What are the 4 Phases of Uptake & Distribution?
- Inspired Anesthetic Concentraiton
- Alveolar Anesthetic Concentration
- Blood Anesthetic Concentration
- Anesthetic from Blood to Tissue
What is "Wash In"?
Using high flows of O2 or O2/N2O @ 5-10L/min to control partial pressure of Anesthetic Gas
What is the Concentration Effect of Anesthetic Gas?
High Concentrations = Greater Uptake = Greater Inspired Volume
What factors effect the Rate of Alveolar Partial Pressure of Anesthetic?
When Alveolar ventilation is high, the partial pressure of the anesthetic at the alveolar ______ rapidly.
When Alveolar ventilation is high, the partial pressure of the anesthetic at the alveolar Increases rapidly.
What is the Second Gas Effect?
First gas (N2O) rapidly goes into blood and pulls the second gas (Sevo) along with it -->
causes rise of second gas more quickly
What factors determine how quickly Anesthetics go from Alveoli to Blood?
Solubilty of Gas
Cardiac Output - Rate of blood flow
Partial Pressure of Gases in Arterial/Venous blood
What is the Blood:Gas Partition Coefficient?
Ratio of Anesthetic Concentration in Blood to Anesthetic Concentration in Alveoli
Pa / PA
The more blood soluble the agent, the _____ time required for induction.
The more soluble the agent, the more time required for induction
How does a higher blood flow affect gas delivery to the tissues?
Higher blood flow = more blood exposed to agent = faster pickup of agent
What factors contribute to the teh Partial Presure of Anesthetic in the Tissue?
Solubility of Gas & Tissue Blood Flow
What happens in Stage 1 of Anesthesia?
Stage of Analgesia
Decrease Dorsal Horn Activity & Synaptic Transmission
Duration: Anesthesia Administration to Loss of Consciousness
What happens in Stage 2 of Anesthesia
Stage of Delirium/Excitement
Block of Inhibitory Neurons = Enhance Synaptic Transmission
↑BP & ↑HR
Begins: Loss of Consciousness
What happens in Stage 3 of Anesthesia?
Stage of Anesthesia
Depression of Ascending Sensory Pathways
Supression of Spinal/Skeletal Activity
Absent Cough, Gag & Eyelid Reflex
What happens in Stage 4 of Anesthesia?
Stage of Depression
Depression of Medullary Centers
Profound Respiratory & Cardiac Depression
The lower the MAC, the ____ potent the agent and the ______ the blood:gas partition coefficent.
The lower the MAC, the more potent the agent and the higher the blood:gass partition coefficent
What are Factors that Decrease MAC?
What are Factors that Increase MAC?
Chronic Drug/Alcohol Use
How does Hyperthermia > 42 C affect MAC?
How does Anemia w/ HCT < 10% affect MAC?
How does a PaO2 > 95 mmHg d/t decrease in pH in the CSF affect MAC?
How does Hypo/Hyperthyroid affect MAC?
How does Hypercalcemia & Hyponatremia affect MAC?
How does Hypernatremia affect MAC?
What drugs increase MAC?
Cocaine, Ephedrine & Acute use of Amphetamine
At what MAC will 95% of patients not move?
99% @ 1.3 MAC
What is MAC-awake?
50% of patients will respond to "Open your eyes"
0.3 MAC = Loss of Recall
What is MAC-BAR?
MAC needed to block Adrenergic Response to Skin Incision
What is MAC intubation?
Same as MAC-BAR - more gas than that needed for surgical incision
What is one thing that restricts the application of using MAC as a guideline?
Frequency of Muscle Relaxant Administration