A nasogastric (NG) tube is a long polyurethane or silicone tube that is passed through the nasal passages via the oesophagus into the stomach. They are commonly inserted in surgical practice for various reasons. According to the National Patient Safety Agency (2005a), 11 deaths and one case of serious harm occurred over a two-year period because NG feeding tubes had been misplaced. Nasogastric tubes are inserted by nurses, junior doctors and sometimes by anaesthetists in theatre. It is vital that staff inserting them know the correct insertion technique as well as the procedure for verifying their correct positioning. This article reviews the indications for NG tubes and the benefits and risks associated with their use, and explains the correct method of insertion, as well as how to verify their correct intragastric positioning. Indications There are only two main indications for NG tube insertion – to empty the upper gastrointestinal tract or for feeding. Insertion may be for prophylactic or therapeutic reasons. Care should be taken in cases where there may be: Ear, nose and throat abnormalities or infections; Possible strictures of the oesophagus; Oesophageal varices; Anatomical abnormalities (oesophageal diverticulae); Risk of aspiration. Gaining consent Practitioners should give patients a reassuring, detailed explanation of the insertion procedure, together with the reasons why the tube is necessary. Verbal consent should then be obtained. Sizes Nasogastric tubes come in various sizes (8, 10, 12, 14, 16 and 18 Fr). Stiff tubes are easier to insert, and putting them in a refrigerator or filling them with saline helps to stiffen them. Some fine-bore tubes come with a guide wire to aid placement. The tube has markings and a radio-opaque marker at the tip to check its position on X-ray. Preparation After washing hands, prepare a trolley including gloves, local anaesthetic jelly or spray, a 60ml syringe, pH strip, kidney tray, sticky tape and a bag to collect secretions. Placing a glass of drinking water nearby is useful. Insertion technique Tubes are usually inserted by nurses or junior doctors by the bedside or by anaesthetists in theatre before or during surgery. External measurement from the tip of the nose to a point halfway between the xiphoid and the umbilicus distance gives a rough idea of the required length. The patient should sit up, without any head tilt (chin up). An appropriately sized tube is chosen and the tip is lubricated by smearing aqua gel or local anaesthetic gel. Anaesthetic gel is a drug so if it is used it must be prescribed, and precautions taken such as checking for allergies. The wider nostril is chosen and the tube slid down along the floor of the nasal cavity. Patients often gag when the tube reaches the pharynx. Asking them to swallow their saliva or a small amount of water may help to direct the tube into the oesophagus. Once in the oesophagus, it may be easy to push it down into the stomach. The correct intragastric position is then verified .The tube is fixed to the nose and forehead using adhesive tapes. The stomach is decompressed by attaching a 60ml syringe and aspirating its contents. Blocked tubes can be flushed open with saline or air. source
