Chest Computed Tomography Image for Accurately Predicting the Optimal Insertion Depth of Left-Sided Double-Lumen Tube

This study is a single-centre, prospective, randomized study in adult patients. Preoperative CT guided tracheal measurements (vocal chords to carina) were used to help guide insertion of a left sided Double lumen Tube (DLT) compared to traditional clinically guided insertion.  Ease, speed and success rate together with incidence of complications was compared between the two groups. Each DLT was inserted and its position checked clinically, including auscultation, to the anaesthetist’s satisfaction. Its position in the airway was subsequently checked by a second, blinded anaesthetist using a fibreoptic scope (FOB).

There were 30 patients in each group: group B (“blind” insertion) and group C (CT aided insertion).

End points Group B Group C Significance?
No. in “optimal” position after FOB check 16/30 27/30 P <0.01
Time taken to intubate to adequate position (secs) 118 +/- 26.2 71.5 +/- 8.7 P <0.01
Time for position confirmation using FOB (secs) 40.8 +/-15.8 18.7 +/- 7.9 P <0.05
Incidence of carinal and bronchial injuries 11/30 3/30 P <0.05
Incidence of postoperative sore throat. 7/30 6/30 P =1.00
Incidence of postoperative hoarseness. 4/30 5/30 P =1.00

Overall, the use of a premeasured VC to carina distance (from CT scan) to help guide insertion depth of a left sided DLT was associated with a quicker, safer and more accurate placement when compared to a traditional “clinical only” intubation in adult patients.


This is a well-designed study with simple, clinically relevant primary and secondary end points. Although the data is clear and well presented the quoting of “generalised” P values (ie P <0.05) rather than actual values was disappointing. The majority of elective and semi elective children that undergo thoracic surgery requiring one lung anaesthesia (OLV) have had a preoperative CT scan. Modern imaging software allows accurate measurements such as tracheal length and diameter by non-radiologists. The problems of providing safe and effective OLV in children are well known. In children approximately 9 years and older the use of a DLT may be a viable option. The child’s size, choice of DLT size and anaesthetist’s experience are all factors in achieving quick, successful placement. Although FOB is recommended for guiding placement and checking subsequent position it is not without its problems; anaesthetic experience, availability of correct size, picture quality and costs are all potential concerns.

Take Home Message

Although this study was done in adult patients I can see no reason why its methodology and techniques could not potentially be utilised in older children considered suitable for DLT placement.

Reviewed by: Dr H. Hack