Trial Outcomes & Findings for CO2 Versus Lund De-airing Technique in Heart Surgery (NCT NCT00934596)

NCT ID: NCT00934596

Last Updated: 2013-12-04

Results Overview

The number of air microemboli (also referred to as gaseous microembolic signals) was concomitantly counted in the right and left medial cerebral artery. The number of signals from the right and the left medial cerebral artery were summed, and presented as the total sum of the gaseous micromebolic signals from the right and left side. Counting of gaseous microembolic signals was done during three time intervals: Before cardiac ejection, after cardiac ejection and during 10 minutes after cardiopulmonary bypass.

• Recruitment status: COMPLETED
• Study phase: NA
• Target enrollment: 20 participants
• Primary outcome timeframe: Before cardiac ejection
• Results posted on: 2013-12-04

Participant Flow

Patients requiring elective aortic valve or aortic root surgery on the waiting list of the clinic were recruited in the study during year 2009.

All 20 consecutive patients recruited in the study fullfilled the inclusion criteria. No patient was excluded.

Participant milestones

Measure	Lund De-airing Technique Before cardiopulmonary bypass (CPB) was established, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart by Trans-esophageal Echocardiography (TEE), the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique The pleural cavities were left intact in the carbon-dioxide(CO2) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before the cannulation for CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completed surgery, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from CPB.
Overall Study STARTED	10	10
Overall Study COMPLETED	10	10
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

CO2 Versus Lund De-airing Technique in Heart Surgery

Baseline characteristics by cohort

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass (CPB) was established, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. Hereafter the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart defibrillated. After a good cardiac contraction and normal central hemodynamics were established, the LV preload was gradually and successively increased. When no air emboli were observed in the left side of the heart by transesophageal echocardiography (TEE), the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The deairing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before cannulation, CO2 was insufflated in the mediastinum at a flow rate of 10 litres/minute and continued until 10 minutes post-CPB. After completed surgery, the heart and lungs were passively re-filled with blood and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under transesophageal echocardiographic (TEE) monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to eject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from CPB.	Total n=20 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Age, Categorical Between 18 and 65 years	1 Participants n=5 Participants	3 Participants n=7 Participants	4 Participants n=5 Participants
Age, Categorical >=65 years	9 Participants n=5 Participants	7 Participants n=7 Participants	16 Participants n=5 Participants
Age Continuous	68 years STANDARD_DEVIATION 11 • n=5 Participants	68 years STANDARD_DEVIATION 13 • n=7 Participants	68 years STANDARD_DEVIATION 12 • n=5 Participants
Sex: Female, Male Female	5 Participants n=5 Participants	5 Participants n=7 Participants	10 Participants n=5 Participants
Sex: Female, Male Male	5 Participants n=5 Participants	5 Participants n=7 Participants	10 Participants n=5 Participants
Region of Enrollment Sweden	10 participants n=5 Participants	10 participants n=7 Participants	20 participants n=5 Participants

PRIMARY outcome

Timeframe: Before cardiac ejection

The number of air microemboli (also referred to as gaseous microembolic signals) was concomitantly counted in the right and left medial cerebral artery. The number of signals from the right and the left medial cerebral artery were summed, and presented as the total sum of the gaseous micromebolic signals from the right and left side. Counting of gaseous microembolic signals was done during three time intervals: Before cardiac ejection, after cardiac ejection and during 10 minutes after cardiopulmonary bypass.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Number of Air Microemboli Registered Over the Middle Cerebral Arteries by On-line Trans-cranial Echo-Doppler (TCD).	41 Air Microemboli Standard Deviation 20	118 Air Microemboli Standard Deviation 70

PRIMARY outcome

Timeframe: After cardiac ejection

The number of air microemboli (also referred to as gaseous microembolic signals) was concomitantly counted in the right and left medial cerebral artery. The number of signals from the right and the left medial cerebral artery were summed, and presented as the total sum of the gaseous micromebolic signals from the right and left side. Counting of gaseous microembolic signals was done during three time intervals: Before cardiac ejection, after cardiac ejection and during 10 minutes after cardiopulmonary bypass.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Number of Air Microemboli Registered Over the Middle Cerebral Arteries by On-line Trans-cranial Echo-Doppler (TCD).	28 Air Microemboli Standard Deviation 19	119 Air Microemboli Standard Deviation 84

