Tubes lead fluids from somewhere to somewhere else. Inserting one may be the aim of surgery, as when you drain the pleural cavity (65.2), or it may merely be part of an operation, as in decompressing a patient's stomach when his gut is obstructed (10-9). You can also use tubes to drain pus and exudate. The insertion of a tube for gastrostomy (11.8), jejunostomy (9.7), caecostomy (9.6), and cholecystostomy (13.3) are described elsewhere: here we describe the use of nasogastric tubes, which are of great value, even though they are a burden to nurses and an irritation to patients.
TUBE, nasogastric, plastic, Ryle's, with several side holes near the tip, 14 Ch, 16 Ch, 18 Ch, ten only of each size. Transparent plastic tubes are better than rubber ones, because they are less irritant, they don't collapse, and you can see what is inside them. Most tubes have markings, the first at 45 cm showing that the tip is about to enter the stomach, and the second that it is in the antrum.
TUBE, stomach, plastic, adult and child, assorted sizes 8 to 22 Ch, five only of each size. These are critically important for making sure that a patient's stomach is empty before he is anaesthetized (A 16.4), and for washing it out if he has swallowed a corrosive (25.15). Adults need tubes of 16 to 22 Ch, children 10 to 14 Ch, and infants 8 to 10 Ch.
NASOGASTRIC TUBES Here we are concerned with the use of a tube to keep a patient's stomach empty[md]for tube-feeding him, see Sections 9.10 and 58.11.
INDICATIONS. (1) To remove fluid from a patient's stomach before anaesthetizing him, so as to reduce the risk of his inhaling it. The solid food from a recent meal will not come up an ordinary nasogastric tube, so if you want to anaesthetize safely a patient who has recently eaten, you will have to empty his stomach with a larger stomach tube (A 16.1), and then pass a nasogastric tube. (2) To decompress the stomach, particularly during upper abdominal surgery when a distended stomach may get in the way of the operation. (3) To empty the stomach during acute intestinal obstruction. (4) To feed a patient (58.10). (5) To monitor gastric bleeding. (6) To minimize abdominal distension postoperatively, so as to reduce tension on the wound, and hence assist respiration. For all these reasons, it is good practice to pass a tube whenever you do a laparotomy.
PASSING A NASOGASTRIC TUBE. Lubricate the tip of the tube with a water-soluble jelly. Sit the patient up and tell him what you are going to do. Choose the nostril which has the widest channel. Pass the tube horizontally through his nose. When the tube touches his posterior pharyngeal wall, he will gag, so give him a little water to sip, as you slowly advance the tube. The act of swallowing will open his cricopharyngeus and allow the tube to enter his oesophagus. Continue to advance it until its second ring reaches his nose; its tip should now be in his stomach.
CAUTION ! If you are only aspirating a tube, you cannot do much harm, but never start tube feeding until you are sure a tube is in the stomach. You can easily pass a tube into the trachea of an elderly, debilitated, or unconscious patient and drown him with feed. To make sure it is in his stomach: (1) Aspirate greenish-grey stomach secretions. (2) Inject a little air down it and listen over his stomach with a stethoscope for a gurgling sound. (3) Listen to the end of the tube. The sound of moving air confirms that the tube is NOT in his stomach, but is in his trachea or bronchi.
When you are satisfied that the tube is in the right place, secure it with two narrow strips of tape, one on the side and the other on the bridge of his nose, extending downwards on to the tube. In this way you will avoid pressure necrosis of his alae nasae.
Connect the tube to a bedside drainage bottle or plastic bag, to let his stomach contents syphon out. Assist this by aspirating. Suck the contents out every hour, or more frequently if there is much aspirate, to prevent the tube blocking. If you cannot aspirate anything, try irrigating the tube with 5 or 10 ml of water; its terminal holes may be plugged.
If the tube fails to decompress his stomach: (1) Its tip may still be in his oesophagus. (2) It may be kinked or blocked. (3) His stomach may be filled with large food particles. Excessive suction may have sucked food or mucosa into the holes in the tube.
Occasional sips (not gulps) of water will help to ease his misery. Keep a fluid balance chart, and as a general rule replace gastric aspirate by normal saline or Ringer's lactate (A 15.5).
CAUTION ! If you don't care for his mouth adequately, his parotid may become infected. So give him 4-hourly mouth care as a routine after major surgery, especially if he has a nasogastric tube in.
REMOVING A TUBE. As a general rule, leave a tube in place until: (1) There are normal bowel sounds. (2) There is no abdominal distension. (3) His bowel has moved normally or he has passed flatus. (4) There are only about 400 ml of gastric aspirate daily. This is the normal volume; if you aspirate 750 ml or more, suspect ileus or gut obstruction.
If his stomach has a suture line in it, remove the tube at 4 to 5 days.
If you are in doubt as to when to remove a tube, clamp it for 24 hours, and if nausea and distension do not return remove it.
CAUTION ! Don't remove a patient's nasogastric tube if he is nauseated, or distended, or he has passed no flatus, or has more than 500 ml of gastric aspirate. If he has any of these, he probably has paralytic ileus (10.13), or obstruction (10.13), or peritonitis (6.2), or an anastomosis that is too narrow.
DIFFICULTIES [s7]WITH NASOGASTRIC TUBES If he is very WEAK, DEHYDRATED OR SHOCKED, the act of passing a tube may cause him to vomit and inhale his vomit. If so, lie him on his side, with his head tilted down, and pass a large stomach tube (30 Ch). If he vomits he will now do so under controlled conditions. Afterwards, pass a nasogastric tube.
If he develops PULMONARY COMPLICATIONS, these may in part be due to the discomfort of the tube: (1) causing ineffective coughing and (2) drying out his mouth by making nose breathing difficult.
If his NASAL CARTILAGES NECROSE (rare), you applied tape unwisely. Pressure is usually caused by an acute angulation of the tube.
If he develops OESOPHAGEAL EROSIONS, you may have been using too hard a tube. A large one may allow regurgitation through the cardiac sphincter and cause an erosive oesophagitis.