ANESTHESIA

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Terminology:
1-Anesthesia It is the art and the science related to production of insensibility.
2-General anesthesia
It is a state of unconsciousness as a result of controlled reversible
intoxication of the central nervous system, and characterized by
lowered sensitivity to external stimuli with diminished motor response
to such stimuli.
3-Anesthetic agent It is the substance that produces controllable loss of consciousness and absence of motor response to noxious stimuli.
4-Analgesic agent It is the substance that temporarily abolishes awareness of pain.
5-Local analgesic
It is a substance that when applied to the nerve endings or nerve
fibers, temporarily prevents the conduction of impulses by the nerve,
by interference with transmission of impulses concerned with
appreciation of pain.
6-Narcotic agent
It is the substance that produces insensibility, or stupor bordering
upon it, and simple stimuli like noise can only produce temporary
partial arousal. Accordingly all anesthetic agents are narcotic but
many narcotics are not anesthetics.
7-Hypnotic agent
It is a narcotic agent that produces sleeping, which is a state of
physiological unconsciousness, from which the animal can easily be
awakened by wide variety of stimuli.
8-Sedative It is a narcotic agent that can be used to calm a nervous, excited, or vicious animal, and these drugs cause drowsiness.
9-Ataractic or tranquilizer It is substance that produces sedation without drowsiness.
TYPES OF ANESTHESIA:
I-Substances Have Selective Transient Paralytic Action On Sensory Nerves
1-Local Analgesia
A-Surface application i-Topical application
ii-Intra-synovial analgesia
B-Intra or sub-dermal infiltration

C-Subcutaneous infiltration i-Linear infiltration
ii-Field block analgesia 1-Cup shape
2-Inverted-L block
3-Ring block
2-Regional Analgesia
A-Perineural nerve block i-Peripheral nerve block
ii-Paravertebral nerve block
B-Spinal nerve block
i-Epidural analgesia 1-Caudal epidural
2-Segmental lumbar epidural
ii-Intrathecal analgesia or sub arachnoid
II-Sedation, Narcosis, And Pre-Anesthetic Medication
1-In Combination With Local Or Regional Analgesia

2-In Adjunction To General Anesthesia

III-Substances
Have Depressant Paralytic Action On The CNS Producing Progressive Loss
Of Consciousness And Voluntary Motor Function (General Anesthesia)

1-By Inhalation – Volatile Anesthesia
2-By Intravenous Injection

3-By Combination Of The Mentioned Types With Or Without Premeditation
GENERAL CONSIDERATIONS IN SELECTING ANESTHETIC METHOD:
1-Nature And Magnitude Of The Operation: -
Local
infiltration suffices for simple interferences like incision of
superficial abscess or neoplasm, or castration in immature animals.
However some simple surgical operations can’t be performed by local
infiltration as a result of severe fibrosis.
2-Site Of Operation: -
Presence
of some critical structures in vicinity of site of operation may render
local infiltration insufficient as the movement of the animal may
endanger his life, and the example is the surgery for retropharyngeal
abscess.
3-Duration Of Operation: -
The
duration of operation affects the choice of anesthetic method,
especially when adopting general anesthesia. Short-duration, simple
dental operations, can be performed by using ultra-short acting
barbiturates, while longer interferences can be performed by using
longer-acting barbiturates with local analgesia, or inhalation
anesthesia. Pre-anesthetic medication should be considered when the
operation is a major operation with long duration and it is required
that the animal remain quite for several hours after surgery.
Pre-anesthetic medications not only reduce the amount of anesthetic
agent and increase duration of anesthesia, but also control undesirable
effect of some anesthetics like salivation.
4-Species: -
Not
only size and temper of the animal affect the choice of anesthetic
method, but also the anatomy and physiology of some species affect that
choice. Generally the larger size animals have greater difficulties and
dangers in induction and maintenance of general anesthesia. The safe
satisfactory methods for general anesthesia in pets may be unsuitable
for large animals, especially for heavy vigorous one, as the upset of
locomotor coordination and prolonged recumbency may entail risks.
Not
all species react to drugs in the same manner, as horse may be excited
when administered sub-anesthetic dose of barbiturate, and cat may
become maniac when given large dose of morphine.
Increased susceptibility for toxicity by anesthesia affected by two main factors, the prolonged fasting (predisposes to depletion of liver glycogen and reduced detoxication capacity of non-volatile anesthetic agents), and disease condition
(toxemia predisposes to degeneration of parenchymatous organs as liver
leading to reduction of its detoxication capacity, also toxemic animal
seems to need smaller dose).
A-The Horse: -
The
animal should be adequately restrained to ensure safety of the
veterinarian and the animal himself. Casting methods of conscious
animal frightening and expose him to injury, accordingly, many muscle
paralyzing drugs can be sued to induce casting without endangering the
animal.
The
possibility of blocking of many peripheral nerves should be considered,
and on using anesthetic method that is associated with slow recovery,
veterinarians have to ensure that this recovery period will be free
from excitement.
Some
sedatives and non-volatile anesthetics are precluded from use in horse,
as they don’t have some requirements like; the ability of the animal to
rise to his feet soon after surgery; and at the outside within 1-2
hours with strong enough locomotor power and coordination to prevent
the animal from falling.
B-Ruminants: -
Generally
they are unsuitable candidate for inhalation anesthesia unless
endotracheal tube is used, but under field condition, light general
anesthesia by intravenous injection has satisfactory results. However
the simpler regional analgesic techniques in this species and side
effects of general anesthesia make regional anesthesia more popular in
these species.
C-The Dog: -
General
anesthesia has a high degree of perfection in this species that make
this method so popular for veterinarians not only for surgery but also
for examination procedures in the animal. Some breeds have
brachicephalic skull predisposing them to asphyxia as a result of
relaxation of jaw muscles during general anesthesia and accordingly
endotracheal tube should be considered on inducing general anesthesia
in such breeds.
D-The Cat: -
Cat
is a difficult subject to be anesthetized quietly and safely as
restraint provokes violent struggling. Accordingly, cat should be
handled quietly with minimal restraint then general anesthesia can be
induced by slow intravenous barbiturate.References:
Hall, C.W. and Clarke, K.W. (1983), Veterinary anesthesia, 8th edition;
Hall, L.W. (1978), Wrights veterinaray anesthesia and analgesia, 7th
edition

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I-LOCAL ANALGESIA
Many
operations can be satisfactorily performed under the effect of local
analgesia, and the use of sedation with this technique depends up on
the species, temper, and health of the animal, and magnitude of the
operation.
Advantages: -
1-Local
analgesia can be performed for operations on standing animals to avoid
injuries as a result of restraint and prolonged recumbency.
2-The technique is simple and requires no expensive or complicated equipments.
3-The technique can be performed by the surgeon himself with no need for anesthetist
Disadvantages: -
1-Injection can’t be performed in infected area to avoid spread of infection
2-When the drug is injected directly to the seat of incision, delay of healing is expected, as the drug is histotoxic.
3-The
amount of used local analgesic drug is relatively high than other
methods like perineural analgesia, accordingly the cost increases.
LOCAL ANALGESICS:
Desirable characteristics of local analgesic agents:
1-Good penetrating qualities in body tissues 2-Rapid onset.
3-High potency so that low concentrations can be used. 4-Long duration of action
5-Low systemic toxicity 6-Non irritant to nerve and other body tissues,
7-It should has reversible action 8-Availability in sterile solution or ease of sterilization
Potentiation by vasoconstriction:
Addition
of vasoconstrictor (epinephrine) to local analgesic, at concentration
of 1:200,000 allows for prolonged analgesic activity by
vasoconstriction and delaying absorption of the drug. The maximum safe
concentration of epinephrine is 1:50,000, and greater concentration may
cause local tissue ischemia and necrosis; accordingly, these agents
shouldn’t be used in extremities, tail, or teat, etc…to avoid the
possibility of ischemia and subsequent necrosis and gangrene. The
exception to this rule is the epidural analgesia where concentration up
to 1:10,000 may be safely used.
Potentiation by hyaluronidase:
Hyaluronidase
is a mucolytic enzyme that hydrolyses hyaluronic acid (the ground
substance preventing diffusion of drug in the tissues).
Advantages:
1-It promotes diffusion and absorption of the drug when added in therapeutic
2-Of particular value in nerve block, especially if the analgesic didn’t deposited accurately.
Disadvantages:
1-Toxicity (the ratio of toxic to therapeutic dose being 200:1).
2-The
duration of analgesia is decreased and the toxicity by analgesic
increased as a result of rapid absorption. This can be counteracted by
addition of epinephrine to the solution.
Available local analgesics:
There
are many local analgesic drugs that vary according to their potency,
toxicity, and cost, and the present three categories are classified
according to duration of analgesic action into;

	Nature	Drug	Duration
A	Short analgesic duration	Procaine	30-60 minutes
B	Intermediate analgesic duration	Lidocaine and mepivacaine	90-180 minutes
C	Long analgesic duration	Tetracaine and bupivacaine	180-300 minutes

A-Short duration analgesic:
1-Procaine HCl:
Procaine HCl is a white, crystalline, water-soluble powder.
Advantages:
1-Relatively stable solutions
2-Can be sterilized repeatedly by boiling without loss of potency.
3-It
is rapidly and completely detoxicated by the liver, so that a second
infiltration can be carried out in the course of an hour or so.
4-Slow absorption (ensured by addition of vasoconstrictors like epinephrine or adrenaline)
Disadvantages:
1-It has low power of penetration
2-It is not used for topical application or intra-synovial analgesia (very low power of penetration of mucous membrane).
Concentration, on set, and duration:

	*On set*	*Duration*
1-General infiltration (2%)	5 minutes	1 hour
2-Epidural injection (1-2%).	10 minutes
3-Perineural in horses and cattle (4-5%)	10 minutes

