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Flashcards in Anesthesia - Total Deck (27)
1

NAme the different forms of anesthesia and the drugs used for them.

IV = Propofol, Ketamine, Etomidate, Dexmedetomidine etc

Inhaled Anesthetics: Isoflurane, Desflurane, SEvoflurane, Nitrous

Sedatives: Midazolam and Diazepam

Narcotics/Opioids: Morpine, Fentanyl etc

Local Anesthetics: Lidocaine and Bupicavaine

Muscle Relaxants: Succinylcholine or Rocuronium 

 

Others: Antiemetics, Anticholinergics, Reversal agents 

2

Name the 4 IV Anesthetic agents (non-barbituate or benzodiazepine). 

 

Of those, which ones cause Respiratory Depression and need skilled airway technicians and which ones can be given outside of OR (like ER/ICU)?

 

Which ones cause bronchodilation? (therefore good for asthmatics and smokers) 

Names: Propofol, Ketamine, Etomidate, and Dexmedetomidine

Propofol can cause POTENT respiratory depression/apnea and also suppresses upper airway reflexes and so is good for Bronchoscopy/Upper Endocopy procedures and instrumentation of the airway and causes Bronchodilation

vs

Ketamine*, Etomidate*, and Dexmedetomidine cause minimal respiratory depression (*if infused slowly); Ketamine and Demedotmidine good for ER/ICU

 

Ketamine causes Bronchodilation (good for asthmatics) but also increased secretions so give with Glycopyrrolate 

3

Name the 4 IV Anesthetic agents (non-barbituate or benzodiazepine). 

 

Of those, which ones cause Cardiovascular depression/instability? 

Names: Propofol, Ketamine, Etomidate, and Dexmedetomidine

ETOMIDATE = good for CV stability!!! Use for Trauma and Cardiac patients

vs

Propofol causes vasodilation and hypotension

Ketamine causes Increased Sympathetic tone - Increased HR, BP, CO and Myocardial Oxygen use - DO NOT USE WITH CAD or cardiac patients 

Dexmedeotimidine causes CV depression, bradycardia and hypotension - DO NOT USE with CV pts or in Kids where CO depends on HR 

4

Name the 4 IV Anesthetic agents (non-barbituate or benzodiazepine). 

 

Of those, which ones are good for Neurosurgery/brain patients? Which ones cause CNS effects and what are those effects? 

Names: Propofol, Ketamine, Etomidate, and Dexmedetomidine

Propofol decreases CBF, CMRO2, ICP, is anti-convulsant and neuroprotective = IDEAL for neurosurgery patients with TBI, Tumor or seizure

vs

Ketamine - Increase CBF, CMRO2 and causes siezuers - DO NOT USE in TBI/neurosurg

Etomidate - decrease CBF and CMRO2 but causes Myoclonus/Seizuers in 50% pts 

vs

Dexmedetomidine - sedation and analgesia with no real changes in CMRO2 or ICP

 

 

5

Name the 4 IV Anestetic agents (non-barbituate or benzo) and their mechanism of action.

 

Which ones have analgesic effects?

Propofol and Etomidate = Potentiates the opening GABA Type A receptor Chloride channel to decrease AP propogation in Post-synaptic neuron

 

Ketamine = NMDA receptor antagonist (stops binding of Glycine and Glutamine which are excitatory) to decrease POst-synaptic AP firing AND causes increased catecholamine release 

 

Dexmedetomidine = Alpha2 Adrenergic Receptor Agonist that acts in Locus Ceruleus to decrease NE release and firing in SC and Brain 

 

Ketamine and Dexmedetomidine have analgesic effects! 

6

Propofol - uses, metabolism and effects. 

Warning? 

Pros  and Cons

- Made with soybean, glycerol and lechicin - EGG ALLERGY!!! and Needs sterile technique

- Metab in Liver and excreted via Kidney but pts wake up in 8-10 after bolus from Redistribution 

- used for induction, maintenance, and sedation (repeat boluse for dental procedure)

- good for Tumor/TBI/Seizure neurosurg patients and for bronchoscopy/endoscopy bc stops Airway reflexes 

EFFECTS: Neuroprotective, CV depression (hypotension), Resp depression but with bronchodilation, Anti-emetic 

WARNING: PIS = lactic acidosis with long term infusion -do not use in ICU

 

Pros: amnesia, fast on/off, ant-emetic, neuroprotective, bronchodilation 

Cons: Pain with injection, no pain relief, cardiac and respiratory depression, Egg allergy, PIS 

 

7

Ketamine - uses, metabolism, effects

 

Warning?

