Nasogastric and Orogastric (NG/OG) Tube Insertion

Confirm position before every use: the measured length, the gastric pH, and an X-ray whenever the pH fails or the patient is high risk.

A nasogastric (NG) tube goes in through the nose, past the nasopharynx and esophagus, and ends in the stomach. An orogastric (OG) tube goes in through the mouth. Both drain the stomach, deliver medications and carry feeds. The main source is NSW Health GL2023_001, written for conscious adults at the bedside. It says it may not extend to critical care, so intubated patients are covered only by its orogastric section. This page follows NSW and UK guidance. It has not been aligned to US practice.

How It Works

• Drainage: open it to free drainage and you relieve the distension. That also reduces vomiting risk.
• Medication and feeding: drugs and nutrition go in only after position is confirmed. Not before.
• Position check: the aspirate pH tells you whether the tip is sitting in acidic gastric fluid.
• Movement: tubes migrate. The exit-point mark is how you catch it.

Where It Fits

Paramedics, ED and ICU nurses and transport teams all place these at the bedside. Put one in the wrong structure, such as the airway, lung or cranium, and you can cause serious harm. That is why confirmation is a required step. It is not an optional check.

Indications

• Gastric decompression for distension, vomiting or ileus, including distension after bag-valve-mask ventilation (local protocol)
• Administration of enteral medications, after confirmation
• Enteral feeding, after confirmation and a documented direction to start
• Gastric lavage for ingested toxins, only with toxicology or poison-centre direction (NSW 1.2; see caution below)

Gastric lavage is not routine for poisoning. The AACT/EAPCCT position paper says it should not be done routinely, if at all. Only trained staff should do it, and only in rare, specifically indicated cases. Make that call with toxicology or the poison centre, and only once the airway is protected.

Absolute Contraindications

No absolute contraindication is listed when the tube is clinically indicated. Each condition below needs senior medical review before insertion. That clinician sets any timeframe (NSW 2.2.1).

Relative Contraindications & Cautions

The NSW list is not complete. It includes:

• Decreased consciousness or impaired airway protection: gag, cough or swallow reflexes are impaired, so the airway is less protected
• Suspected cervical spine injury: hyperflexing the neck may cause permanent damage
• Severe facio-maxillary trauma, nasal injury or possible base-of-skull fracture: the tube may end up in the cranium or trachea
• Active upper GI bleeding, regardless of cause
• Known esophageal varices or chronic liver disease: including recently banded varices
• Upper GI stricture or obstruction, or recent esophageal, gastric or head and neck surgery
• Recent head and neck radiation
• Plastic reconstruction of the mouth, nose or esophagus
• Desquamating mucosal disorders (toxic epidermal necrolysis, Stevens-Johnson syndrome), caustic injury, or inhalation or ingestion burns
• Facial or airway burns
• Bleeding diathesis or anticoagulation: INR and aPTT must be checked before insertion
• Thrombolysis: within 24 hours, or per local practice
• Artificial airway (endotracheal or tracheostomy tube): risk of inadvertent tracheal placement, with caution for an uncuffed tracheostomy (NSW 2.2.1, nasogastric section). For the OG route, NSW section 3 says the principles track the NG route closely, but insertion is timed after intubation by the clinician who intubates (3.2). So the experienced clinician who intubated usually places it. Confirm position by pH or X-ray before use.
• Recent endoscopically diagnosed peptic ulcer or severe reflux esophagitis

Abort / Stop Criteria

• Coughing, gagging, apnea, dyspnea, vomiting, aspiration or change in skin color
• Fall in oxygen saturation during or after passage
• Resistance that persists after withdrawing 1–2 cm and rotating (do not force)

Team Roles During the Procedure

• Operator: measures, passes the tube and stops for any warning sign
• Airway and monitoring: watches SpO₂, breathing and the patient's response during passage
• Confirmation clinician: tests the aspirate pH or orders the X-ray
• Recorder: documents the length, exit mark, confirmation result and time

Anatomic Difficulty

• Nasal history: ask about nasal injury, surgery or bleeding; choose the nostril with the better airflow
• Facial and skull: look for facial, nasal or skull-base injury before a nasal route
• Upper GI history: stricture, varices, recent surgery, ulcer or caustic ingestion

Physiologic Risk

• Airway protection: when the gag or swallow is impaired, aspiration risk climbs
• Coagulation: watch for anticoagulation or a bleeding disorder. INR and aPTT must be checked before insertion. If they cannot be obtained, treat anticoagulation as a bleeding risk and discuss it with medical direction.
• Neck: a suspected cervical spine injury needs medical direction before any hyperflexion

Site / Device Check

• Confirm the tube, lubricant and pH strips are present and in date
• If the tube has a guidewire, leave it in for insertion. Remove and discard it only after placement is confirmed and before first use; never reinsert it.

