Assessment of Patient Positioning
Condition: Neuropraxia
Study type: Observational

Summary: 
      The purpose of this study is to ultimately prevent injuries to nerves during surgical
      procedures. Living donor liver transplant or hepatectomy (removal of a piece of the liver)
      patients will receive an arterial line as standard of care. The arterial line helps monitor
      blood pressure along with the compression of important vessels during surgery. In addition,
      research participants will undergo neuromuscular monitoring using Somato-Sensory Evoked
      Potential (SSEP) or Evoked Potential Assessment Device (EPAD). During an operation,
      neuromuscular monitoring can tell doctors if the nerves being studied are working normally or
      if they are at risk for injury. This study will help investigators to understand what kind of
      monitoring is best to prevent nerve injuries during a surgical procedure.
    

Detailed description: 
      As standard of care, research participants undergoing a living donor liver transplant or
      other liver surgeries will receive a right-sided radial arterial line to monitor his/her
      blood pressure along with the compression of important vessels during surgery. These
      measurements will be captured throughout the surgical procedure. If blunting of the arterial
      line wave form occurs, the anesthesiology team alerts the surgical team to release the
      retractors until the wave form returns to baseline. Depression of the radial arterial line
      wave form will be captured, time-stamped, and stored by the research transplant
      anesthesiology team.

      Additionally as part of research, participants will receive neuromuscular monitoring using
      SSEP or EPAD to measure their nerve signals during the surgery (3-6 hours). SSEP or EPAD
      measurements will occur at the median and ulnar nerve and will be captured throughout the
      surgical procedure. The research neuromonitoring team will consists of highly skilled
      technicians, who monitor patients during neurosurgical and orthopedic surgeries. SSEP or EPAD
      output captured during the surgery will be time-stamped, stored, and interpreted by a
      Neurologist. To investigate if a correlation exists, SSEP or EPAD abnormalities will be
      correlated and analyzed with the arterial wave form depressions.

      To determine whether a correlation exists with clinical outcomes, a prospective medical
      record review will be conducted. Before performing the prospective medical record review,
      authorized research personnel will obtain informed consent from each participant.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        All adult living liver donors and liver surgery patients at Northwestern Memorial Hospital
        (surgical setup is similar for living liver donor surgery and liver surgery (e.g.
        retractors, arterial line for monitoring, surgeons). Investigators will approach both
        living liver donors and liver surgery patients for enrollment to receive additional
        neuromuscular monitoring.
      
Keywords: nerve compression