Which patient would benefit from a nasogastric tube?

Historical Perspective

Originally described by John Hunter in the eighteenth century as eel skin wrapped around whalebone, the NGT initially was used to feed liquid nutrients to the sick. The first description of a flexible tube (Levin tube) used to decompress the gastrointestinal (GI) tract after surgery was in 1921 by American gastroenterologist Dr. Abraham Louis Levin. In 1926 McIver hypothesized that postoperative abdominal distension resulted from swallowed air, which could be prevented by an indwelling NGT. Despite the lack of scientific evidence to support the benefit of routine prophylactic NGT use after GI tract and abdominal surgery, it remained common practice into the twenty-first century. Gerber and colleagues were the first to challenge prophylactic NGT use in 1958 when they published results showing that in their cohort of 600 patients with postoperative ileus, the half managed without an NGT had lower morbidity and mortality as well as fewer respiratory tract complications. Their data were nonrandomized but started the conversation that perhaps NGTs were not mandatory postoperatively. The first prospective randomized trial comparing patients with enteric anastomoses was published in 1984, and although it showed no difference in complication rates between patients with and without NGTs, it was limited by small sample size and too much heterogeneity.

Cheatham and colleagues published the first meta-analysis on the topic in 1995. Their study included 26 clinical trials (3964 patients) that compared the use of selective versus routine NGT decompression after elective laparotomy. Routine use was defined as an NGT placed preoperatively or intraoperatively that remained in place until an unspecified point in the patient’s postoperative course (usually return of bowel function, flatus, or decreased output). Selective use was defined as either no NGT used or an NGT placed intraoperatively but removed in the operating room or in the recovery room and replaced only if the patient developed the need for decompression clinically in the postoperative course. The authors demonstrated a significantly lower rate of overall complications as well as a decreased incidence of postoperative pneumonia, aspiration, and fever. There was no significant difference between groups in the incidence of anastomotic leak, wound infection, wound dehiscence, or LOS. The authors reported that 30.5 patients could be spared nasogastric decompression for every 1 patient who required NGT reinsertion postoperatively. The main limitation of their meta-analysis was that it included a large number of nonrandomized studies.

In the 20 years since that first meta-analysis, numerous randomized controlled trials and subsequent meta-analyses have repeatedly shown that prophylactic NGT decompression after surgery on the abdomen does not afford the benefits ascribed to it by surgical dogma. In fact, the majority of studies indicate that the liberal use of an NGT prolongs hospital postoperative LOS and actually increases the risk of certain complications, especially respiratory complications. A 2010 Cochrane review excluding laparoscopic abdominal surgery identified 37 studies (5711 patients) and showed that prophylactic NGT decompression is ineffective at (1) hastening return of bowel function, (2) decreasing risk of aspiration and subsequent pulmonary complications, (3) improving patient comfort by lessening abdominal distension, (4) protecting intestinal anastomoses from leakage, and (5) shortening hospital LOS. The use of NGTs also is associated with significant morbidity related to both placement and prolonged use, as well as significant patient discomfort.

Nasogastric tubes

NGT are widely used to provide enteral nutrition to patients with dysphagia, especially in the early period after stroke when rapid recovery is expected. Temporary use, no longer than 3–4 weeks, is recommended due to risk of mucosal injury and infection. Complications related to shortterm NGT use (under 2 weeks) are typically not serious and include discomfort, dislodgment, or gastrointestinal complications such as nausea or abdominal distention.51 Some controversy exists regarding the impact of NGT on swallow function, airway protection, and swallow rehabilitation.52,53 However, Leder SB and Suiter DM found no significant difference in airway protection for thin liquids or pureed solids with or without NGT.54

