General Overview Practical Demonstration Drugs and their indications

1. C A N I N E A N A E S T H E S I A
CONTENTS
General Overview
Practical Demonstration
Drugs and their indications
PRESENTED BY
Najmu Saaqib 62
Rabia Ishaq 63
Seema Jani 64
Created by : Najmu Saaqib Raegan

2. Injecting local anaesthetics
around major nerves supplying
to the body areas. e.g
Thigh , Ankle , Hand
Anaesthesia :
It is the use of medicine to prevent the feeling of pain or other
sensation during surgery or procedures that might be painful.
Spinal
Epidural And Caudal
Nerve Block
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3. R O U T E S O F A N A E S T H E S I A
I N T R A V E N O U S
I N H A L A N T
S U B - C U T A N E O U S
I N F I L I T R A T I O N
I N T R A V E N O U S
E P I D U R A L
S P I N A L
T O P I C A L
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4. P R O T O C O L O F A N A E S T H E S I A
Pre Medication
Induction
Maintenance
Skeletal Muscle
Relaxant
Anelgesia
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5. The foundation of safe anaesthesia is the preparation, assessing the patient and
considering the procedure to be performed enables anticipation of problems in
the pre-anaesthetic period. The protocol must be optimum for patient safety but
also practical and affordable.
For more complex cases a management plan
should be compatible to individual patients to try to minimize complications and
prepare for potential adverse events.
Withholding of food and water
Except for emergencies , a dog should probably be starved for 6-8 hrs prior to
anaesthesia and water withheld for about 1-2 hrs.
Starving for longer than 10 hrs increases the acidity of stomach content and risk of
esophagitis. For young puppies the period of starvation should be reduced to
about 3-4 hours to prevent hypoglycemia.
Temperature Control
Small animals become hypothermic following administration of pre-anaesthetics.
Warming these patients at this stage may reduce the risk of hypothermia.
Large dogs become hyper-thermic specially in warm weather. Hyperthermic
patient requires incrased dose of inhalation agent often pant during anaestheisa.
Protocol Approaches
General Management
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6. PRACTICAL EXAMINATION
PHYSICAL EXAMINATION
The first rule of any anaesthesia is the physical examination of the patient
to be anaesthetised. This refers to the examination by the doctor prior to
the examination of any drug. This is to ensure that they are acceptable
surgical patients and compatible to the surgery to be followed up. This
also allows the doctor to make adjustments to the anaesthetic protocols.
PHARMACOLOGICAL
MANAGEMENT
Pre-Anaesthetics
The first drugs to be administered
to the patient i.e dog are known as
pre- anaesthetics or pre-meds as
they are used prior to the general
anaesthetics.
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7. They are give because :
1. They decrease ‘anxiety’
2. Provide Analgesia
3. Reduce the dosage of anaesthetics to be used
on the basis of body weight
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8. Drugs Prescribed Dose Comments
Acepromazine 0.01-0.05 mg/kg Mild sedative effect
Onset of action 20-40 min
Prolonged effect 4-8 hr
Enhanced sedation with opioids
Vasodilation
Midazolam/
Diazepam
0.05-0.4 mg/kg Minor Tranquillizer
excellent muscle relaxant
Minimal cardiopulmonary depressioin
Diazepam is more irritant to the tissue so better to
give IM
Morphine 0.25-1 mg/kg Enhances sedation
Onset of action 10-20 min
Effect 2-6 hrs.
Potent analgesic
Salivation , Vomiting , defecation , Bradycardia.
Xylazine 0.15-0.30 mg/kg Potent sedative effect
Onset of action 5-15 min
Duration of action 60 min
Reduced doses in combination with opioids
Methadone 0.1-0.3 mg/kg IM Enhanced sedation
Rapid onset of action : 5-10 min
Effect 2-6 hrs
Potent analgesia
Bradycardia, dose-dependent resp. depression
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9. After administration of the pre-medications the patient is placed
in a cage and observed frequently for the onset of the sedation
and emesis.
This usually occurs for about after onset of
5-10 minutes and sedation may increase
up-to 30 minutes. The induction of the
sedation should not increase to the timing
more than 30 minutes.
Clean the animal promptly if there is any
vomit. Check frequently for hypothermia
too. Excessive sedation , difficulty
breathing or any other abnormal
response needs immediate notification
of the doctor. If the dog is not able to lift its
head up and look at you, it can be the
example of sedation experienced more
than required dose.
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10. This pre-anaesthetics give a time range for the preparation
of the baggies for each patient.
The baggies must contain :
1. Induction Agent
2. Injectable Pain Medication
3. Vaccines and other services
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11. INDUCTIOIN AGENT
An induction agent should cause the patient to breathily lose
consciousness in order to the technician could place and
Endotracheal Tube in the trachea.
Ketamine + Valium is used in humane alliance
For injectable pain medication we use Meloxicam which is an
NSAID for any patient over 4 months of age.
Patients more susceptible to hypothermia should be brought first
in the surgical order. The patient should be lift on a prep table
into a clean blanket. The patient drug baggie should match the
name tag.
