Fig. 1

Illustration of the systemic ultrasound protocol for positioning nasointestinal tubes (NITs) in critically ill patients. ^†There are two situations: (1) The NIT coils in the stomach cavity; (2) The NIT turns back post-pylorus, with the tip locating in the stomach cavity. ^‡Based on these two situations, different methods are adopted, as follows: (1) When the NIT coils in the stomach cavity, it should be withdrawn to a depth of about 50 cm and then reinserted under ultrasound guidance. (2) When the NIT turns back post-pylorus, it should be withdrawn to a depth of about 75 cm (the tip roughly located in the pylorus) and then reinserted it under ultrasound guidance. ^§The NIT is withdrawn to a depth of about 50 cm and then reinserted under ultrasound guidance. ^ǁIf there is a recurrent failure of NIT insertion under ultrasound guidance, adopt a passive waiting method, and allow the NIT to be guided through the pylorus using gastrointestinal peristalsis