Equipment

• Feeding tube for feeds and medications, or a tube with a sump port for drainage (NSW 2.7.1), used with an enteral-specific connector such as ENFit
• Water-based lubricant (follow the product information)
• pH indicator strips with clear gradation markings; not litmus paper
• Syringe for aspiration and a drainage or collection set
• Securement device that avoids medical-device pressure injury
• Working high-pressure suction (Yankauer), an emesis basin, tissues and gloves

Sizing

NSW sets no sizes for children. Those come from the equipment sizing reference and local protocol. Length is never a guess. You measure it on the patient, every time.

Phase 1: Prepare

1. Confirm the indication and screen contraindications: check consciousness, airway protection, neck, facial and nasal injury, bleeding history and anticoagulation. Confirm the medical order.
2. Measure the NG length: from the tip of the nose to the earlobe, then to the midpoint between the xiphoid process and the umbilicus. Document it before insertion.
3. Select the nostril: occlude each nostril and use the one with better airflow.

Phase 2: Perform

4. Insert posteriorly: lubricate the tip, then advance along the floor of the nose, parallel to the septum and palate, toward the spine.
5. Advance to the nasopharynx: stop just past it and tilt the chin down slightly. If safe and not contraindicated, give a sip of water and ask the patient to swallow. For an obtunded, intubated or unsafe-to-swallow patient, omit the sip and swallow.
6. Advance during the swallow: let the tip follow the esophagus until the measured mark is reached. Stop and withdraw if the patient coughs.
7. Manage resistance: do not force. Withdraw 1–2 cm, then advance slowly while rotating toward the nearer ear.

Phase 3: Confirm & Secure

8. Secure the tube: use a securement technique that avoids pressure injury; document the exit-point centimeter mark at the nostril.
9. Confirm before use: aspirate and test pH, or order a chest X-ray. Do not use the tube until the result is documented.
10. Remove any guidewire: after confirmation and before use, remove and discard it. Never put a guidewire back into the tube.

Alternative Technique: Orogastric (OG) Tube

Go this way when the nasopharyngeal route is off the table, for example with a suspected base-of-skull fracture. An experienced member of the medical team decides and writes down why (NSW 3.1). The tube usually goes in once the airway is secured, by or under the supervision of a clinician experienced in OG insertion (NSW section 3).

1. Insert after the airway is secured: The clinician who intubates usually places the tube. A laryngoscope may be needed to see it pass (NSW 3.2).
2. Pass the tube through the mouth: before passage, set the insertion depth per local policy or the experienced clinician, because NSW GL2023_001 gives no pre-insertion OG length method. Advance the tube through the oral cavity and esophagus into the stomach, and stop for any warning sign as in the NG steps.
3. Read the mark at the teeth or gums: document the exit-point centimeter mark at this level (edentulous: gums) (NSW 3.3).
4. Secure it: if intubated, secure the OG tube to the endotracheal tube. If not intubated, secure it so it cannot dislodge (NSW 3.3).
5. Confirm it the same way as an NG tube: pH or X-ray, then use (NSW 3.3).

Primary Confirmation

Aspirate gastric fluid and test the pH on indicator strips with clear gradations. Under NSW GL2023_001 (2.6.1), a pH of 5 or less points to gastric placement. The UK HSSIB 2021 report does not endorse 5.5 as safe. It calls 5.5 the threshold of earlier guidance. It found no consistent evidence for any one cutoff, and it notes that some trusts use 4.0 or 5.0 (sections 2.2.2, 4.2.13–4.2.16). Local policy sets the cutoff, so use that one.

