Propofol Concentration In The Ambient Air Of The Operating Room And In The Blood Of Anesthesia Care Providers
Condition: Propofol Pollution
Study type: Observational

Summary: 
      The pollution of the operating room environment by anesthetic agents had been questioned,
      studied and documented in the past. These investigations demonstrated the existence of
      teratogenic effects in animals and the possibility of a decrease in mental performance,
      reduced fertility, fetal loss, spontaneous abortion and addictive potential in humans with
      chronic exposure to trace amounts of anesthetic agents. These findings led to the
      establishment of exposure limits and industry standards by consumer protection agencies, such
      as National Institute for Occupational Safety and Health (NIOSH). However, these standards
      applied to inhalation anesthetic agents that were excreted from the lungs of patients during
      expiration. These concerns about operating room pollution weaned away with the introduction
      of intravenous anesthetic agents, such as propofol, because it was believed propofol was
      excreted by systems other than the lungs. Recent research points to the contrary and
      demonstrates the excretion of propofol vapor in the expired gases of patients. Furthermore,
      animal experiments in our laboratory establish the existence of a biological mechanism
      responsible for addiction in animals exposed to trace amounts of propofol. We propose to
      study the exposure levels of anesthesia care providers in the operating room, during propofol
      use, under standardized conditions. Our findings will help to establish preventive measures
      for propofol addiction in anesthesia care providers.
    

Detailed description: 
      This clinical project will be carried out in the operating rooms of the University Hospital
      and the Doctors Office Center. The study will be done during routine surgery where a
      laryngeal mask airway will be used to maintain airway during general anesthesia in 20 adult
      patients with American Society of Anesthesiologists physical status I or II. Routine
      anesthetic care standards will be applied in intravenous line placement and monitoring of
      patients. General anesthesia will be induced with a bolus dose of propofol (2mg.kg-1) and
      maintained with an intravenous infusion of propofol (100-200 mcg.kg-1.min-1). Patients will
      be allowed to breathe spontaneously 40% oxygen in air. Adjuvant intravenous medications will
      be given for amnesia, analgesia and infection prophylaxis as per routine anesthetic practice.
      The ambient propofol concentration will be measured, using a proton transfer reaction mass
      spectrometer (PTR-MS), at a distance of 25cm from the patient's face. The measurement of
      ambient propofol concentration will begin before the administration of propofol to the
      patient and will continue till the patient leaves the operating room. The use of PTR-MS
      device will not interfere with the anesthetic management of patient. In an unforeseen
      circumstance, where the anesthesiologist determines the use of PTR-MS does interfere with the
      anesthetic care of the patient, the device will be immediately removed and the measurement of
      ambient propofol concentration will be suspended for the case. The set-up and usage of PTR-MS
      will be performed by a research team that does not take part in the clinical management of
      the patient. The PTR-MS is a device that depends on the proton transfer reaction to quantify,
      in parts per billion (ppb) by volume, volatile organic compounds in air at extremely low
      concentrations and in real time. The mean and peak ambient propofol concentration will be
      determined during each case and a time weighted average (TWA) will be calculated for an
      eight-hour period at the end of the study. In addition, after receiving written informed
      consent from anesthesia care providers, blood samples will be drawn from them and propofol
      concentrations will be measured by high-performance liquid chromatography (HPLC) within 24hr.
      The blood samples will constitute 3ml on two occasions, one early in the morning before
      anesthesia care starts and one after eight hours of anesthesia care. HPLC is a device that
      uses a spectrofluorometric detector to estimate trace amounts of propofol in blood in
      ng.ml-1. The blood estimation of propofol will also be conducted by a research team that does
      not take part in the clinical management of patients.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Anesthesia care providers
      
Biospecimen description: 
      Standard blood draw
    
Keywords: Propofol; Anesthesia care provider; Pollution; Operating room; Environment