Tubes to Remove Contents (Suction Tubes)

Tubes placed in the gastrointestinal tract can be used to sample contents, to empty the stomach of content, or for decompression. Many such tubes are commonly available ( Table 87-2 ), and are generally larger in diameter with thicker walls. They are also more rigid and they do not collapse when suction is applied. Suction tubes are often made of polyurethane or polyvinyl chloride (PVC). PVC is rather firm and becomes less flexible and more brittle with exposure to gastric acid. The walls are not easily compressed or collapsed, and gastric content can be easily aspirated. PVC tubes are not recommended for tube feedings but may be used for medication administration. Some polyurethane tubes can be used for aspiration without collapsing. Silicon tubes are less suitable for suction.

Nasogastric or orogastric tubes also are used to remove stomach contents to examine the contents for diagnostic purposes, for example, gastric aspirate to detect blood or in preparation for a procedure such as endoscopy. Although commonly used in the past, gastric lavage is no longer considered routine in the treatment of poisoning or ingestions. Decompression with suction is required when there is obstruction, ileus, or pernicious vomiting. Prophylactic nasogastric decompression after abdominal surgery is no longer recommended. Straight drainage tubes have a single lumen and multiple distal ports. If the tube has a single lumen (e.g., Levin, Ewald) it may be left open for venting or attached to intermittent suction. Intermittent suction is used to prevent aspiration of gastric mucosa into the tube. Tubes suitable for aspiration and decompression may have a second lumen for venting. Double-lumen tubes (e.g., Salem Sump, Anderson, and Replogle) are used specifically for decompression and have a second lumen that allows in air during suction and thus prevents the gastric mucosa from being pulled into the tube ports ( Figure 87-1 ). They may be used with continuous or intermittent suction. Both single-lumen and double-lumen tubes should be reevaluated often for patency. Irrigation with air or water can help ensure an open lumen. The tube should be reevaluated periodically for possible migration beyond the pylorus or back into the esophagus.

Algorithm for enteric feeding.

Tubes are no longer designed for decompression of the small bowel and small bowel obstruction (Miller-Abbott, Harris). These are relatively more flexible than other tubes used for suction and have either a weighted tip or a balloon tip. The tubes are passed nasally and positioned in the small bowel, using endoscopy or fluoroscopy. They are usually left to drain. Some gastrojejunostomy tubes have two ports: one in the stomach and one in the small bowel. Nutrition and/or medications can be given into the small bowel (when appropriate) while there is decompression of the stomach.

When there is ongoing fluid loss from drainage of the stomach or small bowel, attention must be paid to fluid balance of the patient. Replacement of gastrointestinal losses and monitoring of electrolytes and urine output is necessary.

Tubes to Add Content (Feeding Tubes)

Ideally, all patients receive nutrition by mouth. However, when a child is unable to eat normally or when oral intake fails to meet nutritional needs for any reason, alternative modes of nutrient delivery are considered. Intravenous routes are used when gut failure is present. Conversely, it is axiomatic that “if the gut works, use it.” Enteral feedings by tube are advantageous in maintaining gut function, promoting mucosal integrity, and reducing infection. There are also advantages in terms of cost and ease of use. However, it should not be assumed that enteral nutrition is safer than parenteral nutrition in all patients. In addition, patients often require some combination of enteral feedings and parenteral nutrition support.

Enteral access allows the delivery of nutrients and medications into the gastrointestinal tract. Generally, feeding tubes have a smaller diameter and are softer than tubes used for decompression. They are most often made of polyurethane, silicon, or silicone elastomer. Polyurethane does not stiffen or discolor and permits a thinner wall construction. Silicone or silicone elastomer tubes are very soft and generally collapse when suction is used ( Figure 87-2 ). They frequently require a stylet to facilitate placement.

Typical “fine-bore” nasoenteric tube without stylus. The single-lumen marking helps to assess placement.

