Effects of Propofol, Etomidate, and Thiopental on Intraocular Pressure and Hemodynamic Responses in Phacoemulsification by Insertion of Laryngeal Mask Airway

Purpose: To evaluate the effects of propofol, etomidate, and thiopental administered during phacoemulsification (PE) cataract extraction on intraocular pressure (IOP) and hemodynamic responses with insertion of laryngeal mask airway (LMA). Methods: In a randomized double-blind clinical trial, patients scheduled for PE with general anesthesia were included. Patients were allocated randomly to 3 groups: group 1 (n=34): 0.3mg/kg etomidate; group 2 (n=33): 2mg/kg propofol; and group 3 (n=34): 4mg/kg thiopental. IOP, systolic blood pressure, and heart rate (HR) were measured before induction as a baseline, 2min after induction (immediately before insertion of LMA), and 1 and 3min after LMA insertion. Blood pressure (BP) and HR of patients during the surgery were monitored and registered before and after induction and intubation. Results: In 3 groups, IOP decreased significantly after injection of drugs and insertion of LMA in comparison to basic values, although IOP after LMA insertion was more than before LMA insertion. In case of propofol, the changes in IOP between 2min after induction and the baseline were higher than others, especially thiopental (P=0.031). BP declined remarkably after induction (P<0.001) and rose significantly after LMA insertion in all groups, except in the propofol group. The HR was decreased significantly after induction, except in thiopental. Conclusion: Propofol prevented IOP increase after induction compared with other drugs. Decrease in BP and HR after induction and LMA insertion was remarkable. Thiopental seemed to be the best drug for controlling cardiovascular parameters, especially HR, and it also prevents IOP rise.