Descriptive and Comparative Study of Respiratory Function in the Postoperative Cardiac Surgery Patient

May 12, 2025 updated by: Andreas Martinsson, Sahlgrenska University Hospital
The study comprises two different objectives. Longitudinal description of postoperative pulmonary dysfunction in the cardiothoracic surgery patient, and the comparison of two different lungrecruitment strategies.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Introduction:

Atelectasis and consolidation of lung tissue is a well recognized clinical scenario following anaesthesia, musclerelaxation and mechanical ventilation. In cardiac surgery during cardiopulmonary bypass (CPB), the lungs are collapsed to a degree depending on surgical opening of the pleura, time on bypass, and gasmixture on termination of ventilation. Recruitment of the lungs on commencement of mechanical ventilation after CPB generally must be repeated before extubation. There are several different approaches to Recruitment Manoeuvers (RM). Increasing pressures in the ventilator (peak-pressures and PEEP), increasing tidal volumes and inspiratory hold are facilities offered by the ventilator. Different body positions by interaction of the abdomen and thorax through the diaphragm, and the action of gravity on the lungs and adjoining organs, are other principles. The contribution of spontaneous ventilatory efforts also play a major roll.

Study rationale:

The study comprises two different objectives. Longitudinal description of postoperative pulmonary dysfunction in the cardiothoracic surgery patient, and the comparison of two different lungrecruitment strategies.

All patients undergoing cardiothoracic surgery develops some degree of postoperative pulmonary dysfunction (PPD), including hypoxemia, increased work of breathing, shallow respiration and ineffective cough. Respiratory symptoms of larger clinical significance are better investigated, known as postoperative pulmonary complications (PPC), including pleural effusion, atelectasis, pneumonia and ARDS. Pathophysiology is complex and multifactorial, and there is a continuum between PPD and PPC that has not yet been well explored. A large proportion of patients readmitted to CICU present respiratory failure, significantly accounting for morbidity, mortality, and costs.

Regarding lungrecruitment, supine position is compared to modified prone position with similar ventilator settings. Initial measurements preoperatively in the awake patient, then during sedation and ventilator treatment, followed up by measurements before discharge from the surgical ward on postoperative day 4-5.

Effect of RM is evaluated from ventilator measurement of compliance (C), arterial oxygenation and P/F-ratio from the arterial blood gas (ABG), and electrical impedance tomography (EIT). EIT measures the impedance of a thoracic sagittal section by emitting and sampling electrical currents between 16 electrodes fixed on a submamillar belt. Radiology report from routine chest X-ray and ultrasonography of the lungs and pleura will be added.

Should RM in prone position prove to be more efficient, postoperative complications in terms of respiratory failure and pneumonia could be reduced, facilitating postoperative recovery and shortening convalescens. This would justify the increased burden of care in the cardiac ICU.

Study objectives:

The study aims to compare lung recruitment in two different body positions, supine (elevated 30 degrees) to left modified prone position (left side up, 120 degrees). Parameters investigated are global and regional pulmonary impedance (EIT), lungcompliance, and arterial oxygenation. Chest X-ray and lung ultrasound will be performed for additional analyses.

A descriptive longitudinal study of the 20 patients lungrecruited in supine position will also be performed.

Study design:

Prospective, randomized clinical trial. Two groups with 20 cardiac surgery patients in each.

Study procedure:

Protocol

Day -1:

1 day preop. EIT measurement in supine (30 degrees elevated) and modified left prone position (left side up, 120 degrees). Two measurements of each 2 min duration in both positions. ABG is performed after breathing through a Venturi-mask delivering FiO2 0.5 for 10 minutes. Randomization to either of the two groups.

Day 0:

Day of surgery. Standard periop care in coherence with department routines. Preoxygenation using FiO2 1.0 during induction of anaesthesia, and before commencing cardiopulmonary bypass (CPB). Inhalational anaesthetics during surgical preparation, and again after weaning from CPB. Apnoea without PEEP or intermittent ventilation during CPB. Before weaning from CPB manual lung recruitment with the APL-valve set to 30 cm H2O, and visual guidance of the lungparenchyma or pleura. After chest closure, FiO2 is set to 0.5, volume controlled ventilation 4-6 ml/Kg titrated according to pCO2, and PEEP is set to 5 cm H2O. Patient ventilation circuit will be broken twice in conjugation with the use of a transport ventilator device before arrival in the CICU. Ventilator settings in the CICU is pressure-regulated volume-controlled ventilation (VKTS), tidal volumes of 4-6 ml/Kg titrated according to pCO2, respiratory frequency of 14/min, and PEEP 8 cm H2O.