B-Intermediate duration analgesic:
1-Lignocaine HCl and Lidocaine HCl ( Xylocaine, or Debocaine):
Advantages:
1-It is extremely stable solution 2-Can be re-sterilized several times even by autoclaving
3-Its onset is twice faster than procaine
4-It has longer duration of action than procaine (90 min alone and 120 min with epinephrine).
5-It has a sedative effect and the dose of tranquilizer must be reduced.
6-Higher
penetration power than procaine and so it is preferred in perineural
injection and it is unnecessary to add hyaluronidase to it for
infiltration or nerve blocking purposes.
7-Can
be used for surface analgesia of mucous membranes (4%) particularly
those of the throat and larynx, prior to endotracheal intubations
8-It can be used for intra-synovial injection
Concentration:
1-General infiltration (0.5:1 % with no vasoconstrictor)
2-Epidural and nerve block (2% with or without vasoconstrictor)
2- Mepivacaine hydrochloride (Mepacaine):
This compound closely resembles lignocaine HCI.
Advantages:
1-It is slightly less toxic.
2-It
has no vasodilatory effect making the addition of a vasoconstrictor
unnecessary, however, a commercial product with levonordefrin is
available in market (Mepacaine-L).
Concentration:
For infiltration and nerve block (1-2%)

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C-Long duration analgesic:
1-Tetracaine hydrochloride (Pontocaine):
Advantages:
1-The onset of analgesia is 5-10 minutes 2-It is 12 times potent than procaine
3-Its toxicity 10 times that of procaine
4-Lesser interference with corneal healing than other agents, so it is the drug of choice for corneal analgesia
Disadvantages:
1-It can’t be autoclaved.
Concentration:
*For the eye (0.2% for 120 min)
*For infiltration and nerve block (0.1%)
2- Bupivacaine HCl (Marcaine):
Advantages:
1-Stable solution and shows no change on repeated autoclaving.
2-Represented in different concentrations with or without adrenaline
3-Its 8 times more potent than procaine 4-It has greater margin of safety than lignocaine
5-Onset
is similar to lignocaine but its effect lasting for 4-6hours so it is
indicated for use in situation where prolonged analgesia is required
(relief of pain in equine during acute laminitis).
Concentration:
*For infiltration (0.25%)
*For nerve block (0.5%)
*For epidural analgesia (0.75%)
D-Other local Analgesics:
1-Ethyl Chloride:
It
is a topical local analgesic, marketed under pressure in containers
with a fine capillary nozzle and a control valve that allows the liquid
to be sprayed. It has a very superficial and transient analgesic
action, and when it is sprayed on the skin, it evaporates leading to
freezing
of the skin with induction of surface analgesia for 30-60 seconds. Its
use is limited to simple incisions or punctures such as incision of an
abscess or hematoma.
2-Ethyl alcohol:
Injection
of absolute alcohol around a nerve produces neuritis, degeneration, and
sclerosis, however, 30% alcohol temporarily destroys sensory nerves
that regenerate again after a variable period, and nerve function will
return by then. Duration of block depends on;
1-The size of the nerve 2-Degree of destruction
Small-unsheathed
nerves may be permanently destroyed, whereas, large heavily sheathed
nerves are only temporarily affected.
TYPES OF LOCAL ANALGESIA: -
1-Surface Analgesia: -
1-Surface
analgesia by freezing of superficial layers of skin by ethyl chloride,
ether, or carbonic acid snow, as a result of their rapid
volatilization. Their action is superficial and transient, and their
use is limited to simple surgical interferences like incision of an
abscess. Excessive use may lead to necrosis, and the thawing after
their use is very painful
2-Surface analgesia by using lignocaine ointment that is applied by kin friction for relief of pruritis.
3-Surface
analgesia by using lignocaine 2% aqueous solution may be used topically
for relief of superficial abraded or eczematous area.
4-Surface
analgesia of mucous membrane of the glans penis and vulva by topical
use lignocaine 2% aqueous solution. Surface analgesia of urethral
mucous membrane by lignocaine 2% gel that works as lubricant and
analgesic. Surface analgesia of the nasal mucous membrane by lignocaine
4% spray for trans-nasal passage of stomach tube in dog or for
procedures of the nasal chamber in the horse.
5-Surface analgesia of the cornea by topical instillation of 4% lignocaine
6-Surface analgesia of the joints by intra-synovial injection.
2-Infiltration Analgesia: -
This technique can be used for minor operations or even for major operation under the effect of basal narcosis.
A-Intra-dermal:
B-Linear infiltration: -
This
method can be performed by creation of insensitive intra-dermal weal
through which the needle is inserted subcutaneously into two directions
to create analgesic line. Another technique is the creation of
insensitive weal beside each other I the form of line.
Disadvantages:
1-Dealyed
healing. 2-Changes in the anatomical features
3-Consumption of large amount of drug
C-Field block analgesia: -
i-Cup shape field block: -
It
is an inverted pyramidal shape analgesic area created by two punctures,
and can be sued when the pass of nerve supply is not exactly known.
ii-Inverted-L block: -
It
is a field block technique through which only the dorsal and anterior
aspects of the flank region are injected to produce complete analgesia
of the flank for induction of rumenotomy or cesarean.
iii-Ring block: -
A
technique used for induction of analgesia by injection of analgesic
drug in a ring manner at one level like in teat or digit. On induction
of analgesia of the teat, adrenaline shouldn’t be incorporated in the
injected solution.
3-Intravenous Regional Analgesia: -
Simple
technique performed by injection of 2-3 ml of 1% lignocaine intravenous
in the cephalic vein after application of tourniquet on the forearm.
Analgesia allover the limb can be achieved and the effect can be
reversed just the tourniquet is removed.
4-Local Analgesia Of Fracture: -
Simple
technique performed by injection of 2-5 ml of 1% lignocaine (small
animals) or 10-15 ml of 1% lignocaine (large animals) into the hematoma
to as near as possible to the ends of bone. Analgesia will ensue within
5 minutes after injection.
References:
Hall, C.W. and Clarke, K.W. (1983), Veterinary anesthesia, 8th edition;
Hall, L.W. (1978), Wrights veterinaray anesthesia and analgesia, 7th
edition

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II-REGIONAL ANALGESIA
1-PERINEURAL ANALGESIAA- Regional analgesia of the head: - The Horse1-Infra-Orbital
Nerve Block 2-Mental Nerve Block 3-Mandibualr Nerve
Block 4-Supra-Orbital Block 5-Retrobulbar
Block 6-Auriculopalpebral Nerve BlockThe Ox1-Cornual Nerve Block 2-Auriculopalpebral Nerve BlockThe Goat1-Nerve Block For DehorningThe Dog1-Infra-Orbital Nerve 2-Mandibular Nerve 3-Auriculpalpebral Nerve BlockB-Regional analgesia of the limbs: - The Horse1-Planter Or Volar Nerve Block 2-Median Nerve Block3-Complete Desensitization Of The Limb Below The Carpus4-Posterior Tibial And Anterior Tibial (Deep Peroneal) Nerves BlockThe Ox1-Nerve Block In The Forelimb 2-Nerve Block Of The Hind Limb Method I Method II The Dog1-Brachial plexus block 2-Infiltration of digital nervesC-Regional analgesia about the trunk The Horse1-Analgesia For CastrationThe Ox1-Paravertibral 2-Pudic Or Internal Pudendal 3-Local Analgesia For CastrationThe Small Ruminants1-Paravertibral 2-Pudendal Nerve Block 3-Local Analgesia For CastrationThe Dog1-Paravertibral2-SPINAL OR EPIDURAL ANALGESIAA-Caudal epidural analgesia The Ox The Buffaloes The Horse The Sheep The DogB-Lumbar epidural analgesia The Ox The Sheep The Dog
II-REGIONAL ANALGESIAAdvantages: -1-The amount of used drug is relatively lesser than local infiltration2-The technique requires no expensive equipments3-The
analgesic area is large enough and there is no need to increase the
size of analgesic field during surgery like with local analgesia.4-Anatomical features of the surgical field don't change as the drug is injected far from surgical field.5-Healing is not delayed, as the drug is not injected to surgical line.6-It can be used with or without sedation for surgery on standing animalsDisadvantages: -1-It is more complicated than local analgesia2-It has risk of toxicity especially when the nerve is associated with blood vessels3-General complications of epidural including fracture, infection of neural canal, etc.... 1-PERINEURAL ANALGESIAA- Regional Analgesia Of The Head: - The Horse 1-Infra-Orbital Nerve Block: -Anatomy:It is the continuation of the maxillary division of the 5^th
cranial nerve. It passes through the infra-orbital canal (innervates
the upper molar teeth, canine, and incisors; and their alveoli and
gum), and then it emerges through the infra-orbital foramen (innervates
skin of upper lip, cheek, and nostril). After it emerges from the infra
orbital foramen, it is partially covered with levator nasolabialis
muscle. Sites of perineural injection:a-After the nerve emerges from the canal: The desensitized area will be the skin of the lip, nostril, and face up to the level of the foramen.b-Within the canal:This will desensitize the upper molar teeth up to the 3^rd, the canine, and the incisors, and their alveoli and gum, and the skin up to the level of the medial canthus of the eye.c-Within the pterygopalatine fossa:This will desensitize the molar teeth up to the 6^th in addition to the previously mentioned regions.Indications:1-Suturing of a wound at the lip or nostril2-Trephining the facial sinus.Dose: 5 mlTechnique a- After the nerve emerges from the canalThe
lip of the infra orbital foramen can be felt as bony ridge lying
beneath the edge of the flat levator nasolabialis muscle, at a point 5
cm forwards and downwards from the anterior end of facial crest. The
needle is introduced until its point can be felt beneath the bony lip
of the foramen.b- Within the canalThe same as mentioned but the needle should pass 2.5 cm up the canal.c- Within the pterygopalatine fossaThe
needle is inserted at a point on the side of the face opposite to the
lateral canthus, inferior to the facial crest, and above transverse
facial vessels. The needle is advanced medially, slightly anteriorly to
pass ventral to the border of zygomatic process and drop into the
pterygopalatine fossa just posterior to maxillary tuberosity. The
needle should be pushed until it strikes the perpendicular portion of
palatine bone in the region of maxillary foramen at a depth of 7 cm.
Generally it is a dangerous procedure. 2-Mental Nerve Block: -Anatomy:The alveolar branch of the mandibular division of the 5^th
cranial nerve enters the mandibular foramen on the medial aspect of the
vertical ramus of the mandible under the medial pterygoid muscle. It
traverses the mandibular canal and giving off dental and alveolar
branches then it emerges from the mental foramen and called mental
nerve. The innervation of the incisors and canines arises from the
trunk nerve 3-5 cm before it emerges from the mental foramen.Technique:The
mental foramen, through which the mental nerve emerges, lies on the
lateral aspect of the ramus in the middle of the inter-dental space and
covered with the tendon of depressor labii inferioris muscle. Injection
of the nerve at this point desensitizes the lower lip only, while
advancing the needle 3-5 cm into the canal will desensitize the
incisors and canine too.Indication:Suturing of wounds of the lower lip 3-Mandibualr Nerve Block: -Technique: The
mandibular nerve is injected at its point of entry into the mandibular
canal at the mandibular foramen. The mandibular foramen lies opposite
to the point of intersection of a line passes vertically downwards from
the lateral canthus and a line extending backwards from tables of
mandibular molar teeth. This nerve can be blocked by two methods.1-The
needle is inserted into a point 3 cm below the temporomandibular joint
between the wing of the atlas and base of ear. Then the needle is
advanced towards the point of intersection of the mentioned lines,
medial to the medial surface of the mandible.2-The
needle is inserted directly in front of the angle of the mandible,
medial to the medial surface of the mandible, towards the mentioned
point. The needle should be inserted 12 cm forwards at least.Dose: 5 ml lidocaine HCl 2% 4-Supra-Orbital Block: -Anatomy:Supra-orbital or frontal nerve is a branch of ophthalmic division of 5^th
cranial nerve, emerges from the orbit through the supra-orbital foramen
in the supra-orbital process. It innervates the upper eyelid and skin
of the fore head.Technique:The
upper and lower borders of the supra-orbital process, close to its
junction to the frontal bone, are palpated, and the foramen is detected
midway between the two borders, then the needle is inserted into the
foramen and the nerve is blocked.Dose:5 ml lidocaine HCl 2%Indication:Operations of the upper eyelid or suturing of wounds

