A prospective randomized controlled double-blind study comparing auscultation and lung ultrasonography in the assessment of double lumen tube position in elective thoracic surgeries involving one lung ventilation at a tertiary care cancer institute

BACKGROUND: As lung ultrasound (LUS) can be used to identify regional lung ventilation and collapse, we hypothesize that LUS can be better than auscultation in assessing lung isolation and determining double lumen tube (DLT) position. METHODS: A randomized controlled study was conducted in tertiary care cancer institute from November 2014 to December 2015, including 100 adult patients undergoing elective thoracic surgeries. Patients with tracheostomy, difficult airway and pleural-based pathologies were excluded. After anesthesia induction and DLT insertion, patients were randomized into group A (auscultation) and group B (LUS). Regional ventilation was assessed by experienced anesthesiologists using the respective method for each group. Final confirmation of DLT position with a bronchoscope was performed by a blinded anesthesiologist. Contingency tables were plotted to determine sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for each method. RESULTS: Data from 91 patients were analyzed (group A = 47, group B = 44). Compared with auscultation, LUS had significantly higher sensitivity (94.1% vs. 73.3%, P = 0.010), PPV (57.1% vs. 35.5%, P = 0.044), NPV (93.8% vs. 75.0%, P = 0.018), accuracy (70.5% vs. 48.9%, P = 0.036) and required longer median time (161.5 vs. 114 s, P < 0.001) for assessment of DLT position. Differences in specificity (55.6% vs. 37.5%, P = 0.101) and area under curve (0.748; 95% CI: 0.604–0.893 vs. 0.554, 95% CI: 0.379–0.730; P = 0.109) were not significant. CONCLUSIONS: Compared to auscultation, LUS is a superior method for assessing lung isolation and determining DLT position.