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Flashcards in Anesthesia - Total Deck (27)

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 


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


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 


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


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 


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


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 


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




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! 


Propofol - uses, metabolism and effects. 


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 



Ketamine - uses, metabolism, effects




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) 


Etomidate - uses, metabolism, effects




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) 


Dexmedetomidine - uses, metab, effects




Pros and Cons

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


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 


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 


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



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)



- 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 


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



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

Unconsciousness, Amnesia, Immobility 


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


What is MAC? Significance? Use? 

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


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 


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 


What are the inhaled anesthetics?

Desflurane, Sevoflurane, Isoflurane, and Nitrous


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!!! 


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)


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 


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


Used alot! 


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 



Effects: - Increased N/V

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

DO NOT USE with Laprascopically 


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 


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 


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 


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




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


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