1. Endotracheal intubation – tubes
Dr. S. Parthasarathy
MD., DA., DNB,
Dip. Diab., DCA,
Dip. Software statistics-
PhD ( physiology) , IDRA, FICA

2. History
As early as 1542, Vesalius recorded intermittently blowing into a reed that was passed into the aspera arteria of an animal whose thorax had been opened.

3. Pugh, a Chelmsford surgeon, constructed an "air pipe" which was made from a coiled wire covered with soft leather--

5. In 1667, Robert Hooke, at the Royal Society in London, similarly kept a dog alive for over an hour by ventilating its lungs with a pair of bellows tied into the trachea which had been severed below the epiglottis.

6. I.W. Magill and E.S. Rowbotham
British army unit
Passed a red rubber tube through the nose blindly–
uncuffed tubes – plastic surgeries and head and neck surgeries
Inhalational anesthesia instead of insufflation anesthesia
Later became !!

7. Kirstein, a Berlin physician, had advocated direct laryngoscopic intubation with the Kirstein Autoscope,
1920 – chevaliar Jackson introduced laryngoscope

8. Minutes !!
In 1941, Gillespie, writing in Endotracheal Anaesthesia, stated:
‘An experienced worker should be able to intubate all but the most difficult cases in ten minutes. The beginner will often require thirty.’

9. In 1542 – vesalius

10. THE TRACHEAL (ENDOTRACHEAL, INTRATRACHEAL) TUBE is a device that is inserted through the larynx into the trachea to convey gases and vapors between the breathing system and the lungs.
It may also be inserted through a tracheostoma as a temporary measure.

11. Tracheal tubes were made of red rubber
not transparent,
can become hardened
sticky with age,
have poor resistance to kinking,
become clogged by dried secretions more easily than plastic tubes,
do not soften much at body temperature.
Latex allergy is one more possible problem
usually have high-pressure cuffs.

12. Original nasotracheal tubes
Bevel angle different
Longer
Thinner
More luminous
Radius of curvature is less

13. PVC

14. Other than this what does a PVC tube have ?
Prior to use, a PVC tube may be cooled to make it more firm during intubation
warmed to facilitate placement over a fiberscope.
smooth surface that facilitates passage of a suction catheter or bronchoscope

15. Material Silicone tubes more expensive than PVC,
soft and can be sterilized and reused.
Chemicals called plasticizers may be added to PVC during manufacture to produce a softer product. The most widely used plasticizers are a group of chemicals called phthalates
Polyurethane has been used for tracheal tube cuffs in recent years.

18. Why bevel ?
the tube is usually introduced from the right, and it is easier to visualize the larynx with the bevel facing to the left.
More opening
Entry point space of tube
– less

20. Murphy eye
a hole through the tube wall on the side opposite the bevel. This is known as a Murphy eye.
provide an alternate pathway for gas flow if the bevel becomes occluded.
A forceps, tube changer, or fiberscope may inadvertently advance through a Murphy eye and become caught.

21. A big murphy eye will weaken the tip
Easier for nasotracheal intubation
Secretions can accumulate
If there is no murphy eye , the cuff can be placed distally and there is more chance of better placement of tube without endo bronchial migration
A big murphy eye will weaken the tip

22. Additional murphy eye in rare tubes

23. Blunt tip and soft

24. Characters of tubes Inertness Rat implantation test
Surface – smooth , no rough edges
Microscopy reveals so irregular surfaces still with colonizing bacteria
Is it the reason for nosocomial pneumonia ?

25. Rigid to prevent kinking But still flexible to cause less damage
Rigidity :
Dual properties
Rigid to prevent kinking
But still flexible to cause less damage
Posterior larynx affected ? By pressure
Can you make S tubes ?
Z 79 standards

27. Lumen integrity:
If we inflate the cuff the lumen should not collapse
Water bath test
40 degrees
24 hours

28. Cuff pressures
Low volume high pressure cuffs
2 – 3 ml in adults – no leak means may be upto 100 mm Hg
But high volume low pressure cuffs – may be less than 25
Tracheal wall is not circular -

29. Keep it below 25 mmHg

30. Nitrous oxide (N2O) diffuses into tracheal tube cuffs filled with air.
This applies also to cuffs on supraglottic airways.
The rate at which diffusion occurs depends on:
• the permeability of the material from which the cuff is constructed (rubber being more permeable than plastic)
• the surface area of the cuff exposed to N2O
• the partial pressure of N2O in the respiratory gas.
Can go up to 90 mm Hg in 20 minutes

31. The Bivona ‘Fome-Cuf’ uses a piece of shaped foam to replace the air within the cuff.
Prior to insertion the cuff is evacuated to collapse the foam and after insertion the pilot tube is opened to the atmosphere to allow the foam to expand, to ‘inflate’ the cuff
Because the pilot tube is left open, diffusion of nitrous oxide does not further inflate the cuff.

32. ASTM testing for rigidity
American society for testing and materials
American national standards institute
Z79  committee that develops standards for anesthetic 
and ventilatory equipment. 
The label  Z79”  signifies that a device meets the established standard.

33. Inflation system Balloon cuff Inflating lumen
Should not bulge , should not compromise the lumen
Inflation valve with a luer lock tip
At least 3 cm the tube should come outside the machine end
Testing the leaking is inflation upto 150% of its diameter and water bath

34. Position of vocal cords
Black line showing where the position of vocal cord and insertion distance

35. Pediatrics

36. Length of the tube
Markings
6 mm tube means internal diameter – 6 mm
20 mm diameter trachea not even a 10 mm tube will go !! Why ?

37. Size of the larynx

38. 6 mm internal diameter - 28 cm approx
0.5 mm increase 2 cm increase in length

39. endotracheal tube used to ventilate elephants
endotracheal tube used to ventilate elephants. This particular tube has an internal diameter of 45 mm !
imagine the length of the tube as Bob is six feet (183 centimeters) tall !

40. Radio opaque line Optical density equal to a piece of aluminium
1 * 1*10 mm - Entire length of the tube or tip

41. Summary
Size

42. Thank you all