Background
Gastric intubation via the nasal passage (ie, the nasogastric route) is a common procedure that provides access to the stomach for diagnostic and therapeutic purposes. A nasogastric (NG) tube is used for the procedure. The placement of an NG tube can be uncomfortable for the patient if the patient is not adequately prepared with anesthesia to the nasal passages and specific instructions on how to cooperate with the operator during the procedure.
Indications
Diagnostic indications for NG intubation include the following:
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Evaluation of upper gastrointestinal (GI) bleeding (ie, presence, volume)
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Aspiration of gastric fluid content
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Identification of the esophagus and stomach on a chest radiograph
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Administration of radiographic contrast to the GI tract
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Identification of cancer cells - In a study of patients with gastric cancer, gastric lavage cytology samples collected via an NG tube inserted preoperatively were examined for the presence (GL1) or absence (GL0) of cancer cells; GL1 was significantly associated with poor overall survival and progression-free survival [1]
Therapeutic indications for NG intubation include the following:
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Gastric decompression, including maintenance of a decompressed state after endotracheal intubation, often via the oropharynx.
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Relief of symptoms and bowel rest in the setting of small-bowel obstruction
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Aspiration of gastric content from recent ingestion of toxic material
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Administration of medication
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Feeding
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Bowel irrigation
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NG tube can be kept following corrosive ingestion for the development of a tract in the esophagus that subsequently can be used for balloon dilatation
Increased abdominal pressure from any cause predisposes patients to gastroesophageal regurgitation (GER), and NG tubes are used to prevent this in patients undergoing surgery with general anesthesia. Lai et al simulated increased abdominal pressure in 15 obese patients by means of laparoscopic pneumoperitoneum and Trendelenburg (LPT) positioning to assess whether NG tubes prevent GER. [2] Assessment was carried out via preinserted esophageal multichannel intraluminal and pH (MII-pH) monitoring. Thirteen patients (86%) developed GER while in the LPT position, indicating that preinserted NG tubes under general anesthesia are not likely to be protective in obese patients.
NG feeding is conventionally done preoperatively or postoperatively. After esophagectomy, however, a feeding jejunostomy is preferred to NG feeding. In a randomized controlled trial by Tao et al, 120 patients who underwent minimally invasive McKeown esophagectomy received either jejunostomy feeding (JF; n = 58) or NG feeding (NF; n = 62). [3] The two groups had similar rates of overall complications. In the first month after surgery, the JF group had a significantly higher body mass index (BMI): 23.6 ± 3.2 versus 20.9 ± 3.5. The JF group also had better global quality-of-life scores. Disease-free survival and overall survival were similar in the two groups.
Role in enhanced recovery after surgery (ERAS)
Although it has been traditional to place an NG tube (NGT) after all major GI surgical procedures for gastric decompression, many studies have shown that NG intubation is not mandatory in all cases. In a propensity score analysis of a prospective database (N = 1561), Venara et al compared patients who had an NG tube during colorectal surgery with those who did not. [4] The no-NGT group had significantly less postoperative nausea, better tolerance of early feeding, reduced postoperative morbidity, and fewer pulmonary complications; however, the risk of postoperative ileus was not significantly reduced in this group.
In a prospective observational study that included 201 patients undergoing pancreaticoduodenectomy, Kleive et al found that 45 patients (22.4%) required NGT reinsertion after the operation and 32 (15.9%) underwent a relaparotomy. [5] NGT reinsertion occurred in 26 of the patients who did not undergo a relaparotomy. The presence of a major postoperative complication was a risk factor for NGT reinsertion. Patients who required NGT reinsertion had a higher frequency of major postoperative complications and relaparotomy than those who did not. The authors concluded that routine use of an NGT after pancreaticoduodenectomy is not justified within an ERAS setting.
Contraindications
Absolute contraindications for NG intubation include the following:
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Severe midface trauma
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Recent nasal surgery
Relative contraindications for NG intubation include the following:
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Coagulation abnormality
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Esophageal varices (usually, a Sengstaken-Blakemore tube is introduced, but an NG tube can be used for lower-grade varices) or stricture
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Recent banding of esophageal varices
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Anastomosis in the esophagus and the stomach - Blind NG tube insertion has traditionally been contraindicated in certain procedures involving these anastomoses because of the fear of damage to the staple line; however, in an animal study of blind NGT advancement after sleeve gastrectomy performed via a flexible gastroscope, Fabian et al observed no sign of trauma to the staple line and no significant mucosal injury (there were several small petechiae of the gastric mucosa, none of which were of full thickness or penetrated the mucosa) [6]
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Alkaline ingestion (the tube may be kept if the injury is not severe)
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Equipment for nasogastric intubation.
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Aspiration of viscous lidocaine into a syringe.
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Instillation of viscous lidocaine 2%.
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Estimation of nasogastric tube length from nostril to stomach.
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Nasogastric tube lubrication with water-based lubricant.
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Patient flexing his neck and drinking water while a nasogastric tube is inserted.
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Auscultation over the stomach.
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Secured nasogastric tube.
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Nasogastric tube in lung.
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Nasogastric tube insertion.
