Automated Control of End-tidal Volatile Anesthetic Concentration

Study Overview
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Brief Summary
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The new MIRUS system as well as the established AnaConDa system uses a reflector to conserve volatile anaesthetics (VA). Both systems act with commercially available ICU ventilators. In contrast to AnaConDa the MIRUS includes an automated control of end-tidal VA concentrations. In this study the investigators compared feasibility, costs and recovery times after anaesthesia with isoflurane (ISO), sevoflurane (SEVO) or desflurane (DES) in ventilated and spontaneously breathing patients.

Detailed Description
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The study was approved by the appropriate Institutional Review Board. After written informed consent 63 ASA I-III patients undergoing elective hip or knee replacement surgery under general anesthesia were included. Patients were randomly organized into 3 groups (20-22 each). Anesthesia was induced with intravenous anaesthetics. After tracheal intubation MIRUS automatically adjusted the end-tidal VA concentration to 1.0 MAC. Patients were ventilated with the Puritan Bennett 840 ICU ventilator. After 1 h of anaesthesia with 1.0 MAC the ventilator mode was switched from SIMV V+ (totally controlled ventilation, passive patient, with a tidal volume of 8 ml/IBW) to proportional assist ventilation (PAV) with 50% support (active patient). At the end of surgery the MIRUS system was stopped (MAC set to 0.0) and recovery times were measured.

Official Title
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Automated Control of End-tidal Volatile Anesthetic Concentration Using the MIRUS System: A Comparison of Isoflurane, Sevoflurane and Desflurane in Anesthesia.

Conditions
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Delayed Recovery From Anesthesia

Intervention / Treatment
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* Drug: Desflurane
* Drug: Sevoflurane
* Drug: Isoflurane


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Signing of the informed consent document (patient or relatives). Patient age 18 years or older. ASA I-III Exclusion Criteria: ASA IV patients Epidural or spinal analgesia Allergy or known hypersensitivity to any of the study drugs Patients with known or suspected genetic susceptibility to malignant hyperthermia Previous participation in this trial Participation in another clinical trial within 4 weeks prior to selection. Pregnant women

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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Desflurane<br>Desflurane 5.0-6.0 Vol% (1.0 MAC) in Oxygen (FiO2 0.8-0.95) | Drug: Desflurane<br>* Group A: Desflurane 5.0-6.0 Vol% (1.0 MAC) in Oxygen (FiO2 0.8-0.95)<br>* Other names: Suprane;|
| Experimental: Sevoflurane<br>Sevoflurane 1.4-2.1 Vol% (1.0 MAC) in Oxygen (FiO2 0.8-0.95) | Drug: Sevoflurane<br>* Group B: Sevoflurane 1.4-2.1 Vol% (1.0 MAC) in Oxygen (FiO2 0.8-0.95)<br>* Other names: Sevorane;|
| Active Comparator: Isoflurane<br>Isoflurane 0.9-1.2 Vol% (1.0 MAC) in Oxygen (FiO2 0.8-0.95) | Drug: Isoflurane<br>* Group C: Isoflurane 0.9-1.2 Vol% (1.0 MAC) in Oxygen (FiO2 0.8-0.95)<br>* Other names: Forene;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| volatile anaesthetics (VA) consumption |  | duration of anesthesia: max. 3 h | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| recovery times |  | duration post anesthesia care: max. 8 h after anesthesia | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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et Control, inhalational sedation, conserve volatile anesthetics