Veterinary anesthesia history

1. Veterinary anesthesia history • In 1872 Pierre use chloral hydrate to anesthetize the horse by intravenous injection. • In 1887 is the earliest time use of inhalation general anesthesia, when the successful administration of ether to horse in royal collage. • In 1900 the use of chloroform widely for general anesthesia in horse. • In 1920 barbiturate drag was discovered, such as pentobarbitone. • In 1927 ether was administration by intra tracheal tube. • In 1934 the first apparatus for inhalation general anesthesia was discovered.

2. Anesthesiology: it is the name giving to whole art and science relating to the production of insensibility. Anesthesia: it is loss of sensation in a part or in the whole body, generally induced by the administration of a drug that depresses nervous tissue activity. General anesthesia: it is a state of complete unconsciousness produced by process of controlled and reversible intoxication of CNS which there is complete analgesia and muscle relaxation.

3. Analgesia: it is absence of pain (to relive pain). Narcosis: it is a state of deep sleep (unconsciousness) a companied with a varying degree of analgesia, such as chloral hydrate. Hypnosis: it is a state like sleep which may be regarded as physiological condition in which the animal can be easily a wakened by different types of stimuli. Sedation: it is a state of calming nervous vicious and exited animal due to mild depression to CNS a companied with analgesia and incoordination.

4. Tranquilization: it is a state of behavioral change in which the animal is relaxed and unconcerned to the surrounding with mild degree of analgesia without incoordination. Basal anesthesia: is a light level of general anesthesia usually produced by pre-anesthetic agents. It serves as a basis for deeper anesthesia on administration of other agents. Surgical anesthesia: it is a state of unconsciousness a companied with muscle relaxation to such a degree the surgery can be performed without pain.

5. Local anesthesia (analgesia): it is loss of sensation in a limited body area without loss of consciousness by nerve block. Regional anesthesia (analgesia): it is loss of sensation in a large but limited area of the body without loss of consciousness by epidural, intrathecal, or spinal cord. Balance anesthesia: it is a system use in anesthesia practice by combination more than one drag or technique to reach the relaxation and analgesia.

6. Indication of general anesthesia • To perform surgical operation or procedure. • For radiographic procedure. • For obstetrical procedure. • For special diagnostic procedure, e.g. in case of endoscopy, or lameness in horse by nerve block. • For cast application. • Euthanasia by giving overdose of anesthesia. • To control the convulsion, e.g. in case of Epilepsy and tetanus.

7. Reasons for administration of analgesics To alleviate pain. To provide relaxation for surgery. Its use for other purposes: Restraint and transportation. Various diagnostic and therapeutic procedures. Behavior modification.

8. Factors effecting general anesthesia • Age of animal: the young animal need large dose of anesthesia / kg B.W., due to high metabolic rate, very young and old animals are more sensitive to anesthesia in comparison to an adult animal. • Sex of animal: males need more anesthesia than females, in the same time the pregnant females are more susceptible to the general anesthesia drugs due to high metabolic rate.

9. Species of the animal: In horses it is necessary to provide adequate restraint. In ruminants the use of endotracheal tube and stomach tube is very necessary in general anesthetic procedure mainly in inhalation anesthesia to prevent regurgitation which lead to aspiration pneumonia. Morphine is contraindicated in cat due to excitatory effect, but in dogs it is a drug of choice for general anesthesia, and in horse it has a depressant and excitatory effect. final effects depend on the dose, rout, and rate of administration.

10. Physical condition of the animal: Animal with large quantity of fat need less anesthesia / kg B.W. also the same thing in toxic and emaciated animals. Fear and excited animal required more anesthesia dose and sometime this will lead to state of over dose. Liver, kidney and lung diseases increase the anesthesia risk, example: intra venous general anesthesia agent should not be giving to animal suffering from liver and kidney diseases.

11. Premedication: tranquilizers decrease the metabolic rate, while the atropine sulphate cause increased in metabolic rate. The administration of muscle relaxant drugs with the general anesthesia should be avoided in animal early treated with antibiotics their names end with mycine and also with organophosphorous compound. • Nature site and duration of the surgical operation: • Local anesthesia used for minor and short surgical operation. • In case of ruminatomy, local anesthesia are used to perform this operation.

12. Anesthesia classification Local anesthesia (analgesia): giving to the animals by the following ways: Topical (surface) application of local anesthesia. Splash block. Intra-articular or synovial block. Intra and sub dermal infiltration. Line block. Ring block. Field block.

13. Regional anesthesia (analgesia): Application of perineural injection. Spinal block by two methods: a) Epidural injection. b) Intra thecal injection. Sedation: Use combination with local anesthesia to perform different surgical operation. Sedation also used as premedication for general anesthesia. General anesthesia: it is accrue by three methods: Inhalation: anesthetic gases or vapors are inhaled.

14. Injectable general anesthesia agent: it induced by injection of drugs by different routes: Intravascular: anesthetic solution is administration by intravenous, intra-arterial, intra-cardiac, or intramedullary (bone marrow) injection. Other injectable routes: anesthetic agent is administration by intramuscular, intraperitoneal, intrathoracic, and subcutaneous injection. Combination: between injectable and inhalation general anesthesia.