Secondary Confirmation

• Chest X-ray: required when no aspirate comes back, the pH is above 5, insertion was difficult, position is in doubt, or the patient is high risk (facial fracture, neurologic injury or abnormality, respiratory concern, absent or reduced gag reflex, or critically ill) (NSW 2.6.2). A radiologist must report the film, or an experienced physician must review it and confirm the tip sits below the diaphragm and in the stomach.
• Exit-point mark: record the centimeter mark at the nostril (or teeth/gums for OG) at insertion, then compare it on every check.

Where pH or X-ray Is Not Available

In the field or in transport, a tube without pH or X-ray confirmation stays unconfirmed. Hold all feeds and medications. Don't use the tube for enteral intake, and document it as unconfirmed. Arrange the X-ray at the receiving facility. Whether to drain before the X-ray is a local-protocol decision.

Ongoing Monitoring

• Check the exit-point mark and tube position at the frequency set by local protocol, and at handover, before feeds or medications, after any move, and after respiratory distress, vomiting or coughing (NSW 2.8.1)
• Observe for vomiting, nausea, coughing and signs of aspiration during feeds or drugs
• Stop feeds at once and notify medical direction if aspiration is suspected

Know these. NG and OG tubes have reported complications including tracheobronchial perforation, sinusitis, epistaxis, pneumothorax and intracranial insertion.

Pediatrics

NSW GL2023_001 excludes children, so its adult length method and pH cutoff do not apply here. For tube size, length and confirmation, follow the equipment sizing reference and local protocol. For weight-based drug use, see weight-based dosing. Airway context is in pediatric airway.

Pregnancy and Obesity

Pregnancy and obesity are outside what NSW GL2023_001 covers. Follow local protocol and medical direction.

Trauma and Cervical Spine

• Suspected base-of-skull or facial fracture: stay off the nasal route until medical direction is in. NSW 3.1 names the OG tube for when nasal placement is contraindicated
• Suspected cervical spine injury: hyperflexing the neck may cause permanent damage. Use the spinal precautions in local protocol

Anticoagulation and Thrombolysis

• Anticoagulated or coagulopathic: INR and aPTT must be checked before insertion. Prehospital, when they are unavailable, treat the patient as a bleeding risk and discuss it with medical direction.
• Thrombolysed within 24 hours: senior medical review, or per local practice (NSW 2.2.1)

Transport and Altitude

• Gas in the stomach expands as cabin pressure falls (Boyle's law). That is physics, not a recommendation. This page gives no altitude figures and cites no recommendation.
• Whether to decompress before flight is a local air-medical protocol decision.
• Confirm position again after each move or transfer (local protocol).

Immediate Aftercare

• Secure the tube and check the exit-point mark against the insertion mark
• Keep the head and shoulders elevated at least 30 degrees during feeds and for the period set by local protocol (NSW 2.7.2)
• Observe the patient's breathing, comfort and tolerance after placement

Ongoing Maintenance

• Check the mark and reconfirm position as local protocol requires, and after any move or dislodgement
• Flush a feeding tube at least every four hours with at least 30 mL water, and before and after medications (NSW 2.8.3)
• A vent lumen is for air only. Do not use it to instill or aspirate fluid, and keep it at a level where fluid does not backflow (NSW 2.8.3).
• Assess venting tubes for change after seven days, with the medical team (NSW 2.8.2)
• Assess and clean the nostrils; change adhesive tape every 24–48 hours (NSW 2.8.2)

Transport Considerations

• Reconfirm position after every move and before feeds or drugs
• Use the gas-expansion precautions in Special Populations for air transport
• Noise and vibration limit reliable checks; rely on the confirmation results already documented, and never on auscultation

Pearls

• Measure first: the length gets decided before the tube moves.
• Swallow helps when safe: during a swallow, the tip follows the esophagus.
• pH is only a first check: continuous feeds or acid suppression limit how useful it is.
• X-ray is indicative: a chest X-ray shows position only at the moment it is taken.

Common Pitfalls

• Forcing the tube → withdraw, rotate toward the nearer ear, and re-advance slowly.
• Listening for air → use the aspirate pH or an X-ray instead.
• Using litmus paper → use indicator strips with clear gradations.
• Feeding after an earlier check → reconfirm after any migration or move.