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NCT Number: NCT01757704

Factors Responsible for the Effectiveness of the Lund De-airing Technique

The Lund de-airing technique is employed for cardiac de-airing in open left heart surgery. It consists of two main elements namely, opening of both pleura after the patient is on CPB (cardiopulmonary bypass)and disconnection of the ventilator before opening the left heart to ensure bilateral pulmonary collapse and a staged filling of the heart at termination of the CPB. The aim of this study is to analyze in a randomized manner two groups of patients to establish if one or both components are of primary importance for the effectiveness of the de-airing technique.

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Key information

Conditions

Complication of Surgical Procedure

Age range

18 year–90 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Lund University

Lund, Skåne County, 22350, Sweden

About this study

Patients planned for open left heart surgery, mainly aortic valve replacement, will be included in the study. Patients with aortic valve replacement and concomitant coronary artery bypass with vein grafts only can also be included.

Exclusion criteria

are; significant chronic obstructive pulmonary disease/emphysema, significant (>50%)carotid artery disease, need of concomitant internal mammary harvesting, prior cardiac or pulmonary surgery, pulmonary adhesions preventing pulmonary collapse, previous radiation to the chest and prior severe chest trauma. Intraoperative exclusion criteria are; failure to obtain adequate bilateral Trans-cranial Echo-Doppler signals from the medial cerebral arteries, finding of adherent pleurae and accidental opening of the pleurae.

Twenty patients will be randomized to two groups:

Group I: Intact pleura bilaterally, disconnection of the ventilator during cardiopulmonary bypass (CPB), followed by staged filling of the heart.

Group II: Open pleura bilaterally, disconnection of the ventilator during cardiopulmonary bypass to ensure bilateral pulmonary collapse followed by conventional filling of the heart.

Data will be compared to a third historical control group, consisting of ten patients with open pleurae with the ventilator disconnected followed by staged filling of the heart.

Primary outcomes:

  • Duration of the de-airing procedure from the release of the aortic cross clamp to finished de-airing.
  • Air microemboli to the brain registered on-line as gaseous microembolic signals on Trans-cranial Echo-Doppler (TCD). The sum of signals from the right and left middle cerebral artery are registered during the following time periods; from the release of the aortic cross clamp to start of cardiac ejection, from cardiac ejection to finished de-airing, and during ten minutes after finished de-airing.
  • Magnitude of residual air emboli in the heart after finished de-airing as monitored by Trans-esophageal Echocardiography (TEE) with a Three-chamber view. The severity of residual air is classified in four grades after the appearance of visible air on TEE in left atrium (LA), left ventricle (LV) and aortic root (AO)as follows; Grade 0: no residual air, grade I: gas emboli detected in one of three anatomic areas during one cardiac cycle, grade II: gas emboli detected simultaneously in two of three anatomic areas during one cardiac cycle; grade III: gas emboli detected in all three anatomic areas during one cardiac cycle.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Patients planned for aortic valve replacement with or without coronary vein bypass grafts

Exclusion criteria

  • Significant chronic obstructive pulmonary disease and emphysema
  • Previous history of thoracic or cardiac surgery
  • Patients requiring internal mammary artery harvesting
  • Unilateral or bilateral pulmonary adhesions to chest wall
  • Previous radiation to the chest

Intraoperative Exclusion Criteria:

  • Inability to obtain adequate bilateral Trans-cranial Echo-doppler signals
  • Adherent pleurae
  • Accidental opening of the pleurae

Treatment and study plan

Open pleurae & conventional filling of heart

Procedure

After completion of the left heart surgery, the heart will be actively filled with blood from the cardiopulmonary bypass circuit and lungs fully ventilated with positive end-expiratory pressure to flush out all air trapped in the lung veins and left heart. When there is no more visible air seen on Trans-esophageal echocardiography, the patient is weaned from cardiopulmonary bypass.

Other names: Cardiac de-airing, Cardiac venting

Intact pleurae & staged filling of heart

Procedure

After the end of the left heart surgery, the heart is gradually filled with blood from the cardiopulmonary bypass circuit. Cardiac contractions fill the lungs with blood til no more air is seen in left heart on Trans-esophageal Echocardiography. Thereafter the lungs are ventilated with 50% of the estimated lung minute volume and 5 cm positive end-expiratory pressure and cardiac filling and de-airing continued. If no air is seen in the left heart full ventilation is started and the patient is weaned from cardiopulmonary bypass.

