Anesthesia in cow gynecology & obstetrics Flashcards
Main drug to be used for obstetric procedures in cattle?
afla2-adrenomimetics / agonists
They cause a drop in blood pressure, analgesia at the spinal cord level:
blocking the pain reflex transfer from periphery to central nervous system.
Main alfa2 agonists used in cattle?
xylazine (rompun)
detomidine (domosedan)
medetomidine (domitor)
romifidine (sedivet)
Detomidine and romifidine have the same effect with the same dose for the horse and cattle (dose amount is the same as Xylazine in cow).
xylazine (rompun) dose for cattle
0.025-1 mg/kg IV or
0.1-0.3 mg/kg IM
Xylazine has potent effect in ruminants. For horse, dog and cat to have same effect dose should be 10x bigger .
Xylazine is contraindicated in cows in
late gestation. Can cause uterine contractions.
Heavy sedation with xylazine should be avoided because it depresses the cough and swallow reflexes.
Main local anesthetic choice in cattle
lidocaine, but also procaine hydrochloride (Novocaine)
For Infiltration anesthesia and nerve block anesthesia.
Contraindications of procaine.
- Contraindicated for dogs and cat (anaphylactic shock risk)
- Not recommended for horses (danger for agitation).
- Not suitable for epidural anesthesia when phenothiazines are used for premedication (e.g. acepromazine).
Difference between lidocaine and procaine / why do we use lidocaine more frequently nowadays?
lidocaines’ effect is 2x stronger
lidocaines’ duration of effect is also longer
What percentage solutions of lidocaine may be used for infiltration anesthesia?
1-3%
(2% is most common)
Most widespread and safe intravertebral anesthesia technique in cattle?
epidural-sacral anesthesia
Spinal cord extends to the following sacral bone segments.
Horse II – III
Cattle I – II
Swine III
Dog II
In epidural-sacral anesthesia, we have 2 options for injection site:
sacrococcygeal (foramen between last sacral bone segment and first coccygeal vertebra)
coccygeal (foramen between first and second coccygeal vertebra)
To find the correct spot, lift the tail and palpate the junction simultaneously.
Anesthetic volume In epidural-sacral anesthesia.
Low sacral anesthesia:
High sacral anesthesia:
Low sacral anesthesia: 8-15 ml
High sacral anesthesia: 25-50-80 ml
> 10 ml administration may cause partial paralysis of hind legs
We always aim to use low sacral! Typically just start with 10-11 ml. Leave needle in place and add more if needed.
The anesthetic should take effect in 5-15 min and duration of effect should be approx. 90 min.
Calculating local anesthetic volume for epidural anesthesia in cattle and horses.
We may calculate the volume of anesthetic by measuring the length of the horse’s pelvis (length between coxal tuber and ischiatic tuber).
For low sacral anesthesia, volume of the anesthetic should be 1 ml per each 3 cm of length.
Typically just start with 10-11 ml. Leave needle in place and add more if needed.
The anesthetic should take effect in 5-15 min and duration of effect should be approx. 90 min.
Low sacral anesthesia will anesthetize what body parts?
anus, vulva, caudal most part of back as well as tail will be anesthetized, + uterus and cervix will be relaxed.
Best way to quickly see whether your epidural is functioning?
loose tail
In male animals, the penis falls out of the preputium.
Where is anterior epidural anesthesia placed, as opposed to posterior?
Anterior is placed cranial to sacrum.
Posterior is placed just after sacrum.
Sometimes just caudal to first coccygeal vertebra is used as well.
Alternative drug for epidural-sacral anesthetic other than lidocaine and procaine.
You can inject diluted Xylazine into the epidural space (off-label use).
At a dose of 0.07 mg/kg.
Mix 1.75 ml of Xylazine in 10 ml of physiological solution.
Anesthesia in case of laparotomy in large animals.
In cattle we can anesthetize the abdominal operation area in 3 ways:
- Infiltration anesthesia
- Paralumbar anesthesia
- Paravertebral anesthesia
Infiltration anesthesia for laparotomy in cattle.
Use 50-100 ml of 2% lidocaine in the incision region for an adult cow. Ideally wait 10 min for it to take effect.
Paralumbar anesthesia for laparotomy in cattle.
Abdominal wall nerves will be anesthetized in the region of the lumbar vertebrae’s transverse processes. Distal to site of emergence from vertebral column.
20 ml of 2% Lidocaine: 10 ml injected close to the nerve root and another 10 ml around the superficial branches of the nerve.
L1-L2-L4
Nerves to block:
- nervus costoabdominalis – first lumbar bone transverse process corner
- nervus Iliohypogastricus – second lumbar bone transverse process extremety
- nervus Ilioinguinalis – fourth lumbar bone transverse process corner
Nerves to block in Paralumbar anesthesia:
And their locations.
L1-L2-L4
- nervus costoabdominalis: at corner of first lumbar bone transverse process
- nervus Iliohypogastricus: at the second lumbar bone transverse process extremity
- nervus Ilioinguinalis: at fourth lumbar bone transverse process corner
Paravertebral anesthesia for laparotomy in cattle.
Nerves will be anesthetized at the proximal site where they emerge from the vertebral column (intervertebral foramen).
Can be challenging to find right spot if cow very fat.
How many C-T-L-S vertebrae do cows have?
7-13-6-5 (fused to form sacrum)
(Dogs & cats are 7-13-7-3)
(Horses 7-18-6-5)
