title: Cardiorespiratory, endocrine and metabolic changes in ponies undergoing intravenous or inhalation anaesthesia.
abstract: Six Welsh gelding ponies (weight 246 +/- 6 kg) were premedicated with 0.03 mg/kg of acepromazine intravenously (i.v.) followed by 0.02 mg/kg of detomidine i.v. Anaesthesia was induced with 2 mg/kg of ketamine i.v. Ponies were intubated and lay in left lateral recumbency. On one occasion anaesthesia was maintained for 2 h using 1.2% halothane in oxygen. The same group of ponies were anaesthetized 1 month later using the same induction regime and anaesthesia was maintained with a combination of detomidine, ketamine and guaiphenesin, while the ponies breathed oxygen-enriched air. Electrocardiogram, heart rate, mean arterial blood pressure, cardiac output, respiratory rate, blood gases, temperature, haematocrit, glucose, lactate and cortisol were measured and cardiac index and systemic vascular resistance were calculated in both groups. Beta-endorphin, met-enkephalin, dynorphin, arginine vasopressin (AVP), adrenocorticotrophic hormone (ACTH) and catecholamines were measured in the halothane anaesthesia group only and 11-deoxycortisol during total intravenous anaesthesia (TIVA) only. Cardiorespiratory depression was more marked during halothane anaesthesia. Hyperglycaemia developed in both groups. Lactate and AVP increased during halothane anaesthesia. Cortisol increased during halothane and decreased during TIVA. There were no changes in the other hormones during anaesthesia. Recovery was smooth in both groups. TIVA produced better cardiorespiratory performance and suppressed the endocrine stress response observed during halothane anaesthesia.
authors.affiliation: Animal Health Trust, Newmarket, UK.
authors.forename: S P
authors.initials: SP
authors.lastname: Luna
authors.forename: P M
authors.initials: PM
authors.lastname: Taylor
authors.forename: M J
authors.initials: MJ
authors.lastname: Wheeler
mesh_terms: D000075:Acepromazine / Q000008:administration & dosage / Q000009:adverse effects; D000324:Adrenocorticotropic Hormone / Q000097:blood; D000700:Analgesics / Q000008:administration & dosage / Q000009:adverse effects; D000704:Analysis of Variance; D000769:Anesthesia, Inhalation / Q000009:adverse effects* / Q000662:veterinary; D000771:Anesthesia, Intravenous / Q000009:adverse effects* / Q000662:veterinary; D000778:Anesthetics, Dissociative / Q000008:administration & dosage / Q000009:adverse effects; D000818:Animals; D001127:Arginine Vasopressin / Q000097:blood; D001784:Blood Gas Analysis / Q000662:veterinary; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature; D002302:Cardiac Output / Q000187:drug effects; D002395:Catecholamines / Q000097:blood; D018492:Dopamine Antagonists / Q000008:administration & dosage / Q000009:adverse effects; D004562:Electrocardiography / Q000187:drug effects / Q000662:veterinary; D004723:Endorphins / Q000097:blood; D006221:Halothane / Q000008:administration & dosage / Q000009:adverse effects; D006339:Heart Rate / Q000187:drug effects; D006400:Hematocrit; D006736:Horses / Q000378:metabolism*; D006854:Hydrocortisone / Q000097:blood; D007093:Imidazoles / Q000008:administration & dosage / Q000009:adverse effects; D007649:Ketamine / Q000008:administration & dosage / Q000009:adverse effects; D019344:Lactic Acid / Q000097:blood
chemical_list: D000700:Analgesics; D000778:Anesthetics, Dissociative; D001786:Blood Glucose; D002395:Catecholamines; D018492:Dopamine Antagonists; D004723:Endorphins; D007093:Imidazoles; D001127:Arginine Vasopressin; D019344:Lactic Acid; D000075:Acepromazine; D007649:Ketamine; C041255:detomidine; D000324:Adrenocorticotropic Hormone; D006221:Halothane; D006854:Hydrocortisone