WHAT ARE GENERAL ANAESTHETICS ? STAGES OF GENERAL ANAESTHESIA Classification and example of general anesthetics

1. General
anesthetics
Shaikh Saniya

2. WHAT ARE GENERAL ANAESTHETICS ?
 Definition : Anesthesia (an =without, aisthesis = sensation )
 The drugs which produce reversible loss of all sensations and consciousness
 Anesthetics achieve this effect by acting on the brain or peripheral nervous
system to suppress responses to sensory stimulation. The unresponsive state
thus induced is known as anesthesia.

3. STAGES OF GENERALANAESTHESIA
Stage-1 • Analgesia : Start from beginning of anaesthesia administration and last upto loss of
consciousness, feels a dream like state, reflexes and respiration remains normal
Stage-2 • Stage of delirium : From loss of consciousness to beginning of irregular respiration.
Apparent excitement is seen. Muscle tone increases. Jaws are tightly closed. Heart rate and blood
pressure may rise.
Stage-3 • Surgical anesthesia : Extends from onset of irregular respiration to cessation of
spontaneous breathing.
This has been divided into 4 planes
Plane1:This plane ends when eyes become fixed
Plane 2: Loss of corneal and laryngeal reflexes
Plane 3:Pupil start dilating and light reflexes
Plane 4: Dilated pupil, decrease muscle tone ,BP falls
Stage-4 • Medullary paralysis : Respiratory and vasomotor control ceases

5. Classification

6. Methohexital sodium
Properties
• It occurs as white powder which is odorless and hygroscopic.
• Water soluble

7. Thiopental sodium

8. Cyclopropane

9. Diethyl ether
 Diethyl ether is purified and completely free of peroxide.
 PROPERTIES
 It is clear , colorless , very mobile liquid.
 Characteristic odor and sweet burning taste.
 It is very volatile and inflammable.
 It forms an explosive mixture with air.
 STABILITY AND STORAGE
 It is oxidized at atm o2 and is affected by light. Hence it is stored in tightly closed
, light resistant containers in cool place

13. Trichoroethylene