A Study to Compare the Effect of Propofol and Etomidate as Induction Agents on Intraocular Pressure

Stress response to laryngoscopy and a consequent rise of Intraocular pressure at the time of induction of anaesthesia is a well-known phenomenon. Various methods have been described to prevent it so that it does not lead to a harmful outcome. While various agents have been used but there is no consensus with regard to the best pharmacological agent.

The aim of the study was to compare the effect of propofol and etomidate as induction agents on IOP in patients undergoing non-ophthalmic surgery.

The randomized double blind study enrolled 60 Adult patients aged between 18–50 years of either sex, belonging to ASAphysical status I or II scheduled for elective surgery. Patients were randomly allocated to either of two groups using 2 different intravenous induction agents: Group P (n=30) received propofol 2 mg kg⁻¹ and Group E (n=30) received etomidate 0.3 mgkg⁻¹. Baseline readings of all parameters like MAP, HR and IOP were recorded. Induction of anaesthesia was achieved with either propofol 2 mg kg⁻¹or etomidate 0.3mgkg¹ intravenously. IOP was measured 1min after administration of induction agent and 2 min and 5 min after tracheal intubation. MAP and HR were also recorded following above intervals.

Mean baseline IOP of all the subjects in group P was 14.32 ±2.07 and group E was 13.46±1.8 mmHg. Drop in mean IOP was observed one minute following induction and was 11.38±2.92 and 8.477±1.5 mmHg in group P and E respectively. IOP values when compared at different points, drop observed was found to be highly significant with p value < 0.001. Heart rate and MAP was comparable and no statistical difference was observed at any time points in both the groups.

We conclude that etomidate and propofol both result in optimal reduction in IOP, but etomidate is significantly better to propofol in lowering the mean intraocular pressure.