Nasogastric tube insertion using conventional versus bubble technique for its confirmation in anesthetized patients: a prospective randomized study

BACKGROUND: Nasogastric tube insertion and confirmation of its position can be difficult in the anesthetized patient. The purpose of the present study was to compare the bubble technique with the conventional method for confirmation of nasogastric tube placement in these patients. METHODS: Two hundred sixty adult patients, aged between 20...70 years, posted for surgeries requiring general anesthesia, tracheal intubation, and a nasogastric tube were enrolled in this study. Patients were randomized into 2 groups: Group B (Bubble group) and Group C (Control group). In Group C, a conventional technique using a lubricated nasogastric tube was positioned through the nostril with head remained neutral. In Group B, 2% lidocaine jelly was added to the proximal end to form a single bubble. The correct placement of the nasogastric tube in the stomach was confirmed by fluoroscopy by an independent observer intraoperatively. RESULTS: The duration of nasogastric tube insertion was 57.2 .. 13.3 seconds in Group B and 59.8 .. 11.9 seconds in Group C (p = 0.111). The confirmation rate of the bubble technique was 76.8% (95% CI: 68.7...83.3), which was significantly better than the conventional method where the confirmation rate was 59.7% (95% CI 50.9...67.9), p < 0.001. When compared to fluoroscopy, bubble technique was found to have a sensitivity of 92.3% (95% CI: 85.6...96.1) with specificity of 81.0% (95% CI: 60.0...92.3), positive predictive value of 96.0% (95% CI: 90.2...98.4), and a moderate negative predictive value of 68.0% (95% CI: 48.4...82.8). CONCLUSIONS: The bubble technique of nasogastric tube insertion has a higher confirmation rate in comparison to the conventional technique. TRIAL REGISTRY NUMBER: Clinical Trial Registry of India (CTRI/2018/09/015864).