IOP Changes Due to Anesthesia (Healthy Patients) Clinical Trial
One important goal in anesthetic management during ocular surgery is to provide adequate
control of intraocular pressure (IOP). An increase in IOP may be catastrophic in patients
with glaucoma or a penetrating open-eye injury. There is an ongoing debate over the effect
of anesthetic agents on the IOP. Anesthetic regimens in this surgical field commonly consist
of short-acting anesthetic agents, such as propofol and sevoflurane, usually combined with
short-acting analgesics, such as remifentanil. Both propofol and sevoflurane are known to
reduce the IOP. To this end there is no data in the literature to support or disprove this
finding.
Study Hypothesis Variations in the end-tidal sevoflurane concentrations have no significant
effect on the IOP.
One important goal in anesthetic management during ocular surgery is to provide adequate
control of intraocular pressure (IOP). An increase in IOP may be catastrophic in patients
with glaucoma or a penetrating open-eye injury. There is an ongoing debate over the effect
of anesthetic agents on the IOP. Anesthetic regimens in this surgical field commonly consist
of short-acting anesthetic agents, such as propofol and sevoflurane, usually combined with
short-acting analgesics, such as remifentanil. Both propofol and sevoflurane are known to
reduce the IOP. Previous studies have compared these two anesthetics protocols in order to
determine which provides superior control of the IOP. Propofol produced significantly lower
IOP measurements compared to sevoflurane (both combined with remifentanil), in cataract
surgery, whereas in non-ophthalmic surgery propofol and sevoflurane caused a comparable
decrease in IOP. Sevoflurane, an inhalational anesthetic, has a rapid onset of action faster
recovery time and is also suitable for inhalation induction because it does not irritate the
airway. A prospective randomized clinical trial compared the effects of ketamine and
sevoflurane on IOP during the eight minutes after induction of anesthesia (in 2-minute
intervals) in children with suspected or diagnosed glaucoma undergoing EUA. During these 8
minutes the IOP decreased significantly only in the sevoflurane group. This finding
contradicted claims that measurements immediately after induction are relatively unaffected
by anesthetics and suggested that variations in sevoflurane concentration do affect the IOP.
Yoshitake et al showed that the remarkable reductions of IOP after inductions are probably
caused by induction agents, suggesting that sevoflurane is a useful anesthetic for elderly
patients receiving ophthalmic surgeries. To this end there is no data in the literature to
support or disprove this finding.
Study Hypothesis Variations in the end-tidal sevoflurane concentrations have no significant
effect on the IOP.
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Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Open Label