Anatomy of the ET Tube

⏺ 15 mm connector – standardized on all airway equipment to avoid a situation where somebody had to look for the right adaptor

⏺ Pilot balloon – contains a spring-loaded one way valve to inflate the balloon.

⏺ One way valve – prevents the air from leaking out when the syringe is disconnected

⏺ Inflatable cuff – has 2 purposes: seals the trachea so that 1) positive pressure can’t escape from lower airways, and 2) seals the trachea so patient doesn’t aspirate any secretions or stomach contents coming from upper airway

⏺ Magill Curve – a natural curvature of approximately 140mm radius, +/- 20mm

⏺ Black line – suggested vocal cords marker

⏺ Size of the ETT – is the internal diameter of the tube

⏺ Depth markings – allow us to measure the depth of the ETT at the teeth or lips (typically 3x size of ETT)

⏺ Radio-opaque line (white here, but I’ve also seen blue!) – helps with the identification of the ETT on X-ray

⏺ Murphy’s Eye – an opening on the right side that allows for ventilation, if the primary opening gets occluded.

NIV: What’s the big deal?


In general,
Type 1 RF requires CPAP type of NIV.

Type 2 RF requires BPAP type of NIV.

PEEP=EPAP=CPAP i.e. they all mean the same!

So you can say in Type 1 RF (Hypoxic failure), the pressure we provide is PEEP or just EPAP or CPAP. 

For Type 2 RF (Hypercapnic), we provide IPAP as well as EPAP. IPAP is greater than EPAP, PS (Pressure Support is the difference between IPAP and EPAP). For instance if IPAP = 15 and EPAP is 10 then PS = 15-10 i.e. 5cm H2O.