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5-Retrobulbar Block: -It is a technique used for blocking of nerves behind the eye ball. Technique:1-The
needle is inserted 1.5 cm behind the middle of the supra-orbital
process and pushed towards the upper molar teeth of the opposite side. 2-The
needle is inserted in the angle between the temporal process of
zygomatic bone and the supra-orbital process and is advanced towards
the base of the orbit (modified Peterson technique).3-The needle is inserted into 4 sites at 3, 6, 9, and 12 O'clock.Dose:20-30 ml lidocaine HCl 2%Indications:Analgesia
and akinesia of periocular muscles for enucleation of the eyeball. The
large amount of injected drugs creates state of exophthalmos to
facilitate enucleation. 6-Auriculopalpebral Nerve Block: -As oxThe Ox 1-Cornual Nerve Block: -Anatomy:It is a branch of the superior maxillary division of 5^th
cranial nerve that innervates the corium and the skin of the horn. It
emerges from the orbit and ascends behind the lateral ridge of the
frontal bone.Technique:The nerve is injected at the upper 3^rd
of the frontal ridge, just behind the ridge, 2.5 cm below the base of
the horn, as it is superficial at this region and covered with thin
layer of frontalis muscle. The needle shouldn't be inserted so deep to
avoid injection under the aponeurosis of temporal muscle. Another
injection 1 cm behind the original site can be done to ensure blocking
of the posterior division.Dose:*5 ml Lidocaine HCl 2%Indication:Dehorning, or surgical intervention of either fractured horn or horn separation 2-Auriculopalpebral Nerve Block: -Anatomy:It is a motor nerve of orbicularis oculi muscle, runs from the base of the ear along the facial crest.Technique:The needle is inserted rostoral to the base of the ear at the summit of zygomatic arch or its dorsal border. Dose:*5-10 ml Lidocaine HCl 2%.Indication:Induction
of paralysis (akinesia) of the eyelids for eye examination, surgical
interferences of the eyeball, or removal of foreign bodies from the
cornea or conjunctive (in conjunction with topical analgesia of the
cornea)The Goat 1-Nerve Block For Dehorning: -Anatomy:The cornual branch of the lacrimal
nerve emerges from the orbit behind the root of the supra-orbital
process covered by thin layer of frontalis muscle and innervates the
caudolateral aspect of the horn, while infra-trochlear nerve emerges from the orbit dorsomedially and divided into dorsal corneal branch that innervates the dorsomedial aspect of the horn, and medial frontal
branch that innervates the caudomedial aspect of the horn, and both
nerves are covered with orbicularis muscle at the lower part and with
frontalis muscle at the dorsal part.Technique:The corneal branch of lacrimal nerve is injected close to caudal ridge of the root of the supra-orbital process.The corneal branch of the infra-trochlear nerve is injected at the dorsomedial margin of the orbit, 0.5 cm deep.Dose:*3 ml lidocaine HCl 2%Indication:Dehorning, or surgical intervention for treatment of fractured horn or horn separationThe DogThis
technique of dental nerve block is no longer be used in dogs as a
result of the development of technique of general anesthesia in this
species, and when it is used, it is combined with sedatives. 1-Infra-Orbital Nerve: -Anatomy:The maxillary nerve derived from the 5^th
cranial nerve, that emerges from the cranium through foramen rotundum,
passes forwards in the pterygopalatine fossa, and continued in the
infra-orbital canal as infra-orbital nerve. -The 1^st and 2^nd molar teeth are innervated by small branches derived from the main trunk before it inters the canal. -The 4 premolars and their alveoli and gum are innervated by filaments derived from the nerve as it passes through the canal. -The nerve supply to canines and incisors is given off in the canal and passes forwards in the maxillary and premaxillary bones.Technique:a-In
the pterygopalatine fossa at its point of entry to desensitize the
whole teeth in the upper jaw in that side. A point 4 cm below the
lateral canthus in the space between the posterior border of malar bone
and anterior border of coronoid process of the mandible is detected.
The needle is inserted in this area and advanced in the soft tissue
until its point passes the egde of malar bone. Then it is redirected
forwards towards the maxillary foramen 3 cm from the point of
insertion. The technique is difficult and may have risk.b-In
the lower part of the infra-orbital canal through infra-orbital foramen
for desensitization of incisors, canines, and first two premolars. This
technique is made through the gum over the 3^rd premolar
tooth at line of reflection of mucous membrane of cheek under which the
lip of the infra-orbital foramen can be detected. The needle should be
advanced 1 cm in the canal. The technique is easy but the area of
desensitization is small.Dose: *Procaine HCl 2% 2 ml for point (a) and 1 ml for point (b). 2-Mandibular Nerve: -It is derived from 5^th
cranial nerve, passes downwards deep to the medial pterygoid muscle and
inters the mandibular canal at the mandibular foramen on the medial
aspect of the ramus. -Molar and premolar teeth are innervated by fibers derived from the main trunk while it stills inside the canal.-The canines and incisors are innervated by branch derived from the main trunk and passes forwards within the ramus. Technique:a-On
the medial aspect of the ramus at the mandibular foramen, that will
desensitize all teeth of the lower jaw on that side. The needle is
inserted at the middle of the depression on the posterior part of the
ventral border of the ramus, in a right angle to the ventral border of
the jaw, close to the medial aspect of the bone, and advanced for 2 cm
to reach the mandibular foramen. The technique is difficult to be
performed.b-In
the anterior part of the mandibular canal through the mental foramen,
that will desensitize lower incisors, canines, and first two premolars
on that side. The mental foramen is injected through the gum
immediately beneath the anterior root of the 2^nd premolar
tooth, and the needle should be advanced 0.7 cm in the canal. The
technique is easy but the area of desensitization is small.Dose:*Procaine HCl 2% 2 ml for (a) and 1 ml for (b). 3-Auriculpalpebral Nerve Block: -Anatomy:The
nerve runs caudal to mandibular joint at the base of the ear, gives the
anterior auricular nerve and then proceeds as temporal branch along the
upper border of zygomatic arch towards the orbit, and finally near the
orbit it divides into medial and lateral branches to innervate the
orbicularis oculi muscle.Technique:Point of needle insertion is the midpoint of posterior 3^rd of zygomatic arch.Dose: *Procaine HCl 2% 1 mlIndication:The
nerve is motor nerve and its blocking has clinical value for
facilitating eye examination, eye operations, and prevention of
blinking and squeezing of the eye after intra-ocular surgery.

