Anesthesia Flashcards
What is MAC
concentration at which 50% of patients won’t respond to skin incision.
Methohexital properties
GABAnergic, suppresses reticular activating system. May potentiate seizures.
What lung capacity is decreased in a pregnant patient and obese patient?
FRC is decreased.
Pediatric larynx position compared to adults?
Anterior and superior.
Propofol + which HTN medication = hypotensive.
Propofol causes vasodilation.
ACE/ARBs- block RAS.
Patient cannot compensate.
Edrophonium/Tensilon test
Test for suspected Myasthenia Gravis. Edrophonium = acetylcholinesterase inhibitor. Looking for approx 5min improvement in muscle strength.
When to give adenosine?
Antiarrythmic for tachycardia/SVT conversion if narrow complex and stable. 6mg rpaid push.
0.05-0.1mg/kg in kids.
When to give Atropine?
Bradycardia.
0.5mg for Bradycardia.
1mg if asystole/PEA arrest.
In kids atropine is 0.02mg/kg for brady.
Dopamine effects on the body
Stimulates alpha, beta-1, and dopaminergic receptors. Pleasure, cognition, memory.
Treatment of myotonic dystonia with laryngospasm
Roccuronium + Positive Pressure O2. Avoid Succinylcholine.
Ketamine mechanism
NMDA antagonist
Malignant hyperthermia is via what enzyme
Creatine phosphokinase.
How is MH treated?
IV Dantrolene 2.5mg/kg every 5 mins until reversal. Or up to 10-20mg/kg total. CK should be trended.
Nitrous teratogen mechanism
Inhibits methionine synthase and vit B12.
Do barbiturates cause seizures?
No. Except for methohexital. Otehrs are seizure treatment.
What is the main complication with prolonged intubation?
Tracheal stenosis.
Why use a cuff-less tube in pedo patients?
Narrowest portion is at cricoid cartilage. Avoid excess pressure on tracheal tissues and reduce post-extubation stridor.
Desflourane has rapid onset and offset due to?
Very low blood gas partition co-efficient. Relatively insoluble in fat making emergence fairly rapid after a long case.
Infants blood pressure is dependent on what?
Heart rate.
How doe benzodiazepines affect sleep?
Reduce time to sleep onset and increase total sleep time.
How much REM sleep at night?
20-25% of total sleep
Which narcotic is metabolized by plasma cholinesterases?
Remifentanyl
How is articaine metabolized.
Plasma (primarily) and liver. Due to ester side chain.
All amide local anesthetics are metabolized in the liver except?
Articaine. Plasma + liver.
Compound A
Product of Sevoflourane.
Causes Kidney damage.
Local anesthetic with lowest pKa
Mepivicaine/Carbacain= .6
Lido,prilo, articaine= 7.8
What determines potency of local anesthetics?
Lipid solubility
What determines duration?
Protein binding
What determines onset
pKA
Lidocaine Max dose
4.5mg/kg w/o epi. w epi 7mg/kg
Articaine Max dose
7mg/kg
Bupivicaine Max dose
1.3mg/kg
Carbocaine max dose
4mg/kg
Which local anesthetic can significantly prolong succcinylcholine?
Procaine
What test can be used to determine is someone has an atypical plasma cholinesterase
Dibucaine number
>80 is normal
,80 may have prolonged effects of succs.
What happens to lungs as they age?
reduced alveolar surface area.
Etomidate side effects?
PONV and adrenal suppresion.
Why can succ be used w/out issue in myasthenia gravis
fewer funcitonal receptors. These patients require more succ than normal. MG patients ARE more sensitive to non-depolarizing neuromuscular blockers.
What anesthetic agents are NOT thought to cause acute intermittent porphyira?
Nitrous and Narcotics.
What is the initial dose of Dantrolene for MH?
2-3mg/kg
How is dantrolene mixed
60ml steriile water/20mg bottle. Then, the appropriate 2.5mg/kg dose is
injected rapidly after reconstitution. Should have 36 bottles on hand for MH crisis if using triggering
drugs.
What durgs can cause methemmogloinemia?
Articaine, Benzocaine, prilocaine, Bactriim, sulfonamides, dapsone.
What is the treatment of methemoglobinemia
O2 and methylene blue 1% solutin dosed at 1-2mg/kg given over 5 minutes.
How to treat Torsades?
1-2g Magnesium over 5-60 minutes.
Fentanyl Dose
Wide range. Intraop 2-50mcg/kg.
Meperidine + MAOIs=
Serotonin Syndrome
cardiac instability HTN and hypotension, hyperpyrexia, coma, respiratory arrest
Serotonin syndrome
Dilaudid Dose
0.01-0.02mg/kg
Can cause histamine release
Morphine Dose
0.1mg/kg
5-10% excreted by kidney. Renal failure may prolong duration.
Naloxone Dose
Generallysmall doses: 0.1-0.2mg q2-3min. Full reversal is 0.4-2mg
Sevoflurane
Blood/gas coefficient is 0.65
MAC is 2.
Low solubility and non-pungency
Isoflurane
Blood gas coefficient is 1.4.
MAC is 1.2.
Desflurane
Blood gas coefficient 0.42
MAC is 6
Low solubility in both blood and body tissues
causes a very rapid induction and emergence. Rapid increases can lead to transient but significant
increases in HR, BP, and catecholamine levels
Nitrous
Blood gas coefficient 0.47
MAC 105
Prolong exposure to Nitrous causes
Bone Marrow suppression.
Megaloblastic anemia.
Nitrous in Pregnancy?
Oxidizes Vit B12 so affects B12 dependent
enzymes, including methionine synthetase.
Halothane
Rare but associated with halothane hepatitis.
MAC is 0.75
Propofol Dose
1-2mg/kg induction dose.
Propofol infusion syndrome
long infusions can cause lipemia, metabolic acidosis,
and death = propofol infusion syndrome
Etomidate Dose
Induction 0.3mg/kg.
Cisatracurium
Hoffman Elimination.
Reglan in Parkinsons
Blocks dopamine receptors. Extrapyramidal effects.
Ondansetron
5HT3 blocker- can cause QT prolongation.
Droperidol
Caution in Parkinsons patients. Also causes prolongation of QT interval.
Metoprolol
Beta 1 selective. Given as bolus of 2.5-5mg over 2 minutes in A-fib and RVR.
Vasopressin
acts as ADH- Directly stimulates smooth muscle V1 receptors casing vasoconstriction.
Levophed
NE. Mostly alpha and beta.1 effects. Usually given as 2-20mcg/min infusion but can bolus 0.1mcg/kg.
Epi
Anaphylaxiss usually in 100mcg increments. As a pressor run from 2-20mcg/min.Ph
phenylephrine
Primarily an alpha 1 agonist. Can cause rebound bradycardia.
Aprepitant
Neurokinin-1 receptor antagonist. Antiemetic.
Diltiazem
CCB, inhibits calcium influx into vascular smooth msucle, relaxes smooth msucle. Decraseses SVR, dilates coronaries, and prolongs AV node refractory period. 0.25mg/kg IV for afib with rvr.