 

Pros and Cons

- Used for induction (can be IM), maintenance, Sedation (for short pain procedures like burn dressing changes), and post-op pain (abdominal, thoracic, ortho) and chronic pain - Sedative/Dissociative and Analgesic 

- Metab to Nor-ketamine (less active metab) in Liver and excreted ~3 hours

- CAN INCREASE CATECHOLAMINES - vasoconstriction and bronchodilation

Given with Midazolam for Emergence Reaction and Glycopyrrolate for Secretions

NOT for Neurosurgery pts or pts with CAD or CV patients. Good for asthmatics.

- Effects: Dissociative, can cause seizures, Emergence reaction/hallucinations, increased Sympathetic tone and Myocardial depression in critically ill pts

 

PROS: Analgesia (good for chronic pain and narcs), MINIMAL Resp depression, can be given IV/IM/Rectal/Oral/Epid, Bronchodilation

 

CONS: Emergence delerium (combat with Midazolam), Increased resp secretions (combat with Glycopyrrolate), HTN + Tachycardia and then cardiac depressio in ill pts, Increased ICP and Seizures (not for TBI pts) 

8

Etomidate - uses, metabolism, effects

 

Warnings?

 

Pros and Cons

- used for Anesth Induction in Unstable CV patients

- Metab by Ester Hydrolysis; peak to brain in 1 minute - fast but then into urine/bile in 2-5 hrs

WARNING: ADRENOCROTICO SUPPRESSION with just 1 dose: blocks 11beta hydroxylase from converting cholesterol to cortisol and so really sick ICU pts can't have life-saving stress response afterwards 

 

Effects: CV stability, minimal resp depression, Decreased CBF and CMRO2 but causes Myoclonus in 50% pts 

 

PROS: CV stability and minimal resp depsession

 

CONS: Pain on injection, Seizures!!!, Adrenocorticosuppression - not for ICU PTS!!!, Myoclonus (rigity and so have to time correctly with muscle relaxants for intubation) 

9

Dexmedetomidine - uses, metab, effects

 

Warnings?

 

Pros and Cons

- used for sedation for procedures and as general anesthesia bc decreses doses for inhaled and analgesics

SOME ANALGESIA

Effects: CNS sedation and analgesia but no changes in ICP etc, CV depression (hypotension and bradycardia - NOT used for CV pts or Kids), Minimal Resp depression

 

Pros: sedation and analgesia, no respiratory depression

Cons: hypotension, bradycardia, Longer onset and Duration 

10

What are the Benzodiazepines? How are they used? Metabolised? Mechanism? Effects?

Midazolam and Diazepam both bind to specific sites on GABA receptor and increase affinity of receptor for GABA leading to increased hyperpolarization of post-syn neuron and decreased AP firing

 

Metab - in liver and Midaz to inactive metabolite and Diazepam to 2 active metabolites which is why it causes the Hangover Effect and has longer half-life

- They have rapid onset into BBB and are off with Redistribution 

- Midaz can be taken lots of ways but diazepam is only oral

Used for Pre-Op anxiety or Amnesia, Sedation in short procedures, and seizure suppression

 

Effects: CNS - sedation, hypnosis, Amnesia, antoconvulsant, decreased CMRO2 and blood flow; Resp - minimal resp depression; CV - lowers TPR and BP (midazolam more) but no real changes in CO 

11

What are the BArbituates? Special Features? Metabolism? Effects? Uses?

 

Warning!

Thiopental and Methoheital are salts that mix with water to make Alkaline pH solutions (pH>10) and bind to GABA A receptors and increase affinity for GABA.

Metabolized in Liver and have INDUCTION effects and are cleared more rapidly with inducers (ex. takes longer to put down an Alcoholic with Thiopental)

- Precipitates with Acid in IV lines

Used for Induction and neuroprotection for putting pts in coma with increased ICP or Focal Ischemia

Effects: CNS - sedation, anesthesia, *DECREASE Pain threshold!!!, decrease CBF, ICP, CMRO2 (can cause coma/flatline); CV - decrease BP and vasodilation thats exagerated in elderly, CV disease, and hypovolemia pts; Resp - decrease minute ventilation, Tidal volume, RR, and responses to hypercapnea/hypoxia but no suppression in airway reflexes; PAIN on injection and GANGRENE if injected into arteries (can lose hand/feet)

 

WARNING: DO NOT USE IN ACUTE INTERMITTENT PORPHYRIA

- stimulate D-ALAS synthesis of Heme and pts with AIP can't convert the final step of Porphyrinobilinogen to Heme and so it builds up and get hallucinations, psychosis, numbness, abdominal pain etc 

12

What is the common moiety for all of the volatile anasthetics?

Ether

13

What are the general effects of Inhaled Volatile Anesthetics? what do they all cause? 

Unconsciousness, Amnesia, Immobility 

BRONCHODILATION

Vasodilation and hypotensoion that's particularly bad in sick patients who can't recover from it 

14

What is MAC? Significance? Use? 

