iv anaesthesia agents

1. IV anaesthetic agent
Dr Smriti Bandhu
Associate Professor
Dept. of Anaesthesia

2. Thiopentone
• Chemical name 5ethyl-5(1 METHYL-butyl)2 thiobarbituric acid’.
• Highly alkaline PH of 10.5, Garlic smell, thiopentone sodium
• 6% anhydrous sodium carbonate is mixed for stability and solubility
• Moa- GABA receptor agonist.
Thiopentone comes as amorphous yellow powder which is dissolved
in normal saline or sterile water to make 2.5% solution.
• Dosage- 3-5 mg/kg/BW
• Shorter duration of action 10-12 seconds and consciousness is
regained within 6-8 mins, hangover after anaesthesia

3. Contd…
• CNS- ⇩ Cerebral metabolic oxygen requirement , ⇩Cerebral blood
flow and ⇩ Intracranial pressure. ( Neuro protective)
• CVS- ⇩ Cardiac output, Systemic vascular resistance, causes
peripheral vasodilation, decrease blood pressure
• Resp. syst- dose dependent respiratory depression.
• Rapid induction and rapid redistribution of drug from central
compartment helps in rapid awakening.
• Metabolized by liver

4. Contd..
• Clinical use –
• 1. induction of anaesthesia
• 2. Narco test (lie detector test)
• 3. Electro convulsive therapy
• 4. status epilepticus
• Barbiturate coma with infusion for head injury
patient.

5. Adverse effect/ side effects
• Laryngospasm
• Allergic reaction due to histamine release
• Accidental intra arterial injection causes vasospasm and gangrene of hand
• Symptoms – severe pain, pallor,gangrene and necrosis.
t/t leave cannula in situ, flush it with 500 unit heparin,1% lignocaine 10 ml is
given , ganglionic block stellate ganglion.
• Shivering
• Delirium
• Hypotension contraindicated in asthma , shock and porphyria

6. PROPOFOL
• 2,6 di iso propyl phenol
• White suspension(oil in water), k/n as MILK OF AMNESIA
• 1% solution , not soluble in water
• Preservatives: soyabean oil, glycerol, egg lecithin( support bacterial
growth) used within 6hr of opening
• Mechanism of action – facilitate inhibitory transmission mediated by
GABA A Receptor.increase the choride conductance and causes
hyperpolarization
• Propofol contain 0.005% of EDTA OR 0.025% sodium metabisulphite
to retard the growth of bacteria.

7. Propofol
• Rapid onset and rapid clear headed recovery
• Patient is uncounscius within 15-45 sec and effect last for 15-20 mins.
• Dose induction dose 1-2.5mg/ kg BW.
• Sedative dose 25-100mcg/kg/min.
• Maintenace dose 50-200/mcg/kg/min.
• Good anaesthetic for ambulatory surgeries.
• Relaxes upper airway so agent of choice for endoscopy, intubation,
and in asthmatic

8. Pharmaco kinetic
• CNS- decreases cerebral blood flow, decrease cerebral metabolic
activity and decrease intracranial pressure.
• CVS- causes direct myocardial depression, decreases Blood pressure,
decreases systemic vascular resistance , dose is reduced in elderly
patient.
• Resp. syt- respiratory depression, causes apnea.
• Other effects- it has antiemetic properties
• Does not trigger malignant hyperthermia.

9. Clinical use
• To induce general anaesthesia
• TIVA (total intravenous anaesthesia)For day care procedure
• For Conscious sedation
• Fo ICU sedation
• SIDE Effects- hypotension, apnea, pain on injection propofol infusion
syndrome, lactic acidosis, hyperlipidemia.
• Not used in shock, egg allergy,
• Excreted via kidney

10. ETOMIDATE
• Imidazole derivative,
• 0.2% aqueous solution in 35% propylene glycol
• MOA- GABA agonist.
• Dose 0.2-0.3mg/kg body weight
• Effects on major system
• 1.CNS- Reduce cerebral metabolic oxygen requirement, Cerebral
blood flow, and Intracranial pressure.
• CVS- minimal changes in HR, BP, Cardiac output ( often used in cardiac
patient)

11. • Endocrine system- adrenocortical suppression
• Clinical use – for induction of anaesthesia, in hypovoluemic shock
• Not preferred for routine cases because
1. High incidence of post op nausea and vomiting.
2. Adrenocortical suppression.
3. Myoclonus – abnormal movement of body parts
4. Pain on injection

12. Ketamine
Phencyclidine derivative, water soluble, ketamine hydrochloride.
MOA- acts as antagonist on NMDA receptor
Its has powerful analgesic, amnesic and pychomimmetic effects
Dose- iv 1-2 mg /kg Bw
Im- 3-5 mg /kg/bw
It can be given orally, sublingually, per rectal, nasaly

13. Effects on system
• CNS- produces disscociative anaesthesia, hallucinations, nightmare,
increase intracranial pressure therefor not used in neurosurgery.
• CVS- increase HR, BP and cardiac output.
• Resp. syste,- direct bronchodilator properties. Safely used in asthma
patients. It protects airway reflexes, it increases oral secretion(for this
glycopyrrolate is given as premedication)
• Metabolized by cyt-p450 to form norketamine which has sedative
property.

14. • Clinical use
• For preop sedation in paediatric patient
• For TIVA
• For induction of anaesthesia along with propofol.
• For MRI/CT SCAN in children
• For chronic pain

15. sideeffects
• Recovery is not pleasant.
• Hallucinations
• Nightmares
• Nystagmus
• Drug abuse potential
• Cannot be used in head neck surgery, cardiac patients, eye surgery.