Nasogastric intubation refers to the process of placing a soft plastic nasogastric (NG) tube through a patient's nostril, past the pharynx and down the esophagus into a patient's stomach.
Nasogastric tubes are inserted to deliver substances directly into the stomach, remove substances from the stomach or as a means of testing stomach function or contents.
The most common purpose for inserting a nasogastric tube is to deliver tube feedings to a patient when they are unable to eat. Patients who may need a NG tube for feedings include: premature babies, patients in a coma, patients who have had neck or facial surgery or patients on mechanical ventilation. Other substances that are delivered through a NG tube may include ice water to stop bleeding in the stomach or medications to neutralize swallowed poisons.
Another purpose for inserting a nasogastric tube is to remove substances from the stomach. A NG tube is used to empty the stomach when accidental poisoning or drug overdose has occurred. A NG tube is used to remove air that accumulates in the stomach during cardiopulmonary resuscitation (CPR). It is used to remove stomach contents after major trauma or surgery to prevent aspiration of the stomach contents. Placing a NG helps prevent nausea and vomiting by removing stomach contents and preventing distention of the stomach when a patient has a bleeding ulcer, bowel obstruction or other gastrointestinal diseases.
A NG tube may be inserted to take samples of stomach contents for laboratory studies and to test for pressure or motor activity of the gastrointestinal tract.
Do not use force when inserting a NG tube. If resistance occurs, rotate and retract the tube slightly and try again. Forcing the tube can cause traumatic injury to the tissue of the nose, throat or esophagus.
Always check the tube positioning before giving feedings. If the tube is out of place the patient may aspirate the feeding solution into the lungs.
Keep the patient in an upright or semi-upright sitting position when delivering a tube feeding to enhance peristalsis and avoid regurgitation of the feeding.
Check patients who are receiving continuous feedings via a pump or gravity hourly or according to the medical settings policy, to assure that the tube is in position, the formula is flowing at the correct rate and the patient is comfortable with no signs of distention or distress.
Cap or clamp off the NG tube when not in use to prevent backflow of stomach contents or accumulation of air in the stomach.
If a patient has severe sinus conditions, nasal obstruction or has had facial surgery, it may be necessary to place a oral-gastric tube to avoid further nasal trauma.
If the amount of gastric aspirate is large prior to a bolus or intermittent feeding, notify the physician and follow the protocol of the medical setting for re-instilling the gastric aspirate. The feeding size may need to be decreased if the patient is not digesting it.
NG tube placement is meant to be a short-term solution for feeding problems. Patients that require long term tube feeding should have surgical placement of a gastrostomy tube or gastrostomy button. Long-term NG tube usage can cause nasal erosion, sinusitis, esophagitis, gastric ulceration, esophageal-tracheal fistula formation, oral infections and respiratory infections.
To insert a nasogastric tube, have the patient tilt his head slightly back and gently ease the lubricated tubing into the nares. As the tube rounds the bend into the throat, have the patient tilt his head forward into a neutral upright position, hold his breath and swallow. Gently rotate the tubing 180 degrees to redirect the curve of the tube. Ease the tubing down the throat past the closed epiglottis. Gravity and swallowing will help move the tube down the esophagus as you gently continue to advance the tube. The patient can assist by swallowing and can even take sips of water to help move the tubing down into the stomach. Advance the tubing until you reach the marker tape that you applied when measuring the distance to the patient's stomach. Secure the tubing with tape and check the tubing for placement. If the patient gags during the procedure, stop advancing the tube and allow the patient to rest. If the tubing comes out of the mouth, retract the tubing and try again. If the patient is unconscious, advance the tube between respirations to avoid placing the tube into the trachea. If the patient becomes cyanotic, coughs or displays any signs of respiratory distress, remove the tubing, allow the patient to rest and begin again.
Once the NG tube is inserted, there are several methods for checking tube placement. Ask the patient to talk. If the patient cannot make sound, the tube has passed through the vocal cords and into the trachea. Remove the tube and start again. If the patient can talk, use a flashlight to look into the patient's mouth to view the tubing. It should appear straight in the back of the throat with no coiling into the mouth. Next, connect a 30 or 60cc catheter tip syringe to the end of the NG tube and aspirate to see if stomach contents return into the tubing. Stomach aspirate is often clear or yellow appearing but this depends upon what is in the patient's stomach. Stomach aspirate has a pH of 1-4 and an effective way to establish that the tube is in the stomach is to check the pH of the aspirate. Methods for checking tube placement, however, vary according to the medical setting. Follow the medical setting policy for checking tube placement. Another, more traditional method for checking tube placement is to draw 10-20 cc of air into the syringe, place the stethoscope over the patient's stomach and quickly inject the bolus of air into the stomach. A whooshing sound should be audible through the stethoscope over the stomach if the tube is in the stomach. If the tube is in the esophagus or trachea, the air sounds will be absent or muffled. The most accurate way to check for tube placement is an x ray of the abdomen. The NG tube is radiographic and will show up clearly on the x ray. A chest x ray is rarely done for NG tube placement because of the cost, but if performed for other purposes the radiologist will usually note the positioning of the NG tube on the report.
