Depth of Anesthesia Monitoring Flashcards
(41 cards)
History of Anesthesia
Morton held a ether-dipped handkerchief over the mouth of the pt in the Ether Dome (considered the first successful anesthetic)
N2O at Mass General
Attempted in 1845 but the pt moved and cried out w incision but had no recall. When they used ether the pt had no mvmt but pt was aware and had no pain
Development of Nursing Anesthesia
- Civil War 1864-1865: Union Army Nurse Catherine Lawerence recorded practicing anesthesia in her autobiography
- many other nurses used chloroform
- Franco-Prussian War 1870-1871: Male and Female nurse taught to induce anesthesia and used as anesthetists
- reports more common in 1880s
Key Figures in Nursing Anesthesia
Sister Mary Bernard: entered St. Vincents in PN 1887 and took over anesthesia duties in 1888
Franciscan Sisters of St. Johns: in IL prepared sisters to serve as nurse anesthetists and sent them to other MW hospitals
Sister Mary Erhard: 1886 administered anesthesia on Maui for 42 years
Sisters of St. Francis in Rochester, MN: 1889 St Mary’s Mayo Clinic built and opened. Etith and Dinah Graham directed and supervised nursing and administered anesthesia
The Mother of Nursing Anesthesia
- trained by Dr. William Mayo
- Dinah Graham administered for awhile
- Edith administered until she married Mayo
- Alice Magaw (MoA) her friend and successor took over
- Florence Hendersen introduced to anesthesia dept
- the NAs became integral to success of St. Mary’s hospital and the Mayo brothers became known for their surgery and excellence in anesthesia
- known for making anesthesia safer
- Henderson developed methods of ether administration and assessment criteria
Evolution of NA
1908: Agatha Hodgins at Lakeside Hospital in Cleveland, OH chosen by Dr. Crile as anesthetist.
- Lakeside konwns for its success in surgery and anesthesia
1915: Lakeside School of Anesthesia was founded as fist NA program in Cleveland and led to other NA programs
Who founded the AANA?
Agatha Hodgins of the Lakeside Hospital and School of Anesthesia
WWI
Prior to WWI, few physicians specialized in anesthesia. In 1911 Francias McMechan felt it should be a profession only for physicians
Lakeside Challenge
1916: letter sent to Dr. Crile by Ohio BOM telling him to cease the training of NAs, or lose the nursing school’s accreditation
1917: at a hearing Dr. Crile persuaded the board to lift the order by citing how many other facilities were successfully using nurse anesthetists
• Crile and supporting physicians successfully advocated for the Ohio legislature to legalize the practice of anesthesia by nurses
1919: bill approved that legalized practice of nursing anesthesia under supervision of a physician
Kentucky (Frank v South)
1916: Louisville society of anesthesiologists passed a resolution that only a physician should administer anesthesia, attorney general concurred
– Louis Frank and his nurse anesthetist Margaret Hatfield joined with that state board of health to file a suit against the Kentucky state medical association
• Lost the initial suit, but won in the appeals – Nurse anesthesia is not the practice of medicine
California (Chalmers-Francais v Nelson)
– Dragmar Nelson a nurse anesthetist charged with practice of medicine
– At every level of the California civil court system it was decided in favor of Dragmar Nelson – established legality of nurse anesthesia practice
Breakthroughs in Technology
- pulse ox (standard of care in 1987)
- anesthesia gas analysis
- improved monitoring technology and devices
- fiberoptic imaging
- US guided techniques
- BIS/Entropy monitoring
Why Monitor Depth of Anesthesia?
- to prevent awareness
Awareness
- the unexpected and explicit recall by pts of events that occur during anesthesia
- estimated at 0.0068 to 1%
- may be higher in children
- most pts don’t have pain but have vague auditory recall, a sense of dreaming generally not disturbing
- some experience total pain and recall (traumatic)
- concern for PTSD and other psychological sequelae
Issue of Awareness More Prominent - 2003/2004
- FDA allowed Aspect Medical (makers of BIS) to declare BIS monitors reduce incidence of awareness
- sentinal alert from TJC 2004 on awareness developed Task Force on IntraOp Awareness
- also a hypothesis that DoA monitors help providers titrate meds and reduce oversedation, morbidity, and mortality
Court of Public Opinion
the movie “Awake” in 2007 brought the issue to the publics eye
Major DoA Monitors
- BIS (Aspect Medical)
- Entropy (GE)
- Narcotrend
- Cerebral State Monitor
- SEDLine
- SNAP II
AEP
Goals of DoA Monitors
- Ability to detect level DoA and risk of awareness
- Determine if patient is unnecessarily too deep and at risk of prolonged recovery and increased M and M
- No matter what, the monitor it should work similarly across all patient pops
- Should work the same regardless of meds and anesthetic technique employed
Baseline Principles of EEG Analysis
- 1937: Gibbs et al, discussed the relationship between brain wave patterns (EEG) and neuronal activity changes associated with drug administration *
- Information is collected by frontal electrodes and the signals are processed to yield an “index value” to determine the depth of anesthesia
EEG Activity and DoA
- Cells in cortex provide synaptic activity and results in changes of voltage that can be detected by electrodes placed on the forehead/scalp
- Multiple waveforms with varying frequency ranges correspond to specific neurophysiological processes
- grouped into frequency bands in order of freq:
delta, theta, alpha, beta
Table Explanation of Waves
Delta
<3 Hz
- very low freq, depressed functions (coma, deep GA, hypoxia, ischemia, infarction, poor metabolism), may result from thalamic depression
Theta
4-7 Hz
- low freq, seen under GA. Inhibition of thalamic pacemaker cells
Alpha
8-12 Hz
- med freq, higher amplitude, awake but eyes closed (EEG seen in occipital lobes)
- prominently seen in awake pts
- thought to reflect cyclical activity of thalamic pacemaker cells
