NCLEX Review Guide: Gastrointestinal Tubes

Nasogastric (NG) Tubes

• Salem Sump tube is a double-lumen tube with a blue air vent (pigtail) that prevents vacuum buildup and mucosal damage during continuous suction.
• Levin tube is a single-lumen tube used for intermittent suction only to prevent mucosal trauma from continuous vacuum.
• Primary purposes include gastric decompression, medication administration, feeding, and gastric lavage.

Nasoenteric Tubes

• Dobhoff tubes are small-bore, flexible tubes designed for enteral feeding that extend beyond the stomach into the duodenum or jejunum.
• These tubes have weighted tips and require fluoroscopic or endoscopic placement verification before initial use.
• Used when gastric feeding is contraindicated due to high aspiration risk, gastroparesis, or gastric outlet obstruction.

Insertion Procedure

1. Measure tube length from nose to earlobe to xiphoid process (NEX method) for NG tubes
2. Position patient in high Fowler's position with neck slightly flexed to facilitate swallowing
3. Lubricate tip with water-soluble lubricant and insert through nares, directing toward ear
4. When tube reaches nasopharynx, instruct patient to swallow water while advancing tube
5. Verify placement before securing tube to nose with tape

Placement Verification Methods

• X-ray confirmation is the gold standard for initial placement verification, especially for small-bore feeding tubes.
• Aspirate gastric contents and test pH - gastric pH should be ≤5.5, while intestinal pH is typically >6.
• Auscultation method (listening for air injection sounds) is unreliable and not recommended as sole verification method.

Routine Care

• Secure tube properly to prevent migration, dislodgement, or pressure ulcers on nares.
• Provide frequent oral and nasal hygiene, including lubricating nares and rotating tape placement every 24 hours.
• Monitor tube patency by irrigating with 30mL normal saline every 4-6 hours or per facility protocol.
• Document tube output characteristics including color, consistency, amount, and pH.

Potential Complications

• Aspiration pneumonia from tube displacement or reflux - always verify placement before instilling anything.
• Electrolyte imbalances from excessive gastric drainage - monitor sodium, potassium, and chloride levels closely.
• Tube obstruction from medication residue or feeding formula - flush with warm water and use liquid medications when possible.
• Tissue trauma including nasal necrosis, esophageal perforation, or gastric ulceration from improper insertion or prolonged use.

NCLEX Success Strategies

• Always prioritize patient safety and airway protection when answering tube-related questions.
• Remember that verification of placement takes priority over all other interventions.
• Focus on complications that can be life-threatening: aspiration, electrolyte imbalances, and tissue perforation.

Quick Check Questions

• ☐ Can you identify the difference between Salem Sump and Levin tubes?
• ☐ Do you know the NEX measurement technique?
• ☐ Can you list three methods of tube placement verification?
• ☐ Do you understand when to use continuous vs intermittent suction?