Delirium Detection

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Delirium Detection

• Eric Mauri
• Michael Marquis
• Matthew Kasztejna
• Advised by Dr. Wes Ely

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Delirium Overview

• Brains form of organ dysfunction
• Defined as a disturbance of consciousness
  characterized by an acute onset and fluctuating
  course of impaired cognitive functioning.
• Direct consequence of medical conditions,
  medication, toxin exposure or a combination of
  all of these.
• Major contributing factor Lack of REM sleep

Ely et al. Seminars in Respiratory and Critical
Care Medicine, Vol. 22, Num. 2, 2001.
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Delirium Demographics

• Occurs in 15-60 of general patients
• Develops in over 80 of ICU patients
• Complicates hospitalization of 2-3 million people
  yearly (affecting mostly the elderly)
• Involves over 17.5 million inpatient days.
• Over 4 billion in Medicare expenditures.
• Development of delirium selected as one of the
  top three most important areas for quality of
  care improvement in older adults.

Ely et al. Seminars in Respiratory and Critical
Care Medicine, Vol. 22, Num. 2, 2001.
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How is it detected?

• Arousal and Attention Assessment
• Confusion Assessment Method (CAM-ICU)
• Acute onset of mental changes
• Inattention
• Disorganized thinking
• Alertness
• Patients are determined to be CAM-positive if
  they have both features 1 2 and either feature
  3 or 4.

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CAM-ICU Cont.

• Example Questions
• As part of the inattention assessment patients
  are shown a set of 5 pictures, then a set of 10
  pictures (5 of which were in the original set).
  They are asked whether the picture was in the
  first set, if they get more than 3 wrong then
  they are inattentive.
• As part of the disorganized thinking assessment
  they are asked questions like Will a stone float
  on water? Are there fish in the sea? Can you use
  a hammer to pound a nail?
• Problems
• Subjective
• No Standardization
• Time Intensive

http//www.aacn.org/pdfLibra.NSF/Files/TrumanB/fi
le/TrumanB.pdf
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Project Objective

• Develop system that can continuously measure
  delirium in ICU patients
• Solution
• Quantitative EEG
• Acquire digital signal
• Transform it into the frequency domain
• Focus on certain frequency bands that have been
  clinically shown to be important to sleep.
• Benefits
• Inexpensive
• Noninvasive
• Software reduces man hours
• Most importantly several studies have shown that
  EEG can be effectively used to monitor sleep

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Stages of Sleep

• Stage 1 Frequency 4 to 8 Hz, 5 of total sleep
• consists mostly of theta waves (high amplitude,
  low frequency (slow))
• brief periods of alpha waves, similar to those
  present while awake
• Stage 2 Frequency 8 to 15 Hz, 50 of total
  sleep
• peaks of brain waves become higher and higher
  (sleep spindles)
• k-complexes (peaks suddenly drastically descend
  and then pick back up) follow spindles
• Stage 3 4 - Frequency .5 to 4 Hz, 7 11
  respectively
• very slow brain waves, called delta waves (lower
  frequency than theta waves)
• REM - Frequency gt 12 Hz, 25 increases as night
  goes on
• beta waves have a high frequency and occur when
  the brain is quite active, both in REM sleep and
  while awake

www.dreamviews.com/sleepstages.html www.silentpart
ners.org
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Possible Systems

• Gold Standard EEG Sleep Labs
• Bispectral Index (BIS) Aspect Medical
• Sleep I/T
• Vitaport Temec
• SNAP Nicolet Biomedical

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Ideal System

• Measures amount of REM sleep and capable of
  making real-time measurements
• Small (155 x 90 x 57 mm), cost-effective,
  comfortable and practical
• Real-Time measurements, data storage and analysis
  of information (software)
• Maximum of 3 to 5 leads
• Capability to store up to 48 hrs worth of data on
  a removable data card for easy data transfer

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Ruled out systems

• Gold standard EEG
• Most complex, 26 lead system is too complicated
  for use in the ICU.
• BIS
• Simplest, 3-lead system which produces a single
  number to describe changes in EEG that relate to
  levels of sedation and consciousness.
• BIS is only effective for the first 3 stages of
  sleep, the BIS number decreases as sleep progress
  from the first to third stage, yet the number
  increases during REM sleep due to increased
  glucose metabolism in the brain.
• Sleep I/T
• Outdated, better technology exists

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Vitaport

• Full clinical polysomnographs (EEG, EOG, EMG,
  EKG, respiratory effort, oxygen saturation)
• 16 channel EEG 600 grams Flexible
• Electrically efficient 48 hrs of continuous
  monitoring with a set of AA batteries
• Can be configured to 3-5 leads
• Various software options independently selectable
  for each of the 16 channels
• Cost 6,500 for Vitaport 3 recorder base with
  setup software
• Leasing available depending upon length of
  lease, it would be 10-15 of the sales price
  (per month)

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SNAP

• Portable, battery-operated, handheld-based single
  channel EEG monitoring tool
• 3 lead system
• Enables accurate measuring of EEG with
  convenience and versatility of a handheld
  computer (PDA)
• Outputs a numerical value (SNAP index)
• 0, fully suppressed, no active EEG signal
• 100, fully active EEG brain state
• Cost 4,500 plus 200 for the PDA

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Recommendations

• SNAP and Vitaport are best equipped for ICU
  setting
• Both are compact, lightweight and extremely
  flexible
• Compatible with review and analysis software
  applications, which will help reduce staff hours
• Cost-effective

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A Learning Process

• Unforeseen Obstacles
• Licensing and leasing issues
• Contradicting schedules and unexpected
  cancellations
• Lengthy delivery times
• Project involved research and collaborating with
  a network of different professionals, each with
  conflicting agendas and personal interests

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