Impedance Cardiography: Clinical Evaluation of Endotracheal Cardiac Output Monitor (ECOM)
|First Received Date ICMJE||June 17, 2009|
|Last Updated Date||August 29, 2013|
|Start Date ICMJE||January 2007|
|Primary Completion Date||September 2008 (final data collection date for primary outcome measure)|
|Current Primary Outcome Measures ICMJE
||Comparison of ECOM Impedance and Thermodilution Cardiac Output Measurements [ Time Frame: perioperative period ] [ Designated as safety issue: No ]
Correlation measured via Linear regression between thermodilution and ECOM, included as r^2 coefficient.
Cardiac output measured by iced-thermodilution and impedance cardiography. Management of the patients done using (standard) thermodilution derived cardiac output measurements only. The ECOM endotracheal cardiac output measurements are for research purposes only and not used in the management of the patient.
ECOM Impedance cardiography measured in the ICU when routine thermodilution cardiac output measurements are made. Endotracheal impedance measurements (ECOM) continued until tracheal extubation. Correlation with thermodilution measurements stopped when either the endotracheal tube or the thermodilution catheter was removed (post op day 0 routinely).
|Original Primary Outcome Measures ICMJE
||Assess the accuracy of the endotracheal cardiac output monitor when compared to pulmonary artery catheter cardiac output measurements in patients undergoing cardiac surgery. [ Time Frame: Perioperative Period, while device is used. ] [ Designated as safety issue: Yes ]|
|Change History||Complete list of historical versions of study NCT00924482 on ClinicalTrials.gov Archive Site|
|Current Secondary Outcome Measures ICMJE
||Safety of Device Measured by Number of Participants With Adverse Events [ Time Frame: perioperative period ] [ Designated as safety issue: Yes ]
Patients were interviewed postoperatively for all complications and specifically for complications related to intubation and/or cardiac output measurements
|Original Secondary Outcome Measures ICMJE
||Safety of device [ Time Frame: perioperative period ] [ Designated as safety issue: Yes ]|
|Current Other Outcome Measures ICMJE||Not Provided|
|Original Other Outcome Measures ICMJE||Not Provided|
|Brief Title ICMJE||Impedance Cardiography: Clinical Evaluation of Endotracheal Cardiac Output Monitor (ECOM)|
|Official Title ICMJE||Impedance Cardiography: Clinical Evaluation of Endotracheal Cardiac Output Monitor (ECOM)|
Introduction: Cardiac output is a key physiological parameter. Unfortunately, it is often difficult to measure without using invasive techniques with associated risk. The pulmonary artery catheter has, since its introduction, been considered the gold standard for the measurement of cardiac output in man. Unfortunately, pulmonary artery catheters have been associated with serious complications.1,2 Thoracic electrical bio-impedance (TEB) has been suggested as a possible non-invasive technique for the measurement of cardiac output. The accuracy and reliability of TEB has been evaluated multiple times with some studies demonstrating good correlation with thermodilution3-7 and others with poor correlation.6,8-15. TEB is not reliable in patients after cardiopulmonary bypass8,9, kidney transplants11, congestive heart failure16, pulmonary edema14, sepsis12, pregnancy15, abdominal surgery11,17, or critical illness13,14.
One of the limitations of TEB is the signal to noise ratio. Commonly TEB systems use an alternating current (1 - 4 ma at 20-100 Khz) applied to the skin and have little control over the percentage of current passing through the vascular structures in the chest. Changes in the electrical impedance of the lungs with respiration change the percentage of the total current passing through blood containing structures. Finally, treating all of the blood containing structures in the chest as a single impedance to be measured, does not allow separation of the signal into its various components. A technique which stabilizes the percentage of current delivered to the target structure and records the electrical impedance signals directly from that target structure improves the accuracy and reliability of impedance based measurement of cardiac output.
The Endotracheal Cardiac Output Monitor (ECOM) is a system which records the voltages produced by a current (2 ma 100 Khz) delivered to the tracheal mucosa by electrodes on an endotracheal tube. The proximity of the ascending aorta and trachea allows the design of a device that can optimize the current delivery and signal recording from impedance changes in the ascending aorta. This study will test the accuracy and efficacy of the ECOM system in anesthetized patients.
Significance: A simple, inexpensive, continuous, non-invasive, accurate, reproducible method of measuring cardiac output in patients would reduce the need for pulmonary artery catheter measurements of cardiac output. Such a technique would allow the rapid diagnosis and treatment of hemodynamic instability in the critically ill patient. The maintenance of cardiac output is essential for the prevention of end organ injury which results in morbidity and mortality. A technique that accurately measured cardiac output would greatly assist the management of the critically ill patient.
