Feasibility and Safety Properties of Metabolic Flow Anesthesia Driven by Automated Gas Control in Pediatric Patients

Study Overview
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Brief Summary
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Low flow anesthesia was considered to be causing rebreathing, hypoxia and hypercarbia in the past. However, developing technologies made anesthesia ventilators safer. Low flow anesthesia is proved to be safe and cost-effective for almost a decade, and newer anesthetic machines with automated gas flow and metabolic flow anesthesia (<0.3 L/min gas flow) features are now becoming prominent. The literature still lacks of pediatric data regarding the cost analysis and safety profile of low flow and especially in metabolic flow anesthesia. In this study, it is aimed to observe inhaled agent expenditure of automated gas flow anesthesia which reaches metabolic flow limits in pediatric patients. For that, automated gas flow will be set to provide a desired end-tidal sevoflurane concentration during general anesthesia. Accordingly, inspired fraction of oxygen and air values will be recorded in 15-minute intervals. Primary outcome will be the inhaled agent (sevoflurane) amount wasted in milliliters for both inhaled agent maintenance speed (8-fast and 4-slow). Secondarily, delta value of set and detected inspired fraction of oxygen (DeltaFiO2=DetectedFiO2-SetFiO2) will be analyzed. DeltaFiO2 higher than 5 units will be accepted as unsafe gas mixture, and the incidence will be evaluated. Secondary outcomes will also include duration of emergence from anesthesia including both extubation and obeying verbal commands.

Official Title
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Feasibility and Safety Properties of Metabolic Flow Anesthesia Driven by Automated Gas Control in Pediatric Patients

Conditions
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Anesthesia

Intervention / Treatment
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* Procedure: Speed 8 (Fast balancing gas flow)
* Procedure: Speed 4 (Medium speed balancing gas flow)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Pediatric surgery patients Elective or Semielective surgeries Patients suitable for inhalation anesthesia Exclusion Criteria: Emergency surgery Patients who are contraindicated for inhalation anesthesia

Ages Eligible for Study
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Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Screening
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Automated Gas Flow Group using speed 8 to reach targeted end-tidal sevoflurane concentration<br>Pediatric patients who are operated under general anesthesia using automated gas flow which is set to speed 8 to achieve targeted end-expiratory sevoflurane concentration (MAC 1.2) will be included in the study. Automated gas flow provides a gas mixture in different proportions which is automatically generated and consists of sevoflurane, oxygen and air. Inspired and end-tidal concentrations of sevoflurane, oxygen and air will be available on the anesthesia ventilator screen which will be recorded accordingly in15-minute intervals. | Procedure: Speed 8 (Fast balancing gas flow)<br>* General anesthesia will be induced via intravenous agents, and anesthesia maintenance will be provided via inhalation for all the patients. The maintenance will be provided with sevoflurane using automated gas flow with the selected speed of 8. The anesthesia machine indicates amount of sevoflurane inhaled, inspired and exhaled oxygen, carbon dioxyde, air and sevoflurane concentrations. Accordingly these data and actual flow rate will be recorded every 15 minutes.<br>|
| Active Comparator: Automated Gas Flow Group using speed 4 to reach targeted sevoflurane concentration<br>Pediatric patients who are operated under general anesthesia using automated gas flow which is set to speed 4 to achieve targeted end-expiratory sevoflurane concentration (MAC 1.2) will be included in the study. Automated gas flow provides a gas mixture in different proportions which is automatically generated and consists of sevoflurane, oxygen and air. Inspired and end-tidal concentrations of sevoflurane, oxygen and air will be available on the anesthesia ventilator screen which will be recorded accordingly in15-minute intervals. | Procedure: Speed 4 (Medium speed balancing gas flow)<br>* General anesthesia will be induced via intravenous agents, and anesthesia maintenance will be provided via inhalation for all the patients. The maintenance will be provided with sevoflurane using automated gas flow with the selected speed of 4 (Medium speed). The anesthesia machine indicates amount of sevoflurane inhaled, inspired and exhaled oxygen, carbon dioxyde, air and sevoflurane concentrations. Accordingly these data and actual flow rate will be recorded every 15 minutes.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total amount of sevoflurane consumed | At the end of the surgery, total amount of sevoflurane, which is indicated on the anesthesia machine screen, will be recorded in milliliters | up to 3 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to extubation after inhalation anesthesia stop | Time between the inhalation anesthesia stop and extubation in minutes | Up to 45 minutes | 
| Time to cooperation after inhalation anesthesia stop | Time between the inhalation anesthesia stop and cooperation to verbal impulses in minutes | Up to 2 hours | 
| Delta Oxygen Concentration | The adjusted oxygen fraction (generally 40%) minus the actual inhaled oxygen fraction will provide the delta value. The data will be recorded every 15-minute during the surgery, and delta >%5 will be considered as unsafe | up to 2 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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pediatric anesthesia, metabolic flow anesthesia, low flow anesthesia