Anesthetics Flashcards
(58 cards)
What are the 3 main components of Anesthesia?
Analgesia
Hypnosis
Relaxation
How do anesthetic agents work ?
Suppressing neuronal activity in a dose dependent fashion.
Interfere with neuronal ion channels.
Which type of anesthesia works rapidly and causes unconsciousness as soon as they reach the brain ?
IV Agents such as propofol
They also have rapid recovery.
Which pump system is used to allow accurate infusions to achieve specific blood and brain concentrations of agents ?
Target Controlled Infusion (TCI) pump
What is the anesthetic which is inhaled for GA ?
Halogenated Hydrocarbons
How do inhaled GA agents get into the patients blood stream ?
Cross the alveolar basement membrane into the circulation.
What is MAC ?
Minimum Alveolar Concentration.
The concentration of the drug required in the alveoli to produce anesthesia with any inhaled agent.
Low number = High Potency
What is the main role of inhaled anesthetic agents ?
Extension and continuation of anesthesia.
How does anesthesia work centrally on the CVS ?
Depresses cardiovascular centers in the brain-stem.
Reduces sympathetic outflow.
Negative inotropic/chronotropic effect on the heart.
Vasodilates = Reduction in SVR.
What happens to the cardiac output during anesthesia ?
Due to the vaso and venodilation there is decreased venous return and therefore decreased cardiac output
Which anesthetic drug is not a depressant of the CVS ?
Ketamine
How do anesthetic agents effect the respiratory system ?
All GA agents are respiratory depressants.
They reduce tidal volume an increase resp. rate (Opiates have the opposite effect).
They reduce hypoxic and hypercarbic drive via the depression of the brainstem resp. centres.
Lung volume is greatly reduced - hence the need for oxygen post-op.
What are the indications for muscle relaxants ?
Ventilation and intubation.
When immobility is essential.
Body cavity surgery.
What problems do muscle relaxants hold ?
Awareness - The seperation of unconciousness and hypnosis.
Incomplete reversal - Airway obstruction.
Maintaining and protecting the airway and providing ventilation to the lungs for as long as the muscle relaxants are working.
Why use analgesia during GA ?
Prevention of arousal
Opiates contribute to the hypnotic effect.
Suppression of reflex responses to painful stimuli i.e. tachycardia and hypertension.
Why use local/regional analgesia ?
Retain awareness/consciousness.
Lack of global effects of GA.
What is the process of anesthesia ?
Pre-op assessment Preparation Induction Maintenance Emergence Recovery Post-op care and pain management.
What is the triple airway manoevre performed by anesthetics ?
Head tilt
Chin lift
Jaw thrust
A laryngeal mask airway does what to the airway ?
Maintains but does not protect
What does an I-gel not protect you from ?
Aspiration
How does an obstruction happen ?
Ineffective triple airway manoevre.
Airway device malposition or kinking.
Laryngeal spasm.
What occurs in Laryngeal spasm ?
Forced reflex adduction of the vocal cords.
May result in complete airway obstruction.
Caused by airway stimulation in light planes of anesthesia.
When is the airway maintained and when is it protected ?
Maintained: Open and unobstructed.
Protected: Only a cuffed tube in the trachea protects the airway from contamination.
What is endotracheal intubation ?
Placement of a cuffed tube in the trachea - oral route.
Laryngeal reflexes must be abolished.
