Ultrasound confirmation of endotracheal tube placement

Ultrasound confirmation of

endotracheal tube placement

Dr James Wheeler BSc MBBS FACEM DDUEmergency Physician, SCGH

Will this replace traditional

methods of ETT confirmation?

• Specifically, does this replace capnography and

auscultation

• NO!

• But no single confirmatory method is entirely reliable in

emergency situations, and in certain circumstance US

confirmation can be a very helpful adjunct

Why would you do it?

• Transtracheal ultrasound is a relatively SIMPLE technique

• FAST (~8 sec vs 18 sec for capnography1)

• May be more reliable than capnography changes in certain patient groups?

• SENSITIVE and SPECIFIC 2,3,4

• The pooled sensitivity and specificity for the detection of proper ETT placement

with US were:

• Sensitivity: 98% (95% C.I. 97-99%); Specificity: 98% (95% C.I. 95-99%);

PPV: 99.5%, NPV: 93.8%

• Does not require ventilations to assess tube placement

• May prevent gastric insufflation and delay in diagnosis of misplacement

When would you use it?

• ETCO2 unreliable or not available

• Cardiac arrest / massive PE

• Emergency blind intubation

• Patient arrives intubated and requires rapid confirmation of

ETT placement

• Any patient not responding as expected after ETT

placement prior to attempting re-intubation

How do you do it?

Direct (Transtracheal)

• Looking for evidence of direct endotracheal intubation or oesophageal intubation (a “second trachea”)

• During intubation OR Post-intubation

Indirect (Transthoracic)

• Looking at the pleural space for evidence of lung ventilation (pleural movement)

• Post-intubation

Direct: Technique

Probe:

• high frequency (6-12MHz) linear probe (but

can use lower freq micro convex or

curvilinear in obese)

Preset:

• Superficial, depth sufficient to see posterior

to trachea, focal zone at trachea

Probe placement:

• in transverse plane just above the

suprasternal notch

• i.e. beneath cricoid

Direct: Technique

Endotracheal intubation:

• One air-mucosal interface

• Hyperechoic reverberation artifacts inside trachea

OR

Oesophageal intubation:

• Dynamic opening of the oesophagus by the ETT seen on US performed during laryngoscopy

• Two air-mucosal interfaces (“two tracheas” , “double track sign”)

• Hyperechoic reverberation artifacts inside oesophagus

May also interrogate cuff position by infiltrating saline

Direct: US Anatomy

Direct: Tracheal Intubation

Direct - Oesophageal Intubation

Indirect

• Looking at the pleural space for evidence of lung

ventilation (pleural movement)

• Differential pleural movement may indicate RMS

intubation

• Requires ventilation

Indirect US Anatomy

Indirect: Ventilating Lung

Indirect: Non-Ventilating Lung

Indirect: Pneumothorax

Indirect: PTX Lung Point

Pitfalls?

• Requires access to US machine

• No single confirmatory method is entirely reliable (esp. in

emergency situations)

• Operator dependent

• Surgical emphysema can obscure view

• Can’t identify supraglottic airway

• Pneumothorax (for indirect)

References

1. Reliability of Ultrasonography in Confirming Endotracheal Tube

Placement in an Emergency Setting. Vimal Koshy, Thomas et al.

Indian J Crit Care Med. 2017 May; 21(5): 257–261.

2. Transtracheal ultrasound for verification of endotracheal tube

placement: a systematic review and meta-analysis. Das SK1, Choupoo

NS, Haldar R, Lahkar A. Can J Anaesth. 2015 Apr;62(4):413-23

3. Ultrasonography for confirmation of endotracheal tube placement: A

systematic review and meta-analysis. Eric H.Chou et al. Resuscitation,

Volume 90, May 2015, 97-103

4. Can Transtracheal Ultrasonography Be Used to Verify Endotracheal

Tube Placement? Gottlieb M, Bailitz J .Ann Emerg Med. 2015 Oct;

66(4): 394-5