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B-Regional Analgesia Of The Limbs: - The Horse 1-Planter Or Volar Nerve Block: -Anatomy:-In the forelimb, the medial high volar
nerve passes with the artery and vein (VAN) in the groove between the
suspensory ligament and digital flexor tendons. At the middle of the
cannon bone, the medial nerve sends branch to the lateral high volar,
that passes behind the flexor tendons and join the lateral branch at
the level of the button of splint bone. At the fetlock region, every
volar nerve divides into three branches named low volar nerves and pass in the same relation to the artery and vein (VAN) but the artery sinks slightly. The anterior branch innervates coronary cushion; the middle branch innervates coronary cushion and sensitive laminae, and the posterior digital branch innervates sensitive laminae and os pedis.-In
the hind limb, planter nerves are the continuation of posterior tibial
nerve. They have the same anatomical position like the forelimb, but
their clinical significance is lower than that of the forelimb, because
the digit is innervated by branches from the anterior tibial nerve
(deep peroneal).Technique for high volar block:The
site of injection is 7 cm above fetlock, in the groove between
suspensory ligament and flexor tendons. The needle is inserted with an
angle of 15° with the vertical line and directed downward and inward.Dose:*5 ml lidocaine HCl 2%Indication: Desensitization of the limb from the fetlock and downward, including pastern and coffen joints for;1-Diagnosis of lameness of affected limb and opposite one 2-Relieve of pain3-Operative procedures a-Neurectomy b-Operative
procedures at the foot, coronet, or heel, like exposure of corn, or
removal of nail, partial operation of quitter or sandcrackTechnique for low volar block (posterior digital):The needle is inserted at the midway between fetlock and coronet in the groove between the 1^st phalanx and the flexor tendon with an angle of 15° with the vertical line and directed downward and inward.Dose:*2-4 ml Lidocaine HCl 2%Indication: Sensation remains in the anterior and lateral parts of the foot, so it is used mainly for diagnosis of navicualr disease. 2-Median Nerve Block: -Anatomy:The
nerve lies 5 cm below the elbow joint in the groove between the
posterior border of the radius and the flexor carpi radialis, deep to
the posterior superficial pectoral muscle, hand fist above the chest
nut.Technique:The needle is inserted in the mentioned site and advanced inward and upward with an angle 20° with the vertical lineDose:*10 ml Lidocaine HCl 2%Indication:Median nerve neurectomy, as the desensitized area is little more than that obtained by medial high volar block. 3-Complete Desensitization Of The Limb Below The Carpus: -Anatomy:For complete desensitization of the limb below the carpus, three nerves should be blocked. Theses three nerves are the median, ulnar, and musculocutaneous
nerves. Ulnar nerve can be located 7 cm above the carpus in the groove
between the ulnaris lateralis and flexor carpi ulnaris, while
musculocutaneous nerve lies at the medial aspect of the limb on the
surface of the radius half way between the elbow and the carpus in
front of cephalic vein.Technique:The needle is inserted in the mentioned sites Dose:*10 ml Lidocaine HCl 2% for each nerveIndication:Any surgical interference below the carpus 4-Posterior Tibial And Anterior Tibial (Deep Peroneal) Nerves Block: -Anatomy:The posterior tibial
nerve lies 15 cm above the point of the hock in the space between
Achilles tendon and long digital flexor. The nerve becomes closer to
the Achilles tendon as the limb is flexed. While the anterior tibial nerve lies in the groove between tendons of long and lateral extensors above the lateral malleolus.Technique:The needle is inserted in the mentioned sitesDose:20 ml lidocaine HCl 2% for posterior tibial and 10 ml for anterior tibial nerveIndication:Desensitization
of the posterior aspect of metatarsus, the medial and lateral aspects
of the fetlock, and the whole digit. For complete desensitization down
the hock, the saphenous, superficial peroneal, and posterior cutaneous
nerves should be blocked.

زائر

The Ox 1-Nerve Block In The Forelimb: -Nerve
supply of the digits of the ox is much more complex than the horse. For
complete analgesia of the digits, five points (1, 2, 3, 4 & 5)
should be blocked. For analgesia of the medial digit, points (1, 4
& 5) should be injected with analgesic. While for complete
analgesia of the lateral digit points (1, 2, 3 & 4) should be
blocked.1-Dorsal metacarpal nerve (Radial) at the middle of metacarpal medial to extensor tendon.2-The dorsal branch of ulnar nerve about 5 cm above the fetlock on the lateral aspect in the groove between suspensory ligament and metacarpal bone.3-The volar branch of ulnar nerve about 5 cm above the fetlock, and caudal to the suspensory ligament at the same level of dorsal ulnar nerve.4-The lateral branch of the median nerve and small branch of the ulnar nerve can be injected at the midline just above the fetlock on the caudal aspect of the limb.5-The medial branch of the median nerve can be injected in the grove between suspensory ligament and flexor tendon on the medial aspect.However
the technique is not easy and missing of one nerve block requires
re-blocking of all the sites again, so it is preferred to make ring
block rather than perineural injection for surgical interference at the
digits. 2-Nerve Block In The Hind Limb: -Method I: -The tibial and external popliteal (common peroneal) are blocked above the hock and they produce complete loss of sensation down the fetlock.Advantages:1-Only two injections are necessary.2-Injection
to soft tissue and at convenient level permits easy application with
thin needle, during standing with minimal restraint.3-The nerves can be located by clear landmarks.4-There is moderate interference with the motor function of the limb.5-Most of the lower limb rendered analgesic.6-It avoids complications of injection at the diseased tissue of the digit.Technique:1-The
common peroneal nerve (external popliteal) can be blocked behind the
posterior edge of the lateral condoyle of the tibia, over the fibula
and before it dips down between the extensor pedis and flexor metatarsi
muscles, for giving off superficial and deep peroneal nerves.2-The
tibial nerve can be blocked 10 cm above the summit of os calcis on the
medial aspect of the limb anterior to Achilles tendon.Dose: 1-The common peroneal nerve is blocked with 20 ml Lidocaine HCl 2%2-The tibial nerve is blocked with 20 ml Lidocaine HCl 2%Method II: -Technique:1-The superficial peroneal is blocked in the upper 3^rd of metatarsus subcutaneously over the dorsal aspect of the metatarsus.2-The deep peroneal nerve can be located halfway down the metatarsus in a groove on the dorsal aspect and covered with extensor tendons.3-The planter metatarsus nerves can be blocked on both sides like high volar in horse. Dose: *5 ml Lidocaine HCl 2% for each nerve of the mentioned 4 nervesThe Dog 1-Brachial plexus block: -It
is a simple method for induction of analgesia of the forelimb, and it
causes analgesia and relaxation from the elbow joint and downwards. Technique:With
the animal standing, the depression at the center of the triangular
area (bounded by the anterior border of supraspinatus muscle, the chest
wall, and the dorsal border of brachiocephalicus muscle) is detected.
The head is held away, and the 7.5 cm long needle is inserted into of
that depression after locating the 1^st rib. The needle is
guided backwards lateral to the chest wall and medial to subscapularis
muscle until its point is judged to be at the level of scapular spine. Dose:Lidocaine HCl 2% 2 mlComplications:1-Hematoma. 2-Acedintal intravenous injection of the drug3-Damage and neuritis of the plexus 4-Penetration of the thorax 5-Infection of the axilla 2-Infiltration of digital nerves: -These nerves are injected subcutaneously, medial and lateral to the 1^st phalanx of each digit, with 2 ml lidocaine HCl 2%.

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C-Regional Analgesia About The Trunk: - The Horse 1-Analgesia For Castration: -Local infiltration of the scrotum and direct injection of up to 20 ml lidocaine HCl 2% into the testicle itselfThe Ox 1-Paravertibral Block: -It
is a perineural injection of spinal nerves as they emerge from the
vertebral canal through the inter-vertebral foramina. It can be used
for induction of laparotomy (rumenotomy or caesarian). The last
thoracic and the 1^st and 2^nd lumbar nerves can be blocked for induction of rumentomy, while the 1^st three lumbar nerves should be blocked for caesarian section in the flank region. Advantages:1-Complete and uniform desensitization of the abdominal wall and peritoneum2-Relaxation of the abdominal muscles with reduction of intra-abdominal pressure3-Short post-surgical convalescence period 4-Lower amount of local analgesia can be used.5-It over comes the disadvantages of inverted-L block and linear infiltrationTechnique:1-The last thoracic can be blocked 5 cm from the midline caudal to the head of the last rib and 5 cm deep.2-The
lumbar nerves can be blocked by insertion of the needle 5 cm far from
the midline on a level with a line drawn just behind the spinous
process of particular vertebra.Dose:*20 ml Lidocaine HCl 2% for each nerve (15 ml below the inter-transverse ligament and 5 ml above it) 2-Pudic Or Internal Pudendal Block: -This
nerve is blocked for induction of protrusion of the penis by a method
other than epidural analgesia to avoid the disadvantages of epidural in
large or heavy bulls.Technique:1-After
location of the nerve per rectum, in the sacrosciatic foramen, the
needle is introduced via the ischiorectal fossa medial to the
sacroisciatic ligament, and is directed forwards and downwards for 7 cm.Dose:*30-40 ml Lidocaine HCl 2% (20-25 at the mentioned site and 10-15 slightly behind)Disadvantages:1-The success rate of this technique is 66%. 2-The onset can be delayed as late as 30-45 minutes.3-Some bulls may show protrusion of the penis as long as 24 hours post injection. 3-Local Analgesia For Castration: -1-The
site of the proposed incision in the scrotum may be rendered analgesic
by local or subcutaneous infiltration, however this will not block the
nerve fibers in the spermatic cord. Accordingly, these fibers can be
rendered analgesic by;2-Direct injection of 10 ml Lidocaine HCl 2% into each cord at the neck of the scrotum.3-Direct
injection of 5-25 ml Lidocaine HCl 2% into the testicle itself.
Accordingly the drug will pass through the lymph, diffuses, and blocks
the fibers in the spermatic cord.For
bloodless castration, both local infiltration at the scrotal neck and
direct injection into the spermatic cord should be used.The Small Ruminants 1-Paravertibral Block: -It
can be performed as with cattle, and each nerve is blocked by 7 ml
lidocaine HCl 1% (5 ml below the inter-transverse ligament and 2 ml
above it). 2-Pudendal Nerve Block: -Anatomy:The
anterior tuberosity of tuber ischii is used as fixed point, and the
length of sacro-tuberous ligament is sued as a radius. This distance is
used to establish a site on a line parallel to the midline in front of
the fixed point. A finger is introduced through the rectum for
detection of the lesser sciatic foramen, and the needle is inserted at
the previously mentioned point. The penis will protrude 5 minutes post
injection.Dose:7 ml lidocaine HCl 2% 3-Local Analgesia For Castration: -1-Direct
injection of 2-10 ml lidocaine HCl 1% into the testicle itself,
followed by local subcutaneous infiltration at the line of incision. 2-Other methods mentioned in cattle.The Dog 1-Paravertibral Block: -The last three thoracic and the 1^st four lumbar
nerves should be blocked to produce analgesia and relaxation of
abdominal muscles; accordingly it can be sued with light general
anesthesia. This technique can be used bilaterally to induce complete
relaxation of abdominal muscles, however, disadvantage of this
technique is time consuming, and its advantage is there is no need for
muscle relaxant and artificial ventilation. Dose:Lignocaine HCl 1 % 2 ml

