Abstract
Purpose :
To compare the effects of both injectable anesthesia (Ketamine/Dexdomitor versus Ketamine/Xylazine) and inhalant anesthesia (Isoflurane) on IOP using continuous, bilateral IOP telemetry in nonhuman primates (NHP).
Methods :
Continuous bilateral IOP was recorded continuously 500 times per second using a proven implantable telemetry system in five different sessions at least 2 weeks apart in 4 male rhesus macaques aged 3-6 years old under two conditions: 1) Ketamine (3 mg/kg) with Dexdomitor (50 mcg/kg) followed by Isoflurane inhalant anesthesia (1-3%) for maintenance or 2) Ketamine with Xylazine (0.5 mg/kg) for induction, followed by Isoflurane for maintenance. The IOP transducers were calibrated via anterior chamber manometry, and all data corrected for signal drift. Bilateral IOP averaged over 2 minutes was quantified after anesthetic induction, and again after Isoflurane inhalant had stabilized the anesthetic plane, and compared to baseline IOP measurements acquired immediately prior to anesthesia.
Results :
The results show that the average change is generally < 2 mmHg for Ketamine/Dexdomitor post-injection. IOP with Ketamine/Dexdomitor was significantly lower by 1.3 mmHg post-injection compared to baseline. IOP was not significantly different from baseline after isoflurane anesthetic plane was achieved with either Ketamine/Dexdomitor or Ketamine/Xylazine injectable anesthesia.
Conclusions :
General anesthesia is common in both animal studies and human patient procedures, but its effects on IOP are largely unknown. Results show that Ketamine/Dexdomitor injectable anesthesia lowers IOP significantly by 1.3 mmHg on average, but IOP returned to baseline levels shortly after Isoflurane gas anesthesia was initiated. This should be taken into account in both experiments and clinical practice when consideration of IOP or its effects is important.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.