NURSING MANAGEMENT OF PATIENTS UNDERGOING NASOGASTRIC OR NASOENTERIC INTUBATION
Nursing interventions include the following:
• Instructing the patient about the purpose of the tube and the procedure required for inserting and advancing it
• Describing the sensations to be expected during tube insertion
• Inserting the NG tube and assisting with insertion of the nasoenteric tube
• Confirming the placement of the NG tube
• Advancing the nasoenteric tube
• Monitoring the patient and maintaining tube function
• Providing oral and nasal hygiene and care
• Monitoring for potential complications
• Removing the tube
Before the patient is intubated, the nurse explains the purpose of the tube; this information may assist the patient to be coopera-tive and tolerant of what is often an unpleasant procedure. The general activities related to inserting the tube are then reviewed, including the fact that the patient may have to breathe through the mouth and that the procedure may cause gagging until the tube has passed the area of the gag reflex.
Before inserting the tube, the clinician determines how much tubing will be needed to reach the stomach or the small intestine. A mark is made on the tube to indicate the desired length. This length is determined by measuring the distance from the tip of the nose to the earlobe, and from the earlobe to the xiphoid process, then adding 6 inches for NG placement or 8 to 10 inches for intestinal placement (Fig. 36-3).
While the tube is being inserted, the patient usually sits up-right with a towel spread bib-fashion over the chest. Tissue wipes are made available. Privacy and adequate light are provided. The physician may swab the nostril and spray the oropharynx with Cetacaine (tetracaine/benzocaine) to numb the nasal passage and suppress the gag reflex.
This makes the entire procedure more tol-erable. Having the patient gargle with a liquid anesthetic or hold ice chips in the mouth for a few minutes can have the same effect. Encouraging the patient to breathe through the mouth or to pant often helps, as does swallowing water, if permitted.
A polyurethane tube may need to be warmed to make it more pliable. To make the tube easier to insert, it should be lubricated with a water-soluble substance (K-Y jelly) unless it has a dry coat-ing called hydromer, which, when moistened, provides its own lubrication. The nurse wears gloves during the procedure.
The patient is placed in Fowler’s position, and the nostrils are inspected for any obstruction. The more patent nostril is selected for use. The tip of the patient’s nose is tilted, and the tube is aligned to enter the nostril. When the tube reaches the nasopharynx, the patient is instructed to lower the head slightly and to begin to swallow as the tube is advanced. The patient may also sip water through a straw to facilitate advancement of the tube. The oropharynx is inspected to ensure that the tube has not coiled in the pharynx or mouth.
To ensure patient safety, it is essential to confirm that the tube has been placed correctly, particularly because tubes may be acci-dentally inserted in the lungs, which may be undetected in high-risk patients. Examples of high-risk patients are those with a decreased level of consciousness, confused mental state, poor or absent cough and gag reflexes, or agitation during insertion. Pres-ence of an endotracheal tube and recent removal of an endotra-cheal tube also increase the risk for inadvertent placement of the tube in the lung (Metheny, 1998). Initially, an x-ray study should confirm tube placement. However, each time liquids or medica-tions are administered, and once a shift for continuous feedings, the tube must be checked to ensure that it remains properly placed. The traditional recommendation has been to inject air through the tube while auscultating the epigastric area with a stethoscope to detect air insufflations. However, studies indicate that this auscultatory method is not accurate in determining whether the tube has been inserted into the stomach, intestines, or respiratory tract (Metheny et al., 1999). Instead of the auscul-tation method, a combination of three methods is recommended:
• Measurement of tube length
• Visual assessment of aspirate
• pH measurement of aspirate
After the tube is inserted, the exposed portion of the tube is measured and the length is documented. The nurse measures the exposed tube length every shift and compares it with the original measurement. An increase in the length of exposed tube may in-dicate dislodgement, or a leaking or ruptured balloon if the tube has a balloon.