Position the patient in bed with the head of the bed elevated 45-90 degrees and place a towel across the chest up to the patient's neck. Explain the nasal intubation procedure to the patient. Let them know that by holding their breath as the tube is passed through the pharynx, they will close off the airway and that if they swallow when instructed, it will help move the tubing down the esophagus into the stomach. Have the patient blow their nose to clear out the nasal passages and remove dentures if they have them. Question the patient about whether they have had sinus problems, nasal problems such as nosebleeds or nasal surgery in the past. Consult with the physician if the patient has a history of nasal problems. Select a nostril to use for intubation. Assemble the equipment needed, including a nasogastric tube, flash light, emesis basin, tissues, 30cc-60cc catheter tip syringe and irrigation set, a glass of water, water-soluble lubricant, clear plastic tape, a transparent dressing, stethoscope and gloves. Obtain a suction apparatus and connection tubing if the NG tube is to be used for suctioning the stomach. Prepare a piece of 1-inch tape that is cut horizontally half way through the piece of tape to make two tails. The uncut end will be placed along the patient's nose and the tails wrapped around the tube in opposite directions to secure the tube to the nose after insertion. Develop a hand signal with the patient so that they can ask to stop the procedure to let them rest if they are in distress during the procedure.
NG tubes are available in a variety of types, lengths and sizes. Large-bore tubes (some with a second lumen) are used for suctioning stomach contents. Small-bore tubing is used for feedings. Select the tube appropriate to the patient's size and the purpose for which the tube is being inserted. Wash the hands and put on gloves. Remove the tube from the packaging and uncoil it. Examine the tubing for flaws. Run some water through the tubing to check for leaks. To find the distance to the patient's stomach, use the tube to measure from the tip of the patient's nose back to the ear and then down to the tip of the sternum. Mark this place on the tube using a small piece of tape. Moisten the tip and first few inches of the tubing with water-soluble lubricant and lay it back into the packaging.
After correct positioning of the NG tube has been established, secure the NG tube to the nose with a second piece of plastic tape or use a transparent dressing to hold the tubing to the nose. The intent is to secure the tube so that it will not slip in or out, the method of securing the tube may vary according to the size of the patient, their type of skin and the amount of perspiration on the nose. Securing the other end of the NG tube to the patient's gown with a looped rubber band and safety pin can prevent accidental pulling on the NG tube as the patient moves around. The end of the NG tube should be plugged or clamped when not connected to suction or in use for feedings. Ongoing care of the patient with a NG tube includes encouraging good mouth care and cleansing the nares routinely. Change the tape position daily and examine the tissue around the nose and under the tape for signs of irritation or breakdown. Keep the head of the bed elevated 30 degrees at all times to decrease gastric reflux. Place the head of the bed 30-45 degrees during tube feedings and for 30-60 minutes after intermittent tube feedings if the patient can tolerate this position.
When a NG tube is used to administer tube feedings, they may be given by gravity or by pump. Tube feedings may also be given either intermittently or continuously. The physician will calculate the patient's nutritional needs within a 24-hour period and order the solution, frequency and rate of flow. Tube feedings are supplemented liquid nutrition and may be prepared by the dietary department in a medical setting or provided in prepared cans of formula (such as Ensure) that are manufactured for this purpose. There are a large number of formulas to select from according to the patient's nutritional needs. Be certain that the formula used for tube feeding exactly matches the physician's orders.
Intermittent tube feedings may be given using a large catheter tip syringe or a feeding bag. Check the position of the NG tube according to the policy of the medical center. Aspirate the stomach contents for residual formula from the last feeding. If the residual exceeds 100 cc for an adult, hold the feeding and notify the physician. Re-instill the gastric aspirate according to the policy of the medical center or the physician's order. Review the physician's order and select the appropriate type and amount of feeding. Be sure that the patient remains in an upright position during the feeding. Shake prepared formulas before administering them. Formulas that have been refrigerated should be allowed to warm up to room temperature before administering them. To give the feeding using a syringe, remove the barrel from the syringe. Open the end of the NG tube and connect it to the end of the syringe. Pour the feeding into the wide end of the syringe and hold or secure the syringe to the bed or an IV pole just above the patient's head so that it will flow in slowly by gravity over 15-30 minutes. If more feeding is needed than can be held in the syringe, watch the syringe and refill the syringe until the feeding is complete. When the feeding is complete, rinse the tube with 30 cc of water. Disconnect and recap the end of the NG tube and rinse the syringe according to the medical setting's policy. To give an intermittent feeding using a feeding bag, pour the correct feeding amount into the bag and through the tubing connected to the bag down to the tip of the tubing. Clamp the tubing using the roller clamp apparatus. Hang the bag on an IV pole just above the patient's head. Open the NG tube and connect it to the feeding bag tubing. Open the feeding bag roller clamp apparatus and adjust the flow rate to run the feeding in over the prescribed amount of time (usually 15-30 minutes). When the feeding is complete, purge the line by putting 30 cc of water into the bag and allowing it to flow in wide open. Clamp and disconnect the feeding bag tubing. Recap the NG tube. Rinse and reuse the feeding bag according to the medical center's policy. Feeding bags and syringes are usually replaced every 24 hours to prevent bacterial contamination.
