Ketamine increases intraocular pressure in horses

California – mechentel news – The findings from T.H. Ferreira et al. concerning Effects of ketamine, propofol, or thiopental administration on intraocular pressure and qualities of induction of and recovery from anesthesia in horses, support the use of thiopental or propofol in preference to ketamine for horses in which increases in IOP should be minimized. To assess the effects of ketamine hydrochloride, propofol, or compounded thiopental sodium administration on intraocular pressure (IOP) and qualities of induction of and recovery from anesthesia in horses,the US-scientists from Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, sedated 6 horses with xylazine hydrochloride (0.5 mg/kg), and  included anesthesia with guaifenesin followed by ketamine (2 mg/kg), propofol (3 mg/kg), or thiopental (4 mg/kg) in a crossover study with ≥ 1 week between treatments. For each horse, IOP in the right eye was measured with a handheld applanation tonometer before and after xylazine administration, at the time of recumbency, and every 3 minutes after induction of anesthesia until spontaneous movement was observed. Cardiorespiratory responses and venous blood measurements were recorded during anesthesia. Induction of and recovery from anesthesia were subjectively evaluated by investigators who were unaware of the anesthetic treatment of each horse. Data were analyzed via a repeated-measures ANOVA with Holm-Ŝidák post hoc comparisons. The reserchers concludet in the August issue from Am J Vet Res, that compared with findings after xylazine administration (mean ± SD, 17 ± 3 mm Hg), thiopental decreased IOP by 4 ± 23%, whereas propofol and ketamine increased IOP by 8 ± 11% and 37 ± 16%, respectively. Compared with the effects of ketamine, propofol and thiopental resulted in significantly lower IOP at the time of recumbency and higher heart rates at 3 minutes after induction of anesthesia. No other significant differences among treatments were found.

Autoren: Ferreira TH, Brosnan RJ, Shilo-Benjamini Y, Moore SB, Hollingsworth SR. Korrespondenz: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, CA 95616, USA. Studie: Effects of ketamine, propofol, or thiopental administration on intraocular pressure and qualities of induction of and recovery from anesthesia in horses. Quelle: American Journal of Veterinary Research 2013 Aug; 74(8):1070-7. doi: 10.2460/ajvr.74.8.1070. http://avmajournals.avma.org/doi/abs/10.2460/ajvr.74.8.1070