Visual assessment of the color of the aspirate may help iden-tify tube placement. Metheny et al. (1994) found that gastric as-pirate is most frequently cloudy and green, tan or off-white, or bloody or brown. Intestinal aspirate is primarily clear and yellow to bile-colored. Pleural fluid is usually pale yellow and serous, and tracheobronchial secretions are usually tan or off-white mucus. Researchers suggest that the appearance of the aspirate may be helpful in distinguishing between gastric and intestinal placement but is of little value in ruling out respiratory placement. This method is less helpful when the patient is receiving continuous feedings, because aspirate often looks like the formula that is used for the feeding (Metheny & Titler, 2001).
Determining the pH of the tube aspirate is a more accurate method of confirming tube placement. The pH method can also be used to monitor the advancement of the tube into the small intestines. The pH of gastric aspirate is acidic (1 to 5). The pH of intestinal aspirate is approximately 6 or greater, and the pH of respiratory aspirate is more alkaline (7 or greater). pH testing is best suited for distinguishing between gastric and intestinal placement. A pH sensor enteral tube is available which does not require fluid aspirate to obtain pH values; it can be useful in dis-tinguishing gastric from small bowel placement of the tube. The pH method is less helpful with continuous feedings, because tube feedings have a pH value of 6.6 and neutralize the GI pH (Metheny & Titler, 2001). For more information, see Nursing Research Profile 36-1.
Using gastric aspiration as a means of verifying that the NG tube has been placed correctly may be a problem because of the characteristic properties and diameter of the tubes. Studies suggest that aspiration may be performed more easily with polyurethane tubes and tubes with a size 10 Fr diameter. Metheny et al. (1993) recommended the following steps if problems occur with aspira-tion of fluid from small-bore feeding tubes:
i) Insufflate 20 mL of air through the tube with a large syringe (30 to 60 mL).
ii) Pull back on the plunger.
iii) If step 2 is ineffective, insufflate another 20 mL of air and re-place the large syringe with a smaller one (12 mL); attempt to aspirate.
iv) If the measure is still ineffective, repeat step 3.
v) Change the patient’s position and attempt to aspirate.
After the correct position of the tip has been confirmed, the NG tube is secured to the nose (Fig. 36-4). A liquid skin barrier should be applied to the skin where the NG tube will be secured. The prepared area is covered with a strip of hypoallergenic tape or Op-site; the tube is then placed over the tape and secured with a second piece of tape. The nasoenteric tube can be secured by taping it to the forehead (see Fig. 36-4). This keeps the tube from dislodging when the patient moves but still allows it to pass into the intestine. Instead of tape, a feeding tube attachment de-vice (Hollister) can be used to secure the tube. This device ad-heres to the nose and uses an adjustable clip to hold the tube in place (Fig. 36-5). After the nasoenteric tube has progressed into the intestine (after approximately 24 hours), the tube may be taped in place.
After the tube has passed through the pyloric sphincter, it may be advanced 5 to 7.5 cm (2 to 3 in) every hour. To enable gravity and peristalsis to assist in the passage of the tube, the patient is generally asked to lie in the following positions in this order: on the right side for 2 hours, on the back for 2 hours, and then on the left side for 2 hours. Ambulation, if possible, also helps ad-vance the tube. If the tube is advanced too rapidly, it will curl and kink in the stomach. The tube is irrigated with normal saline so-lution every 6 to 8 hours to prevent blockage.
If the NG tube is used for decompression, it is attached to inter-mittent low suction. If it is used for enteral nutrition, the end of the tube is plugged between feedings. The nurse confirms tube placement before any fluids or medications are instilled and once a shift for continuous feedings. Displacement of the tube may be caused by tension on the tube (when the patient moves around in the bed or room), coughing, tracheal or naso-tracheal suctioning, or airway intubation. If the NG tube is re-moved inadvertently in a patient who has undergone esophageal or gastric surgery, it is replaced by the physician, usually under fluoroscopy to avoid trauma to the suture line.
It is important to keep an accurate record of all fluid intake, feedings, and irrigation. To maintain patency, the tube is irri-gated every 4 to 6 hours with normal saline to avoid electrolyte loss through gastric drainage. If an automatic flush enteral pump is used, the flushing schedule may be altered. The nurse records the amount, color, and type of all drainage every 8 hours.
