ETCO2 Nasal Sampling Cannula: How It Works and When to Use

By Medical Supply Group | Published: 2026-10-26

Category: How-to Guides

Learn how an ETCO2 nasal sampling cannula works, when to use it, and step-by-step setup tips for accurate capnography in non-intubated patients.

Quick Answer

An ETCO2 nasal sampling cannula continuously draws exhaled gas from the nostrils to measure end-tidal carbon dioxide in non-intubated patients. Use it when you need reliable capnography without delivering supplemental oxygen.

Why Use a Dedicated Sampling Cannula Instead of a Standard Nasal Cannula

A standard nasal cannula delivers oxygen but does not reliably sample exhaled CO₂. A dedicated ETCO2 nasal sampling cannula has a separate sampling lumen that continuously aspirates gas from the nasal cavity, giving accurate capnography waveforms even when the patient breathes through their mouth.

The trade-off: these cannulas do not deliver oxygen. If your patient requires both oxygen and capnography, you need a combined nasal cannula that offers both functions. The ETCO2 Nasal Sampling Cannula Salter-Style® Pediatric Curved Prongs is designed purely for sampling, so it is ideal for monitoring patients who are already on a separate oxygen source or who do not need supplemental oxygen.

When to Choose a Pediatric Low-Flow Sampling Cannula

Pediatric patients have smaller airways and lower tidal volumes, which can make capnography challenging. A pediatric-specific sampling cannula with curved prongs, like the Salter-Style® model, helps maintain proper positioning and reduces the risk of dislodgment. The low flow rate of the sampling line is matched to the child's lower exhalation volume, preventing excessive aspiration that could dilute the sample.

Use this cannula for continuous monitoring during procedures, in the emergency department, or on the ward. It is not for patients who need high-flow nasal oxygen or who are intubated.

How to Set Up and Use an ETCO2 Nasal Sampling Cannula

1. Select the Correct Size: Choose a pediatric or adult size based on the patient's age and anatomy. The Salter-Style® Pediatric Curved Prongs are designed for smaller nares. Ensure the prongs fit snugly without causing pressure on the nasal septum. Common mistake: using an adult-size cannula on a child can cause poor seal and inaccurate readings.
2. Connect the Sampling Line to the Capnograph: Attach the Luer-lock or barbed connector on the sampling line to the port on your capnography monitor. Ensure the line is not kinked or occluded. Most monitors require a water trap to protect the sensor. Checkpoint: confirm the monitor shows a normal waveform before placing the cannula on the patient.
3. Position the Cannula on the Patient: Place the prongs into the patient's nostrils with the curve pointing downward. Adjust the head strap or ear loops so the cannula stays in place without sliding. The sampling port should be at the nares, not resting on the upper lip. Common mistake: if the cannula slips forward, the sampling port may draw room air instead of exhaled gas, causing a low or absent CO₂ reading.
4. Verify the Waveform and Adjust as Needed: Observe the capnography waveform. A normal waveform shows a rapid upstroke, a plateau, and a sharp downstroke. If the waveform is blunted or absent, check for leaks around the prongs, a blocked sampling line, or incorrect placement. Checkpoint: if the patient is mouth-breathing, gently close their mouth or use a nasal-oral sampling cannula designed for that scenario.
5. Monitor Continuously and Document Readings: Record ETCO₂ values and waveform shape at regular intervals per your facility's protocol. Note any changes that may indicate hypoventilation, hyperventilation, or airway obstruction. Common mistake: relying solely on the numeric value without interpreting the waveform can miss important clinical clues like rebreathing or airway obstruction.

Product Highlight

ETCO2 Nasal Sampling Cannula Salter-Style® Pediatric Curved Prongs 7 Foot Tubing Low Flow Rate: Non-flared capnography cannula for non-intubated patients, designed for ETCO₂ sampling without simultaneous oxygen delivery. This ensures that the capnography reading is not affected by supplemental oxygen flow, giving a clearer waveform for clinical decision-making.
ETCO2 Nasal Sampling Cannula Salter-Style® Pediatric Curved Prongs 7 Foot Tubing Low Flow Rate