زائر

2-SPINAL OR EPIDURAL ANALGESIA A-Caudal Epidural: -The OxIt
is a process through which the analgesic solution is injected between
the two layers of dura matter and affects the terminal nerves or cauda
equina thus producing analgesia of the posterior half of the animal.
The term anterior and posterior epidural analgesia is related to the
dose of injected analgesic solution and not to the site of injection. 1-Posterior epidural
characterized by no affection of the motor function of the hind limbs,
but analgesia or loss of sensation can be observed over the tail, croup
as far as the mid-sacral region, the anus, vulva, perineum, and
posterior aspect of the thighs. Paralysis of motor fibers predisposes
to relaxation of anal sphincter and ballooning of posterior part of the
rectum. Defecation will be suspended and stretching of the vulva
provokes no response. The vagina will dilate and straining, during
parturition, ceases without affecting uterine contraction. 2-Anterior epidural
shows some degree of interference with motor function of the hind
limbs. This will vary from partial paralysis of stifle flexors, and
flexors and extensors of hocks and digital joints, to complete
paralysis. In coordination may predispose to injury to the animal or
the workers. Loss of sensation spreads forwards, according to the dose;
over the croup; between hind limbs till the inguinal region, scrotum,
and prepuce; over the hind limbs; mammary gland; and finally flanks and
abdominal wall till the umbilicus. As the drug blocks the sympathetic
outflow of the thoracic and lumbar segments, hypotension will occur and
the normal compensatory mechanism (tachycardia) will be affected as the
cardiac accelerator nerves will be blocked so the heart rate will not
be increased to compensate the hypotension. This hypotension has the
advantage of lowering the chance of bleeding during surgery but on the
other hand, minimal loss of blood threatens the animal life.Seat of injection:The first intercoccygeal space between the 1^st and 2^nd
coccygeal vertebra. Its dimensions are 2 cm transversely, 2.5 cm
anterior-posteriorly, and 0.5 cm deep. The canal is 2-4 cm deep from
the skin surface. Technique:The
needle is inserted with 15° degrees with the vertical. When the needle
reaches the accurate site, there will be no resistance for injection,
and suction of the drug from the hub of the needle can be seen.1-The tail is gripped 15 cm from its base and raised in pump-handle fashion. Seat of injection is the 1^st obvious articulation behind the sacrum.2-Stand beside the animal and detect the 1^st prominence after the croup (prominence of the sacrum), seat of injection is the depression directly behind this prominence.3-A
line has drawn directly over the back connecting two points (one on
each side) 10 cm anterior to posterior prominence of the ischeal
tuberosity. Seat of injection is the point of intersection between this
line and midline.Dose:1-Caudal block:

a-Procaine HCl*15-20 ml 1%.*10-15 ml 2%.*5-10 ml 3-5%.

b-Lignocaine HCl or lidocaine HCl5-10 ml 2%

2-Anterior block:

a-Procaine HCl*40 ml 3% (mastectomy)*170 ml 1% or 120 ml 1.5% (amputation of the digit)*45 ml 2% (caesarean)

b-Tutocaine 1% *60-100 ml (difficult obstetrical interferences) *120 ml (caesarean)

Onset and duration: a-Caudal block:Paralysis
of the tail can be observed after 1-2 minutes, the maximal effect
appears after 10-20 minutes, and lasts for 60 minutes, and the animal
becomes normal again by the end of 120 minutes.b-Anterior block:Paralysis
of the tail can be observed after 1-2 minutes, the maximal effect
appears after 10-20 minutes, and the animal will be unable to rise for
120 minutes, and in coordination may persist for 3-4 hoursIndications:1-Caudal block:a-Obstetrics:1-To overcome straining for correction of malpresentation, or for simpler embryotomy2-Operative treatment of parturient injuries 3-Reduction of prolapsed uterus or vaginab-General:1-Surgical operations of the tail 2-Surgical correction of tears of vulva or perineum3-Examination of the vagina or external cervical os 4-Protrusion of the penis2-Anterior block:a-Obstetrics:1-To overcome straining during extensive embryotomy 2-Amputation of gangrenous prolapsed uterus 3-Caesarian sectionb-General:1-Surgery of penis 2-Cutting operations about the prepuce or inguinal region3-Amputation of the udder 4-Castration 5-Surgery of hind limb like amputation of digitDisadvantages:1-Infection of the nervous system2-Fracture of the animal pelvis, and injury to workers, or veterinarian (anterior block)3-Hypovolumic
shock due to involvement of vasomotor nerve fibers and pooling of blood
in the venous side with absence of compensatory tachycardia (anterior
block)4-Asphyxia due to paralysis of phrenic nerve 5-Twisting of the tail few days or even permanent paralysis after injection due to injury of nerve fibers innervate the tail

زائر

The BuffaloesThe needle is inserted downwards and forwards in the sacrococcygeal with an angle 45º with the vertical.The HorseThe
technique is not common in equine as in bovine because the indications
for such technique in equine are not frequent and the detection of site
of injection is more difficult.Seat of injection:1^st intercoccygeal space in horse and 2^nd intercoccygeal space in donkey. The depth of the canal is 4-8 cm. Technique:The
needle is inserted forwards and downwards with an angle of 30° degrees
with the horizontal (60° with the vertical).1-A
line drawn connecting the hip joints and intersects the midline at the
level of the sacrococcygeal joint caudal to which the dorsal spine of
the 1^st coccygeal bone can be felt. The needle inserted into the depression directly caudal to this point.2-The space is opposite the caudal fold formed on each side of the tail when raised.Indications:1-Caudal block:a-Obstetrics:1-To overcome straining during manipulative correction of simpler forms of malpresentation 2-Partial embryotomyb-General:1-Amputation of the tail 2-Operations about the anus, perineum, or vulva3-Operation for rectal prolapse 4-Caslick operation for windsucking2-Anterior block:a-Obstetrics:Obstetrical difficult manipulative repositions and extensive embryotomyb-General:Scrotal hernia and cryptorchidism Dose:1-Caudal block:

a-Procaine HCl 2%*5-15 ml (amputation of the tail)*10-25 ml (perineal and vulvar operation)*15-30 ml (obstetric manipulation)

b-Lignocaine HCl or lidocaine HCl*10 ml 2%

2-Anterior block:

a-Procaine HCl *50-120 ml 1% (severe obstetrical interferences)*30-80 ml 2% (cutting operation)

b-Lignocaine HCl or lidocaine HCl*100-150 ml 2% (analgesia of hind limbs to the costal arch)

The SheepSeat of injection:Sacrococcygeal spaceDose:*3-4 ml 2% lignocaine HCl (intravaginal obstetrical procedures)*1 ml 5% procaine HCl (docking of lambs)Indications:1-Intravaginal obstetrical procedures2-Relief of painful conditions of vagina and rectum that provoke severe strainingThe DogSeat of injection:Sacrococcygeal or 1^st intercoccygeal spaceDose:*1 ml 2% lignocaine HCl Indications:1-Docking of tailB-Lumbar Epidural Analgesia: -Injection
of analgesic solution into the epidural space in the caudal region
(caudal epidural) affords very save method of inducing epidural
analgesia, but sometimes it is not easy to produce satisfactory
anterior block via this site. The lumbar epidural analgesia through the
anterior lumbar region or lumbosacral spaces, affords a belt of
analgesia around the trunk of the animal without affecting the motor
function of the hind limbs.The OxSeat of injection:Seat of injection is just to the right of the lumbar spinous process of the 2^nd lumbar vertebra, 1.5 cm caudal to the anterior edge of the second lumbar transverse process.Dose:* 10-15 ml Tutocaine 2%* 10 ml Procaine HCL 4% (15 ml weakens the hind limbs- 20 ml the animal lie down)*8 ml Lignocaine 3%*10 ml Lignocaine 2%Indications:This technique is used for induction of flank analgesia for rumenotomy or caesarian.The SheepSeat of injection:Lumbosacral
space to avoid puncturing of meninges. It is located just behind the
spinous process of last lumbar vertebra that lies at a point of
intersection between line drawn to connect the anterior borders of the
two illiums and midline.Technique:The needle is inserted in the mentioned space with an angle 10° anterior and 15° lateral with the vertical.Dose:8-15 ml Lignocaine 3%Indication:Intra-abdominal, pelvic, or hind limb surgeryThe DogSeat and technique:Lumbosacral space as sheepDose:0.5 ml/KgIndications:1-Posterior abdominal (hysterectomy, or cystotomy) or inguinal surgery2-Treatment of hind limb fracture

