Cardioplegia Cannulation and Venting
◆ A purse-string suture (4-0 polypropylene) is placed on the right atrial wall, caudal to the IVC cannulation site and about 1 cm from the atrioventricular junction, at the level of the acute margin of the right ventricle (Fig. 2.13).
◆ The cannula is passed through a stab in the purse string and is rotated so that the tip abuts on the atrial septum at a point just medial to the IVC and curls toward the left shoulder as the cannula is advanced. Proper placement is indicated by easy passage of the cannula tip and by external palpation of the cannula in the coronary sinus medial to the IVC. The pressure tracing from the tip of the cannula will also be characteristic, and the position can be confirmed using TEE.
◆ If the cannula cannot be easily inserted, after snaring down the two single-stage cannulae, a small transverse atriotomy (1.5 cm) may be made and a purse-string suture placed around the coronary sinus ostium to secure the retrograde cannula after insertion under direct vision.
◆ A purse-string suture (4-0 polypropylene) is placed on the right superior pulmonary vein with the medial suture line placed into the left atrium (Fig. 2.14).
◆ The vent can be placed prior to or after cross-clamp application. If the vent is placed prior to application of the cross-clamp, the surgeon must ensure that the left ventricle is not ejecting to avoid possible air embolization during vent placement.
◆ The venting cannula can be tailored by creating a question mark curve to allow for placement of the cannula into the left ventricle through the left atrium and mitral valve. The cannula is passed through a no. 11 blade stab in the pulmonary vein purse string, and the cannula is gently advanced in a left inferolateral direction. If feasible, the surgeon’s hand can be placed behind the heart in the oblique sinus and can palpate and guide the cannula through the mitral valve.
◆ To achieve effective venting and minimize bleeding during aortic procedures, the cannula should sit in the left ventricle.
◆ Less common alternative sites for ventricular venting include the superior aspect of the left atrium, the pulmonary artery, and the foramen ovale.
Similar image to Figure 2.13 but showing the right superior pulmonary vein and a cannula being advanced to the apex of
|the LV. A gloved hand can be placed behind the heart.|
Keywords : Cannulation Techniques for Cardiopulmonary Bypass, cannulation techniques, cardiopulmonary bypass, Surgical Anatomy, Operative Steps, Postoperative Care, Pearls and Pitfalls, Ascending Aorta, Femoral and Iliac Vessels, Axillary Artery