Types of Anaesthesia

Prof. med. Nabil H. MohyeddinAnesthesiologist & Intensivist

Board certified University Rostock, Germany

nhm1955@hotmail.com

Objectives Short History Definition/types of anaesthesia General anaesthesia/drugs Phases of GA Regional anaesthesia

Early history Ancient/Medieval period- Opium- Alcohol- Cannabis

History 1845- Horace Wells- N2O 1846- William Morton- Ether 1847- Simpson- Chloroform 1853-John Snow 1878- ETT 1884- Cocaine 1895-98- Spinal analgesia/anaesthesia

History 1921- Epidurals 1934- Thiopentone, cyclopropane 1942- Curare 1946- Lignocaine 1951- Suxamethonium 1952- IPPV 1956-Halothane

Definition ‘Loss of sensation’ General Regional Local

Triad of General anaesthesia

Hypnosis

Analgesia Muscle relaxation

Amnesiasedation

Hypnosis

Coma

Death

Awake

Hypnosis

Hypnotic drugs-intravenous

Gold standard- thiopentone Propofol others Etomidate Benzodiazepines Ketamine

Inhalational anaesthetics Nitrous oxide-weak Isoflurane Sevoflurane Desflurane Halothane

Analgesia Good analgesia= good anaesthesia Hypnotic sparing effect Opiates Local anaesthetics NSAIDS Paracetamol

Analgesia-Opiates Gold standard – morphine Derivatives- diamorphine, codeine Synthetic agents- Pethidine- Fentanyl/Alfentanil-short acting- Remifentanil-ultra short acting

Analgesia-NSAIDS Gold standard- aspirin Ibuprofen Diclofenac Cox-2 inhibitors

Muscle relaxation Aids intubation Helps surgeon/surgery Surgery of long duration Reduces maintenance dose of

anaesthetics agents

Muscle relaxants Two types Depolarising-short acting eg;suxmethonium Non-depolarising- medium/long acting- Tracurium- Vecuronium- Rocuronium

Prerequisites Oxygen Suction Tilting trolley Resuscitation drugs Monitoring Anaesthetist Skilled assistance Drugs and machine

Phases of general anaesthesia

Induction Maintenance Recovery

Induction Intravenous- majority Inhalational- children, needle

phobics Monitoring Preoxygenation Hypnotic/analgesic and or relaxant Mask/LMA/ET tube

Stages of anaesthesia Alcohol1.Dizzy, delightful2.Drunk, disorderly3.Dead drunk4.Dangerously deep

General Anaesthesia1.Amnesia, analgesia2.Uninhibited

response to stimuli3.Surgical

anaesthesia4.Vital centre

depression

Maintenance Intravenous or inhalational Oxygen –40%-100% Nitrous oxide Muscle relaxant Analgesia

Recovery Turn off agent Reverse relaxation Cough reflex Extubate when awake Recovery position Monitor until discharge

Advantages No absolute contraindications Quick to establish Never fails to work

Disadvantages Polypharmacy Effects on various systems Allergic reactions Recovery profile Post operative Nausia &Vomiting Awareness

Regional anaesthesia Spinal/epidural- surgery below umbilicus- Provides analgesia/muscle

relaxation Plexus blocks eg brachial plexus Intravenous- Bier’s block

Regional anaesthesia

Analgesia Muscle relaxation

Local anaesthetics Lignocaine- quick/short acting Bupivacaine/levobupicvacaine-

slow and long action Ropivacaine- as above Amethocaine- topical Prilocaine- intravenous

Advantages Effective alternative to GA Avoids polypharmacy Allergic reactions Extended analgesia Patient can remain awake Early drink/feed

Disadvantages Limited scope Higher failure rate Time constraints Anticoagulants/Bleeding diathesis Risk of neural injury