Alternatively, femoral artery cannulation can be performed with the aid of the Seldinger technique and direct cannulation without extensive dissection or subtotal femoral artery transection. Once the femoral artery is dissected and exposed, a rectangular purse string is placed in the artery (Fig. 1.5). The needle and guide wire are introduced into the artery, followed by the dilator and femoral catheter (Fig. 1.6). Often, a small incision at the wire site may be needed to facilitate the catheter placement (not shown). The catheter is secured by a Rommel tourniquet (Fig. 1.7). Figure 1.8 shows the repaired artery after the catheter has been removed.
In general, most resternotomy procedures are accomplished without prophylactic peripheral cannulation, reserving this part of the procedure for indications such as false aneurysms, conduits that traverse the midline, and aortas that are adhered to the undersurface of the sternum. Under these circumstances, the surgeon has the choice of prophylactic peripheral arterial cannulation as a “stand-by” option during sternal reentry or as a therapeutic option, which requires accompanying venous cannulation, institution of cardiopulmonary bypass, and systemic cooling. Whatever the circumstances of peripheral arterial cannulation, it is best to convert to central arterial (aortic) cannulation as soon as possible to prevent the unwanted complications of lower extremity ischemia and compartment syndrome.
The “stand-by” option allows the surgeon the confidence of established arterial cannulation in the event of cavitary entry. If cavitary entry occurs, the effluent mediastinal hemorrhage can be captured by pump suckers and then reinfused into the arterial line while peripheral venous cannulation is performed. If there is no unwanted cavitary entry, central venous cannulation can be implemented to complete the circuit for the intracardiac procedure. Whatever the circumstances of peripheral venous cannulation, it is best to establish central uniatrial or bicaval venous cannulation at the earliest possible convenience during the dissection.
1.2 Resternotomy Using Internal Mammary Retractor Placement, and Direct Dissection
Once the skin incision is performed and continued to the outer table of the sternum, the surgeon has the choice of starting the resternotomy. If the resternotomy is further challenged by dangerous adherence of vital structures to the undersurface of the sternum—which can be anticipated in patients with transposed arteries (anterior aorta), false aneurysms, central position of the right ventricular-to-pulmonary artery conduit, and gigantic right atria—peripheral cannulation is recommended for safe reentry in the event of an untoward event, as noted above. Preoperative anatomic studies, the number of resternotomies, and the overall experience of the surgical team guides the use of peripheral cannulation.
The resternotomy is commenced by dissecting a plane at the most inferior portion of the sternum by electrocautery or scissor dissection (Fig. 1.9), assisted by handheld retractors. The motion of the heart can help to determine the safe plane between the heart and the sternum and offer a safe physical purchase for placement of the self-retaining internal mammary artery retractors (one on each side, Fig. 1.10). This allows cautious upward (anterior) retraction of the sternum away from the heart without depending on human interactions, which could be unreliable owing to normal variations of strength, attention to detail, and fatigue. Once the retraction is established, a “Delta” is created, with the superior portion of the “Delta” in the center of the undissected sternotomy. Using direct electrocautery or scissor dissection, the “Delta” is moved superiorly while the lateral planes of the underside of the sternum are enlarged and dissected into the pleural cavities, if possible. The actual sternal division can be accomplished with a saw (Fig. 1.11), which can be used segmentally to divide the sternum up to the dissected plane that has been created. This “Delta” is then used as a dissection module to move the dissection plane superiorly until the dissection is complete. Because most self-retaining internal mammary retractors have two arms, in this application one of the arms is covered with a sterile towel to prevent unwanted injury to the surgical team. Once the sternum is opened, the second arm can be freed and used to retract each of the sternal edges for further dissection. Figure 1.12 shows the technique of sternal retraction using only one retractor, manual manipulation of the lung, and electrocautery dissection to lyse adhesions.