Insertion of a Double Lumen Tube

The blind guided technique for insertion of double lumen (tracheobronchial) tubes was described in 1992 (Anaesthesia & Int. Care 20,71-74). Since then this technique has been taught widely. There are several important steps in the effective use of this technique.

These are:-

a) Recognition that the diameter of the bronchus (usually the left) is a crucial determinant of success. This size can be found from the standard P-A chest X-ray, which magnifies the air bronchogram by about 10% as the bronchi are about 15 cm from the plate. Once this is known, the correct size double lumen tube can be selected. Unfortunately, the diameter of the bronchial tube for any nominal size varies with the manufacturer. A table is given to guide the correct size.

Manufacturer	X-Ray size mm (110% actual)
	28Fr	32Fr	35Fr	37Fr	39Fr	41Fr
Sheridan	9.6	-	11.4	12.2	12.5	12.8
Mallincrodt	8.2	9.3	11.3	12.2	12.5	13.0
Portex	-	-	10.8	11.8	12.1	12.8
Rusch	-	-	11.2	12.4	12.5	13.0

b) Once the patient is anaesthetised and paralysed, the selected tube is inserted into the trachea until the tracheal cuff is just below the vocal cords. This should leave the tube about 6 cm above its final position. At this point, the bronchial cuff is inflated in the trachea until the leak on inflation stops. Now the bronchial arm is connected directly to the circuit and both lungs of the patient ventilated through the bronchial tube (Fig 1).

Figure 1. DL Tube with bronchial cuff inflated firmly to seal in the trachea. Both lungs ventilated.

c) With each breath, the tube is advanced into the trachea until the bronchial segment plugs the bronchus (Fig 2).

The endpoint signs are:

1. Resistance to advancement. (Good even with low compliance lungs).
2. Unilateral ventilation by observation and by auscultation.
3. Reduction in compliance (Often best seen with IPPV with a ventilator).

At this point, the tube is about 2.5 to 3 cm (bronchial cuff length plus 1 cm) from its final position.

Figure 2. DL tube with over-inflated bronchial cuff plugging left main bronchus.

d) Once the bronchial plugging point has been identified, the cuff is deflated and the tube inserted an additional length (bronchial cuff length + 1 cm). The final bronchial cuff inflation to seal is then usually about 1-2 ml. The patient connection is now changed to the tracheal connection and the tracheal cuff inflated until a seal is made in the trachea (Fig 3).

Figure 3. The Double Lumen Tube with final position in the left main bronchus with the bronchial and tracheal cuffs inflated.

e) If desired, further checks can be made by auscultation.

In a difficult case, the estimated length from plugging can be used for final insertion even if the bronchial cuff has to be deflated to get the tube positioned into the left main bronchus. If a tube goes right, turning the head 90° so that the chin is on the right shoulder and rotating the tube on its axis to restore the bronchial tube to point laterally, can usually achieve insertion into the left main bronchus. The distance inserted is then that previously determined from the right bronchial plugging.