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Abstract
Cardiopulmonary bypass has been linked to neurocognitive dysfunction in numerous studies. Air emboli are one of the main causes of neurocognitive dysfunction. The air emboli can come from the surgical field, the heart lung machine, or from anesthesia. This study investigated the amount of venous air returning to the heart lung machine from the surgical field. Venous air can come from a number of sources, including; loose purse strings, a trans-atrial approach to a mitral valve repair or replacement, or openings in the venous lines of the heart lung machine. Air may also come from an atrial septal defect, a patent foramen ovale, or if the left atrium or left ventricle are opened.
Since venous air comes from a variety of sources and is harmful to the patient, a device to remove this air could limit the amount of air emboli and improve patient outcomes. The purpose of this study was to look at the effects of placing an arterial bubble trap in the venous lines to reduce these air emboli. This was done by comparing the use of a bubble trap placed in the venous line to a circuit without a venous bubble trap under conditions of three air injection doses. Additionally the study tested the efficiency of the bubble trap in the venous lines [it is usually placed in the arterial line] by comparing air volume amounts before and after the bubble trap as measured by probes on each side of the trap. For each set of experimental conditions ten trials were performed, and the data were assessed using Minitab [version 14].
An arterial bubble trap placed in the venous lines was found to be effective at air removal when the volume amounts before and after the bubble trap were analyzed. There was a statistically significant reduction in air volume amounts when analyzing the injection site volume and after the arterial line filter with a bubble trap in the circuit as well as without a bubble trap in the circuit. There was not a statistically significant difference in the air volume amount removed when comparing a circuit with a bubble trap to one without a bubble trap in the venous lines. One possibility for this is the efficiency of the circuit’s components at air removal. Based on the results of this study, the arterial bubble trap does reduce the amount of air before it enters the cardiotomy and should be considered as another form of prevention for air emboli reaching the patient.