MAC = concentration of anesthetic to stop movement in 50% of patients

GOAL = MAC 1 

At MAC .5  Amnesia

At MAC 1.2 or 1.3 can get dangerous (CV failure and coma) 

IN GENERAL: Increase MAC then Decrease Potency and MACs are additive 

 

Measure of Potency essentially 

15

What is the blood gas partition coefficient and what does it mean?

Measure of solubility of the gas in blood (trends are generally applicable to tissues as well)

Lower Number = Less soluble 

N2O < Des < Sev < Iso 

Iso is most soluble - therefore takes the longest for emergence 

Nitrous and DES are least soluble in all tissues 

16

What are the inhaled anesthetics?

Desflurane, Sevoflurane, Isoflurane, and Nitrous

17

Desflurane - MAC, solubility effects/uses

Least Soluble (low Blood Gas Partition coeff) therefore good for long surgeries and obese patients  bc Rapid on/off

Least potent (High MAC) - have to use ALOT and is VERY expensive!!! 

 

Effects - Tachycardia!!! 

18

Sevoflurane - MAC, solubility, uses and effects

Medium Solubility (BGpartition coeff) so good for long cases and obese people for on/off rapidity 

Medium Potency (MAC)

CHEAP!

Non-pungent so no resp secretions or coughing

Effects - Emergence Delerium, can Prolong QT Interval 

Uses - used in PEDS for induction bc non-pungent and then once IV is placed switched to Iso so no emergence delerium 

19

Isoflurane - MAC, solubility, effects, and uses

MOST soluble (highest coefficient) - therefore longer emergence and so bad for long surgeries and obese people bc long-acting

MOST Potent (Lowest MAC)

Most economical

*HEMODYNAMIC STABILITY

Used alot! 

20

Nitrous - MAC, Uses, Contraindications, effects 

Can NEVER achieve a MAC of 1 with it bc then there would be no oxygen in inhaled gas so used in combination with others

Cheap and can cause Second Gas Effect: diffuses faster than nitrogen and so increases air spaces in lungs so can get more of other gases in faster 

Cheap 

USED FOR PEDS INDUCTION bc non-pungent 

Effects: - Increased N/V

NOT FOR USE IN SURGERIES WITH AIR SPACES: bowel, distension, lungs - pneumothorax, middle ear 

DO NOT USE with Laprascopically 

21

Why is PA measured with inhaled Anesthetics? What are the factors that change PA? 

PA = Pa = Pbr and when constant Pbr then constant PA measured

1) Solubility: based on blood gas partition coefficient

- MAIN factor for induction and emergence

- Dont want gas to be very soluble in blood bc want it to go out to act in brain

- N2O < Des < Sevo< Iso

2) PI - inspired anesthetic partial pressure 

- increased parital pressure then faster induction and then once uptake into blood slows then can decrease PI for maintenance and constant Pbr

3) Alveolar Ventilation: increased ventilation accelerates induction bc faster when breathing more/harder

4) CO: lower CO then increased induction bc more passengers able to get on/off the train 

22

Factors for Emergence from inhaled anesthetics?

Solubility - less soluble then out from tissues/sytem faster (ex. Iso most soluble and longest emergence)

Alv Ventilaion and CO 

 

Tissue Concentration - reservoir for gas that determines duration

Metabolism - not clinifcally significant 

23

Organ effects for Inhaled Anesthetics: Cardiovasular

Volatile Anesthetics decrease MAP bc cause Vasodilation (N2O no change MAP)

Changes in HR - Desflurane causes Tachycardia

Few arrhythmias

*Cardioprotective! Ischemic preconditioning

 

Sevoflurane - can Prolong QT 

24

Organ Effects for Inhaled Anesthetics: Respiratory 

Incresaes in RR but decreases in Tidal volume = no change in Minute Ventilation but are breathing shallower and faster so get Decrease FRC and Increase Dead Space

Reduced gas exchange = increase PaCO2 and less responsive to it at high MAC = Apnea 

 

Sevo and Nitrous = non-pungent so no coughing or secretions

 

ALL VA CAUSE BRONCHODILATION

25

Organ Effects for Inhaled Anesthetics: CNS

- Cerebral Vasodilation, Increased CVF and ICP!!!!

*VA cause Uncoupling of CBF and CMRO2!!!! BAD for tumors and bleeding 

... but sometimes decrease CMRO2 can be neuroprotective

 

Dose-dependent CNS depression 

N2O has some analgesic effects

26

Organ Effects for Inhaled Anesthetics: Random other effects

Neuromuscular - VA can cause dose-dependent skeletal muscle relaxation and enhances paralytics

 

Renal = transient decreases in renal blood flow and GFR

Liver = reduced hetapic flow 

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