PRIMARY outcome

Timeframe: During 10 minutes after cardiopulmonary bypass

The number of air microemboli (also referred to as gaseous microembolic signals) was concomitantly counted in the right and left medial cerebral artery. The number of signals from the right and the left medial cerebral artery were summed, and presented as the total sum of the gaseous micromebolic signals from the right and left side. Counting of gaseous microembolic signals was done during three time intervals: Before cardiac ejection, after cardiac ejection and during 10 minutes after cardiopulmonary bypass.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Number of Air Microemboli Registered Over the Middle Cerebral Arteries by On-line Trans-cranial Echo-Doppler (TCD).	5 Air Microemboli Standard Deviation 4	46 Air Microemboli Standard Deviation 53

PRIMARY outcome

Timeframe: 0-3 minutes after end of cardiopulmonary bypass

Population: The number was determined before hand as per protocoll.

Grade 0, no residual gas emboli; grade I, gas emboli observed in 1 of the 3 anatomic areas - left atrium, left ventricle or aortic root during 1 cardiac cycle; grade II, gas emboli observed simultaneously in 2 of the 3 anatomic areas during 1 cardiac cycle; grade III, gas emboli observed simultaneously in all 3 anatomic areas during 1 cardiac cycle.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Number of Participants With <=Grade I Gas Emboli as Assessed by Trans-esophageal Echocardiography TEE).	10 participants 4 • Interval 25.0 to 75.0	4 participants 53 • Interval 25.0 to 75.0

PRIMARY outcome

Timeframe: 3-6 minutes after end of cardiopulmonary bypass

Population: The number was determined before hand as per protocoll.

Grade 0, no residual gas emboli; grade I, gas emboli observed in 1 of the 3 anatomic areas - left atrium, left ventricle or aortic root during 1 cardiac cycle; grade II, gas emboli observed simultaneously in 2 of the 3 anatomic areas during 1 cardiac cycle; grade III, gas emboli observed simultaneously in all 3 anatomic areas during 1 cardiac cycle.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Number of Participants With <=Grade I Gas Emboli as Assessed by Trans-esophageal Echocardiography TEE).	9 participants	7 participants

PRIMARY outcome

Timeframe: 6-10 minutes after end of cardiopulmonary bypass

Population: The number was determined before hand as per protocoll.

Grade 0, no residual gas emboli; grade I, gas emboli observed in 1 of the 3 anatomic areas - left atrium, left ventricle or aortic root during 1 cardiac cycle; grade II, gas emboli observed simultaneously in 2 of the 3 anatomic areas during 1 cardiac cycle; grade III, gas emboli observed simultaneously in all 3 anatomic areas during 1 cardiac cycle.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Number of Participants With <=Grade I Gas Emboli as Assessed by Trans-esophageal Echocardiography TEE).	9 participants	7 participants

SECONDARY outcome

Timeframe: After removal of aortic cross-clamp to complete de-airing, an average of 11 minutes

The total de-airing time as measured in minutes.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Total Time Required for De-airing	9 Minutes Interval 8.0 to 10.0	15 Minutes Interval 11.0 to 16.0

SECONDARY outcome

Timeframe: Measured during intraoperative course

Time in minutes starting at t1 (removal of aortic cross clamp) and ending at t2 (beginning of cardiac ejection).

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
De-airing Time Before Cardiac Ejection	6 minutes Interval 4.0 to 7.0	7 minutes Interval 5.0 to 10.0

SECONDARY outcome

Timeframe: During de-airing procedure

The duration in minutes of the period after cardiac ejection to finished de-airing procedure.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
De-airing Time After Cardiac Ejection	3 minutes Interval 2.0 to 3.0	5 minutes Interval 4.0 to 8.0

SECONDARY outcome

Timeframe: Intraoperative

The amount of carbon dioxide gas flow through the oxygenator was measured and compared between groups.

