Placement of Nasogastric Tube

Key Clinical Questions

What are the indications for nasogastric tube (NGT) placement?
What are the contraindications to NGT insertion?
What are the immediate and long-term complications associated with NGT insertion?
What is the best method for insertion of an NGT to minimize complications?
What are the standards of care for postinsertion confirmation of position of an NGT?

Case 119-1

A 69-year-old woman with a past medical history of diabetes mellitus type II, hypertension, and colon cancer, status post remote partial colectomy, developed abdominal pain, nausea, and bilious vomiting for the past twelve hours. Her vital signs were within normal limits with the exception of a heart rate of 110 beats per minute (bpm). She appeared uncomfortable, and her abdominal examination was notable for decreased bowel sounds with a succussion splash, mild guarding, and tenderness to palpation of the left and right lower quadrants without rebound. A CT scan of the abdomen reported a small bowel obstruction with a transition point in the distal ileum.

A nasogastric tube (NGT) was inserted through her nose with appropriate analgesia—auscultation of bubbling sounds in the epigastrium suggested correct placement in the stomach which was confirmed by chest x-ray. The NGT, which suctioned approximately 500 cc of yellowish-green bilious material, was subsequently attached to wall suction. Due to minimal drainage and resolution of her pain over the ensuing 3 days, her inpatient physicians removed the tube from her stomach and successfully advanced her diet.

Introduction

Nasogastric tube (NGT) insertion is a relatively common procedure performed in the hospital setting for a wide variety of indications, including enteral feeding, administration of drugs and other agents and gastric decompression after trauma or intestinal obstruction. The first use of a nasogastric tube is attributed to a 16th-century Italian professor of anatomy and surgery, Hieronymus Fabircius ab Aquapendent who used a silver tube for enteral feeding. Usually inserted at bedside, NGT placement enables early commencement of enteral feeding, thereby maintaining intestinal function even in critically ill patients. Traditionally, the nasogastric tube is a large tube that is inserted blindly through the patient’s nose until its tip lies approximately 10 cm below the gastroesophageal junction. For patients in whom feeding beyond the ampulla of Vater is preferable (eg, pancreatitis, gastroparesis), small-bore postpyloric feeding tubes are also available. Recent advances in endoscopic and feeding tube technology allow postpyloric tube placement, with simultaneous gastric decompression, via double-lumen nasogastric decompression and jejunal feeding tubes. These are placed using flexible transnasal endoscopes that can pass small-diameter (5–6 mm) feeding tubes over a guidewire.

Physiology

Nasogastric tubes have been used for decades in chronically ill patients to provide bolus enteral feeds on a temporary basis until a more permanent surgical gastrostomy can be carried out. In the 1960s, the invention of total parenteral nutrition (TPN) allowed another method of providing nutrition to critically ill patients. However, a growing body of literature supports the view that patient outcomes are better with enteral feeding than with TPN, with regard to infection rates, multiorgan failure, and mortality. Although the exact mechanism for reduced complications and associated benefits of enteral feeding are not completely understood, mucosal vulnerability induced by histologic changes in the intestinal mucosa (eg, atrophy of intestinal villi in parenterally fed rats) is considered to play a major role. Furthermore, there is evidence that the enteric nervous system and antigen stimulation of mucosal surfaces drives IgA defense. The actual processing of nutrients via the gastrointestinal tract appears to stimulate a complex series of responses which affect immunologic integrity. Please see Table 119-1 for key evidence based references for the proven benefits of enteral feeding.

Table 119-1 Evidence-Based Medicine: Key References for Proven Benefits of Enteral Feeding

