Effects of Phenylephrine on Cardiac Preload

Study Overview
=================
Brief Summary
-----------------
In patients under general anesthesia, episodes of hypotension are often treated with phenylephrine. The effect of phenylephrine is conventionally attributed to afterload increase. The aim of the study is to describe the time course of the effects of phenylephrine on the cardiac preload and cardiac output, and to evaluate whether phenylephrine, as an exclusive alpha-mimetic, could be beneficial for preload optimisation.

Detailed Description
-----------------
In consecutive patients scheduled for laparoscopic sigmoidectomy, all hemodynamic and respiratory variables are recorded electronically for subsequent offline analysis. All patients are ventilated in volume control mode with a tidal volume of 8 ml/kg ideal body weight. During steady-state Target Controlled Infusion (TCI) propofol/remifentanil anesthesia, when the Mean Arterial Blood Pressure (MAP) dropped below 80% of the awake state for at least 5 minutes, a phenylephrine bolus of 2 μg/kg is administered. If necessary this is repeated, or a continuous administration of phenylephrine is started at a rate of 10-30 μg/kg/u. All patient manipulations during the procedure are electronically recorded and time stamped for subsequent off-line data analysis. The first episode in each patient where phenylephrine is administered and in a period of at least 10 minutes when minimal or absent patient manipulation occurred, the hemodynamic variables are analysed to describe the effects of phenylephrine administration on the dynamic preload parameters and macro-hemodynamics.

Official Title
-----------------
The Dynamic Effects of Phenylephrine on Preload and Cardiac Output in Patients Under General Anaesthesia

Conditions
-----------------
Arterial Hypotension, Anaesthesia

Intervention / Treatment
-----------------
* Drug: Phenylephrine


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Adult necessity for arterial blood pressure monitoring necessity for central venous blood pressure monitoring Exclusion Criteria: unwilling or unable to grant written informed consent cardiac arrythmia contra-indication for phenylephrine contra-indications for atropine contra-indication for Total Intravenous Anesthesia

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 85 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Patient receiving phenylephrine 2ug/kg<br>phenylephrine 2ug/kg in case of hypotension | Drug: Phenylephrine<br>* Intravenous administration<br>* Other names: Phenyl;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cardiac output | The evolution of the Cardiac Output in a time course <20 minutes after administration | perioperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pulse Pressure Variation | The evolution of Pulse Pressure Variation in a time course <20 minutes | perioperative | 
| End-Tidal CO2 | The evolution of the EtCO2-value in a time course <20 minutes | perioperative | 
| Arterial Blood Pressure | The evolution of The Arterial Blood Pressure in a time course <20 minutes | perioperative | 
| central venous pressure | The evolution of the central venous pressure in a time course <20 minutes | perioperative | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
phenylephrine, alpha mimetics, pulse pressure variation, venous return