Nano gastric tubes are meant for feeding the patients both liquid, semi liquid food where the volume in a normal case should not exceed more than 2500 ml in a single day. This is also known as Ryles Tube and is ideal for the patients not able to swallow the foods. If the patients are not injected intravenously the volume stated above is applicable.
Since the Ryles Tube is devoid of side effects, it can be used for a prolonged period as the doctor thinks fit. So there is no case of your apprehension in this regard. Some are given feeds life long.
Feed volume has to be decided depending upon the age of the patient. Children below 5 years of age would require 1gm/ kg/ day as total Protien requirement but for the adults it should remain in the range of 0.5 to 0.75 GM/ kg/ day.
In case of fever, infection or tissue damage, intake of fluids can adjusted depending upon the recommendation of the doctor.
In a single feed, 100 - 150 ml of milk is fed and the same can be given 10-12 times in a day to compensate nutritional requirements. Sugar may be added in such feeds as per needs of calories of the patients.