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12. Drug Prescribed Dose Effect
Ketamine +
Diazepam
0.25 + 5 mg/kg Produce Less CV
Depression
Tiletamine +
Zolazepam
(Telazol)
4 mg/kg Deep Sedation
Other sedatives and
opioids can be mixed to
increase sedation ,
analgesia and duration
of effects
Propofol 5-8mg/kg in non pre-
medicated patients
Reduced dose after
premedication
Rapid recovery (1-2min)
Recovery after 5-15 min
Rapid metabolism
CV & Resp. Depression
Thiopental 5-10 mg/kg after
acepromazine – opioid
premedication
Half dose after alpha-2
Rapid effect (30-60sec)
Recover after 5-15 min
CV & Resp Depression
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13. Drug Prescribed Dose Effect
Tiletamine zolazepam 7-13 mg/kg IM
Reduce dose by 50-60 %
for IV use
Effect in 5-10 min
Duration 40-45 min
Excitement during
recovery
Ketamine 2.5-10 mg/kg IM
Half the doses for IV use
Effect in 5-10 min
Duration 20-3- min
Excitement during
recovery
Alfaxalone 2-3 mg/kg
Lower doses may be
required after sedation
Inject slowly (over 1 min)
to avoid resp. depression
Rapid effect ( 1-2min )
Rapid metabolism
Minimal CV depression
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14. INTUBATION AND MAINTENANCE
Intubation is necessary to protect the airway and to maintain the dog
under anaesthesia using anaesthetic gas. Try to avoid mask induction as
much as possible as they increase the risk of contaminants. The doctor
may opt ½ or ¼ of the original dose depending on the on-going
procedure.
Preparation Of Endotracheal Tube:
The Endotracheal tube suitable for the dog must be lubricated with a
sterile lubricant. The string can be looped around the tube to tie the
tube and place after intubation.
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15. Placing a Cephalic catheter:
Requirements : Clippers , Cleaning Solution (Alcohol / povidone-
iodine), App. Size I/V Catheter large dogs = 18ga, Puppies =
24ga and Small dogs = 22ga, Inj. Cap, Tape to secure the IV
catheter in place.
Procedure :
Clip the area
Locate the Cephalic vein
Disinfect the area
Insert the catheter
Troubleshoot the catheter placement
See final catheter placement
Place the T.set adaptor
See final T.set placement
Tap the catheter
The technician after this obtain the induction agent i.e
Ketamine and Valium with 25 Guage needle and an alcohol
swab. The assistant positions the dog and holds the front leg for
the administration into the Cephalic Vein.
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16. Inserting the Endotracheal Tube:
Over the next 2-3 minutes the dog is allowed
to deeply relax until the jaw could be opened,
the tongue could be pulled outward and
downward. Only after this the technician is
able to insert the endotracheal tube into the
trachea.
.
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17. The string attached to the endotracheal tube
needs to be tied behind the ears or around
the maxilla.
During this the technician may attempt
intubation again and
again once the patient
is further relaxed.
After this lubricate the
dogs eyes for protecting
the eyes to dry out as
anaesthetics decrease the tear production.
Corn oil can be used here to lubricate the
eyes
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18. After this place the dog in a V-tray if available and roll
the dog onto his back with dorsal recumbency
The F-Circuit is designed to maintain humidity and
prevent heat loss. It is designed to deliver rebreathing
anaesthesia.
The oxygen flow is turned
on to 1L/minute and
the F-Circuit is attached
to the endotracheal tube.
At this time select a gas
anaesthesia
i.e Isoflurane,
Halothane,
Sevoflurane etc.
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19. The concentration of the Isoflurane is dependent on how
awake the patient may be. The technician then inflates the
cuff of the endotracheal tube. During this the cuff should
form a gentle seal so that the gas should not escape and
should not damage the trachea too.
Place the pulse oximeter on the
tongue and obtain the reading.
During this check the dogs reflexes
including withdrawing of the foot
when lifted , relaxation of the jaw
and blinking of the eye when the
lower eye lid is touched
The patient should maintain
minimal jaw tone and no toe
pinching reflexes.
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22. IF THE DOG IS TOO AWAKE:
If the dog is too awake, options that can deep the
anaesthesia are :
1. Increasing O2 level to 2L/minute while keeping Isoflurane
at same level
2. Increasing Isoflurane by 1-2 % while keeping the O2 at
the same level
3. By giving breathes to the patient
During this the dog should not be left unattended as close
monitoring is needed.
IF THE ANESTHESIA IS TOO DEEP :
If the dog is too deep the decrease or shut off the
Isoflurane. Depending on the depth of the patient
anesthetised, remove the access to Isoflurane. Unhook the
F-Circuit from the endotracheal tube, Cover the F-circuit by
palm of your hand and squeeze the reservoir bag and
hook the F-circuit back to the endotracheal tube with the
O2 flow of 1 L/minute.
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23. When the surgery is about to end shut off the
Isoflurane and leave the dog on oxygen. Ideally after
removal of the Isoflurane let the dog undergo 5
minutes on oxygen after removal of Isoflurane. Before
removing the patient from the surgery table always
deflate the cuff of the endotracheal tube and the
tube anchored untill the patient is positioned for
recovery then untie the string.
Pull the tongue out of the side of the mouth facing up
to be easily visible.
Check the swallowing attempts. Once the dog is able
to make several attempts of swallowing it ensures
respiration and reduces the risk of aspiration. This is the
time when the endotracheal tube can be gently
pulled out following the curvature of trachea.
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24. Monitoring:
The depth of an anesthesia can be measured by observing
physical movement or jaw chwing, eye position , muscle
tone, and palpebral reflexes.
ECG is helpful to monitor the cardiac dysrythmia.
Pulse oximetry or arterial blood gas analysis provides
information of the ventilatory efficiency.
Occular reflexes are used to monitor the CNS.
Opthalmic ointment should be applied to the eye during
anesthesia to prevent corneal injury.
Body temperature is also important to monitor anesthesia.
Supplemental heat are often required to maintain
adequate body temprature.
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25. Recovery :
Body temperature must be maintained so as to not
prolong the recovery.
Endotracheal tube must remain in place untill the dog
regains at least couple of strong swallowing reflexes to
protect the airway.
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