Decreasing Environmental Impact and Costs of Using Inhalational Anesthetic With a Carbon Dioxide Membrane Filter System

Study Overview
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Brief Summary
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Efficient inhalational anesthetic delivery requires the use of low-flow air and oxygen to reduce drug waste and minimize workspace contamination and environmental pollution. Currently, excess anesthetic gas is scavenged and removed from the operating room via the hospital ventilation system, where it is released into the atmosphere. CO2 is removed from the anesthesia circuit by the use of CO2 removal systems to prevent re-breathing and potential hypercarbia. Carbon dioxide is currently removed using chemical granulate absorbers (CGAs), which trap CO2 in the granules that are later disposed of when absorption capacity is reached. They require replacement approximately every other day when used in moderate to high volume surgical centres, placing a costly burden on the healthcare system and environment (landfill). One of the more concerning downfalls of using CGAs is the potential for the inhalational anesthetics to react with the granules and potentially produce toxic byproducts known as compounds A-E that are nephrotoxic and neurotoxic and require excess amounts of anesthetic gas to dilute. This excess use of anesthetics gases places a financial burden on the healthcare system and has a detrimental impact on the environment. The vast majority of the gases used are eventually released into the environment with little to no degradation where they accumulate in the troposphere and act as greenhouse gases. DMF Medical has created Memsorb, a new CO2 filtration membrane. Memsorb can remove CO2 from the anesthesia circuit without the use of CGAs, thereby eliminating the potential for toxic byproducts and allowing for significantly lower air and oxygen flow to be used, resulting in less use of inhalational anesthetics. Memsorb uses a polymeric membrane (similar to the ones used in oxygenators for cardiac surgery) that selectively allows CO2 to leave the rebreathing system, while maintaining the inhalational anesthetic in the circuit. The lifespan of Memsorb is at least 12 months, resulting in less particulate waste and a decreased cost to the healthcare system. We wish to evaluate the ability and efficacy of Memsorb in removing CO2 from the anesthesia circuit while maintaining physiologic minute volume ventilation, as compared to the traditional CGAs in a variety of surgical procedures, patient populations, and anesthesia gas flows.

Official Title
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Decreasing Environmental Impact and Costs of Using Inhalational Anesthetics by Replacing Chemical Absorbers With an Innovative Carbon Dioxide Membrane Filter System - a Prospective, Randomized, Clinical Trial

Conditions
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Anesthesia, Inhalation; Vapor

Intervention / Treatment
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* Device: Memsorb
* Drug: Chemical granulate absorber


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA I - III Elective surgical procedure Laparoscopic surgery for study aim III Exclusion Criteria: ASA > IV Emergency surgery Severe respiratory disease (eg Asthma) Raised intracranial pressure Regional anesthesia Absence of arterial line for study aim III Self-reported pregnancy

Ages Eligible for Study
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Minimum 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: Health Services Research
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Memsorb GA<br>Memsorb Filter will be used during general anesthesia (GA), fresh gas flow and ventilator settings are not modified | Device: Memsorb<br>* Memsorb uses a polymeric membrane (similar to the ones used in oxygenators for cardiac surgery) that selectively allows CO2 to leave the rebreathing system while maintaining the inhalational anesthetic in the anesthesia circuit<br>|
| Active Comparator: CGA GA<br>Chemical CO2 absorber (CGA) will be used during general anesthesia (GA), fresh gas flow and ventilator settings are not modified | Drug: Chemical granulate absorber<br>* Chemical granulate absorber trap CO2 chemically in granules that are later disposed of when absorption capacity is reached<br>|
| Experimental: Memsorb low-flow<br>Memsorb Filter will be used during low flow general anesthesia (GA) | Device: Memsorb<br>* Memsorb uses a polymeric membrane (similar to the ones used in oxygenators for cardiac surgery) that selectively allows CO2 to leave the rebreathing system while maintaining the inhalational anesthetic in the anesthesia circuit<br>|
| Experimental: CGA low flow<br>Chemical CO2 absorber (CGA) will be used during low flow general anesthesia (GA) | Drug: Chemical granulate absorber<br>* Chemical granulate absorber trap CO2 chemically in granules that are later disposed of when absorption capacity is reached<br>|
| Experimental: Memsorb laparoscopic surgery<br>Memsorb Filter will be used during general anesthesia for laparoscopic surgery | Device: Memsorb<br>* Memsorb uses a polymeric membrane (similar to the ones used in oxygenators for cardiac surgery) that selectively allows CO2 to leave the rebreathing system while maintaining the inhalational anesthetic in the anesthesia circuit<br>|
| Experimental: CGA laparoscopic surgery<br>Chemical CO2 absorber (CGA) will be used during laparoscopic surgery | Drug: Chemical granulate absorber<br>* Chemical granulate absorber trap CO2 chemically in granules that are later disposed of when absorption capacity is reached<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effectiveness of Memsorb compared to CGA to eliminate CO2 | etCO2 (mmHg) and tidal volumes (ml) will be measured with the two systems in GE / Dates Ohmeda anesthesia machines | Duration of general anesthesia (up to 12 hours) | 
| Impact of Memsorb, using minimal flow anesthesia (≤ 0.50 L/min), on the amount of inhalational anesthetic (ml) used, compared to standard practice | Usage of Desflurane in ml will be measured during minimal flow (≤ 0.5 L/min) anesthesia, compared to traditional higher gas flow (> 2 L/min). | Duration of general anesthesia (up to 12 hours) | 
| Effectiveness of using Memsorb during ventilation for removal of CO2 in laparoscopic surgeries resulting in high CO2 exposure, compared to CGAs | etCO2 (mmHg), paCO2 (mmHg) and tidal volumes (ml) needed remove CO2 during laparoscopic surgery, resulting in higher CO2 exposure. | Duration of general anesthesia (up to 12 hours) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Amount of inhaled anesthetics used | Usage on inhaled anesthetics in ml for the surgery. | Duration of general anesthesia (up to 12 hours) | 
| Duration of anesthesia | Durantion measured in minutes | Duration of general anesthesia (up to 12 hours) | 
| Water build up in anesthesia circuit | Likert scale to measure water build up (1- no water, 3 - large amount of water) | Duration of general anesthesia (up to 12 hours) | 
| Freshgas flow during general anesthesia | Measured in ml/min | Duration of general anesthesia (up to 12 hours) | 
| Number of CGAs used during the study period | absolute number of canisters used | Duration of general anesthesia (up to 12 hours) | 
| Minute volume ventilation | tidal volume (ml) x respiratory rate (/min) | Duration of general anesthesia (up to 12 hours) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Anesthesia, Inhalation, Vapour, CO2 Absorber, Minimal Flow Anesthesia, Memsorb, Healthcare Cost, Greenhouse gas, Environment Healthcare