زائر

III-PREANESTHETIC MEDICATION
Definition:
It
is the drug that usually administered prior to induction of anesthesia
for sedation if the animal is to be operated under the effect of local
or regional analgesia, or for sooth induction and smooth recovery from
general anesthesia, and reduction of the anesthetic dose.
Aims:
1-Potentiation of anesthetic agent
2-Reduction and abolishing of pain
3-Soomth induction and smooth recovery of anesthesia
4-Avoiding harms to the animal and surgeon
5-Reducing the amount of anesthetic agent and its toxicity
6-Reduction of salivary and bronchial secretions and the subsequent possibility of asphyxia
7-Reduction of GIT motility
8-Stimulation of cardiac and respiratory functions
TYPES
1-Anticholenergic drugs
2-Muscle relaxants
3-Tranquilizers
1-Anticholenergic drugs (Atropine)
It
is a water-soluble sulfate used as atropine sulfate. It is very safe
drug with wide therapeutic margin except individual animals that have
proved to be sensitive to the drug.
Uses:
Used
as pre-anesthetic medication with wide safety margin for stimulation of
cardiac and respiratory functions, and inhibition of salivary and
bronchial secretions. Used prior to wide verity of anesthetic agents
(barbiturates, or inhalation anesthetics), sedatives, and narcotics.
Effect on CNS: -
1-The
clinical dose produces initial reduction of heart rate due to vagal
stimulation, before its peripheral anticholenergic effect ensues
2-Over dose causes central cholenergic syndrome with fluctuations between hyper excitability and depression
Effect on eye: -
It causes mydriasis and it is contraindicated in cases of glaucoma
Effect on Respiration: -
It
causes relaxation of bronchial musculature, dilates bronchi, prevents
laryngeal spasm during intubation, and reduces bronchial secretion
Effect on Cardiovascular system: -
It prevents vagal inhibition induced by narcotics, or tranquilizers, accordingly it prevents bradycardia
Effect on GIT: -
It reduces muscle tone of GIT, inhibits motility, and reduces salivation
Side effects:
The use of this drug in equines is prohibited due to
1-Equine don't produce copious salivation
2-Posibility of formation of viscid bronchial secretion with subsequent occlusion of alveoli
3-Interfernce with vision and the animal becomes uncontrollable
4-Reduction of intestinal motility with subsequent intestinal distention, and colic
Dose and concentration:
Concentration is 0.6 mg/ ml (0.06%)
Rout of administration:
Injection by IV, IM, or SC

Animal	1 Kg
Ruminants	0.005 (up to 0.2-0. mg/ Kg B wt. (1% concentration)
Equine	0.7 mg/ kg, (up to20-60) mg/ Animal
Dogs	0.3-1.8 mg/ animal* 0.04 (0.02-0.1) mg/ Kg B wt. (over dose causes convulsion, coma, and death)
Cat	1 mg/ Kg, Up to 0.3 mg/ animal. in adult cat (average 0.1 mg/ Kg B wt)
Pigs	0.3-1.8 mg/ animal.

2-Muscle relaxant
A-Gallamine triethiodide (Gallamine-Flaxedil): -
1-Gallamine produces a non-depolarization block at the neuromuscular junction, vagal block, and tachycardia.
2-It does not produce histamine release in the dog, so it is the non-depolarizing relaxant of choice in dog.
3-It
is not detoxicated in the body, but it is excreted unchanged in urine,
so it shouldn't be given to animals suffering from renal insufficiency.
Uses:
1-Surgical application (muscular relaxation)
It is very useful in;
a-Abdominopelvic surgery b-Thoracic and lung surgery
c-Tracheal intubation during anesthesia d-Immobilizing wild animals.
e-Reduction of muscle spasm (help in reduction of dislocated joint)
f-Reduction of amount of general anesthetic agent
2-Obstitrical application
Especially
during parturition in small animals at the stage of full dilatation (as
the drug not pass via placental barrier) for relaxation of the perineum
to avoid risk of injury or laceration.
3-Medical application
a-Reduction of traumatic and rheumatic pain
b-Relief of myositis, and tetanus spasm
Side effect:
1-Tachycardia with increased arterial blood pressure with subsequent high incidence of hemorrhage
2-The drug has histamine-releasing effect except in dogs
3-The
drug should be used cautiously, as it may cause respiratory failure,
accordingly, it can't be used unless artificial respiration tools are
available.
Dose and rout of administration:

*Animal*	*1 Kg*	*Rout*
Cattle and equine	0.1 mg/ Kg	IV
Dog	1 mg/ Kg
Cat	1-2 mg/ Kg

Antidote:
Neostigmine
B-Succinylcholine: -
Advantages:
1-It is free from the usual complications of muscle relaxants like
a-Hypotension c-Tachycardia b-Histamine release and urticaria
2-It
has a rapid rate of destruction due to hydrolysis by plasma
cholinesterase (the later is inhibited by phenothiazine like
chlorpromazine HCI), so it has no cumulative effect.
3-The myoneural action is intensified when procaine is injected after it.
Dose and rout of administration:

*Animal*	*1 Kg*	*Rout*
Equine	0.6 mg/ Kg	IV
Cattle	0.04 mg/ Kg
Dogs	0.01 mg/ Kg

زائر

3-Tranquilizers or Ataractics, and Sedatives
They are drugs used to depress the CNS, and are useful in wide verities of conditions in animals
Classification:
A-Weak acting drugs: -
Like meprobamate derivatives (Equinal) and used for human only
B-Strong acting drugs: -
1-Phenothiazine derivatives: -
a-Acepromazine (Acetylpromazine)
b-Chlorpromazine (Largactil or Neurazine)
c-Promazine (Sparine)
d-Propionylpromazine (Comblen)
2-Thiazine derivative: -
a-Xylazine HCl (Rompun or Xylaject)
b-Detomidine
3-Benzodiazepine derivative (Diazepam, or Valipam): -
a-Short acting (Valium, Neuril, Diazepam or Valipam)
b-Very long acting (Lorazepam)
Clinical use:
1-Preanesthtic drug
2-Relief anxiety of hospitalized animal
3-Restrain of refractory animal during examination
4-Prevention of animals from licking wounds or chewing bandage and splints
5-Used in minor surgical operations like abscess incision
6-Used in conjunction with local or regional analgesia
Clinical effect:
1-The ear drops with sluggish response
2-The eyes close or become semi-closed with protrusion of third eyelid
3-The tongue protruded in some cases
4-In
cattle, the muzzle becomes dry with excessive salivation and reduced
deglutition, that may cause dehydration and disturbance of acid base
balance as a result of excessive loss of bicarbonate of the saliva
5-In cattle the head and neck drop and deviate to lateral side
6-Stugering gait of animal that becomes unconscious to the surrounding and try to lie down, and finally the animal lies down
7-Protrosin of penis and dilatation of anal and vulval sphincter
8-Reduction of temperature, pulse, and respiration
Advantages:
1-Easier handling of the animal during induction of anesthesia
2-Reduction of the required amount of anesthetic agent with subsequent reduction of toxicity
3-Smooth induction and recovery from anesthesia (reduction of struggling)
4-Inhibition of vomiting by the anti-emetic action of the drug
5-Phenothiazine derivatives help in prevention of shock
Warning:
1-Tranqulizer doesn't produce true analgesia
2-Occisionally severe or fatal reactions may occur
3-Not economical as the cost is high in many occasions
4-When administered to shocked animal, alpha-blockage may produce fatal hypotension
STRONG ACTING DRUGS: -
1-Phenothiazine derivatives: -
a-Acepromazine (Acetylpromazine): -
Dose:
0.1-0.2 mg/ Kg B. wt. in pets and large animals
b-Chlorpromazine (Largactil or Neurazine): -
Preparations:
Suppositories, tablets, drops, and vials for injection.
Effect and properties:
1-Produces
state of calmness with reduction of motor activity, but it doesn't
interfere with responses to unconditioned stimuli such as needle pricks
and painful manipulations
2-It has potent anti-emetic, anti-adrenaline, and vagolytic properties.
3-It
causes vasodilatation and should be used cautiously in shocked animals,
but its use prior to operation counteracts tendency of tissue hypoxia,
and prevents the onset of shock.
4-It
has a wide safety margin and animals will recover from the effects of
very large doses, but it should be used cautiously if there is severe
depression of the heart or central nervous system, or if there are
extensive liver or lung lesions.
5-The liver is the main site for detoxication so the action enhanced in during liver damage.
Uses:
1-Preanesthetic medication, to potentate the anesthetic agent
2-Long acting strong tranquilizer
3-Antiemitic, and used in cases of uremia or gastroenteritis in pets, or with drugs causing nausea and vomiting.
4-In case of tetanus to control titanic spasm and convulsions, and to diminish pain.
5-Its use in the horse ensures that the animal will recover quietly from anesthesia
6-Its
use in dog ensures absence of narcotic excitement during recovery from
barbiturate, and doesn't suppress respiration of puppies or labour of
bitch.
Dose and administration:

*Animal*	*1 Kg*	*Rout*
Horse	Not more than 0.2-0.4 mg	IM	Larger doses cause panic state due to muscle weakness and the animal's response may be alarming and difficult to control
Cattle	Not more than 1 mg (Not to lie down)	IM 1 hour before local or regional analgesia	Not recommended prior to general anesthesia due to relaxation of the cardia with increased risk of regurgitation, and delayed recovery, but it can be used with local or regional analgesia
Dog	0.5-1 mg 1 mg 2 mg	IV or IM Oral Rectal	The maximum effect appears after 60-90 mins with IM, and 10-15 mins with IV injection
Cat	Up to 1 mg	IV or IM

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c-Promazine HCl (Sparine 5%): -
Use and indication:
Like chlorpromazine HCl
Dose and administration:

*Animal*	*1 Kg*	*Rout*
Large animals	1 mg	IM only
Pets	5 mg	IM only

d-Propionylpromazine (Combelen 1%): -
It
is one of phenothiazine derivatives, yellow crystalline, and soluble in
water. The solution used for injection contains 1% of active principle
propionylpromazine.
Uses:
1-Sedation
a-Prior to drug administration b-Examination c-Minor operations
d-Radiographic examination e-Dressing of wounds
2-Preanesthtic medication for induction of general anesthesia
3-Potentiation of anesthetic agents by deepening and prolongation of its effect, and reduction of 10-40% of anesthetic dose
Disadvantages:
Should be used cautiously in case of cardiac disorders, and in case of severe lung, liver, or kidney problems.
Antidote:
Caffeine or nor-adrenaline
Duration:
1-8 hours according to rout of administration, dose, and age
Recovery:
Effect disappears completely within 24 hours
Dose:

