Total intravenous anesthesia with alfaxalone, dexmedetomidine and remifentanil in healthy foals undergoing abdominal surgery.

This research article explores the effects of anesthesia, induced with alfaxalone and maintained with alfaxalone, dexmedetomidine and remifentanil, on foals undergoing abdominal surgery. The conclusion of this study indicates that this combination of anesthetics provides suitable aid for laparotomy, and prolonged recovery may occur at the studied doses.

Experimental Methodology

• The study is prospective and experimental, involving a group of six healthy foals within the age range of 11 (8-33) days undergoing abdominal surgery.
• Anesthesia was administered intravenously. Initial sedation for the insertion of a pulmonary artery catheter was provided by dexmedetomidine (3-7μgkg). Anesthesia was then induced with alfaxalone (2mgkg), and maintained using alfaxalone (6mgkghour), dexmedetomidine (1μgkghour) and remifentanil (3μgkghour).
• Following the induction of anesthesia, the foals were endotracheally intubated and their lungs were mechanically ventilated with oxygen.
• Various physiological parameters were monitored and assessed, including cardiac output, heart rate, systemic arterial pressure, oxygen utilization, and intrapulmonary shunt.
• Anesthetic depth was subjectively assessed, and systemic vascular resistance (SVR) was calculated.
• Blood was also drawn and analysed for PO and PCO, and glucose, lactate, and electrolyte concentrations.

Key Findings

• Anesthesia lasted for an average duration of 129 ± 22 minutes. One foal needed additional alfaxalone following induction.
• Cardiac index decreased over the course of anesthesia, from a baseline of 157 ± 33mLkg/minute to 107 ± 31mLkg/minute at 60 minutes and further to 87 ± 21mLkg/minute at 80 minutes post-anesthesia start.
• Systemic vascular resistance (SVR) increased to 1223 ± 166dynessecondcm at 80-minutes compared to the baseline measurement taken 10 minutes post-anesthesia induction (+10B) of 704 ± 247dynessecondcm.
• Time from stopping infusions to regaining standing capability ranged from 46 to 106 minutes.
• All foals were hypothermic (body temperature <36°C) post-procedure. Three of the six foals were administered atipamezole during recovery.

Conclusion and Clinical Relevance

• The combination of alfaxalone, dexmedetomidine, and remifentanil proved to be a suitable anesthetic approach for laparotomy procedures in foals. However, the doses used in this study may lead to a prolonged recovery phase.