Baics Of General Anaesthesia Flashcards
What are the 4 stages of Anesthesia
- Analgesia
- Excitement
- Surgical Anaesthesia
- Medullary Depression
Nimbex
Cisatracurium
Define the word anesthesia
Anesthesia is described as a temporary and reversible loss of awareness and reflex reactions to noxious stimuli
List three types of ion channels
Ligand gated channels.
Voltage gated channels.
Metabotropic (Gprotein) receptor gated channels
Define hyperpolarization
It’s a natural phenomenon in which the membrane potential is made more negative. This increases the need of more stimulus to obtain an action potential. It is the opposite of depolarization.
What is the name of the main inhibitory neurotransmitter in the central nervous system?
Gamma, amino, butyric acid
GABA
Where can you find gabba sub type a receptors?
On the post synaptic neuronal membranes
What happens when GABA binds to the receptors found on the post synaptic neuron membranes
It’s activates chloride channels (GABA gated chloride channels)
Negatively charged chloride ions enter the neuron through open channels, cause hyper polarization of the nerve membrane, rendering the neuron less excitable
How do benzodiazepines achieve the effects of hyper polarization
Benzodiazepines increase the frequency of opening of the chloride channels
(FREN zodiazepine)
How do barbiturates cause hyperpolarization in the post synaptic neuron
Barbiturates achieve its effect by increasing the duration of the opening time of the channels
(Barbi DUR ates)
Benzodiazepines, barbiturates, etomidate and propofol, depress central nervous system activity, by increasing the action of GABA.
Unlike the other IV anesthetics, how does ketamine function
Ketamine depresses central nervous system activity by suppressing excitatory synaptic transmission mediated by L glutamate
Ketamine depresses central nervous system activity by suppressing excitatory synaptic transmission mediated by
L-glutamate
How does L glutamate function
Binding of El glutamate to channel protein sites on the post, an optic nerve cell membrane activates calcium channels.
The influx of positively charged calcium ions into the cell through these open channels, cause depolarization of the membrane potential and facilitates neuronal excitation
Which channels does GABA act on?
Chloride channels
When GABA binds to its post synaptic receptor, it causes an influx of chlorine into the cell, which causes hyperpolarization
How does N methyl D aspartate work?
NMDA is a L glutamate agonist having its own binding site
How does ketamine work?
It is an L glutamate antagonist, having its own binding site
Describe, or define ketamine as an anesthetic agent
Ketamine is a dissociative and inhibits post sign up excitatory action of L glutamate
Describe two types of non-competitive antagonist
Type one can be described as an antagonist that binds irreversibly to the main binding site
Type two can be described as an antagonist that binds to an allosteric site that causes changes
What is the relationship between minimum angular, concentration, and lipid solubility of an anesthetic agent?
The minimum alveolar concentration required to maintain anesthesia, is lower for more lipids, soluble inhalation agents
There are four stages of anesthesia describe stage one
Analgesia the state of analgesia last from onset of jest to loss of eyelash reflex
How do you characterize stage two of anesthesia?
Stage two of anesthesia is described as the excitement stage it’s characterized by agitation and delirium.
(RDDR)
Respi Irregular (start)
Dilated pupils
Divergent eyes
Respi Regular (end)
The surgical anesthesia stage three is divided into how many planes
4 planes
Plane 1, Plane 2, Plane 3, Plane 4
Describe plane one in stage three of anesthesia
rhythmic respiration
rapid eye movement
Describe a plane two in stage three anesthesia
This plane lasts from the cessation of rapid eye movement to onset of paresis of intercostal muscles
Describe plain three of stage three anesthesia
This last, from the onset of paresis of intercostal muscles to paralysis of these muscles
Describe plan for in stage three anesthesia
This last, from paralysis of intercostal muscles, the paralysis of the diaphragm, the patient ceases to breathe at the end of this plane
Describe stage four of anesthesia
This is titled in pending death. It is the stage of impending death that lasts from the onset of apnea to failure of circulation, and represents medullary depression.
What is the Seldinger technique
An over-wire technique of catheter insertion to obtain safe percutaneous access to vessels and hollow organs. The Seldinger method of guide-wire catheterization - CVP
What does pulmonary capillary wedge pressure measure?
Left Ventricular End Diastolic Pressure
What is the formula for Cardiac Output
SV x HR
What is the formula for blood pressure
CO x SVR
What does a decreased SV in the setting of a low PCOP / LVEDP indicate ?
Hypovolemia and the need for volume administration
What does a “full heart”, high PCOP/LVEDP and low SV indicate?
The need for positive inotrope
Epinephrine ie, because of a cardiogenic shock
How do you treat a normal or increased stroke volume in the setting of hypotension ?
Administer Vasoconstrictors (Vasopressin, Angiotensin II)
List one way that haemodynamic performance can be assessed that is less invasive than Pulmonary Artery Catheterizaetion
Transpulmonary Thermodilution CO measurement
Pulse contour analyses of the arterial pressure waveform
