Brazilian Journal of Anesthesiology
Brazilian Journal of Anesthesiology
Original Investigation

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

Inserção de sonda nasogástrica pela técnica convencional versus técnica de bolha para sua confirmação em pacientes anestesiados: estudo prospectivo randomizado

Ankur Sharma, Varuna Vyas, Shilpa Goyal, Pradeep Bhatia, Priyanka Sethi, Akhil Dhanesh Goel

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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.

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.

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).

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).


Nasogastric intubation;  General anesthesia;  Fluoroscopy



A inserção da sonda nasogástrica e a confirmação de sua posição podem ser difíceis no paciente anestesiado. O objetivo do presente estudo foi comparar a técnica da bolha com o método convencional para confirmação da colocação da sonda nasogástrica nesses pacientes.


Duzentos e sessenta pacientes adultos, com idade entre 20 e 70 anos, encaminhados para cirurgias que necessitaram de anestesia geral, intubação traqueal e sonda nasogástrica foram incluídos neste estudo. Os pacientes foram randomizados em 2 grupos: Grupo B (grupo Bolha) e Grupo C (grupo Controle). No Grupo C, técnica convencional com sonda nasogástrica lubrificada, posicionada pela narina com cabeça neutra. No Grupo B, foi adicionada gel de lidocaína a 2% na extremidade proximal para formar uma bolha única. O posicionamento correto da sonda nasogástrica no estômago foi confirmado por fluoroscopia por um observador independente no intraoperatório.


O tempo de inserção da sonda nasogástrica foi de 57,2 .. 13,3 segundos no Grupo B e 59,8 .. 11,9 segundos no Grupo C (p = 0,111). A taxa de confirmação da técnica da bolha foi de 76,8% (IC 95%: 68,7...83,3), o que foi significativamente melhor que o método convencional onde a taxa de confirmação foi de 59,7% (IC 95% 50,9...67,9), p < 0,001. Quando comparada à fluoroscopia, a técnica da bolha apresentou sensibilidade de 92,3% (IC 95%: 85,6...96,1) com especificidade de 81,0% (IC 95%: 60,0...92,3), valor preditivo positivo de 96,0% (IC 95%: 90,2...98,4) e valor preditivo negativo moderado de 68,0% (IC 95%: 48,4...82,8).


A técnica de bolha de inserção de sonda nasogástrica apresenta maior taxa de confirmação em comparação à técnica convencional.

Número de registro do teste

Registro de Ensaios Clínicos da Índia (CTRI/2018/09/015864).


Inserção de sonda nasogástrica pela técnica convencional versus técnica de bolha para sua confirmação em pacientes anestesiados: estudo prospectivo randomizado


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