Drugs in General Anesthesia Flashcards
Drugs used in GA
IV induction agents
Inhalational induction agents
Muscle relaxants and reversals
Analgesics
All the induction agents are _____ and act on _____ receptors which causes ______ and subsequently _______
- Depressants
- GABA receptors
- Increased chloride conductance
- membrane hyperpolarization
Examples of barbiturate induction agents
Thiopentone sodium
Methohexital
What is arm brain circulation time?
Time taken for onset of induction agents
Onset of Thiopentone sodium
15 secs
ph of Thiopentone sodium
10.5 (most alkaline)
Thiopentone sodium:
1. Smell
2. Termination of action is by ____ because the drug is highly ______
3. Dose
4. AOC in ________
5. Other use
6. Accidental intraarterial injection causes
7. Mx in case of intraarterial injection
- Garlic/ onion
- Redistribution, lipophillic
- 3-5mg/kg
- NeuroSx, Hyperthyroidism
- Truth serum
- pain, pallor, gangrene, edema
- Retain cannula (to prevent vasospasm), saline/ heparin flush, stellate ganglion block (lower cervical sympathetic ganglion)
Why is Methohexital avoided in neuroSx?
Proconvulsant
Indication of Methohexital
Dose
ECT
1-1.5 mg/kg
Examples of non barbiturate induction agents
Propofol
Etomidate
Ketamine
Propofol
1. Form? This leads to? What is done to prevent this?
2. Made of?
3. Should be used within?
4. Properties
5. Dose:
6. Duration
- Oily–> painful–> add lignocaine
- Egg lecithin, soya bean oil
- 6 hrs
- Antipruritic, antiemetic
- 1-2.5 mg/kg
- 8-10 mins (w/o hangover)
Propofol
1. AOC in?
2. Side effects?
- Day care Sx and MAC Ophthalmic Sx bc dec IOP
LMA insertion and in laryngospasm bc dec reflexes
TIVA
Endoscopy and colonoscopy - Propofol infusion syndrome– on prolonged–
green urine, severe metaolic Acidosis, asystole
addictive d/t pleasant hallucinations
Etomidate
1. Form:
2. Properties
3. Dose
4. AOC in
5. Side effects
- oily– propylene glycol
- Most cardiostable
- 0.2-0.3 mg/kg
- DC cardioversion, cardiac aneurysm Sx
- myoclonus, emetic and epileptogenic, inhibits adrenocortical synthesis
Ketamine
1. Form
2. Properties
3. ___ receptor antagonist
4. DOse:
5. How to increase duration
- Phencyclidine derivative
- Dissociative anesthesia, depressant (in vivo)
- NMDA; increases catecholamine
- 1-2 mg/kg IV; 4-6 mg/kg IM
- intrathecal admin; used with LA
Ketamine
1. AOC in
2. Side effects
3. C/I
- Shock ( to incr HR and BP)
Asthma/ COPD (bronchodilator)
TOF
In low resource settings (burns, i and D)
Pediatric Sx - inc oral secretions (Tx: atropine/ glycopyrrolate), unpleasant hallucinations/ emergence (reduces with midazolam)
- HTN, cardiac conditions, ocular sx (inc IOP)
Inhalational agents enter and exit circulation via?
lungs
Inhalational induction agents are used to _____
maintain depth of anesthesia
Newer inhalational agents
Halothane, Isoflurane, Desflurane, Sevoflurane
They are non flammable
Older inhalational agents
Ether, chloroform, trilene, cyclopropane
Meyer overton rule
Potency proportional to lipid solubility