Carbon dioxide de-airing in minimal invasive cardiac surgery, a new effective device

Abstract

Background: Arterial air embolism during open heart surgery may cause postoperative complications including cerebral injury, myocardial dysfunction, and dysrhythmias. Despite standard de-airing techniques during surgery large amounts of arterial air emboli may still occur, especially during weaning from cardiopulmonary bypass. To prevent this insufflation of carbon dioxide in the wound cavity has been used since the 1950s. The aim of this study was to assess a new mini-diffuser for efficient carbon dioxide de-airing of a minimal invasive cardiothoracic wound cavity model. Up until now no device has been evaluated for this purpose.

Methods: A new insufflation device, a mini-diffuser, was tested. A thin plastic tube was used as control. The end of the mini-diffuser or the control, respectively, was positioned in a minimal invasive thoracic wound model. Remaining air content was measured during steady state and during intermittent suction with a rough suction device at different carbon dioxide flow rates. Measurements were also carried out in the open surgical wound during minimal invasive aortic surgery in six patients.

Results: The air content was below 1% 4 cm below the surface of the open wound model during continuous carbon dioxide inflow of 2-10 L/min with the mini diffuser. In comparison, carbon dioxide insufflation via the open-ended tube resulted in a mean air content between 10 and 75%. The mean air content of the wound model remained below 1% at a carbon dioxide flow rate of 3-5 L/min during intermittent application of a suction device with a suction rate of 15 L/min. In 6 patients undergoing minimal invasive aortic valve replacement air content in the open surgical wound remained below 1% at a continuous carbon dioxide flow rate of 5 and 8 L/min via the mini-diffuser, respectively.

Conclusions: The mini diffuser was effective for carbon dioxide de-airing, i.e. < 1% remaining air, of a minimal invasive cardiothoracic wound cavity model with and without intermittent rough suction as well as in patients undergoing minimal invasive aortic valve surgery.

Keywords: Carbon dioxide; Emboli; Minimal invasive cardiac surgery; de-airing.

Fig. 1

Photo of the mini-diffuser

Fig. 2

Measured air content at steady state when insufflating CO₂ at various flow rates into a minimal invasive cardiothoracic wound cavity model with a new CO₂ insufflation device. Air content was measured at a depth of 15 mm and 40 mm from the opening surface of the wound cavity model

Fig. 3

Measured air content at steady state when insufflating CO₂ at various flow rates into a minimal invasive cardiothoracic wound cavity model with an open tube (inner diameter of 1 mm). Air content was measured at a depth of 15 mm and 40 mm from the opening surface of the wound cavity model

Fig. 4

Air content measured every five seconds, when using the new CO₂ insufflation device and intermittent rough suction rate of 10 L/min for two seconds from time zero. CO₂ was insufflated at a flow rate of 2, 3, 4, and 5 L/min, respectively

Fig. 5

Air content measured every five seconds, when using the new CO₂ insufflation device and intermittent rough suction rate of 15 L/min for two seconds from time zero. CO₂ was insufflated at a flow rate of 2, 3, 4, 5, and 10 L/min, respectively

Fig. 6

Measured air content at steady state when using the new CO₂ insufflation device and continuous rough suction force of 5, 10, and 15 L/min. CO₂ was insufflated at a flow rate of 2, 3, 4, 5, and 10 L/min, respectively