therefore, in order to include an equal number of successful and 
unsuccessful ETE procedures, the first 40 successful and the first 40 unsuccessful ETE 
procedures were included in the study. One participant from each group was excluded due to 
missing data. 
Workflow 
 
Patients who underwent ETE outside the hospital or in the first hour of arrival to the 
emergency department were evaluated after the procedure. Out-of-hospital ETE was 
performed by experienced paramedics working in the emergency ambulance service, and ETE 
in the emergency department was performed by emergency medicine residents or emergency 
medicine specialists with at least 2 years of emergency department experience. Out-of- 

hospital procedures were performed at the first visit to the emergency department, and 
procedures performed in the emergency department were confirmed by ETE immediately 
after the procedure. 
 
Statistical analysis 
Descriptive statistics were presented as numbers and percentages. Demographic data were 
presented as mean±standard deviation (SD) for normally distributed variables and median, IQR 
(25-75%) for non-normally distributed variables. Pearson's chi-square test and Fisher's exact test 
(when the expected number of cells was less than five) were used for independent categorical 
variables. Bonferroni correction was used for subgroup analyses and p<0.016 was considered 
significant. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, positive 
predictive value and negative predictive value were calculated at 95% CI for the index tests of 
gastric compression fluctuation, epigastric sound and lung sounds based on the reference test of 
ultrasound confirmation. Statistical analyses were performed using IBM Corp. Released 2017. 
IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp. A P value less than 
0.05 was considered statistically significant. 

Confirmation was performed single-blind by emergency medicine specialists with at least 5 
years of experience, without knowing who performed the procedure and where (in or out of 
the hospital). Confirmation was performed by auscultation of lung sounds (from the anterior 
and lateral sides of both lungs, upper and lower zones), evaluation of equal participation of 
both thoraxes in breathing by inspection, auscultation of the epigastric region, placement of 
capnography, monitoring of water vapor in the tube, manual compression of the epigastric 
region at least three times and evaluation of fluctuation in the tube, and pulse oximetry 
monitoring. 
Epigastric compression was performed by applying pressure to the epigastric region at least 
three times with the volar side of the intubated patient while the patient was ventilated with a 
balloon-valved mask. During this procedure, the fluctuation of the air and fluid in the stomach 
inside the esophageal tube can be observed and its sound can be heard. It can be applied from 
the first inhalation. 
The USG procedure was evaluated by placing a linear ultrasound probe [SonoSite M-Turbo 
linear probe (13-6 MHz), Sonosite, Inc, Bothell, WA, USA] in the transverse position on the 
anterior side of the neck, just above the suprasternal notch, and observing the position of the 
tube (presence of a double path sign) and pleural sliding movement. While a single 
semicircular echogenic area is observed when the tube is in the trachea, a second semicircular 
echogenic area is observed when the tube is located in the esophagus.. USG was performed 
immediately after the ETE procedure. In patients in whom double pathway sign was observed 
and pleural sliding motion was not observed, the patient was re-intubated by the experienced 
specialist performing USG. It was confirmed by USG again. These procedures were 
categorized as "failed". 
ETCO2 measurement by capnography was performed using a mainstream EMMA® 
Capnograph (PHASEIN AB Svärdvägen, Danderyd, Sweden) for intubated patients. It was 
assessed by the detection of PETCO2 greater than 5 mmHg after five breaths and the 
appearance of a typical square waveform. 
Statistical analysis 
 
Descriptive statistics were presented as numbers and percentages. Demographic data were 
presented as mean±standard deviation (SD) for normally distributed variables and median, 
IQR (25-75%) for non-normally distributed variables. Pearson's chi-square test and Fisher's 
exact test (when the expected number of cells was less than five) were used for independent 

categorical variables. Bonferroni correction was used for subgroup analyses and p<0.016 was 
considered significant. Sensitivity, specificity, positive likelihood ratio, negative likelihood 
ratio, positive predictive value and negative predictive value were calculated at 95% CI for 
the index tests of gastric compression fluctuation, epigastric sound and lung sounds based on 
the reference test of ultrasound confirmation. Statistical analyses were performed using IBM 
Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM 
Corp. A P value less than 0.05 was considered statistically significant.