Many nasoenteric tubes have weights on the distal tip (see Figure 87-3 ). They come in several sizes, styles, and materials. Historically, weighted tips were thought to be advantageous when advancing a tube past the pylorus; however, research has shown similar rates of passage are achieved using unweighted tubes. Furthermore, it is not clear whether weighted tubes stay in place longer than unweighted tubes.

Nasoenteric tube with stylet and weighted tip.

Evaluation

There are a number of conditions that make oral feeding difficult or unsafe. In pediatrics, the provision of enteral feedings is often required because of an inability to swallow or progressive dysphagia. Patients with neurologic and neuromuscular disorders, head and neck malignancy, major trauma, or congenital anomalies often have normal gastrointestinal tracts but are unable to take adequate feeds orally. Supplemental enteral feeding may also be needed when the patient is unable to consume adequate nutrition orally because of illness or choice. Feeding tubes provide a means of delivering continuous feedings or unpalatable diets, which may be needed in a wide variety of disorders including cystic fibrosis, short bowel syndrome, severe gastrointestinal allergy, metabolic disorders, anorexia associated with malignancy, chronic diarrhea, intestinal hypomotility, chronic renal failure, intestinal lymphangiomatosis, Crohn’s disease, chronic cholestasis, or congenital heart disease. Some common indications and relative contraindications are noted in Table 87-3 and Box 87-1 . Feedings by tube pose risks to the child ( Box 87-2 ), and the potential benefits of nutrition must be evaluated in each patient. Careful patient selection and evaluation will minimize complications.

The decision to use an enteric tube requires a thoughtful analysis of the clinical situation, nutritional status and predicted needs, respiratory status, and prognosis of associated disease ( Figure 87-4 ). The indications, risks, potential benefits, and possible alternatives should be reviewed for each patient. All patients should have an evaluation to assess risk of aspiration and document the ability to protect the airway. Other factors to be considered include size of the patient, medical condition, surgical history, and presence of gastroesophageal reflux disease. The probable duration of treatment and the proposed type of feed need to be considered. Attention must be paid to the child’s developmental abilities, social situation, and growth potential ( Box 87-3 ). The evaluation is enhanced when a team of professionals is available to assess the child. The team may include oromotor specialists, dietitians, nurses, and social workers as well as gastroenterologists, surgeons, and the child’s primary doctor. If the tube feedings are to be relatively short term and take place while the child is in the hospital, the issues are often straightforward. If tube feedings are to be longer in duration and used at home or at an alternative site, the issues may be more complex. It is crucial to include the parents (and the patient, if appropriate) in the decision process.

Tube for Nasogastric suction. Note the thick wall and “sump” port.

Selection of enteral tubes is guided not only by composition ( Table 87-4 ) but also by patient comfort and tube performance. Multiple tubes are available, and the choice is influenced by product availability, local resources, and expertise and cost. Feeding tubes may be placed into the stomach or advanced beyond the pylorus. Transpyloric feeds are suggested when there is vomiting, gastroparesis, or a risk of aspiration. The benefit of transpyloric placement has not been clearly demonstrated. In some instances, patients may have more problems when fed directly into the small bowel and feedings are often delayed while awaiting passage of a transpyloric tube.

The anticipated duration of need for the tube is another consideration in selecting the route and type of enteral tube. Tubes can be divided arbitrarily into those best suited for short-term and those for long-term use. For short-term feedings, tubes are most often passed through the nose into the gastrointestinal tract. In special situations, orally placed tubes are also used. Nasoenteric tubes are readily available, relatively easy to place, less invasive, and less costly than surgically placed tubes. However, care must be taken when positioning the tubes, and they are easily displaced and must be monitored carefully. Use of an electromagnetically guided placement device for placement and monitoring of select tubes is helpful.

If long-term use is anticipated, a more permanent enterostomal tube is preferred. These are generally placed through the skin into the desired area of the gastrointestinal tract; a surgical procedure is required for placement. There is no consensus as to what is long term versus short term, although most agree that less than 4 weeks is short term and more than 8 to 12 weeks is long term.