Effects of propofol alone or in combination with ketamine on intraocular pressure in unpremedicated dogs.

Abstract

OBJECTIVE: To determine the effects of propofol (P) alone and in combination with ketamine (KP) at ratios of 1:1, 1:2, and 1:3 on intraocular pressure (IOP) in unpremedicated dogs. ANIMALS STUDIED: A total of 28 cross-bred healthy dogs. PROCEDURES: Dogs were randomly assigned to one of four groups (n&#x2009;=&#x2009;7 per group) to receive intravenous P or KP at 1:1, 1:2, and 1:3 ratios, respectively. The infusion was administered at 0.6&#x2009;mg/kg/min for 60&#x2009;min. IOP, cardiorespiratory variables, rectal temperature (RT), and pedal reflex were recorded every 5&#x2009;min for 60&#x2009;min, starting from baseline (BL). RESULTS: There was a statistically significant increase in IOP in all groups: P (p&#x2009;=&#x2009;.011), KP 1:1 (p&#x2009;=&#x2009;.003), KP 1:2 (p&#x2009;=&#x2009;.023), and KP 1:3 (p&#x2009;=&#x2009;.008). The IOP increase was less pronounced in the KP 1:2 group and was only significant (p&#x2009;=&#x2009;.023) at T45 compared with BL. A significant correlation was observed between IOP and SpOin P (r&#x2009;=&#x2009;-.215, p&#x2009;=&#x2009;.02), KP 1:2 (r&#x2009;=&#x2009;-.579, p&#x2009;<&#x2009;.01), and KP 1:3 (r&#x2009;=&#x2009;-.402, p&#x2009;<&#x2009;.01) groups. IOP significantly increased due to decreased SpObelow 86.5% (p&#x2009;<&#x2009;.05). CONCLUSIONS: Propofol alone and in combination with ketamine may increase preexisting IOP in unpremedicated dogs. SpOlevels below 86.5% may trigger an increase in IOP. Administering KP in a 1:2 ratio at an infusion rate of 0.6&#x2009;mg/kg/min does not significantly alter IOP for under 45&#x2009;min in unpremedicated dogs with sufficient oxygenation.