Nasogastric Tube Rehydration

Nasogastric (NG) rehydration is a potentially effective, safe, and cost-effective alternative to parenteral rehydration in children who refuse to take fluids orally in the quantity required for rehydration. In developing nations, NG hydration has been shown to be effective for severe dehydration as well.95 NG rehydration is accomplished by placement of an NG tube, with a 5-Fr feeding tube typically being adequate for children younger than 3 years. For comfort, the use of topical anesthetic or nebulized lidocaine (5 mg/kg diluted in NS) before insertion is recommended. A bolus of 50 mL/kg of electrolyte solution (e.g., Pedialyte [Abbott]) is administered by continuous infusion via an enteral feeding pump over a 3-hour period. Twenty-four-hour rehydration regimens (50 to 100 mL/kg for the first 10 kg of body weight and then 25 to 50 mL/kg for the remaining body weight) have also been proposed but seem to have equivalent outcomes to more rapid rehydration protocols.96 Unscheduled revisit rates are not significantly different compared with patients who have received IV rehydration. Additionally, NG hydration has been used for infants with bronchiolitis with hospital lengths of stay comparable to those receiving IV hydration, and also with better placement success.97 No study has evaluated the use of frequent, small boluses; however, experience with ORT would indicate that 5- to 10-mL parent-administered syringe boluses to equal 50 mL/kg would be an option in the event that a pump for continuous administration is unavailable.

POSTOPERATIVE COURSE

The nasogastric tube is left in place overnight. On the first postoperative day, a barium swallow is performed to exclude a perforation. If the findings are normal, the nasogastric tube is removed and the patient's diet is advanced slowly to thickened liquids. Patients are typically discharged on the second or third postoperative day. In the absence of dysphagia, the patient's diet may be liberalized after the first postoperative visit (typically 2 weeks after surgery). Routine endoscopic surveillance is recommended for all patients with achalasia because of the associated increased incidence of esophageal cancer.

Properties of NG and Feeding Tubes

Polypropylene is the material most commonly used for Levin and Salem sump NG tubes (Fig. 40.1), but it is too rigid for long-term use as a feeding tube. Polypropylene tubes are less likely to kink than others but are more capable of creating a false passage during placement. Latex (rubber) tubes are moderately firm, require greater lubrication for passage, are relatively thick walled, and induce a greater foreign body reaction than tubes made of other common materials. Latex, especially in latex balloons, deteriorates more rapidly than other materials.1

Foley catheters are primarily latex, although silicone Foley catheters are available for patients with latex allergies. Silicone tubes are thin walled, pliable, and nonreactive; however, the walls of silicone tubes are weaker and may rupture if fluid is introduced into a kinked tube.2 Polyurethane tubes are nonreactive and relatively durable. Rigidity varies from manufacturer to manufacturer, depending on the thickness of the tube. A stylet may aid in the passage of polyurethane and silicone tubes, but it increases rigidity and the potential for tissue dissection, especially with tubes that have a small distal end-bulb.3 Some feeding tubes have weights, which are usually made of tungsten and are nontoxic if released into the GI tract.

Percutaneous Gastrostomy

Nasogastric tubes are not suitable for long-term use because they are uncomfortable for patients and may become dislodged. Long-term tube feeding to the stomach or the jejunum can best be achieved by placing the tube percutaneously through the anterior abdominal wall directly into the lumen of the stomach. This can be done during open surgery, by laparoscopic techniques, by combined gastric endoscopy and surgery, and most simply by direct puncture under fluoroscopic guidance by the interventional radiologist. The interventional radiology technique is to inflate and distend the stomach with air injected down a nasogastric tube. The stomach pushes up against the anterior abdominal wall and displaces all other structures. The entry site is just below the left costal edge in line with the nipple. The procedure is performed using local anesthesia and moderate sedation. A needle is passed percutaneously into the distended air-filled stomach, which is easily seen fluoroscopically. T-fasteners are deployed through three separate needle punctures and are used to fix the stomach to the anterior abdominal wall. A fourth puncture is used to place a stiff guide wire into the stomach. Serially enlarging dilators are used over the wire to enlarge the tract. Finally, a 14-French self-retaining catheter is passed over the wire and provides access to feed the stomach.

POSTOPERATIVE COURSE

The nasogastric tube may be removed on the first postoperative day if the output is low. Once the nasogastric tube is removed, patients can be started on a clear liquid diet and advanced as tolerated. The Foley catheter should be removed early in the postoperative period as well. Early ambulation and regular use of an incentive spirometer should be encouraged. If stress-dose steroids are administered at the time of the operation, they should be tapered quickly in the postoperative period. Blood counts should be routinely monitored, especially in patients undergoing splenectomy for hematologic abnormalities. Leukocytosis and thrombocytosis are common and can persist for several months. Aspirin therapy should be started if platelet counts are greater than 1 × 106/mm3 because of the associated risk of thrombosis.