Continuous tube feedings are given using a feeding bag with connected tubing and an automatic food pump to deliver the feeding at a specific rate of flow. Patients receiving continuous tube feedings should be kept in an upright position of 30-45 degrees to prevent reflux of formula. The feeding bag is filled with formula solution for no more than four hours and the pump is set at the flow rate that the physician has ordered. Check the NG tube for correct placement every four hours and aspirate the NG tube to check for formula residual. If the residual is1.5 times greater than the amount administered each hour, notify the physician. Re-instill the residual by gravity using a syringe and flush the line with 30-60 cc of water. Refill the formula bag for the next four hours. Observe the patient hourly to be sure that the patient is in no distress, the patient's abdomen is not distended, the formula is flowing at the correct rate and that the tubing connections are secure. Refill the bag as necessary or every four hours. The feeding bag and tubing should be changed according to the medical setting's policy, usually every 24 hours to prevent bacterial contamination.
The complications of nasogastric intubation may include:
- aspiration of the stomach contents leading to asphyxia, abscess formation or aspiration pneumonia;
- trauma injury including perforation of the nasal, pharyngeal, esophageal or gastric tissue
- pulmonary hemorrhage, empyema, pneumothorax, pleural effusion or pneumonitis from a malpositioned tube
- secondary infection in the sinus, throat, esophagus or stomach
- development of a tracheal-esophageal fistula
- erosion and/or necrosis of nasal, pharyngeal, esophageal or gastric tissue
The complications of nasogastric tube feedings may include:
- obstruction of the tube
- perforation of the tube
- tube migration out of correct position
- regurgitation and aspiration of the feeding
- nausea and vomiting
- abdominal distention, cramping and discomfort from too much feeding or a rate of feeding that is too rapid
- any of the complications listed above in the complications of nasogastric intubation
Empyema collection of pus in the lung cavity.
Fistula passageway or connecting duct that is abnormal and connects body cavities or tissues that should not be connected. Fistulas develop as the result of injury, disease or congenital deformity.
Gastrostomy button soft plastic apparatus with a button closure that is surgically inserted and sutured onto the surface of the abdomen. The gastrostomy button is placed in a surgical opening that leads from the stomach to the surface of the abdomen and is used for long term tube feedings in patients who cannot eat to prevent malnutrition.
Gastrostomy tube soft plastic tube that is inserted and sutured into a surgical opening that leads from the stomach to the surface of the abdomen. A gastrostomy tube is used for long term tube feedings in patients who cannot eat to prevent malnutrition.
Peristalsisuscular contractions of the gastrointestinal tract that move food, fluids and refuse in a wave-like motion through the system.
Reflux backward flow of food or fluid from the stomach into the esophagus.
Regurgitation vigorous reversed flow of the stomach contents up the esophagus and out of the mouth.
The use of a nasogastric tube for feedings can effectively prevent malnutrition in the patient who is unable to eat. A nasogastric tube is also an effective temporary measure for decompression and removal of stomach contents and free air in a variety of gastrointestinal illnesses, major trauma, or surgery.
Health care team roles
Nasogastric intubation is usually performed by a licensed nurse or physician in the medical setting. Paramedics or other emergency personnel may receive special training to insert NG tubes as appropriate in the field. Patients' families may be trained to insert or change nasogastric tubes in the home setting if a patient is discharged with a NG tube in place. It is unusual, however, to continue NG tube feedings in the home setting. Most patients who require long-term tube feedings will have a gastrostomy tube or gastrostomy button placed for feedings.
Tube feedings are usually administered by a licensed nurse in the medical setting. Non-licensed personnel may receive special training to start, stop or check tube feedings under the direction of a licensed nurse in some medical settings. Patients and patients' families may be taught by a licensed nurse to administer tube feedings in the home. Patients receiving tube feedings in the home should be monitored by visiting nurses or undergo frequent medical check-ups to assess the their responses to the feedings and the their ongoing nutritional needs.
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Mary Elizabeth Martelli, R.N., B.S.
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