Lecture notes for diploma students (Animal Science)

1. འབྲུག་རྒྱལ་འཛིན་གཙུག་ལག་སློབ་སྡེ།
རང་འབྱུང་འཐློན་བསྡེད་མཐློ་རིམ་སློབ་ྲྭ།
སྤུ་ན་ཁ་རློང་ཁག།
ལློད་སྦུད་ས།
དློག་ཏྲར་་་འཇིགས་འབྡེལ་རློ་རྡེ།
རང་འབྱུང་འཐློན་བསྡེད་མཐློ་རིམ་སློབ་ྲྭ། སྤུ་ན་ཁ་རློང་ཁག།
ལློད་སྦུད་ས།
Anesthesia

2. • Greek word meaning absence of sensation an for
"without" and esthesia for "sensibility".
• Animal can not feel pain when anesthesia is induced
• Anaesthetic is the substance used to induce anesthesia
Principles of anesthesia
• Depresses activity of CNS, patient can not perceive pain
Anesthesia

3. History of Anesthesia

4. A brief History of Anesthesia
• Ether was first used as anaesthetic (1846)
• Un till 1846, people used alcohol, opium, cannabis
and even concussion and asphyxiation.
• Horace Wells used nitrous oxide as anesthethetic for
the first time.
• James Simpson introduced chloroform in 1847.
• Cyclopropane in1929
• Halothane in 1965 and revolutionized inhalant
anesthesia.

5. Reasons for Anesthesia
• Alleviate pain
• Immobilize patient
• Protect patient from injury
• Prevent injury to surgeon
• Prevent injury to assistant

6. Classification of Anesthesia
General Anesthesia Local Anesthesia
Regional• Injectable (Ketamine, Propofol)
• Inhalant (Isoflurane, Sevoflurane) • Injectable
• Topical/Spray
• Infiltration
Lignocaine
Maintenance Anesthesia = Top up
Requires anesthetic working station

7. Routes Of Administration
Local – application on surface
- Infiltration at the site
Regional – injection over main nerve trunk
General – Intravenous or intramuscular injection
- inhalation
Routes of drug administration is always written on the vial

8. Preanestetic - given before general Induction anesthesia to
- restrain
- reduce anxiety
- Smooth induction
- smooth recovery
- Reduce dose of General anaesthetic
e.g. Xylazine, Triflupromazine
Local – e.g. Lignocaine HCL
General - Thiopentone Sod, Ketamine, Propofol= Induction
Anesthetics

9. Preanestetic
•Anticholinergics
•Tranquilizers
•Sedatives
•Analgesics/Opiod(Morphine)
•Combinations

10. Anticholinergics:
1. Atropine.
• Decreases respiratory, oropharyngeal and eye secretions
• Counteracts bradycardia induced by Xylazine
• Dose rate (pre-anesthetic)
• → 0.065 mg/kg IV, IM, SQ
Contraindication :- As atropine dilate the pupil, if animal is
placed directly in sun light retina may get damage. ( Tell Owner
to observe the Dogs)
Rabbits is refractory to atropine due to enzyme atropinase

11. 2. Glycopyrolate:
• Decrease Respiratory, Oropharyngeal, GIT, Eye secretion etc.
• Longer duration than atropine
• Dose: 0.01mg/kg
• Used commonly in L.A
Tranquilizers
•Relieve anxiety
•To quiet patient
•Physical Examination
•Transportation
• Prevent Licking wounds
• Chewing bandages/splints
• Antiemetic e.g. car sickness

12. Agents
• Chlorpromazine
• Promazine
• Triflupromazine
• Acepromazine -ACE
Hypotensive: Aggressive fluid therapy
 Epinephrine contraindicated
Doses
•Dog 0.03-1 mg/kg
•Cat 0.03-1 mg/kg
•Horse 0.02-0.05 mg/kg
Acepromazine

13. Tranquilizers continued..
2. Benzodiazepines (Diazepam)
• Muscle relaxant property
• Anticonvulsant
• Given with ketamine (mixture) 1:2
• Calming effect
Dose Dog /cat
• 0.1-0.5 mg /kg
Horse
• Dose: 0.05- 0.2 mg/kg IV
Cattle Dose: 0.5-1.0 mg/kg IM 0.2 mg/kg IV

14. Opioids/Analgesics
• Not commonly used except in human medicine under the
prescription of the Doctor Except in wild animal restraint as
dart gun.
• Fentanyl patch: in dog
Etorphine:
• X 80-1000 Morphine
• IM--Hand held syringe or dart
• Animal remains on feet can be approached
Nalorphine (Antagonist)

15. Sedatives Alpha2 agonist
Drugs
•Xylazine: Yohimbine as antagonist
•Medetomidine: Tolazoline as antagonist
•Detomidine
•Dexmedetomidine
•Romifidine
Actions
•Analgesia
•Sedation
•Anxiolysis
•Muscle relaxation
•Anticonvulsant

16. Xylazine:
• Used mostly as preanestetic in small animals.
• Never use in Cats
• Causes bradycardia which can be counteracted by atropine
• Causes vomitions in dogs and cats
 Doses Dog/cat : (1 mg/kg)
 Horse (1.1 mg/kg)
 Cattle (0.1 mg/kg)/ 1/10th of the Horse
Administer Anticholinergics before administration in dogs and cat

18. Anesthetic Combinations
1. Combinations of :
- Ketamine (50mg/ml) – 5 ml
- Diazepam (5mg/ml) - 0.5 ml
- Siquil (20mg/ml) – 1 ml
Given IV @ 1 ml per 4.5 kg body weight
In a syringe
Used at NAH Chubachu, Thimphu
Or refer the HSI protocol chart

19. 2. Vets beyond borders (VBB).
Pre-anesthetics – combination of
- Xylazine (20mg/ml) @ 1ml/10kg (max 2ml only)
(Pups < 6 months @ 0.03ml/kg
- Atropine Sulphate (0.6mg/ml) @0.2ml/10kg
Induction by IV injection
- Diazepam (5mg/ml) 0.5ml
- Ketamine (50mg/ml)0.5ml
1ml of mix/10kg

20. Site for General Anesthesia - dogs
Recurrent tarsal vein
Cephalic vein

21. Drugs and Dosages
Weight × dose rate ÷ concentration = Total volume needed
• The Concentration of the drug has to be found out
from the drug vial while dose rate has to be known by you.
• Concentration of the drug is always in mg/ml and not in %.
• Always convert the % (If given in %) into mg/ml to calculate
the dosage of the drug.
• Remember 1000mg/ml= 100%

22. Activity
• Dog wt. = 20 kg
• Dose rate of drug = 0.2 mg/kg
• Concentration of drug in vial = (2%)
1. Calculate the volume of the drug to be given?
2. Calculate the quantity of Fasinex 250 mg
tablet for sheep weighing 75 kg at the dose
rate of 10mg/kg bwt?