Tube Feeding

Nasogastric, gastrostomy, gastrojejunostomy, and jejunostomy tubes have all been used successfully to provide additional nutrition, fluids, and/or medications by intermittent bolus or continuous infusion. Indications for tube feeding include recurrent emesis, an oral intake that is less than recommended, and poor weight gain and growth. Tube feeding helps to minimize the risk of force feeding, and, despite caregivers' initial reluctance to agree to their insertion, tube feeding helps to relieve the stress that can accompany the meeting of nutritional requirements. Oral stimulation and nonnutritive sucking should be provided to infants who are totally dependent on tube feeding to help smooth their transition to oral feeding after successful transplantation. Using a multidisciplinary approach, several centers have reported transitioning all of their patients over to complete oral feedings within 2 to 6 months after successful transplantation,43–45 thereby illustrating that tube feeding need not preclude the development of normal oral feeding skills.

The choices of formula and feeding are guided by age, biochemistries, gastrointestinal function, fluid allowance, and, where possible, the consideration of monetary costs to the caregivers. Feedings are initiated and advanced according to pediatric guidelines46 and tolerance. Volumes and rates that are based on body weight help to avoid intolerance in patients who are underweight or small for their age (Table 48-1). Whenever possible, the volume of feeds should be minimized to optimize tolerance and keep the hours of feeding manageable within the child's daily schedule. Infants are preferentially given intermittent bolus feeds to maintain normal blood sugars. Continuous overnight feeds are generally avoided for infants as a result of an increased risk of vomiting and gastroesophageal reflux associated with uremia and the potential for aspiration; continuous feedings may be required if the patient's gastrointestinal tolerance of bolus feedings is poor. Continuous overnight feeds are generally preferred for children and adolescents to facilitate daytime hunger and oral intake.

Reported complications include emesis, obstruction, exit-site infection, tube displacement, and peritonitis.47–49 When vomiting and gastroesophageal reflux are not responsive to medical therapy, jejunal (gastrojejunostomy or jejunostomy) feeding or a fundoplication may be warranted.1 To decrease the risk of peritonitis, the placement of gastrostomy, gastrojejunostomy, and jejunostomy tubes should occur before or concomitant with insertion of a PD catheter, whenever possible.49–51 In particular, percutaneous endoscopic gastrostomy insertion after PD initiation carries a high risk for fungal peritonitis and potential PD failure. Suggested precautions for lowering the risk of peritonitis include antibiotic and antifungal prophylaxis, withholding PD for 2 to 3 days, and gastrostomy placement by an experienced endoscopy team.51

Equipment

The following equipment should be assembled:

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Nasogastric tube of proper diameter. Two types of NG tubes are in common use—the single-lumen tubes (Levin) and the double-lumen sump (Salem's sump) tubes. The single-lumen tubes are best for decompression, and the double-lumen sump tube is best for continuous lavage or irrigation of the stomach. Both may be used for either purpose. While sizes of catheters range from 10 F to 18 F, most adults require a 16 F to 18 F tube. The limiting factor is the size of the nostril or any deviation of the nasal septa.

Suction syringe (30 mL) with a catheter tip.

Suction tube and suction device (wall or portable suction).

Sterile lubricating jelly.

Glass of water and a straw.

Emesis basin.

Disposable latex gloves, goggles, and gown.

Hypoallergenic tape and benzoin.

Nasogastric Tube.

A nasogastric tube (NGT) is placed through the nostril down the esophagus to the stomach for liquid feeds to pass. It is generally used as a short-term alternative for nutritional intake.

Percutaneous Endoscopic Gastrostomy.

A percutaneous endoscopic gastrostomy is a tube inserted surgically with an endoscope through the mouth and into the stomach, exiting out through the stomach wall and dermis (Fig. 1-13).

Precautions for both feeding tubes include elevating the head of the bed to 30 degrees or greater while administering the tubes to prevent aspiration. Depending on the hospital guidelines, the therapist may be allowed to turn off the feeding before the therapy session, but it is recommended that the primary care nurse be consulted before doing so for patient safety (see Chapter 30).