Recruitment maneuver (RM) is performed within 10 min on arrival in the CICU. Patient must be stabile in hemodynamic parameters, including volume status. PEEP is set to 20 cm H2O, pressure controlled ventilation with peak pressure 40 cm H2O for 30 s (5 inspirations), thereafter PEEP-trial starting from 15 cm H2O for optimal PEEP using the "Open Lung Tool" (Maquet Flow-i software). During the PEEP-trial, VKTS for tidal volumes of 6 ml/Kg is used.

Supine position group: RM in supine position. EIT, ABG and lung compliance measurements in supine position before RM (30 degrees elevation), then immediately and 30 min after RM, and again 30 minutes after extubation. FiO2 0.5 at all ABG measuring points.

Modified prone position group: RM in modified prone position (120 degrees, left side up). EIT, ABG and lung compliance measurements in supine position before RM (30 degrees elevation), and then immediately after RM when turned back to supine position (30 degrees elevation), and 30 minutes after RM. Finally, measurements 30 minutes after extubation. FiO2 0.5 at all ABG measuring points.

Day 4-5:

Supine and prone position groups: EIT in supine position (30 degrees elevation) and ABG repeated at day 4-5 postop. ABG is performed after breathing through a Venturi-mask delivering FiO2 0.5 for 10 minutes. Ultrasonography of the pleurae. Chest-X-ray performed routinely on the day after chest-drain removal.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

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

  • Sweden
      • Gothenburg, Sweden, 41345
        • Department of cardiothoracic anaesthesia, Sahlgrenska 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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Signed informed consent
  • Scheduled cardiac surgery (CABG or valve surgery)
  • Cardiopulmonary bypass

Exclusion Criteria:

  • Diagnose of obstructive or restrictive lung disease
  • Medical therapy with bronchodilators
  • Smoking or former smoking > 5 years
  • Obesity (BMI > 30)
  • Perioperative FiO2 >60% or PEEP >12
  • Haemodynmic instability, use of inotropes (low dose vasopressors accepted)
  • Postop clinically significant bleeding (>100 ml/h, reoperation)
  • Postoperative haemothorax or large pleural effusion detected with ultrasonography
  • Postoperative clinically significant pneumothorax or large chestdrain airleak

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

  • Primary Purpose: Supportive Care
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Prone position
Intervention: Lungrecruitment in prone position. Device: Ventilator Flow-i, Peak inspiratory pressure 40 cmH2O, PEEP 20 cm H2O during 30 s.
Procedure: Lungrecruitment manoeuver in prone position.
Postoperative lungrecruitment in prone position, pressure-controlled ventilation peak inspiratory pressure 40 cm H2O combined with PEEP 20 cm H2O during 60 seconds.
Other Names:
  • "Prone Lungrecruitment in ventilator"
Active Comparator: Supine position
Intervention: Lungrecruitment in supine position. Device: Ventilator Flow-i, Peak inspiratory pressure 40 cmH2O, PEEP 20 cm H2O during 30 s. Clinical routine.
Procedure: Lungrecruitment manoeuver in supine position.
Postoperative lungrecruitment in supine position, pressure-controlled ventilation peak inspiratory pressure 40 cm H2O combined with PEEP 20 cm H2O during 60 seconds.
Other Names:
  • "Supine Lungrecruitment in ventilator"

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Electrical impedance
Time Frame: 5 days
Electrical impedance tomography, thoracical transverse plane measurment. Dräger Pulmovista device is used for collecting the data. Data will be transferred to a personal computer, and processed in Excel.
5 days
Lungcompliance (ml/cm H2O)
Time Frame: 2 hours
Pulmonary dynamic compliance, ventilator measurment.
2 hours
P/F ratio
Time Frame: 5 days
Oxygenation ratio, pO2 divided by FiO2, indication of pulmonary shunt
5 days
Ultrasonography
Time Frame: 5 days
Lungultrasound to exclude pleural effusion.
5 days
Chest X-ray
Time Frame: 5 days
Chest X-ray to exclude pneumothorax
5 days

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Safety and Tolerability of prone position (turned 180 dgrees from supine position, Intensive Care Unit Bed), number of adverse events observed by the primary investigator.
Time Frame: 2 hours
Placing a patient in prone position in the immediate postoperative and sedated setting in the Cardiac Intensive Care Unit. Adverse events will be observed and noted by the primary investigator. Adverse events will be divided in less severe (e.g disruption of monitoring, uncoupling of breathing curcuit) and severe (e.g accidental extubation, decubitus ulcers, emergency return to supine position).
2 hours

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Sahlgrenska University Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Study Chair: Sven-Erik Ricksten, Professor, The Salgrenska Academy

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.

General Publications

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 25, 2017

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 25, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 25, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
December 14, 2016

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
January 3, 2017

First Posted (Estimated)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
January 4, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
May 15, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 12, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • AMartinssonthorax

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

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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