When double- or triple-lumen tubes are used, each lumen is labeled according to its intended use: aspiration, feeding, or bal-loon inflation. To avoid tension on the tube, the portion of the tube from the nose to the drainage unit is fixed in position, either with a safety pin or with adhesive tape loops that are pinned to the patient’s pajamas or gown. The tube must be looped loosely to prevent tension and dislodgement (see Fig. 36-4).
Regular and conscientious oral and nasal hygiene is a vital part of patient care, because the tube causes discomfort and pressure and may be in place for several days. Moistened cotton-tipped swabs can be used to clean the nose, followed by cleansing with a water-soluble lubricant. Frequent mouth care is comforting for the pa-tient. The nasal tape is changed every 2 to 3 days, and the nose is inspected for skin irritation. If the nasal and pharyngeal mucosa areexcessively dry, steam or cool vapor inhalations may be beneficial. Throat lozenges, an ice collar, chewing gum, or sucking on hard candies (if permitted), and frequent movement also assist in relieving patient discomfort. These activities keep the mucous membranes moist and help prevent inflammation of the parotid glands.
Patients with NG or nasoenteric intubation are susceptible to a variety of problems, including fluid volume deficit, pulmonary complications, and tube-related irritations. These potential com-plications require careful ongoing assessment.
Symptoms of fluid volume deficit include dry skin and mucous membranes, decreased urinary output, lethargy, and decreased body temperature. Assessment of fluid volume deficit involves maintaining an accurate record of intake and output. This in-cludes measuring NG drainage, fluid instilled by irrigation of the NG tube, water taken by mouth, vomitus, water administered with tube feedings, and intravenous (IV) fluids. Laboratory values, particularly blood urea nitrogen and creatinine, are monitored. The nurse assesses 24-hour fluid balance and reports negative fluid balance, increased NG output, interruption of IV therapy, or any other disturbance in fluid intake or output.
Pulmonary complications from NG intubation occur because coughing and clearing of the pharynx are impaired, because gas buildup can irritate the phrenic nerve, and because tubes may become dislodged, retracting the distal end above the esopha-gogastric sphincter. Medications (antacids, simethicone, and metoclopramide) are administered to decrease potential prob-lems. Signs and symptoms of complications include coughing during the administration of foods or medications, difficulty clearing the airway, tachypnea, and fever. Assessment includes regular auscultation of lung sounds and routine assessment of vital signs. It is important to encourage the patient to cough and to take deep breaths regularly. The nurse also carefully confirms the proper placement of the tube before instilling any fluids or medications.
Irritation of the mucous membranes is a common complica-tion of NG intubation. The nostrils, oral mucosa, esophagus, and trachea are susceptible to irritation and necrosis. Visible areas are inspected frequently, and the adequacy of hydration is assessed. When providing oral hygiene, the nurse carefully inspects the mucous membranes for signs of irritation or excessive dryness. The nurse palpates the area around the parotid glands to detect any tenderness or enlarged nodes, indicating parotitis, and ob-serves for any skin or mucous membrane irritation or necrosis. In addition, it is important to assess the patient for esophagitis and tracheitis; symptoms include sore throat and hoarseness.
Before removing a tube, the nurse may intermittently clamp and unclamp the NG tube for a trial period of 24 hours to ensure that the patient does not experience nausea, vomiting, or distention. Before the tube is removed, it is flushed with 10 mL of normal saline to ensure that it is free of debris and away from the gastric lining; then the balloon (if present) is deflated. Gloves are worn to remove the tube. The tube is withdrawn gently and slowly for 15 to 20 cm (6 to 8 in) until the tip reaches the esophagus; the remainder is withdrawn rapidly from the nostril. A nasointestinal tube is withdrawn at intervals of 10 minutes until the end reaches the esophagus. If the tube does not come out easily, force should not be used, and the problem should be reported to the physician. As the tube is withdrawn, it is concealed in a towel, because the sight of it may be unpleasant to the patient. After the tube is re-moved, the nurse provides oral hygiene.