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Oxygenator Gas Flow at 45 Minutes of CPB	0.65 L/minute Interval 0.6 to 1.25	2.2 L/minute Interval 1.63 to 3.1

SECONDARY outcome

Timeframe: Intraoperative

pH measured by arterial bloodgas at 45 minutes of CPB, comparison between groups

Outcome measures

Measure	Lund De-airing Technique n=10 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=10 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
pH at 45 Min of CPB	7.30 units on a scale Interval 7.27 to 7.33	7.35 units on a scale Interval 7.32 to 7.38

POST_HOC outcome

Timeframe: Pieces of tubing collected after weaning from cardiopulmonary bypass

Population: Samples were collected from 5 participants in each Group (total of 10 participants). For each participant 4 pieces of tubing were collected (20 pieces in each Group, total 40 pieces). Samples were photographed. One photograph from each individual was randomly selected and studied by an investigator blinded to Group (total of 10 photographs).

Pieces of tubing from the cardiopulmonary circuit were prepared and photographed in a Scanning Electron Microscope. Visual inspection of each photograph by an investigator blinded to which group the photograph belonged to was performed. The proportion of damaged red blood cells over the total number of red blood cells were calculated.

Outcome measures

Measure	Lund De-airing Technique n=5 Participants Before cardiopulmonary bypass(CPB) was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The de-airing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation Technique n=5 Participants The pleural cavities were left intact in the CO2 (carbon-dioxide) group. During cardiopulmonary bypass (CPB), the patient was administered dead space ventilation. Before CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from C
Fraction of Morphologically Damaged Red Blood Cells as Assessed by Scanning Electron Microscopy Studies.	0.18 Fraction of Damaged Red Blood Cells Interval 0.11 to 0.3	0.97 Fraction of Damaged Red Blood Cells Interval 0.64 to 1.0

Adverse Events

Lund De-airing

Serious events: 0 serious events

Other events: 1 other events

Deaths: 0 deaths

Carbon-dioxide Insufflation

Serious events: 0 serious events

Other events: 1 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Measure	Lund De-airing n=10 participants at risk Before CPB was started, both pleural cavities were exposed to atmospheric air through small openings in the mediastinal pleurae. After CPB was established the patient was disconnected from the ventilator, allowing both lungs to collapse. After completion of the surgical procedure the aortic crossclamp was released and the heart was then defibrillated. After a good cardiac contraction and normal central hemodynamics, the LV preload was gradually and successively. When no air emboli were observed in the left side of the heart, the patient was reconnected to the ventilator and the lungs were ventilated with half of the estimated minute volume using 100% oxygen and 5 cm H2O positive end-expiratory pressure. The deairing was continued, and when no air emboli were observed in the left side of the heart, the lungs were ventilated to full capacity and the heart was allowed to eject by reducing the LV vent.	Carbon-dioxide Insufflation n=10 participants at risk The pleural cavities were left intact in the CO2 group. During CPB, the patient was administerd dead space ventilation. Before the cannulation for CPB, the CO2 was insufflated in the mediastinum at a flow rate of 10 L/min and continued until 10 minutes post-CPB. After completion of the surgical procedure, the heart and lungs were passively filled with blood from the CPB circuit and the left side was de-aired continuously through the LV apical vent. Full ventilation was then resumed. The heart was defibrillated and the LV preload was gradually and successively increased by reducing the venous return to the CPB circuit. The de-airing continued through the vent in the LV apex under TEE monitoring. When no gas emboli were observed in the left side of the heart, the LV vent was reduced and the heart was allowed to ject. De-airing was continued, and when no further gas emboli were observed in the left side of the heart, the patient was weaned from CPB.
Nervous system disorders Postoperative neurological dysfunction	10.0% 1/10 • Number of events 1 • Data was collected during the postoperative course when patient was still in ward (median time 7 Days). Method of detecting adverse events was screening of patients charts for reports of neurological dysfunction.	10.0% 1/10 • Number of events 1 • Data was collected during the postoperative course when patient was still in ward (median time 7 Days). Method of detecting adverse events was screening of patients charts for reports of neurological dysfunction.

Additional Information

Dr. Bansi Koul MD, PhD, Principal Investigator

Cardiothoracic Surgery, Skåne University Hospital Lund

Phone: +46 46 171649

Email: bansi.koul@skane.se

Results disclosure agreements

• Principal investigator is a sponsor employee
• Publication restrictions are in place