Emergency Ultrasound in Airway

Emergency Ultrasound in Airway(1)

大里仁愛醫院急診部

江鴻逸醫師

Scenario

• Middle-aged man, sent to our ED via ambulance, C/O shortness of breath

• PaO2: 89% • PE: R’t breath sound decreased• What’s your impression?• Next step?

Confirmation of ETT

• Clinical assessment: - Chest expansion bil. - Listening over epigastrium & lung bil. - Laryngoscope to visualize

• Use of devices - Capnography, waveform - Esophageal Detector Devices - Thoracic Impedance

2010 AHA Guidelines Part8 ACLS

Confirmation of ETT

• Clinical assessment: - Chest expansion bil. - Listening over epigastrium & lung bil. - Laryngoscope to visualize

• Use of devices - Capnography, waveform - Esophageal Detector Devices - Thoracic Impedance

2010 AHA Guidelines Part8 ACLS

False-positive: - animals, ingest large carbonated fluid- waveform didn’t continue during subsequent breaths

False-negative: - blood flow, delivery CO2 to lungs: low- Gastric content or acidic drug- severe airway obstruction (asthma) pulmonary edema

Confirmation of ETT

• Clinical assessment: - Chest expansion bil. - Listening over epigastrium & lung bil. - Laryngoscope to visualize

• Use of devices - Capnography, waveform - Esophageal Detector Devices - Thoracic Impedance

2010 AHA Guidelines Part8 ACLS

EDD ≠ Auscultation, direct visulization

False-negative:- morbid obesity- late pregnancy, - status asthmatics- copious ET secretion

Clinical Indications of Ultrasound

• Location of thyroid, cricoid, tracheal cartilages

• Visualize motion of the vocal cords and arytenoids

• Visualize the real-time passage of an endotracheal tube

Value of Ultrasound

• Very low pulmonary flow

• Earlier detection of esophageal intubation before ventilation of stomach: prevent emesis and aspiration

• Supervising trainees intubations

• Gross tuning of ET tube position

• In ED, ICU, and out-of-hospital areas

J Ultrasound Med. 2010 29:79-85

J Ultrasound Med. 2010 29:79-85

J Ultrasound Med. 2010 29:79-85

Two parallel echogenic lines linear in long axis; curved in short axis post. acoustic shadowing

Echogenic but irregular in contour with comet-tail artifacts

• Identify location:“ gentle oscillation of the tube tip up and down in airway a few millimeters in each direction” Slovis et al. Radiology. 1986; 160:262-3

• Foam and fluid-filled ETT cuffs, at level of suprasternal notch (midway between vocal cords & carina) Raphael et al. J Clin Ultrasound 1987; 15:459-62

• Real-time confirm esophageal intubation, 97% sen, 100% spec Ma et al. Acad Emerg Med. 1999; 6:515

• Suprasternal position: 97% sen, spec Cricothyroid position: 73% sen, 56% spec

James et al. Acad Emerg Med. 2000; 7:526

Acad Emerg Med. 2000;7: 722-725

Periodic resonance artifactNormal, nonintubated trachea

Hyperechoic shadow or “comet sign” Intubated trachea

Longitudinal view: ETT passing into trachea while intubationTransverse view: ETT placed in esophagus

Ann Emerg Med 2007; 49: 75-80

• EP with ultrasonographic training, in controlled environment, can differentiate tracheal vs esophageal tube passage in real time before ventilation• L’t trachea (29/33), R’t trachea (2), posterior (2)

Ann Emerg Med 2007; 49: 75-80

Crit Care Med 2004; 32(Suppl): S374-377

• 59pts(newborn-17y/o); subxiphoid window • Ultrasound imaging of diaphragm motion is a useful, quick, noninvasive, portable, and direct anatomic method for assessment of ETT position

Crit Care Med 2004; 32(Suppl): S374-377

Correct endotracheal intubation: bil. equal motion of diaphragm

Crit Care Med 2004; 32(Suppl): S374-377

Esophageal intubation: bil. equal paradoxic motion of diaphragm

Crit Care Med 2004; 32(Suppl): S374-377

R’t endotracheal main bronchus intubation

Acad Emerg Med. 2005; 8: 239-244

• Ultrasound sliding lung sign in cadaver model: accurate method for confirmation of ETT placement• Some utility in d/d RMS bronchus from main trachea

Tracheal Rapid Ultrasound Exam (T.R.U.E)

for Confirming Endotracheal Tube Placement in Emergency Intubation

• This study is currently recruiting participants • Sponsor: National Taiwan University Hospital • ClinicalTrials.gov Identifier: NCT01148732

http://clinicaltrials.gov/ct2/show/NCT01148732

Take Home Message

• 在 suprasternal area, 先由 transverse view 看是否 esophageal intubation, 再轉成 longitudinal view 確定 endotracheal tube 和 cuff 位置 , 可以 gentle to and fro移動管子來輔助 .

• Diaphragmatic movement 與 lung sliding可以間接確定 .

• 若單側 lung sliding(-), 尋找 lung point, 檢查是否有 lung pulse.