Demand-Driven Method for Gas Delivery in a Dental Setting

Not Applicable

• Conditions: Nitrous Oxide; Dentistry; Comfort; Drug Administration, Inhalation; Feasibility; Drug Delivery System
• Interventions: Device: Demand-driven delivery method; Device: Free-flow delivery method

• Registration Number: NCT04305990
• Lead Sponsor: University of Toronto

Brief Summary

This study compares two methods of gas delivery in a dental setting: 1) demand-driven (DD) and 2) free-flow (FF).

Nitrous oxide and oxygen sedation (NOS) is a common form of minimal sedation for adult and paediatric patients undergoing dental procedures. In order for NOS devices to be utilized during dental treatment, dentists must be able to provide gas flow to the patient, and subsequently scavenge used and unused gasses. Gas delivery is via a nasal mask, since the oral cavity must be accessible to the dentist throughout treatment.

Current devices for NOS in the dental setting utilize a free-flow gas method, where nitrous oxide and oxygen are released continuously from their tanks. The flow rate is set by the dentist according to the patient's minute ventilation needs, and unused and exhaled gasses are scavenged via the nasal mask. The demand-driven gas flow method, where inspiration triggers gas flow, has been used successfully in other medical settings, such as in obstetrics, medical emergencies, and for patients with chronic obstructive pulmonary disease. However, in these settings the mask used covers both the nose and mouth, and patients can trigger the demand-driven method through inspiration of the nose or mouth. The demand-driven gas flow method has a significant gas-sparing advantage over the free-flow method. With a demand-driven method, the patient dictates the flow rate and gas is only delivered when they are inspiring, compared to the free-flow method which provide gas flow throughout inspiration and expiration. However, the demand-driven method have not been studied in a dental setting where flow can only be triggered through the nose. It is therefore unknown whether it is feasible or comfortable for patients to trigger a demand-driven method nasally when their mouth is open during dental treatment.

This study will aim to assess the feasibility and comfort of a nasal demand-driven gas delivery method utilizing 100% oxygen in healthy, adult participants in a simulated dental setting. If the device is feasible and comfortable with 100% oxygen in a simulated dental setting, future research can be conducted to assess its use for NOS for dental treatment.

Detailed Description

The study design is a within-subjects, single-blinded, randomized control trial. Participants will be randomzied to inspire 100% oxygen through their nose utilizing a demand-driven (DD) gas delivery method and a free-flow (FF) gas delivery method for 2 minutes each in a simulated dental setting.

The study will take place at the University of Toronto's Faculty of Dentistry Children's Clinic. Participants will be positioned supine in the dental chair. A child size, rubber bite block will be inserted with an attached capnography device to measure end-tidal carbon dioxide at the mouth. A double-mask nasal hood with disposable insert will be placed on the participant's nose. The participant will be instructed to breathe through their mouth for 1 minute. Baseline respiratory rate and presence/absence of end tidal carbon dioxide at the mouth will be obtained through the capnograph and recorded. The presence of carbon dioxide at baseline during mouth breathing will confirm that the capnograph is able to measure end-tidal carbon dioxide at the mouth.

The researcher will then open the envelope with the randomization plan for the participant and will indicate whether they will receive the FF or DD gas delivery method first. The gas delivery device will be attached to the nasal hood, and set to either DD or FF gas delivery method. Once the device is connected, the participant will be instructed to breathe through their nose for 2 minutes. During this time, respiratory rate, presence/absence of end tidal carbon dioxide at the mouth, and oxygen flow rate per minute will be observed and recorded. The absence of end-tidal carbon dioxide at the mouth during this testing phase will provide a verifiable measure that patients are breathing through their nose. After 2 minutes, the flow will be stopped and the bite block removed. The participant will be instructed to breathe through their mouth. The participant will then complete the VAS on comfort of breathing through their nose during the first gas flow delivery method. The bite block will then be reinserted, and the flow resumed using the second gas flow delivery method for 2 minutes. During this time, respiratory rate, presence/absence of end tidal carbon dioxide at the mouth, and oxygen flow rate per minute will be observed and recorded. After 2 minutes, the gas flow will once again be stopped and the bite block removed. The participant will be instructed to complete the VAS on comfort of breathing through their nose. The nasal hood will be removed. The participant will be debriefed to the order of gas flow received (DD or FF first) and the participant will then be dismissed.

Study Timeline

• Status Verified: 2020-03
• Study Start: 2020-03
• Study First Submitted: 2020-03-10
• Study First Submitted QC: 2020-03-11
• Last Update Submitted: 2020-03-11
• Study First Posted: 2020-03-12
• Last Update Posted: 2020-03-12
• Primary Completion: 2020-10
• Study Completion: 2020-10

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 100

Inclusion Criteria

1. Participants must be adults, 18 years of age or older.
2. Participants must be ASA I (a normal, healthy patient) or ASA II (a patient with mild systemic disease).

Exclusion Criteria

1. Participants who are ASA III (a patient with a severe systemic disease that is not life-threatening) or higher.
2. Participants who indicate they are claustrophobic.
3. Participants with nasal obstruction of both nostrils.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Demand-driven delivery followed by free-flow delivery	Demand-driven delivery method	Participants will inspire 100% oxygen through their nose with the gas delivery device set to a demand-driven delivery setting through a nasal hood for 2 minutes followed by inspiration of 100% oxygen through their nose with the gas delivery device set to a free-flow delivery setting through a nasal hood for 2 minutes.
Demand-driven delivery followed by free-flow delivery	Free-flow delivery method	Participants will inspire 100% oxygen through their nose with the gas delivery device set to a demand-driven delivery setting through a nasal hood for 2 minutes followed by inspiration of 100% oxygen through their nose with the gas delivery device set to a free-flow delivery setting through a nasal hood for 2 minutes.
Free-flow delivery followed by demand-driven delivery	Free-flow delivery method	Participants will inspire 100% oxygen through their nose with the gas delivery device set to a free-flow delivery setting through a nasal hood for 2 minutes followed by inspiration of 100% oxygen through their nose with the gas delivery device set to a free-flow delivery setting through a nasal hood for 2 minutes.
Free-flow delivery followed by demand-driven delivery	Demand-driven delivery method	Participants will inspire 100% oxygen through their nose with the gas delivery device set to a free-flow delivery setting through a nasal hood for 2 minutes followed by inspiration of 100% oxygen through their nose with the gas delivery device set to a free-flow delivery setting through a nasal hood for 2 minutes.

Primary Outcome Measures

Name	Time	Method
Comfort of the demand-driven gas delivery mechanism	Assessed immediately after breathing through each mechanism for 2 minutes	To assess patient comfort of breathing through their nose with the demand-driven gas delivery method vs the free-flow method. In order to assess comfort, the patient will report perceived comfort on a 100mm visual analog scale immediately after each device is turned on. We will test for non-inferiority in comfort of the demand-driven as compared to the free-flow delivery method.
Feasibility of the demand-driven gas delivery mechanism	Procedure (Assessed for the duration of time when the patient is breathing from either delivery system)	To assess whether it is feasible for participants to inspire 100% oxygen through a nasal hood when utilizing a demand-driven gas delivery mechanism when their mouth is open, in a simulated dental setting. In order to assess feasibility, we will monitor for the presence or absence end-tidal carbon dioxide at the mouth to confirm whether the patient is breathing through their nose or mouth. Absence of carbon dioxide at the mouth indicates the patient was able to trigger the mechanism and breathe through their nose.

Trial Locations

Locations (1)

University of Toronto, Faculty of Dentistry; 🇨🇦 Toronto, Ontario, Canada