Study	Methodology	Results	Limitations	Bottom Line
Lewis SJ, Egger M, Sylvester PA, Thomas S. Early enteral feeding versus “nil by mouth” after gastrointestinal surgery: systematic review and meta-analysis of controlled trials. BMJ. 2001;323:773.	Meta-analysis of RCTs comparing any type of enteral feeding started within 24 hours after surgery with nothing by mouth in elective gastrointestinal surgery.	11 studies with 837 patients. Early feeding reduced the risk of any type of infection (RR, 0.72; P = 0.036) and mean length of stay in hospital (number of days reduced by 0.84; P = 0.001).	Meta-analysis of 11 small, clinically heterogeneous, randomized trials of varying quality.	No clear advantage to keeping patients NPO after elective gastrointestinal resection. Early feeding may be of benefit.
Kudsk KA, Croce MA, Fabian TC, et al. Enteral vs parenteral feeding: Effects on septic morbidity following blunt and penetrating trauma. Ann Surg. 1992;215:503–513.	RCT of enteral vs parenteral feeding after blunt and penetrating trauma looking at effects on septic complications.	98 patients enrolled. Enteral group had fewer pneumonias, intra-abdominal abscesses, and line sepsis; and sustained significantly fewer infections per patient. Significantly fewer infections in patients with injury severity score >20 and abdominal trauma index >24.	Small study	Significantly lower septic morbidity in patients fed enterally after blunt and penetrating trauma; most significant benefit seen in the more severely injured patients.
Gramlich L, Kichian K, Pinilla J, et al. Does enteral nutrition compared to parenteral nutrition result in better outcomes in critically ill patients? A systematic review of the literature. Nutrition. 2004;20(10):843–848.	Meta-analysis of RCTs comparing enteral nutrition with parenteral nutrition in critically ill patients with respect to clinically important outcomes.	13 studies included. EN was associated with a significant decrease in infectious complications but not with any difference in mortality compared to PN. No difference in number of days on ventilator or length of hospital stay. Some cost-savings with enteral nutrition.	Meta-analysis of small trials	Use of EN as opposed to PN results in an important decrease in the incidence of infectious complications in the critically ill and may be less costly. EN should be the first choice for nutritional support in critically ill.
McClave SA, Chang W-K, Dhaliwal R, Heyland, DK. Nutrition Support in acute pancreatitis: a systematic review of the literature. J Parent Enter Nutr. 2006;30(2):143–156.	Meta-analysis of 27 RCTs of adult patients with acute pancreatitis.	Use of EN was associated with significant reduction in infectious morbidity and hospital length of stay but had no effect on mortality when compared with PN.	Meta-analysis of small, diverse trials.	Patients with acute severe pancreatitis should begin enteral nutrition early—this is new gold standard therapy. When PN is used, it should be initiated after 5 days.

Despite all of the beneficial effects of enteral feeding, it is important to remember that enteral feeding has its limitations. For example, it does not prevent microaspiration from oropharyngeal contents in the cognitively impaired patient. It is also associated with an increased risk of gastroesophageal reflux.

Indications for the Procedure

Nasogastric tubes may be placed for both diagnostic and therapeutic purposes (Table 119-2). Diagnostically, emergent examination of gastric aspirate provides essential information in clinical situations such as the source and severity of upper gastrointestinal bleeding and in poisoning when undigested tablets are identified. Therapeutically, in severe upper gastrointestinal bleeding, nasogastric intubation and suctioning can provide symptomatic relief and prepare for endoscopic visualization of the gastric and duodenal mucosa. In trauma settings, NGTs may prevent vomiting and aspiration and in cases of drug overdose, they are used to lavage or drain stomach contents. In small bowel obstruction, NGT placement will decompress the gastrointestinal tract proximal to the obstruction; however, NGTs should not be used for enteral feeding in complete obstruction. NGTs are commonly employed when patients are NPO due to temporary aspiration risk following stroke, and other neurologic states, for the purposes of administering medications as well as enteral feeding.

Table 119-2 Indications for Nasogastric Tubes

Nasogastric Tubes

Diagnostic indications:
- Sample gastric contents, especially in the assessment of GI bleeding
Therapeutic indications:
- Prevent vomiting and aspiration, especially in trauma settings
- Provide drainage and/or lavage in drug overdose or poisoning
- Drain gastric contents and decompress the stomach (gastric motor failure, partial small bowel obstruction, postoperative ileus, palliation in metastatic cancer)
- Introduce a passage into the GI tract for initial, less than 1 month, of enteral feeding

Post-pyloric Tubes

Enteral feeding in the setting of:
- Poor gastric emptying due to critical illness or from gastric motor failure
- Severe acute pancreatitis and other states where nasojejunal feeding tube positioning is required

An alternative method to the NGT of enteral feeding is the nasoduodenal/nasojejunal (postpyloric) tubes. Postpyloric feeding tubes are used in settings where it is desirable to feed beyond the ampulla of Vater. The main benefit of postpyloric tube placement is it bypasses the stomach, thereby, providing a large feeding capacity with less of a concern for aspiration in patients with poor gastric emptying. If the nasoenteric tube is placed more than 40 cm into the jejunum, past the ligament of Treitz, enteral feeding can be given without pancreatic stimulation which makes it useful in the management of severe acute pancreatitis. At the bedside, experienced personnel can place postpyloric tubes using bent guide wires in conjunction with a standard feeding tube. However, such techniques are less successful in critically ill patients and those with disturbed upper gastrointestinal motility and function in whom the feeding tube usually fails to pass beyond the ligament of Treitz. In such cases, an interventional radiologist or gastroenterologist can place a tube beyond the pyloris under radiographic guidance or endoscopically with guidewire exchange. Fully transnasal endoscopic procedures as well as double-lumen tube systems that include a proximal port for gastric decompression and a distal port for jejunal feeding have been developed.

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