Ethereal 

MOST PUNGENT 

Desflurane 

Sevoflurane

N2O

N2O

Metabolized in GI tract 

TFA

Chloride

Bromide 

Inorganic Fluoride

Organic Fluoride 

Inorganic Fluoride

Organic Fluoride

CANNOT LEAD TO HEPATOTOXICITY 

TFA

Fluoride

CO2

Water 

1st highest: Desflurane

2nd: Enflurane

3rd: Isoflurane 

Halothane

Isoflurane

Desflurane

Nonflammable BUT combustable

IMPOSSIBLE to reach 1 MAC

Least amount of muscle relaxation

Inactivates B12

GAS EXPANDER! NEVER use in ENT, MVAs, pnuemos, etc.

Useful in 2nd gas effect

Can cause Diffusion Hypoxia if d/c abruptly

May play a role in post-op NV  

No analgesic properties only hypnotic properties 

Stored in brown bottles because of Thymol preservative!

Tends to enhance the arrhythmogenic effects of epineprine

Decreases seizure threshold= more likely to sz

Metabolites are nephrotoxic 

Does NOT enahance the arrhythmogenic effects of epi OR cause hepatotoxicity 

Isomer of Enflurane

Extremely stable when exposed to CO2 absorber

Boils at room temperature

Needs heated gas vaporizer- fixed ratio output

AIRWAY IRRITANT

Rapid Induction and Emergence

Produces Bronchodilation!!!

Perfect for Inhalation induction

Compound A- keep flows greater than 1L/min

No hepatotoxicity- exposure to renal tubles is limited due to rapid pulmonary elimination 

Inspired Partial Pressure

Alveolar Ventilation

Characteristic of Anesthetic Breathing System

Functional Residual Capacity (FRC) 

Blood: Gas coefficient

Cardiac Output

Arterial-Venous Partial Pressure Difference

Brain: Blood partition coefficient

Cerebral Blood Flow

Arterial- to Venous Partial Pressure difference 

Individual Varations in Water, Lipids, protein, and hematocrit

Age- neonates need less 

DOES NOT ehance arrhythmogenic effects of epinephrine

caues HEPATIC TOXICITY and NEPHROTOXICITY (especially with prolonged exposure) 

High solubility so prolonged induction and slow recovery

Analgesic properties  

Nonflammable

Poorly Lipid Soluble

Resistant to Metabolism

Volatiles are Ethers (R-O-R) with no more than 4 hydrocarbons 

75% N2O can double a pneumo in 10 mins, triple in 30 mins

Do NOT use in traumas, carotids, cranies, ENT, tympanoplasty  

Can also expand PA catheter balloons and ETT cuffs 

Accumulates in middle ear, may explain PONV 

MAC: 63-71%

Nonexplosive, nonpungent, odorless, chemically inert

High cost

B:G Coefficent 0.115

Hyponotic and analgesic

NO HEMODYNAMIC DEPRESSION- in adults 

The greater the alveolar ventilation to functional residual capacity ratio, the more rapid the rate of increase in PA 

Induction of anesthesia in neonates is faster than adults 

5-10 L

Negative the buffer system on the tubing 

Increase PI- faster induction 

Increase in temperature decreases solubiilty of gas 

Overpressurizing helps to overcome solubility 

Ingestion of fatty meal increases solubility 

Young and elderly have 18% less solubility

1= 63%

3= 95%

4=98%

Takes 3 time constants to reach SS

Brain, Heart, Kidneys

10% of body mass but recieve 75% CO 

After 3 time constants 75% of returning venous bloos is @ same partial pressure as the PA 

Greatest in the first 1 to 5 mins after discontinuation of N2O

Due to intial high- volume outpouring of N2O from blood 

Hyperthermia

Hypernatremia

Chronic ETOH

Red Headed Females

Increased Central Neurotransmitter Levels

Increasing Age, and infants

Hypoxia

Acidosis

Hypothermia

Hyponatremia

Pregnancy

Acute ETOH

NMBs (10x clinical dose?)

Opioids and Barbiturates 

Anemia 

Duration of anesthesia

Gender

Hyocarbia/Hypercarbia

HTN

Thyroid

Hyperkalemia

1.5 MAC

50% greater than MAC

Stereoisomers have different potentcies but same oil:gas coefficients

Certain drugs are highly soluble lipids but are convulsants

Increases in body temp change membrane but dont cause anesthesia

Increasing chain length increases lipid solubility but potency stops at cutoff length 

Ligand-gated ion channels- 

Metabotropic receptors- g protein coupled (protein kinases, K and Ca Channels)

Glycine receptors

Inhibits glutamate receptors (NMDA) 

Two Pore Potasssium Channels- stay open longer (TREK & TASK)

Presynaptic voltage gated Na Channels 

Female Gender

Middle Age

Obesity

Previous exposure to halothane

Polyuria

Hypernatremia

Hyperosmolarity

Increased Plasma Creatinine

Inability to concentrate urine

with Methoxyflurane 

Inhibits leukocytes

0.2 MAC all anesthetics inhibit virus replication

Oxidizes vit B12- unusable for certain ezymes causes congenital defects and decreases formation of RBCs 

< 0.4 MAC increased frequency and voltage (excitment phase)

0.4 MAC decrease in CMRO2, go from awake to unconscious

1MAC decrease in frequency and max voltage 

1.5 MAC burst supression

2 MAC electrical silence

(Des/Sevo-dose related similiar)

> 2 MAC 

or 

hyperventilation to PaCO2

Decrease in Amplitude

Increase in Latency

Waveforms adequate @ 0.5-0.75 MAC

0.4 Iso prevents recall

>0.5-0.6 MAC Nitrous 

Increases CBF up to 4 hours

>0.6 causes cerebral vasodilation= increased BF

maintains good CBF

Auto-regulation remains intact 

< 0.8 does NOT increase ICP

1.1 MAC increases ICP by 7 mmHg

Enflurane increase production and decreases reabsorption

Iso- increases reabsorption and doesnt change production 

Increase RR

Iso ceiling effect > 1 MAC

N2O increases RR more than other VA @ > 1 MAC 

Decrease ventilatory response

Increase CO2

@ 1.5-2 Des/Sevo cause Apnea

N2O does NOT increase CO2 (but doesnt decrease ventilatory response) 

Decreases response

0.1 MAC= 50-70% depression

1.1 MAC= 100% depression 

Iso, Sevo, Des decrease BP due to SVR

Halothane decreases BP due to decreased CO/contractility 

Iso/Des/Sevo increase HR

Halothane no change

Sevo doesnt increase until > 1.5 MAC 

Halothane decreases CO

Nitrous increases CO 

IDS decreases SVR

Halothane and N2O= NO CHANGE 

Halothane

Enflurane

Isoflurane 

Increase coronary blood flow

Iso= Coronary Steal Syndrome 

Abrupt increase in Des and Iso causes huge SNS stimulation

Des>Iso

Iso= hepatic vasodilator

Halothane= hepatic vasoconstrictor

VA increase portal vein BF 

Decreases Renal BF

Decreases GFR

Decreaes UOP

Increased UOP

Hypernatremia

Increase osmolairty of blood 

Increased Creatinine

Cant concentrate urine 

Halothane Biggest Trigger

N2O the least 

Decrease in uterine contractility

Decrease in uterine BF

N2O does not decrease contractility

Mild at 0.5--> substanial @ > 1 MAC 

Affects erythrocyte formation

DNA snythesis

Myelin formation