Anesthesia Hx Flashcards
Anesthesia Definition
Lack of feeling/sensation ; artificially induced loss of the ability to feel pain –> great for permitting surgery!
General Anesthesia
DRUG-INDUCED loss of consciousness. Pt. not arousable, ventilatory function often impaired, cardiovascular function may be impaired
Regional Anesthesia
Insensibility caused by interrupting the sensory nerve conduction of a specific region of the body
Ex:
Peripheral
Spinal
Epidural
Level of consciousness unchanged. Ventilatory, airway protection is maintained
Sedation
A “spectrum” of consciousness between awake and unconscious
Sedation Scale
Minimal:
Responsiveness = to verbal commands
Airway, spont. ventilation, cardiovascular function = UNAFFECTED
Moderate:
Responsiveness = to verbal, touch
Airway = No assistance needed
Spont. Ventilation = Adequate
Cardiovascular function = usually maintained
Deep:
Responsiveness = repeated or painful stimulation
Airway = assistance may be required
Spont. Ventilation = possibly inadequate
Cardiovascular function = usually maintained
Hippocrates
Accommodate the operator, “make it easy on the surgeon” rather than the patient
Dioscorides
Wrote Materia Medica which was used for 15 centuries; 360 medical properties (ie antiseptic, anti-inflammatory, etc)
Big on “Mandragora” –> Human shaped plant with “magical” and hallucinogenic properties
The Middle Ages
for sedation/analgesia, a common cocktail was mixed on a “soporifics,” ie sponges. This included:
-opium
-mandrake juice (harry potter plant)
-hemlock juice
-hyposcyamus (L-isomer of atropine)
-water
Reversal:
-inhaled vinegar (like ammonium salts)
Diethyl Ether
“Ether”
-first inhaled anesthesthetic (volatile anesthetic)
-made from sulfuric acid and ethyl alcohol
-ether: Greek for “ignite”
- Super flammable
-tested on chickens & dogs
- habit/addiction forming
Valerius Cordus
German botanist/physician who discovered ether
Why were volatile anesthetics first utilized before IV inducing agents?
IV “technology,” ie angiocatheters, IV tubing, etc was not yet available at the time.
Christopher Wren and Robert Boyle
- used a goose quill to create IV therapy
-administered alcohol into a dog’s vein - Members of the Royal Society of London
…“[paraphrase] I injected wine into a living dog, he was extremely drunk, he pisseth it out.”
Joseph Priestly
-English chemist
-discovered oxygen and nitrous oxide
- discovered photosynthesis
Humphry Davy
-English chemist
- discovered potassium, sodium, magnesium, etc.
-suggested nitrous oxide be used for surgical analgesia
- no one believed it. Became used recreationally
Horace Wells
-Dentist
-Noticed that under the influence of n2o, people have no recall of pain/injury
-Self administered n2o for tooth extraction and used it on several patients
-“humbug” –> because it’s not a paralytic and patients can still move when n2o is administered, it fell out of favor
Nitrous oxide
- volatile anesthetic
-analgesic and amnestic properties
-initially administered with air, now mixed with pure oxygen to prevent hypoxia
Andrews
-Chicago surgeon
-administered nitrous oxide with oxygen. No cyanosis!
Hewitt
-1st anesthesia machine with nitrous oxide/oxygen
Other guys who used Ether
Crawford Long:
- used ether for patient with 2 neck tumors
- also used whiskey with ether…. nice
William Morton:
- Dentist who used ether for denture fittings
First public display of the use of ether
-1846
- “Ether Dome” at Mass General in Boston
- Within 60 days, the use of ether had spread “across the pond”…. from America to Europe
- inhaler fit poorly, no way to quantify the ether that was actually inhaled.
- no IV access. No way to save the patient if they lost their BP lol
- Emergence from the use of ether was very prolonged
Dr. Robinson Squibb
-developed process for pure ether
- founded Squibb pharmaceuticals
What sucks about ether?
-flammable
-prolonged induction
-n/v, prolonging their stay in the hospital
Chloroform
-discovered in many different places around the same time. USA, France, Germany, Great Britain
-caused controversy d/t deaths of healthy individuals who underwent anesthesia from chloroform
-Hyderabad commissions 1888 and 1891; found that chloroform is actually pretty safe with proper administration and monitoring. Many deaths occurred without patient monitoring
-hepatotoxic in children, light administration seems to cause adrenaline spike, leading to fatal vf seen in animals
Sir James Simpson
-OB who used chloroform
- pain the result of “actual or potential tissue damage”
- Face religious opposition to his use of chloroform during child birth
Dr. John Snow
-Anesthetist who used chloroform on Queen Victoria for the child births of Prince Leopold and Princess Beatrice
- “discovered” epidemiology when he traced the London cholera outbreak to water source
Cocaine!!!!!