We propose to compare measurement of cardiac output made with the Conmed ECOM 6-3D endotracheal tube to those made with a pulmonary artery catheter using. We will do correlation studies of cardiac output against those performed using the standard thermodilution technique in patients, who in the normal course of their clinical care, are having cardiac outputs measured by the thermodilution technique. We will compare cardiac output measured by impedance cardiography to transit time measurements.
These correlation studies will be done in the O.R. and intensive care units on patients scheduled for cardiac surgery who routinely have cardiac output measurements using the standard thermodilution method.
Many different algorithms have been developed for the conversion of thoracic impedance signals into a calculation of cardiac output including Kubicek18 , Bernstein-Sramek19, Shmulewitz20, adaptive algorithms.20 Each of these algorithms requires some sort of empirically derived factor to convert from measurements of resistance into measurements of volume. The ECOM system uses an adaptive multi-parameter algorithm which allows for the reduction of between subject variability. We have derived the empiric fit for the porcine model but have not done so for patients. This study will be therefore divided into two components. The first data collection of 15 patients will provide the data for the empiric fit between the ECOM system and true cardiac output. The second set of 300 patients will be the test group for the algorithm.
Informed consent: Informed, written consent is to be obtained from each study subject before any study-related procedures are begun. A full disclosure of the nature of the study is to be made in accordance with the guidelines described in the Code of Federal Regulations (21CFR 50.20).
Withdrawal: A patient may choose to or be withdrawn from the study for any reason, including:
a. Refusal of the patient to participate further; b. Refusal of the physician to allow patient participation. j. Costs to the subject: There will be no costs to the subject. The cost of all study related testing will be covered by Conmed.
k. Reimbursement of Subjects: None will be provided.
l. Confidentiality of records: All records will be confidential. All data will be analyzed by code number only. Code numbers will be kept at the VAMC under the control of the principal investigator. No reports will include patient identifiers.
5. Qualifications of Investigators: Dr. Arthur Wallace, M.D., Ph.D. has done medical research since 1978 including large animal, human clinical trials, and human physiological measurement. He has a Ph.D. in biomedical engineering and completed a medical internship, anesthesia residency, and a fellowship in cardiac anesthesiology. He has been a faculty member of anesthesiology at UCSF since 1992 during this time he has been the PI on several clinical trials in high risk patients including the Afterload, Warm Cardioplegia, Atenolol, Clonidine, EDRF Intraop, L-ARG, AVD Study, PCRRT, and Aneurysm Trials. Dr. Wallace has worked with impedance devices since 1991 and has been the chief scientific advisor on the ECOM projects since their inception in 1996. He has been responsible for the tube design, algorithm development, electronic design, in-vivo experiments, as well as the animal and human trials.
|Study Type ICMJE||Interventional|
|Study Phase||Phase 2
|Study Design ICMJE||Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Prevention
|Condition ICMJE||Cardiac Output|
|Intervention ICMJE||Device: Placed ECOM endotracheal cardiac output monitor in patients undergoing cardiac surgery
Measure cardiac output during perioperative period and compare to pulmonary artery thermodilution cardiac output measurements.
|Study Arm (s)||Single Arm - Device
Placed ECOM endotracheal cardiac output monitor in patients undergoing cardiac surgery
Intervention: Device: Placed ECOM endotracheal cardiac output monitor in patients undergoing cardiac surgery
|Publications *||Wallace AW, Salahieh A, Lawrence A, Spector K, Owens C, Alonso D. Endotracheal cardiac output monitor. Anesthesiology. 2000 Jan;92(1):178-89.|
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
|Recruitment Status ICMJE||Completed|
|Completion Date||September 2008|
|Primary Completion Date||September 2008 (final data collection date for primary outcome measure)|
|Eligibility Criteria ICMJE||
|Ages||18 Years and older|
|Accepts Healthy Volunteers||No|
|Contacts ICMJE||Contact information is only displayed when the study is recruiting subjects|
|Location Countries ICMJE||Not Provided|
|NCT Number ICMJE||NCT00924482|
|Other Study ID Numbers ICMJE||H7565-14654|
|Has Data Monitoring Committee||Yes|
|Responsible Party||University of California, San Francisco|
|Study Sponsor ICMJE||University of California, San Francisco|
|Collaborators ICMJE||ConMed Corporation|
|Information Provided By||University of California, San Francisco|
|Verification Date||August 2013|
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