Definition : Anesthesia (an =without, aisthesis = sensation ) Anesthesia is medication that attempts to eliminate pain impulse from reaching the brain. In general anesthesia this is accomplished by putting the patient asleep. STREPTOKINASE StreptokinaseANAESTHESIA

A drug that brings about a reversible loss of all sensation and consciousness. These drugs are generally administered by an anesthesiologist in order to induce or maintain general anesthesia to facilitate surgery and unpleasant procedure. General anesthetics depress the central nervous system. It causes immobility and muscle relaxant. What Are General Anaesthetics?

Principle of General Anaesthesia The practice of anesthesia is usually neither therapeutic nor diagnostic. The development of new anesthetic agent have been driven by three general objectives –  Sustaining physiologic homeostasis during surgical procedure. That may involve – reperfusion of ischemic tissue,major blood loss,fluid shift and impaired coagulation.  Minimize the potentiolly deleterous effects of anesthetic agent and technique.  Improving postoperative out comes.

Stages of anaesthesia Stage I : Analgesia : Start from beginning of anesthetic administration and last upto loss of consciousness, feels a dream like state, reflexes and respiration remain normal. Stage II : 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 III : Surgical anesthesia : Extends from onset of irregular respiration to cessation of spontaneous breathing. This has been devided into 4 planes- Plane 1: 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 IV : Medullary paralysis : Respiratory and vasomotor control ceases.

Minimum alveolar Concentration (MAC) MAC is the concentration necessary to prevent responding in 50% of population. Blood gas partition coefficient Lower the Blood : Gas partition coefficient the fester the induction and recovery.

1. INHALATIONAL a. Gas * Nitrous oxide b. Volatile liquids * Halothane * Enflurane * Isoflurane * Desflurane * Sevoflurane 2. INTRAVENOUS * Theopentone sod. * Etomidate * Propofol * Kitamine * Methohexitone sod.