Effects of Phenylephrine on Cardiac Preload


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.

Full Title of Study: “The Dynamic Effects of Phenylephrine on Preload and Cardiac Output in Patients Under General Anaesthesia”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: N/A
    • Intervention Model: Single Group Assignment
    • Primary Purpose: Treatment
    • Masking: None (Open Label)
  • Study Primary Completion Date: July 2016

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.


  • Drug: Phenylephrine
    • Intravenous administration

Arms, Groups and Cohorts

  • Other: Patient receiving phenylephrine 2ug/kg
    • phenylephrine 2ug/kg in case of hypotension

Clinical Trial Outcome Measures

Primary Measures

  • Cardiac output
    • Time Frame: perioperative
    • The evolution of the Cardiac Output in a time course <20 minutes after administration

Secondary Measures

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

Participating in This Clinical Trial

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

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: 85 Years

Are Healthy Volunteers Accepted: No

Investigator Details

  • Lead Sponsor
    • Algemeen Ziekenhuis Maria Middelares
  • Provider of Information About this Clinical Study
    • Principal Investigator: Dr. Alain Kalmar, MD, PhD, Dr – Algemeen Ziekenhuis Maria Middelares
  • Overall Official(s)
    • Alain F Kalmar, MD, PhD, Principal Investigator, Department of Anaesthesiology and Intensive care medicine, Maria Middelares hospital, Ghent, Belgium

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