الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Securing the airway by endotracheal intubation is a fundamental skill in anaesthesia, emergency medicine and critical care. Unrecognized misplacement of endotracheal tube (ETT) can lead to morbidity and mortality, with a reported incidence of approximately 2.9–16.7% in previous cardiac arrest studies.
The current study had a primary outcome that evaluated the sensitivity, specificity of TRUE and chest sonography in comparison with the conventional method using auscultation of the chest and epigastrium, and quantitative EtCO2 measurement for confirmation of Endotracheal Intubation (ETI). In addition to evaluating the value of tracheal and chest ultrasonography in confirmation of ETI without interruption of chest compressions in cases of cardiac arrest. The secondary outcome of the study included figuring out the time consumed for confirmation by either method and degree of difficulty of confirmation methods used. The effect of the method of intubation on the confirmation method used as regards clearance of the tracheal ultrasound image obtained.
The present study included 57 patients admitted to the Emergency Department (ED) in Alexandria Main University Hospital(AMUH) due to polytrauma or cardiac arrest. 7 patients were excluded, where in one case there was cuff leakage which lead to false positive result by capnography, 2 cases had oesophageal intubation which was detected by tracheal ultrasound, and 4 cases had bilateral tension pneumothorax which lead to failure of visualization of pleural sliding by chest ultrasound. All of the 7 cases excluded were admitted due to polytrauma.
Regarding the demographic data of the present study population and their indications of admission, the majority of the study population were males, and the ages ranged between 18-70 years. 54% of the study population were admitted to the emergency department secondary to polytrauma while 46 % were secondary to cardiac arrest.
The indications of intubation in the study included cardiac arrest, respiratory failure, shock and Glasgow coma scale less than or equal to 8. Patients with any neck distortion secondary to any reason were excluded from our study.
In the present study, four methods of confirmation of correct endotracheal tube placement were used, which were quantitative waveform capnography, real time tracheal rapid ultrasound examination, ultrasound visualization of pleural sliding and 5 points auscultation.
Judgement of ETT position with capnography was done after tracing 5 subsequent normal waves of the capnogram; mainstream capnography was used. ETT placement confirmation by TRUE was judged when two hyperechoic parallel lines replace the multiple reverbation artefacts at the site of the trachea by using a linear high frequency probe positioned horizontally just above the suprasternal notch. Tracheal ultrasound was done realtime as the tube was inserted. The ETT was defined as oesophageal if 2 hyperechoic lines were seen in the oesophagus by placing the linear probe horizontal just above the suprasternal notch and by sliding the probe slightly to the left of the trachea. Pleural sliding was visualized by placing a linear high frequency probe in the second intercostal space midclavicular line (MCL), or fourth intercostal space midaxillary line(MAL) on both sides of the chest, and finally 5 points auscultation was done by bilateral auscultation at the midclavicular and mid axillary lines and epigastrium. All intubations were done by emergency residents using direct laryngoscopy in all cases except a single case that was intubated by fiberoptic bronchoscopy due to unstable cervical spine fracture.
There was a correlation with a significant kappa value between the novel techniques using ultrasound and capnography which is considered the gold standard for confirmation of correct endotracheal tube placement. Also, the novel techniques showed high sensitivity and positive predictive value in confirmation of correct endotracheal tube placement.
When the four methods for confirmation of correct ETT placement were compared, there was a statistically significant shorter time for confirmation of ETT position using the ultrasound methods compared to 5 points auscultation and capnography.
In cardiac arrest patients, there was a statistically significant longer duration for capnography to confirm ETT placement relative to the ultrasound methods. This was mostly attributed to the decreased lung perfusion in cardiac arrest patients, bearing in mind that the first reading of capnography was recorded after at least 2 CPR cycles in most of the cardiac arrest patients. In addition, all patients included in the study suffered OHCA.
When the 4 methods of confirming correct endotracheal tube placement in the polytrauma patients were compared, there was also time difference between capnography and the novel ultrasound techniques, in favor of ultrasound, but it was not highly significant as in cardiac arrest patients.
In the present study, it was observed that neither of the confirmation methods used to confirm ETT placement was associated with any complications, but some of them might have been associated with interruption in chest compressions in the cardiac arrest group of patients. Regarding auscultation, it is considered difficult in emergencies due to noise, presence of chest pathology which makes laterality difficult to determine, also frequent bagging to confirm laterality carries the risk of gastric insufflations and vomiting, this made such method time consuming as previously mentioned, in addition, it might necessitate minimal interruption in CPR. Sometimes visualization of pleural sliding required pausing chest compressions or waiting until the image is obtained during the pause between CPR cycles, because the vigorous chest movement during CPR affected the glare of the image. This effect was more pronounced if the operator placed the probe at the second intercostal space MCL. This proves that TRUE was the best to confirm correct ETT placement in cases of cardiac arrest, as it was not associated with interruption in chest compressions, even the technical difficulties faced during the scan such as obesity, short neck or prominent Adam’s apple did not necessitate CC interruption; compared to using waveform capnography which did not interrupt chest compressions, yet it consumed a significantly longer time.
In the current study, first of all pleural sliding was visualized by scanning the chest, then the probe was moved to the abdomen to look for any fluid collection. the right upper quadrant (RUQ) was scanned to visualize the hepatorenal space (Morrison’s pouch) and the right pleural recess, then the probe was moved to the left upper quadrant (LUQ) to visualize the splenorenal space, and left pleural recess, followed by the subcostal (subxiphoid) view to scan the pericardium and the IVC, and finally, the pelvis was scanned.
The present study showed that bed side ultrasound helped in diagnosing certain etiologies that contributed to shock or cardiac arrest in the patients enrolled., such as intra- abdominal collection, tension pneumothorax, cardiac tamponade, and finally intrauterine pregnancy.