Influence of Anesthesia on Mechanical Efficiency of Left Ventricle in Patients Undergoing Open Heart Surgery
Information source: Sheba Medical Center
ClinicalTrials.gov processed this data on August 23, 2015 Link to the current ClinicalTrials.gov record.
Condition(s) targeted: Heart; Dysfunction Postoperative, Cardiac Surgery; Disorder; Heart, Functional, Postoperative, Cardiac Surgery
Intervention: Isoflurane (Drug); Propofol (Drug)
Phase: Phase 4
Status: Recruiting
Sponsored by: Sheba Medical Center Official(s) and/or principal investigator(s): Sergey Preisman, M.D., Principal Investigator, Affiliation: Department of Anesthesia and Intensive Care, Sheba Medical Center, Israel 52621
Overall contact: Sergey Preisman, M.D., Phone: +972-3-5302754, Email: Sergey.Preisman@sheba.health.gov.il
Summary
The aim of the study is to delineate and compare the changes in coupled mechanical
properties of left ventricle and arterial vascular bed caused by two popular anesthetic
protocols commonly used in cardiac surgery (intravenous, based on the infusion of propofol,
versus inhalational, based on isoflurane) on different stages of the surgery.
Clinical Details
Official title: Influence of Anesthesia on Mechanical Efficiency of Left Ventricle in Patients Undergoing Open Heart Surgery
Study design: Allocation: Randomized, Endpoint Classification: Safety/Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Outcomes Assessor), Primary Purpose: Treatment
Primary outcome: Changes of the relationship between left ventricular end-systolic elastance and effective arterial end-systolic elastance.
Secondary outcome: Changes in vascular tone and cardiac afterloadChanges of measures of global systolic left ventricular function
Detailed description:
Background
From mechanical point of view the goal of the cardiovascular system is to distribute the
kinetic energy of blood ejection from the left ventricle (LV) to body organs with minimal
loss and greatest efficiency. The left ventricle and the arterial circulation work as
"coupled" system. The ideal coupling supposes that a maximum of the energy produced by the
LV is converted into forward flow to perfuse the body organs. This matching between "the
source" (LV) and "the load" (arterial circulation) is governed by the mechanical properties
of these parts of cardiovascular system.
Variety of pathological conditions change this coupling in such a way that may adversely
affect the organ blood flow in the presence of unchanged or even high cardiac output, or
significantly increase the metabolic demand on the LV for the maintenance of adequate
systemic perfusion due to decrease of mechanical efficiency of the work produced by LV.
Although effects of anesthetic agents on myocardial contractility and peripheral vascular
tone were extensively studied in clinical conditions, little is known about their influence
on ventriculo-arterial coupling. Propofol and inhalational agents appear to impair this
equilibrium in animal experiments. This is not surprising, since these agents cause complex
dose-dependent changes in many physiologic parameters, including myocardial contractility,
left ventricular preload and afterload, diastolic properties of myocardium and baroreceptor
control of hemodynamics. Although these properties of anesthetic agents have been delineated
extensively, very limited data characterizing their influence on ventriculo-arterial
coupling in clinical conditions exist. This information is especially meaningful while
planning the anesthetic management of patients undergoing cardiac surgery, where maintenance
of circulatory homeostasis is of outmost importance. Since the main hemodynamic goal during
anesthesia of the patient with cardiovascular disease is to provide optimal tissue perfusion
with minimal myocardial oxygen demand, i. e. with maximal mechanical efficiency, knowledge of
anesthetic induced changes in ventriculo-arterial coupling is extremely relevant from the
clinical point of view.
The most convenient method for the evaluation of ventriculo-arterial coupling is the
analysis of the relationship between LV end-systolic elastance, load-independent measure of
myocardial contractility, and effective arterial end-systolic elastance, measure mechanical
loading conditions8. Physiological data necessary for the calculation of these parameters
may be acquired in relatively non-invasive way by combining and analyzing together recording
of arterial blood pressure waveform and data of changes of LV volume, which may be obtained
by means of echocardiography.
Objectives
General
The aim of the study is to delineate and compare the changes in ventriculo-arterial coupling
caused by two popular anesthetic protocols commonly used in cardiac surgery (intravenous,
based on the infusion of propofol, versus inhalational, based on isoflurane) on different
stages of the surgery.
Specific
1. To compare influence of two anesthetic protocols on myocardial contractility at the end
of the surgery.
2. To assess net changes in effective arterial elastance produced by surgery with the use
of cardiopulmonary bypass and evaluate possible differences between these two
anesthetic protocols in respect to changes of arterial tone.
3. To evaluate the preservation of ventriculo-arterial coupling by two different
anesthetic modes.
Eligibility
Minimum age: 18 Years.
Maximum age: N/A.
Gender(s): Both.
Criteria:
Inclusion Criteria:
- Patients undergoing elective cardiac surgery
Exclusion Criteria:
- Emergent surgery.
- History of previous cardiac surgery.
- Significant arrhythmias.
- More than trivial valvular disorder.
- Absence of written informed consent.
- Contraindications for transesophageal echocardiography.
- Pregnant women.
Locations and Contacts
Sergey Preisman, M.D., Phone: +972-3-5302754, Email: Sergey.Preisman@sheba.health.gov.il
Department of Anesthesia and Intensive Care, Sheba Medical Center, Tel Hashomer, Ramat Gan 52621, Israel; Recruiting
Additional Information
Starting date: July 2010
Last updated: July 18, 2011
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