General Anesthesia 1 Flashcards
A pharmacologically-induced state of unconsciousness, amnesia, relaxation of skeletal muscles, and reduction in
autonomic responses. This refers to _
General anesthesia
A lack of recall refers to _
Amnesia
Impaired perception and response to stimuli refers to _
Unconsciousness
The absence of pain sensation without loss of
consciousness refers to _
Analgesia
The two major uses of volatile anesthetics are _
Maintenance Induction (sometimes)
What types of drugs are able to produce amnesia, muscle relaxation and suppress hemodynamic responses to surgical stimuli?
Volatile anesthetics
True or false; Volatile anesthetics require a low inspired percentage (1-10%) and have low solubility in blood.
True
The percentage occupied by a single gas in a mixture of gases is referred to as _. Where can this be measured?
Partial pressure
In the lung
When delived, the partial pressure of an anesthetic gas equilbrates in 3 different areas at equilibrium. They are _
Alveoli (PA)
Arterial blood (Pa)
Brain (Pb)
Regarding anesthetics, what does MAC stand for? What is 1 MAC?
Minimum alveolar concentration
Concentration of anesthetic that prevents response to noxious stimulus in 50% of patients. (Think ED50) Used to compare one anesthetic to another
What is a useful index of anethetic potency? I.e. how can you compare one anesthetic to another?
MAC (1.3 MAC knocks out most patients)
Isoflurane, Nitrous oxide, desflurane, sevoflurane. Rank the preceeding in decreasing MAC.
Iso - 1.15
Sevo - 2.05
Des - 7.25
NO - 105 - 110
The ratio of blood to gas partition coefficient defines _. This term determines what 2 properties of any anesthetic?
Anesthetic solubility
Onset and Elimination
An anesthetic that has a slow onset and offset would be expected to have _ solubility. An anesthetic that has fast onset and offset would be expected to have _ solubility
High solubility
Low solubility
The partial pressure of an anesthetic in what area produces general anesthesia?
The brain
Which represents a more soluble anesthetic.
- A blood:gas partition coefficient =1
- A blood:gas partition coefficient =2
A blood:gas partition coefficient = 2, more of it is in the blood
Isoflurane, Nitrous oxide, desflurane, sevoflurane. Rank the preceeding in order on increasing blood:gas partition coefficient. What does this mean practically?
Des - 0.42
NO - 0.46
Sevo - 0.68
Iso - 1.4
The higher the number, the longer to induce and the longer to wake up (most soluble)
Identify the anesthetic. Irritating to airways, 0.2% metabolism (moderate) and minimal myocardial depression, not as prompt recovery as others
Isoflurane
Identify the anesthetic. Irritating to airways, 0.02% metabolism (low), prompt recovery and minimal myocardial depression.
Desflurane
Identify the anesthetic. Non-irritating to the airway, 2-5% metabolism (relatively high), minimal myocardial depression and prompt recovery
Sevoflurane
Identify the anesthetic. Adjunct to volatile anesthetics, reduces MAC requirements, very insoluble.
Nitrous oxide
What are the receptors thought to be facilitated by general anesthetics? What receptors are thought to in inhibited?
Facilitated - GABA and glycine
Inhibited - Excitatory glutamatergic transmission
Anesthetics are most likely to affect _ and _ receptor signaling systems. Adjuncts are most likely to affect _ (3) signaling systems and would therefore have MAC sparing effects
Glu and GABA signaling
His, Ach and NE
What is the effect of volatile anesthetics on:
- Respiratory rate
- HR
- Cardiac output
- Systemic vascular resistance
- Decrease
- Decrease
- Decrease
- Decrease (vasodilators)
In some individuals, a drug increases skeletal muscle metabolism, which overwhelms the body’s capacity to supply O2, remove CO2, and regulate. body temperature. This refers to _. What are 2 types of drugs that can cause this? What drug is used to treat it?
Malignant hyperthermia
Volatile anesthetics, succinylcholine
Dantrolene
General anesthetics are administered by mixing with _(3)
Air
Nitrous oxide
Oxygen
Anesthetics are analgesic or amnestic, or both?
Amnestic, not analgesic
What is the major neurotransmitter of the reticular activating system (2)? Where is it found?
NE and glutamate
Brainstem
What is the major neurotransmitter by which the thalamus communicates with the cortex? The Cortex connects with the thalamus via what NT?
GABA
Glutamate
An EEG is a recording or activity in what area of the brain? It can be used as a proxy for_
Cortical activity
Depth of anesthesia
The hypothalamus and basal forebrain communicate with the cortex via what neurotransmitters (3)?
NE, Ach and Histamine
Hyperacidosis, rigiditiy, hyperkalemia, myoglobin release and kidney failure can all develop if _ is not treated
Malignant hyperthermia
What is the mechanism by which dantrolene works? What is the mechanism?
Blocks calcium release from the sarcoplasmic reticulum, which relaxes skeletal muscle and decreases high metabolism
