Comparison of Different Ventilator and Vaporizer Technologies to Study Economic and Environmental Implications
Condition: Anesthetic Gas Consumption and Cost-Effectiveness
Study type: Interventional

Summary: 
      The purpose of this study is to test whether or not the use of a low volume ventilator in an
      anesthesia machine reduces anesthetic costs significantly as compared to other high volume
      machines. The study will compare the a low-flow anesthesia machine to a traditional
      anesthesia machine during routine elective general surgery in patients with ASA ratings of
      1-2 under general anesthesia receiving standard care.
    

Detailed description: 
      The study member will screen for potential subjects using the UCIMC surgical schedule. If a
      subject is deemed ineligible based on the inclusion and exclusion criteria after reviewing
      the medical history, his/her record will be discarded. No records will be retained from
      ineligible subjects. After discussing with the patient's surgeon, study team member will
      initiate the informed consent process by approaching each eligible subject to explain the
      study and what it entails. The Lead Researcher will address all questions and concerns from
      the subject before asking the subject to sign the research consent form.

      The GE anesthesia machines currently owned by the operating room will be used to serve as the
      comparator to the Flow-i machine. The high volume anesthesia machines do not use a low volume
      system. Subjects will be randomized by recruitment day. On a given recruitment day, all
      consented subjects will receive anesthesia from one of two groups:

      (1) MAQUET FLOW-i device (2) GE anesthetic device

      Time points for both groups include:

      T0: Time of intubation, when volatile anesthetic are typically first delivered to the
      patient. We will use 15L/min fresh gas flow, while dictating tidal volumes of 6-8 mL/kg ideal
      body weight and a PEEP of 6 centimeters of water (cm H2O) in accordance with current best
      practices.

      T1: Time of incision, which typically represents the time of reaching steady state conditions
      of volatile anesthetic delivery. We will reduce fresh gas flow to 2 L/min in accordance with
      local practice and weigh the vaporizer at this point, allowing us to measure comparative
      anesthetic consumption during this wash-in time period (T0-T1).

      T2: Time of anesthetic weaning, typically the time when preparing for patient emergence
      begins by discontinuing the delivery of volatile anesthetics to the patient. The vaporizer
      will be re- weighed at this point, allowing us to measure comparative anesthetic consumption
      at steady state maintenance of anesthetic depth (T1-T2) Logically, we will also be able to
      use T0-T2 in order to understand total comparative anesthetic consumption.

      Aside from the randomization to either Group 1 or Group 2, there will be no changes in the
      surgical or anesthetic procedure, including the medication or treatments given to the
      subjects as determined by the treating physician. All subjects will receive general
      anesthesia in accordance to local practice.

      For this study, the vaporizer(s) will be weighed on a tared scale before research procedures
      commence, after induction, and when the gas is shut off during weaning of anesthesia in
      preparation for extubation to calculate the amount consumed during this time (grams/minute).
      In addition, the following variables will be recorded:

      Subject weight (kg) Tidal Volume (TV) Respiratory Rate (RR) 9 of 24

      Positive end-expiratory pressure (PEEP) Fresh Gas Flow Volume % gas End Tidal (%) Time of
      extubation Time when Aldrete score > 8

      This is not a physician-blinded study being that the physical characteristics of the standard
      delivery units are distinguishable from the MAQUET FLOW-i machine.

      All MAC concentrations are standard of care: After the surgical procedure, patient will be
      assessed for time to reach Aldrete score greater than 8, level of pain and time to
      extubation. Their medical records will be reviewed to determine need for times and adverse
      events. Patients will not be contacted for study-related follow-up after they are discharged
      from recovery.

      No photographs or audio/video recording will be collected for this study.

      Subject's Privacy:

      The study team member will screen for potential subjects using the UCIMC surgical schedule.
      If a subject is deemed ineligible based on the inclusion and exclusion criteria after
      reviewing the medical history, his/her record will be discarded. No records will be retained
      from ineligible subjects.

      Study team member will approach each eligible patient to explain the study and what it
      entails. The study team member will address all questions and concerns from the subjects
      before asking the patient to sign the research consent form.
    

Intervention name(s): ICU certified ventilator; Non-ICU certified ventilator
Intervention type(s): Device; Device
Intervention description(s): Examine anesthetic consumption rates; Examine anesthetic consumption rates
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: general anesthesia; anesthesia machines; sevoflurane; low volume ventilator; anesthetic costs; cost-effectiveness; fresh gas flow