*Animal*	*Weight Kg*	*Slow IV ml*	*IM ml*
Horse	100	0.5	1
Cattle	100	13 (penile protrusion)	2
Camel	100	2	4
Sheep and goat	10		Up to 1
Dog	1	0.03	0.05
Cat	1		Up to 0.2

2- Thiazine derivative (Sedatives): -
a-Detomidine: -
Stills under investigation
b-Xylazine HCl (Rompun or Xylaject): -
It is used in concentration of 2%
Properties:
a-It is sedative (depressant effect on CNS), analgesic, anesthetic, and muscle relaxant.
b-Ruminants are 5-10 times sensitive than equine.
c-It has emetic effect in pets.
d-Reduces dose of anesthetic
1-Sedation:
This effect is of clinical importance for;
a-Transportation of animals,
b-Changing environment and familiarization with new surrounding
c-Examination and treatment of claw, or shoeing of horse
d-Surgery e-Artificial examination of less domesticated cattle
Duration of sedation:

*Animal*	*Period*
Horse	0.5-1 hour
Cattle	0.5-5 hours
Small animals	1-2 hours
Wild animals	0.5-1 hour

2-Analgesia:
This effect is of clinical importance for;
a-Management of udder and teat injury
b-Dehorning, fitting of nose ring, flushing of nasolachrymal duct
c-Bloodless castration d-Treatment of foot affections
Duration of analgesia:

*Animal*	*Period*
Horse	Variable
Cattle	Up to 45 mins
Small animals	30 mins

3-Anesthesia:
a-It has local analgesic effect on the cornea of rabbit several times higher than that of procaine HCl (0.2%)
b-Local anesthetic effect in dogs by 0.1-0.2% with induction of local insensibility for 60 mins
c-Used for epidural analgesia
4-Muscle relaxation:
Used in surgical operations to avoid tetany and to capture the animal
Duration of muscle relaxation:
According to the dose it varies from 20-120 mins
Side effect:
1-Cardiovascular system:
It causes bradycardia, in a manner resembles that of atropine
2-Respiratory:
No great changes with recommended doses
3-GIT:
It
depresses GIT and ruminal motility and may cause tympany in ruminants
but this reduction of motility is helpful in case of equine colic.
4-Uterous:
It
increases intra-uterine pressure in pregnant cows in a manner resembles
that of oxytocin, accordingly it shouldn't be used in the last
trimester. This is not the same in mares that can be given xylazine
along the all gestation period with no harm

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Dose and rout of administration:

*Animal*	Kg	IV	IM
Horse	1	0.5 mg On set is almost immediate Lasts 15-20 minsRecovery after 30 mins	2-3 mg On set over 10-15Lasts 15-20 minsRecovery after 60-120 mins
Cattle	1	0.05 mg	0.05-0.1 mg (standing animal) On set* over 8-12 Lasts 30 mins*0.2-0.3 mg (recumbency)
Sheep	1	0.11 mg	0.22 mg
Goat	1		0.0.5 mg (more sensitive than sheep and sedation may last 12 hours)
Pets	1		Up 0.2 ml 2%

3-Benzodiazepine derivative: -
a-Short acting (Valium, Neuril, Diazepam or Valipam): -
Uses:
1-Preanesthetic medication 2-Sedative and hypnotic 3-Control of convulsions
4-Produces muscular relaxation 5-Epidural analgesia
Dose and administration:

*Animal*	*1 Kg*	*Rout*
Large animals	1 mg	IM
Dogs	1 mg5 mg	IM, pre-anesthetic and for control of restlessness Oral, for control of behavioral problems
Sheep and goat	Up to 15 mg1-2 mg	Oral, for wild sheep and aggressive pucksIM or slow IV, for radiographic examination or as pre-anesthetic medication

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b-Very long acting (Lorazepam): -
It
is 4 times potent than diazepam, with shorter on set of action and
prolonged duration and recovery, and used as pre-anesthetic medication
prior to ketamine HCl especially in cat

IV-BASAL NARCOSIS
Definition:
It
is a stage during which the animals losses consciousness but still
responding to painful stimuli, so it is of clinical importance for
performing operations in horses and cattle under local or regional
analgesia. Its administration should be limited to avoid interference
with vital processes. The most common drug is chloral hydrate.
1-Chloral hydrate: -
1-It is a white crystalline, easily soluble in water, and has penetrating odor
2-Mainly used for equine and may be used for cattle
3-Detoxicated in liver and excreted by kidney
4-Can be used in different doses to induce three stages of narcosis
5-Can be used strictly IV, orally, or rectally
6-Hypnotic
dose doesn't affect respiration, but over dose predisposes to
respiratory failure via affecting the respiratory center
Stages of narcosis, doses, and effect:

Stage	Dose / 50 Kg	Conc.	Rout	Effect
Light	3-4 gm	10%	IV	The animal still in standing position with motor in coordination and reduced response to external stimuli, which facilitate examination of the animal.
Medium	4-5 gm	10%	IV	The animal becomes unable to stand, lies down, with reduced response to external stimuli
Deep	5-6 gm	10%	IV	The animal lies down in lateral recumbency, becomes on the border of general anesthesia, with reduced response to external stimuli

Routs of administration:

Rout	Dose / 50 Kg	Conc.	On set	Recovery
IV	3-4 gm4-5 gm5-6 gm	10%	Few mins	1-2 hours	The drug is highly irritant, even after dilution to 10%, so it should be injected strictly intravenous into jugular vein, to avoid cellulites and phlebitis.
Oral	6-7 gm	6-8 L Water	10-20 mins		It can be applied either in drinking water after fasting for 24 hours, or by stomach tube after dilution in water, to reduce its irritant effect.
Rectal	8 gm	3-4 L Water	20-30 mins		By rectal enema

Advantages:
1-Easily dissolved in water
2-Wide safety margin
3-Detoxicated by liver and excreted by kidney
4-Easily absorbed from mucous membrane of GIT
5-The animal able to stand under effect of light and medium narcosis
Disadvantages:
1-Very irritant, and can't be injected IM or SC
2-Over dose causes hypotension and respiratory failure

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2-Morphine: -
It is used either as morphine sulfate or HCl, and mainly used in dogs
Dose, rout, on set, and duration:

Dose	Rout	On set	Duration
Up to 5 mg/ Kg	SC or IV	5-10 mins (maximum is 30-45 mins)	12 hours

Action:
1-It depresses the higher functions of the brain
2-Stimulates then depresses medullary functions, and stimulates spinal reflexes
3-Produces depression, analgesia, and sleeping in dogs, but in large doses cause coma. Also it Produces pin-point pupil
4-Produces delirium or 'maniacal excitement in cat
5-Produces
unreliable effect in horses, cattle, and pigs (narcosis or excitement).
Also it may cause sufficient excitement to dilate the pupil.
Side effects:
1-It
is advised that the dose of morphine as a preanesthetic should not
exceed 15 mg even in the large dogs because larger dose causes
respiratory depression.
2-It
crosses the placenta and reaches the fetus, depressing its respiratory
center and making the initiation of breathing difficult after birth,
but the analgesic doses of morphine do not affect normal uterine
contractions at parturition, accordingly it shouldn't be used for
caesarian section.
3-The stimulant effect on the vagal center
a-Increases gastro-intestinal activity
b-Increases
the tone of the visceral muscle (especially pyloric, ileo-colic and
anal sphincters). c-Increases segmenting contractions
d-Diminishes the truly propulsive movements.
e-Delays intestinal contents in the large bowel and allows an increased absorption of water
f-Inhibits the normal defecation reflex because the distended rectum no longer produces the usual discomfort.
4-In
species with developed vomiting center, it stimulates then suppresses
vomiting, and when vomiting occurs, it is not associated with the usual
unpleasant emotional reactions, so that animals do not appear
distressed.
5-Morphine also produces retention of urine, distension of the bladder
6-It
affects respiratory system through the central nervous system and
decreases respiratory activity (respiration becomes slow and deep),
however the analgesic effect of morphine improves respiration when it
is fast, shallow, and inefficient due to pleural pain or trauma, or
when lungs are edematous, as in left ventricular failure.
7-Therapeutic
doses have negligible effects upon the heart rate and blood pressure,
but larger doses slow the heart by depressing conduction in the
myocardium and stimulation of the vagal center.
References:
Hall, C.W. and Clarke, K.W. (1983), Veterinary anesthesia, 8th edition;
Hall, L.W. (1978), Wrights veterinaray anesthesia and analgesia, 7th
edition

