Introduction

• Maintenance of anesthesia involves keeping the patient at a suitable depth of anesthesia to allow surgery to be carried out safely for both the patient and personnel.
• Anesthesia may be maintained by giving incremental bolus doses or continuous infusion of intravenous anaesthetic agents   Anesthesia: intravenous (IV)  , or via inhalation of volatile agents   Anesthesia: inhalational  .
• Intravenous maintenance of anesthesia tends to be restricted to shorter procedures up to a maximum of 90 min. 
• For extended periods of anesthesia, inhalation anesthesia is currently more appropriate.
• Monitoring is critical to ensure adequate anesthesia and early identification of any problems.
• Anesthesia in foals presents specific considerations   Anesthesia: neonate  .

Side effects of maintaining anesthesia in horses

Intravenous anesthesia

Inhalation anesthesia

Further Reading

Publications

Refereed papers

• Recent references from PubMed and VetMedResource.
• Raisis A L et al (2000) A comparison of the hemodynamic effects of isoflurane and halothane anesthesia in horses. Equine Vet J 32, 318-326 PubMed.
• Carroll G L et al (1998) Maintenance of anesthesia with sevoflurane and oxygen in mechanically ventilated horses subjected to exploratory laparotomy treated with intra- and post-operative anesthetic adjuncts. Equine Vet J 30 (5), 402-407 PubMed.
• Taylor P M et al (1998) Cardiovascular effects of surgical castration during anesthesia maintained with halothane or infusion of detomidine, ketamine and guaifenesin in ponies. Equine Vet J 30 (4), 304-309 PubMed.
• Benson G J & Thurmon J C (1990) Intravenous anesthesia. Vet Clin North Am 6 (3), 513-528 PubMed.
• Brunson D B (1990) Use of halothane and isoflurane in the horse. Vet Clin North Am 6 (3), 529-542 PubMed.

Other sources of information

• Hubbell J A E (2004) Anesthesia of the Horse: Monitoring, Recovery and Complications. In: 50th AAEP Convention Dec 2004.
• Kronen P W (2003) Anesthetic Management of the Horse: Inhalation Anesthesia. In: Recent Advances in Anesthetic Management of Large Domestic Animals. Ed: Steffey E P.
• Mama K R (2000) Anaesthetic Management of the Horse: Intravenous Anaesthesia. In: Recent Advances in Anesthetic management of Large Domestic Animals. Ed: Steffey E P.
• Hall L W, Clarke K W & Trim C M (2000) Veterinary Anesthesia.9th edn. Bailliere Tindall, UK.
• Tayler P M & Clarke K W (1999) Handbook of Equine Anesthesia. W B Saunders.
• McMurphy R M, Young L E, Marlin D J et al (1998) Comparison of the Cardiopulmonary Effects of Total Intravenous Anesthesia with Romifidine, Guaifenesin and Ketamine vs Halothane in Horses. In: Proc Ann Mtg Am Coll Vet Anes 13.
• Taylor P M (1992) Total Intravenous Anesthesia for Major Surgery in Horses - The Way Forward? Bain Fallon Lectures.
• Muir W W & Hubbell J A E (1991) Equine Anesthesia Monitoring and Emergency Therapy. Mosby Year Book.
• Trim C M (1990) Intravenous Anesthesia - Induction and Maintenance. In: Current Practice of Equine Surgery.Eds. White N A & Moore J N. J B Lippincott Company, USA. pp 69-77.
• Steffey E P (1990) Inhalation Anesthesia. In: Current Practice of Equine Surgery.Eds: White N A & Moore J N. J B Lippincott Company, USA. pp 77-83.
• Brander G C, Pugh G M & Bywater R J (1982) Veterinary Applied Pharmacology and Therapeutics.4th edn. Bailliere Tindall, UK.