-used as an anesthetic for ophthalmic procedures by Dr. Koller
- utilized as a regional mandibular nerve block by Dr. Halsted
Dr. August Bier:
-developed the “Bier block”
- 1st spinal anesthetic with cocaine
First CRNA’s
Alice Magaw
-“mother of anesthesia”
- badass who did 14,000 ether cases without a single patient death
Agatha Hodgins
- opened one of 1st CRNA schools
-founded AANA
-taught in France
Recent volatile anesthetics
Cyclopropane
- violently explosive
Halothane
- hepatitis
-slow onset
Isoflurane
-relatively safe
-less n/v
-quicker onset than halothane
- slow emergence
Desflurane
- rapid uptake and distribution (most rapid)
- high vapor pressure, similar to atmospheric pressure
- large quantities needed to achieve anesthesia
Sevoflurane
-intermediate action between isoflurane and desflurane
-unstable in soda lime; toxic degradation product concerns
- doesn’t irritate airway, ideal for use in children
Edmund Egar
created the concept of MAC (minimum alveolar concentration)
MAC:
- compares potency of different inhaled anesthetics
-the concentration of an inhaled anesthetic that prevents movement in half of test subjects in response to a stimulus
The “triad”
-Amnesia
-Analgesia
-Muscle Relaxation
Amnesia
-achieved by stimulating inhibitory transmissions OR inhibiting stimulatory transmissions
INHIBIT ACh, STIMULATE GABA
Analgesia
Today’s analgesics
-narcotics
-cox inhibitors
-gaba analogues
-acetaminophen
-peripheral nerve blocks
Morphine
- initially not in favor, high death rate until it was more understood
Muscle Relaxation
Curare
- S. American Indians –> poison darts
-decreased amount of anesthesia required d/t relaxation, therefore decreasing mortality
Achieving homeostasis
Now considered a fourth principle of the initial “triad”
-maintenance of adequate cardiac output
-maintaining adequate ventilation
-maintaining euvolemia
-preventing hypo/hyperthermia
-managing acid/base balance
etc.
Dr. Liston
Dummy who thought surgical cases all needed to be completed under 20 minutes. Once killed 3 people from a single surgery
George Crile
Proponent of local anesthetics
- local infiltration of procaine, pre-emptively inhibiting pain signalling
-light nitrous/oxygen anesthesia
-Cleveland clinic
Harvey Cushing
-local anesthetics/regional blocks
-known for anesthetic records, BP/HR measurements perioperatively that really helped solidify the importance of “data collection”
Neurolept Anesthesia
-opioids, antipsychotics
-blocked autonomic and endocrine response to stress
-high incidence of awareness, dysphoria, and extrapyramidal movements
Phases of Anesthesia
Preoperative period
-bzd, H1 and H2 blockers, bronchodilators
Induction
-etomidate, ketamine, propofol, narcotics
Maintenance
-volatile anesthetics, neuromuscular blockers, pressors
Emergence
-NMB reversal, local anesthetics
Postoperative period
Stages of Anesthesia
Stage 1:
Stage 1: beginning of induction of general anesthesia to loss of consciousness
-1st plane: no amnesia or analgesia
-2nd plane: amnestic, but partial analgesic
-3rd plane: complete analgesia and amnesia
Stages of Anesthesia
Stage 2
Stage 2: loss of consciousness to onset of automatic breathing
-eyelash reflex gone
-coughing, vomiting, struggling may occur
-irregular respirations
***uncomfortable stage. Risk of aspiration, bradycardia, reduced CO. THE QUICKER YOUR PATIENT PROGRESSES THROUGH THIS STAGE, THE BETTER
Stages of Anesthesia
Stage 3
Stage 3: onset of automatic breathing to respiratory paralysis (surgical plane)
-1st plane: automatic respiration to cessation of eyeball movements
-2nd plane: cessation of eyeball movement to beginning of intercostal paralysis. secretion of tears
-3rd plane: intercostal muscle paralysis, dilated pupils, desired plane PRIOR TO MUSCLE RELAXANTS
-4th plane: complete intercostal and diaphragmatic paralysis
Stages of Anesthesia
Stage 4
Stoppage of respiration until….. death