Other names: Cardiac de-airing, Cardiac venting

Primary outcomes

  1. Quantitative Assessment of Air Embolism to the Brain After Completion of Open Left Heart Surgery

    Time frame: Time from the release of the aortic crossclamp to cardiac ejection, an average of 10-15 minutes

    Cerebral air emboli will be assessed quantitatively by On-line counting of gaseous microembolic signals (MES) by Trans-cranial Echo-Doppler (TCD) monitoring of the right and left middle cerebral artery. The sum of the gaseous microembolic signals registered from the right and left middle cerebral artery will be reported.

  2. Quantitative Assessment of Air Embolism to the Brain After Completion of Open Left Heart Surgery

    Time frame: Time from cardiac ejection to finished de-airing, an average of 5-10 minutes

    Cerebral air emboli will be assessed quantitatively by On-line counting of gaseous microembolic signals (MES) by Trans-cranial Echo-Doppler (TCD) monitoring of the right and left middle cerebral artery. The sum of the gaseous microembolic signals registered from the right and left middle cerebral artery will be reported.

  3. Quantitative Assessment of Air Embolism to the Brain After Completion of Open Left Heart Surgery

    Time frame: Period of ten minutes after finished de-airing

    Cerebral air emboli will be assessed quantitatively by On-line counting of gaseous microembolic signals (MES) by Trans-cranial Echo-Doppler (TCD) monitoring of the right and left middle cerebral artery. The sum of the gaseous microembolic signals registered from the right and left middle cerebral artery will be reported.

  4. Participants With <=Grade I Air Emboli as Assessed by Trans-esophageal Echocardiography (TEE) After Finished De-airing.

    Time frame: 0-3 minutes after finished de-airing

    The severity of residual air emboli in three anatomic areas; left atrium, left ventricle and aortic root, is assessed by Trans-esophageal Echocardiography (TEE) and classified in grade 0-3 as follows, Grade o: no residual air; grade I: gas emboli detected in one of three anatomic areas during one cardiac cycle; grade II: gas emboli detected simultaneously in two of three anatomic areas during one cardiac cycle; grade III: gas emboli detected simultaneously in all three anatomic areas during one cardiac cycle.

  5. Participants With <=Grade I Air Emboli as Assessed by Trans-esophageal Echocardiography (TEE) After Finished De-airing.

    Time frame: 3-6 minutes after finished de-airing

    The severity of residual air emboli in three anatomic areas; left atrium, left ventricle and aortic root, is assessed by Trans-esophageal Echocardiography (TEE) and classified in grade 0-3 as follows, Grade o: no residual air; grade I: gas emboli detected in one of three anatomic areas during one cardiac cycle; grade II: gas emboli detected simultaneously in two of three anatomic areas during one cardiac cycle; grade III: gas emboli detected simultaneously in all three anatomic areas during one cardiac cycle.

  6. Participants With <=Grade I Air Emboli as Assessed by Trans-esophageal Echocardiography (TEE) After Finished De-airing.

    Time frame: 6-10 minutes after finished de-airing

    The severity of residual air emboli in three anatomic areas; left atrium, left ventricle and aortic root, is assessed by Trans-esophageal Echocardiography (TEE) and classified in grade 0-3 as follows, Grade o: no residual air; grade I: gas emboli detected in one of three anatomic areas during one cardiac cycle; grade II: gas emboli detected simultaneously in two of three anatomic areas during one cardiac cycle; grade III: gas emboli detected simultaneously in all three anatomic areas during one cardiac cycle.

  7. Duration of the De-airing Procedure

    Time frame: Time from release of aortic crossclamp to finished de-airing

    The de-airing procedure is deemed completed when the Trans-esophageal Echocardiography (TEE) no longer visualizes air emboli in the heart Chambers. The duration is likely to vary between individuals and reflects the complexity of the de-airing procedure.

Sponsors and collaborators

Lead sponsor

Lund University

Other

Registry information

Official study title

Factors Responsible for the Effectiveness of the Lund Technique for De-airing Following Open Left Heart Surgery.

Important dates

Study start
2012
Primary completion
2013
Study completion
2014
First posted
Dec 31, 2012
Registry last updated
Feb 10, 2014

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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