1. General Anesthesia in
Equine Emergencies

2. Introduction
There are several emergent cases affect horses like fractures , deep wounds , respiratory obstruction as well as surgical intervention in case of dystocia.
There are several problems affect administration of general anesthesia in horses which lead to serious physiological disturbances may lead to death of the animal.

3. Preanesthetic drugs Acepromazine 0.05 mg/kg IM Xylazine 2mg/kg IM
Detomedine 20 µg/kg IM

4. Induction of Anesthesia
Kitamine + Xylazine + Guaifenesin
Xylazine 1.1 mg/kg IM then Guaifenesin 1.1 mg/kg IV after that Kitamine 1.3 mg/kg IV give anesthesia for 25 min.
Kitamine + Xylazine + Diazepam
Diazepam 0.2mg/kg IM and after 20 min Xylazine 1.1 IV then Kitamine 2.2 mg/kg IV give anesthesia for 40 min.

5. Induction of Anesthesia
Pentobarbitone Na 6.6 mg/kg 5%
Guaifenesin 2.2 mg/kg 5%
Pentobarbitone + Guaifenesin
2gm from pentobarbitone /1ltr of Guaifenesin the dose is 2.2 mg/kg.
Ketamine + Xylazine
Xylazine 1.1 mg/kg IV and then ketamine 2.2 mg/kg IV give anesthesia for 10 min.

6. Maintenance of Anesthesia
IV injection
Chloral hydrate 80 mg/kg IV.
Equithesin (Chloral hydrate 28 gm + Magnesium sulphate 14 gm + pentobarbitone Na 6.5 gm ) give 80 mg/kg IV.

7. Maintenance of Anesthesia
Inhalation
Halothane 1.1 %.
Enfluthane 2.3%.
Isoflurane 1.5%.

8. parentral general anesthesia
Contraindication of
parentral general anesthesia
Cases of hepatitis and diseases of kidney. Shock. In very young animal (less than 1 month) and also in the senile one.

9. Side effects of parentral general anesthetics
Barbiturate:
Thiopentone sodium:
Induction apnea due to central inhibition of respiratory center.
Arrhythmia: due to direct affection on myocardium .
Oligurea: liberation of ADH due to stimulation of supraopticohypophyseal system.

10. Pentobarbitone sodium:
Prolonged recovery period if used alone.
Hypotension due to dilation of peripheral blood vessels.
Tachycardia due to central inhibition of vagus nerve.
Respiratory failure due to inhibition of respiratory centre in the medulla oblongata.
fetus mortality due to crossing the BPB.

11. Narcotics Chloral hydrate: Prolonged recovery period (1-4 hrs).
Hypotension due to inhibition of vasomotor center in the medulla oblongata.
Bradycardia due to vagal activity.
fetus mortality due to crossing the BPB.

12. Steroidal anesthetic agent
Kitamine:
Not good for horses due to convulsions more than inhibitions.
Transient apnea.
Aspirated pneumonia due to affection of swallowing reflexes.
Hypertension and tachycardia.

13. Side effects of inhalant general anesthetics
Diethyl ether
Production of saliva and mucous.
Coughing and apnea.
Acidosis due to decrease the pH and serum bicarbonate.

14. Halothane
Hypoxia due to inhibition of ventilation and increase shallow respiration.
Dilation of trachea due to direct affection on the smooth muscles so it is used in patient with asthma (advantage).
Dilation of blood vessels of skeletal muscles so can’t be used in case of severe hemorrhage.

15. Problems facing general anesthesia cardiovascular system
Bradycardia:
Atropine sulphate + fluid therapy.
Stop or decrease administration of drugs and give positive ventilation.

16. Tachycardia
Stop administration of drugs.
Positive ventilation and fluid therapy (increase Co2 lead to increase of heart beats.

17. Respiratory system Decrease the anesthetic depth. Improve ventilation.
Decrease respiratory rate or apnea:
Decrease the anesthetic depth.
Improve ventilation.
Increase respiratory rate:
Increase anesthetic depth.
Increase Co2 in blood lead to increase respiratory rate

18. General anesthesia in equine emergencies
These points should be regarded:
Correction the status of the animal before anesthesia by administration fluids, NaHCo3, antibiotics.
Placing the nasogastric tube.
Activation of ventilation.
Give supportive drugs as calcium solutions.

19. Wounds Suturing of wound.
Using xylazine alone or with morphine, phenothiazine tranquilizers are contraindicated due to hypotensive effect.
If these tranquilizers are used then must give norepinephrine with fluids.
In anesthesia can use Guaifenesin with ketamine.
Nitrous oxide is contraindicated due to decrease the cardiac output.

20. Fractures
Anesthesia by mephenesin derivatives as Guaifenesin cause muscles relaxation with less affect on the cardiovascular and respiratory systems.

21. Dystocia
Anesthesia by mephenesin derivatives as Guaifenesin if the epidural anesthesia was not enough.
Guaifenesin can cross BPB but with no noticeable inhibition to the vital organs of fetus.

22. CS. Operation Guaifenesin can be used with positive ventilation.
After getting the colt out from uterus thiobarbiturate can be added to the anesthetic regimen or administration of halothane by endotracheal tube.
Halothane and enfluthane decrease the uterine contractility and decrease the bleeding.
Nitrous oxide can be used safely after getting colt from uterus, opioids can be given as well as benzodiazepine compounds.

23. Colic
Pethidine IM with high doses because the low doses can’t give the required effect.
Xylazine and Detomedine with low doses can give a good effect besides there are no negative effects to the digestive canal.
Disappearing the signs of pain in not treated patient is bad prognosis which usually related to the explosion the dilated organ.
Acepromazine cause hypotension with limited importance in the treatment of pain of colic.