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IV-GENERAL ANASTHESIA Definition:It
is a state of unconsciousness and transit paralytic action of the motor
center produced by process of controlled reversible intoxication of the
CNS without interfering with vital centers. General anesthesia can be
classified according to physical characters of anesthetic agent into
injectable anesthesia and volatile anesthesia.Use:It offers the ideal situation for 1-Aseptic surgery2-Proper handling of tissue3-HemostasisReflexes that disappeared during general anesthesia:1-Pedal reflex 2-Anal reflex 3-Tail reflex 4-Ear reflex 5-Skin pinching reflex6-Pharyngeal and laryngeal reflexes 7-Ocular reflex (corneal)I-Nonvolatile Compounds (Injectable): -A-Chloral hydrate: -It is the same as mentioned in narcosis but the dose should be increased up to 7 gm/ 50 KgB-Magnesium sulfate + Chloral hydrate + Pentobarbiturate sodium: --It is satisfactory general anesthesia in equinePreparation:6% chloral hydrate, 3.5% magnesium sulfate, and 0.5% pentobarbiturateDose:30 ml/ 50Kg IV for equine and bovine and the sedative dose should be reduced to 0.25 of anesthetic doseAdvantages:1-Smooth induction and recovery2-Complete muscle relaxation3-wide safety margin4-short anesthetic period (up to 30 mins)C-Ketamin H Cl (Ketalar®, Vetalar®, or Ketaset®): -Definition:It is a non-barbiturate general anesthesia with rapid action and short durationClinical effect:1-Good analgesic 2-Poor muscle relaxant 3-Mild respiratory distress4-It raises arterial blood pressure 5-It is dissociative anesthetic6-It work well when combined with xylazine or diazepamDoses:1-Calves: -Calves from one week to one year can be anesthetized in the following mannera-Ketamin 20 mg/ kg (IM or IV)b-Ketamin 10 mg/ kg + Xylazine 0.2 mg/ kg (IM)Onset is few minutes; duration is 35 minutes, and recovery after 80-90 minutes2-Small ruminants: -They should be premedicated with atropine sulfate 0. mg/ kg IMa-Ketamin 20 mg/ kg (IM or slow IV)b-Ketamin mg/ kg + Xylazine 0.22 mg/ Kgc-Ketamin 4 mg/ kg + Xylazine 0.05 mg/ kg + Diazepam 1-2 mg/ kg3-Dog: --5 mg/ Kg IM (premedicated with Xylazine or chloropromazine)-Duration of anesthesia is 30 mins and recovery is 90 mins4-Cat: --11-22 mg/ Kg IM (premedicated with Xylazine or chloropromazine)-Duration of anesthesia is 30 mins and recovery is 90 minsD-Barbiturate: -Barbiturates
(thiopental sodium, thiopenton sodium, or pentobarbital sodium) are
sodium salt of barbituric acid and when dissolved in water they act as
weak acids, and effectiveness (depth of anesthesia) of these
derivatives is directly proportional to the acidity of the solution and
blood pH.Clinical effect:1-Circulatory and respiratory depression 2-Lowering body temperature3-Complete muscle relaxationThiopental sodiumDefinition:It
is a barbiturate, intravenous general anesthetic agent, and produced
rapid action (1-2 mins), short duration (20-30 mins), and short
recovery (60-90 mins). Solution should be freshly prepared and kept at
5-6 C° to retard deterioration.Dose:20-30
mg/ Kg, 2.5-5 % strictly IV, and the dose is controlled by absence of
reflex in small animals. Concentration of 2.5% is preferred (0.5 gm/ 20
ml pyrogen free water);1-To avoid spasm of vein and thrombosis2-To avoid sloughing and necrosis of the skin if the peri-vascular tissue is infiltrated with the concentrated solution

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Advantages of Injectable general anesthetics:1-The most direct rout in reaching the CNS with very short induction phase2-Very economic when compared with inhalation general anesthesia3-Most injectable general anesthetics are stable and not flammable4-Most injectable anesthetics can be utilized intraperitoneally5-Can be utilized with minimal need for assistanceDisadvantages of Injectable general anesthetics:1-Longer recovery period2-Management and control of over dose is not as accurate as inhalationII-Volatile Or Gaseous Substances (Inhalation Anesthesia): -A-Chloroform: --It is a clear flammable liquid with a pleasant odor and non-irritant vapor-It is not recommended for patients with cardiac, respiratory, renal, or hepatic insufficiencyB-Ether (Ethyl ether): --It is a colorless highly volatile liquid with a pungent odor and irritating vapor -In presence of air or oxygen it forms aldehydes by oxidation (which are toxic)-It
is decomposed by light and heat therefore the liquid should be stored
in sealed dark containers that should be kept in cool dark place-It causes irritation to; a-Respiratory
mucosa leading to increased flow of respiratory and salivary secretions
that interfere with respiration and lowers immune resistance with
increased susceptibility of post operative pneumoniab-Renal mucosa with reduction of urine out put during anesthesia with post anesthetic albuminurea-It has minimal effect on liver and cardiac muscle-It has wide safety marginC-Ethyl chloride: --It is gaseous at room temperature but under pressure and low temperature it is a colorless liquid with ethereal odor-It is a potent general anesthetic with narrow safety marginWarning:Over dose causes;a-Death due to ventricular fibrillation with sudden fall in blood pressureb-Hepatitis and renal failureD-Nitrous oxide: --It is the oldest anesthetic agent, and recently its use in veterinary anesthesia is limited -It is colorless, odorless, and non-flammable gas E-Halothane (Fluthane): --It
is non-flammable, good muscle relaxant, produces minimal mucous
membrane irritation, has wide safety margin, and it is popular in
veterinary anesthesia as it is potent and ideal inhalant anesthetic
agent.Methods of induction of inhalation anesthesia: -1-Open method: -It
can be used for ether or ethyl chloride spray, by dropping it on a
piece of gauze or lint that should be kept of the nostril of the
animal. This piece of gauze can be stretched over a wire frame to form
a mask with preservation of free flow of air between the mask and the
face.Disadvantages:1-Lack of control of ventilation, as oxygen enrichment should be always given during general anesthesia2-Excessive loss of volatile agnets2-Semi-open method: -All
inspired air is made to pass through the mask in which the vapor of
anesthetic agent is present. The space between the mask and the face is
closed with double thick layer of gamgee. Disadvantages:Same as open method3-Semi-closed method: -Vapors
flow from anesthetic apparatus into reservoir bag from which the animal
inhales through endotracheal tube, while part of all exhaled mixture
passes out through an expiratory valve into the atmosphere. 4-Closed method: -In
this method, vapors flow from anesthetic apparatus into reservoir bag
from which the animal inhales through endotracheal tube. The exhaled
anesthetic agent, which is mixed with Co2, is directed to closed bag at
which Co2 is removed (by soda lime of 90% calcium hydroxide, 5% sodium
hydroxide, and 5% silicates and water to prevent powdering) and O2 is
added, then the same vapor is re-breathed.

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Advantages:It is a simple method that consumes less anesthetic agentHinz's BoxIt is a glass or transparent plastic box used for inhalation anesthesia (ether) in cat and dog.Advantages:1-Require no restraint and no assistant2-Minimised anesthetic emergency3-Animal passes into a state of anesthesia with minimal amount of strugglingStages of general anesthesia:-1-Stage I (Stage of voluntary excitement or Induction stage): -a-The animal is consciousb-Respiratory and pulse rates increasec-Dilatation of the pupild-Urine and feaces may be voided2-Stage II (Stage of involuntary excitement or Delerium stage): -a-Loss of consciousnessb-Exaggerated reflex to stimulic-Very irregular respirationd-Eye ball moves from side to sidee-Vomiting may occur due to pharyngeal reflex3-Stgae III (Stage of surgical anesthesia): -a-Increase regular automatic breathingb-Fixation of the eyeballc-Absence of all reflexesd-Complete muscle relaxation4-Stage IV (Over dose stage): -a-Complete
paralysis of thoracic muscles with active diaphragm, which causes
bulging of the relaxed abdominal wall while the relaxed thoracic wall
moves inward like resting position during expirationb-The respiration is gasping in character as a result of jerky movement of the diaphragm.c-The pulse rate increased-The pupil dilate and the eyeball present in fish-eye appearance due to cessation of lachrymal secretione-The animal enters stage of death with coma and cyanosisTreatment of overdoses inhalation anesthesia: -1-Stop of gas inhalation2-Increase oxygen supply3-Artificial respiration4-Adminsteration of cardiac and respiratory stimulant5-Prtruding the tongue of the animal and try to supply the animal with Co2 which cause stimulation of medullary center6-Warming of the animal by strawComplications of over doses of anesthesia: -1-Syncopy, and pathologic affection of respiration and circulation2-Respiratory arrest3-Liver intoxicationProblems encountered in general anesthesia in bovine: -General
anesthesia in bovine is so dangerous so that nerve block and
infiltration analgesia are preferred. HoweveriIn some of the more
sophisticated surgical procedures, general anesthesia becomes mandatory
for sake of asepsis, and complete restraint as in case of ;1-Repair of penile hematoma2-Inguinal herniorrhaphy3-Cercumcission and correction of preputeal adhesionGenerally, the problems encountered in bovine general anesthesia are;1-Bloat and regurgitation: -the
excessively formed gas in the rumen can't be regurgitated normally with
the animal in lateral recumbency, due to higher level of ruminal fluid
than cardiac opening. This large amount of gases causes;a-Interference with the already impaired respiration, caused by the recumbence position and pressure on diaphragmb-As
the pressure increases it will press the cardiac opening that is
augmented by the depth of anesthesia, with relaxation of the cardia, so
that the fluid flows from the rumen, then it may be collected in the
pharyngeal region and may be aspirated leading to drenching pneumonia
or death2-Anoxia: -It resulted from; a-Respiratory embarrassment by compression of the lower lung due to lateral recumbency. b-Deep anesthesia causes more diaphragmatic breathing c-Pressure on diaphragm by abdominal visceraImportance of endotracheal tube: -a-It reduces many of potential problemsb-It provides a potent air wayc-It prevents aspiration of saliva as well as regurgitation of food materials3-Radial paralysis: -This condition may lasts from few minutes to few weeks and its occurrence depends up on;a-Length of time of recumbencyb-Body weightc-Thickness of subcutaneous fatgenerally this condition can be avoided by placing inflated tire under the point of shoulder at the time of casting4-Salivation: -Use of atropine sulfate reduces amount of saliva and increases its thicknessReferences:
Hall, C.W. and Clarke, K.W. (1983), Veterinary anesthesia, 8th edition;
Hall, L.W. (1978), Wrights veterinaray anesthesia and analgesia, 7th
edition