Utility of surface landmark technique in providing optimal intratracheal endotracheal tube placement during orotracheal intubation.

Background and aims: Optimal endotracheal tube (ETT) placement in patients with short tracheas by the existing techniques is challenging because of the fixed intratracheal ETT length of insertion. However, in the surface landmark technique (SLT), the individual's tracheal length (distance between mid-thyroid and manubrium-sternum) was estimated and 3 cm was deducted from it to obtain the desired intratracheal ETT length of insertion. Being a new technique, its reliability in providing optimal placement is yet to be evaluated. Hence, to assess the utility and reliability of SLT in achieving optimal placement, this study was planned.

Material and methods: In this prospective study, 406 participants were equally randomized between SLT and intubation guide mark (IGM) groups for ETT placement. In both groups, ETT tip-carina distance (D_TC) was measured to assess optimal placements. The placements were compared by paired t-test. The receiver operating characteristic (ROC) curve analysis was used to assess optimal ETT placement between techniques.

Results: The mean D_TC in the SLT (3.52 ± 0.68 cm) group was significantly higher than in the IGM (2.23 ± 1.01 cm) group, with P < 0.0001. Consequently, optimal placements were significantly higher in the SLT group (190 [95%]) compared to the IGM (121 [60.5%]) group (P < 0.0001). On ROC, at a cut-off value for D_TC of 1.5 cm, the observed area under the curve to assess optimal ETT placements was significantly better in SLT (0.997, 95% confidence interval [CI] 0.997-1.000) compared to IGM (0.968, 95% CI 0.933-0.988), with P < 0.0001.

Conclusion: Based on the measurement of an individual's tracheal length, SLT is a reliable and useful technique to achieve optimal tube placement.