By Rose Dodson, MSc, CEO; Sedation Resource, Inc.

Let’s Talk About Capnography in Dental Offices

Capnography stands out as an essential monitoring tool that is reshaping patient safety in dental practices, especially during sedation. Whether you are a seasoned dentist or a dental assistant looking to broaden your expertise, understanding how to use this monitoring tool can greatly enhance patient care.

This guide is tailored for the entire dental team, combining fundamental capnography principles with practical application. It is designed to bring clarity to this valuable technology and aims to equip every team member with the knowledge to effectively utilize capnography for enhanced patient monitoring and care.

The Role of Capnography in Monitoring Sedated Patients

Capnography measures the carbon dioxide that comes out when a patient exhales, giving us forewarning if they start having trouble while sedated. It is like getting a play-by-play of their breathing, which helps us evaluate how well their lungs are working when viewing the waveform patterns on the monitor’s screen. However, this is predicated on having accurate readings.

Overcoming the Challenge of Moisture

When a patient breathes out, there is always a bit of moisture mixed in with the air. Capnography devices require a moisture-free sample of breath to accurately measure CO2 levels. Each monitor has its own method of accomplishing this, either via a moisture trap or dehumidification tube. This not only ensures that the readings we get are accurate, but also helps in protecting the internal CO2 device from moisture exposure, which can extend the lifespan of the monitor.

The Right Sampling Strategy

Selecting the right sampling line is an important aspect of effectively monitoring CO2 levels. It is imperative to select the correct sampling lines based on your method of administering oxygen.

Oxygen Delivery via a Nitrous Hood

  • Nasal Sampling Cannula: The most accurate CO2 measurements for non-intubated anesthesia, like moderate sedation, are achieved with a nasal sampling cannula. When using nitrous oxide, this cannula’s thin-walled design allows it to fit comfortably under the hood.
  • Straight Sampling Line Alternatives:
    Trimming Method: Carefully maneuver the sampling line to run it alongside the nitrous hood. Then, tuck it under the nostril to ensure it is exposed to the patient’s exhaled breath, allowing the monitor to accurately detect CO2 levels.
    Hood Puncture Method: Make a round opening in the nitrous hood for a nitrous hood adapter. Once the adapter is in place, the male luer on the sampling line can be securely attached to the female luer of the adapter.
    Inline Adapter: More recently, plastic adapters have been developed specifically to work with nitrous hoods. These are available in single lumen and double lumen formats.

Each option is tailored to effectively gather CO2 levels, while prioritizing the patient’s comfort during the entire sedation procedure. It is important to understand that scavenging can affect the monitor’s ability to capture a sample of the patient’s breath.

Oxygen Delivery via a Cannula

The ideal configuration for administering oxygen and monitoring CO2 during sedation involves a cannula designed with a two-tube system. One tube connects to the oxygen supply, and the other attaches to the water trap on the capnography monitor.

Each prong of the cannula serves a specific purpose: one delivers oxygen, and the other samples the exhaled air. This arrangement prevents the mixture of fresh oxygen with exhaled CO2, ensuring a clear and accurate assessment of the patient’s breathing.

While some cannulas aim to deliver oxygen and measure CO2 through both nostrils simultaneously, this can sometimes compromise the accuracy of the CO2 readings. A cannula that separates these functions, assigning one to each nostril, ensures the patient receives consistent oxygen flow and CO2 measurements are as accurate as possible, which is crucial for patient care during sedation.

The Importance of Calibration

Calibrating your capnography monitor is like setting a scale to zero before you weigh something—it makes sure the readings are on point. Even though most monitors adjust themselves from time to time, doing a quick calibration check before each patient can make your equipment last longer and give you better results. It is a simple step, but it makes all the difference in getting accurate information for every case.


Capnography is an indispensable tool in the dental office, especially when providing sedation. It empowers both dentists and dental assistants with immediate feedback on the patient’s breathing and, ultimately, their safety. Embracing this technology means embracing a commitment to the highest level of patient care.

Sedation Resource, Inc. is dedicated to supporting dental professionals in providing safe and effective care with the help of advanced monitoring technologies.