Continous Cardiac Output - Non-Invasive Evaluation (CONNIE) (CONNIE)

January 10, 2019 updated by: Anil Gupta, Karolinska Institutet

The Performance of a Capnodynamic Method Compared to Transpulmonary Thermodilution in Open Abdominal Surgery

The capnodynamic method non-invasively calculates effective pulmonary blood flow (EPBF) continuously during surgery. In this study EPBF is compared to cardiac output (CO) measured with Transpulmonary Thermodilution (TPTD) att baseline and during hemodynamic changes in patients scheduled for open abdominal surgery at the Karolinska University Hospital, Solna, Sweden.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

The capnodynamic method continuously calculates effective pulmonary blood flow (EPBF) with the help of a capnodynamic equation:

ELV x (FACO2(n) - FACO2(n-1)) = deltat(n) x EPBF (CvCO2 - CvCO2(n)) - VTCO2

ELV Effective lung volume [L] EPBF Effective pulmonary blood flow [L/min] n current breath n-1 previous breath FACO2 mean alveolar carbon dioxide fraction CvCO2 mixed venous carbon dioxide content [Lgas/Lblood] CcCO2n pulmonary end-capillary carbon dioxide content [Lgas/Lblood] VTCO2n volume [L] of carbon dioxide eliminated by the current, nth, breath delta t n current breath cycle time [min]

The equation above describes the mole balance between the CO2 delivered to lungs (EPBF), the volume taking part in the gas exchange (ELV) and CO2 excreted from the lungs (VTCO2). Normally there is no difference in CO2 between the actual and the preceding breath as the same amount of CO2 as delivered to the lungs as is excreted. When small changes in CO2 concentration are inserted into the equation obtained with short inspiratory or expiratory pauses in three out of nine breaths, nine different equations are obtained. The three unknown variables; ELV, EPBF and CvCO2can be solved with a linear least square optimization, a well-known numerical mathematical principle. The breathing pattern is automatically controlled by the ventilator which provides continuous calculations of EPBF where each value represents the average of the preceding nine breaths and renews with each breath as the newest replaces the oldest in the equation system.

At the day of surgery, included patients arrive 45 minutes earlier than otherwise at the surgical unit. After safe surgical checklist, vital signs are measured and epidural catheter inserted during a light sedation. Patients are anesthetized and muscle relaxed. An endotracheal tube is inserted in the trachea. Central arterial and vein catheters are inserted in sterile conditions with ultrasound guidance. Anesthesia is maintained with propofol in target controlled infusion and a short acting opioid is added as needed.

The protocol in the first 25 patients comprises simultaneous measurements of EPBF and CO at 1) Baseline (three measurments), 2) PEEP 15cmH2O, 3) PEEP 5cmH2O 4) before epidural activation, 5) 10-15 minutes after epidural activation 6) before volume infusion (when the patient is considered hypovolemic by the attending anaesthesiologist) and 7) shortly after volume infusion.

The attending anesthesiologist has the final responsibility on deciding the order of the protocol, for example if volume infusion should precede PEEP 15 cmH20 if hypovolemia is suspected.

The succeeding 10 patients (patients 26 to 35) are PEEP optimized before start of protocol using a standardiazed open lung tool recruitment. During the PEEP elevation (step 2 in the protocol above) 10cmH2O is added to the optimal PEEP and then released back to the baseline optimal PEEP (step 3).

Each comparative measurement of CO and EPBF in the protocol includes as an average of three TPTD measured with PiCCO2 and and the average of EPBF registered in the beginning of the first TPTD and in the end of the last TPTD.

Study Type

Observational

Enrollment (Actual)

35

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

      • Stockholm, Sweden, 17176
        • Karolinska University Hospital

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

14 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Non-Probability Sample

Study Population

Patients having major abdominal surgery requiring advanced hemodynamic monitoring

Description

Inclusion Criteria:

  • Elective major abdominal surgery requiring advanced hemodynamic monitoring

Exclusion Criteria:

  • Symptomatic coronary artery disease, chronic obstructive pulmonary disease with emphysema

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Case-Only
  • Time Perspectives: Prospective

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Absolute values of EPBF compared to Cardiac output
Time Frame: Mean CO vs EPBF from zero to 4 hours perioperatively
Mean cardiac output as measured with transpulmonary thermodilution compared to mean effective pulmonary blood flow measured with the capnodynamic method at the start of first thermodilution and during the time interval zero to 4 hours.
Mean CO vs EPBF from zero to 4 hours perioperatively

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in EPBF compared to changes in Cardiac output
Time Frame: Mean CO vs mean EPBF from zero to 4 hours perioperatively
Measurement of cardiac output and EPBF as described in Outcome 1 before and after hemodynamic changes.
Mean CO vs mean EPBF from zero to 4 hours perioperatively

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Collaborators

Investigators

  • Study Director: Håkan Björne, PhD, Karolinska Institutet

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 29, 2015

Primary Completion (Actual)

September 28, 2018

Study Completion (Actual)

December 31, 2018

Study Registration Dates

First Submitted

January 30, 2018

First Submitted That Met QC Criteria

February 22, 2018

First Posted (Actual)

February 23, 2018

Study Record Updates

Last Update Posted (Actual)

January 11, 2019

Last Update Submitted That Met QC Criteria

January 10, 2019

Last Verified

January 1, 2019

More Information

Terms related to this study

Other Study ID Numbers

  • CONNIE 1

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Undecided

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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