Phenylephrine Versus Norepinephrine in Ophthalmic Surgery

Study Overview
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Brief Summary
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In ophthalmic surgery the specific anaesthesiological challenges necessitate the administration of a combination of relatively high doses of hypnotics and analgetics. In order to preserve adequate organ perfusion, there is often a need to administer pharmacological agents for haemodynamic support. Depending on the experience of the anaesthetist a continuous infusion of phenylephrine or norepinephrine is used. It is currently not known which of these agents has the most favorable haemodynamical profile. Haemodynamic parameters (continuous blood pressure, cardiac index, stroke volume and systemic resistance), peripheral tissue oxygenation and cerebral tissue oxygenation will be monitored noninvasively using the Nexfin® , Inspectra®, and Foresight® and O2C® monitoring devices.

Official Title
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Comparison of the Effects of Phenylephrine and Norepinephrine on Hemodynamics and Tissue Oxygenation in Patients Undergoing Ophthalmic Surgery

Conditions
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Bloodpressure

Intervention / Treatment
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* Drug: phenylephrine
* Drug: norepinephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients requiring general anaesthesia for ophthalmic surgery. Age > 18 years and older Diabetes or cardiovascular disease or age >55 years Exclusion Criteria: Patient refusal Patient < 18 years

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Single Group Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: phenylephrine<br>If the mean arterial pressure drops below 20% of the baseline value and/or below 90 mmHg, a syringe pump with phenylephrine will be started. The anaesthetist will be blinded for the type of vasopressor. Concentrations phenylephrine (20 µg /ml) will be used in the syringes | Drug: phenylephrine<br>* If the mean arterial pressure drops below 20% of the baseline value and/or below 90 mmHg, a syringe pump with phenylephrine or norepinephrine (depending on randomisation) will be started. The anaesthetist will be blinded for the type of vasopressor. Concentrations phenylephrine (20 µg /ml) of Norepinephrine (10 µg/ml) will be used in the syringes<br>|
| Active Comparator: norepinephrine<br>If the mean arterial pressure drops below 20% of the baseline value and/or below 90 mmHg, a syringe pump with norepinephrine (depending on randomisation) will be started. The anaesthetist will be blinded for the type of vasopressor. Concentrations Norepinephrine (10 µg/ml) will be used in the syringes | Drug: norepinephrine<br>* If the mean arterial pressure drops below 20% of the baseline value and/or below 90 mmHg, a syringe pump with norepinephrine (depending on randomisation) will be started. The anaesthetist will be blinded for the type of vasopressor. Concentrations Norepinephrine (10 µg/ml) will be used in the syringes<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| the haemodynamical effects of norepinephrine and phenylephrine during ophthalmic surgery |  | 1 day |