**5. Procedural phase—conduct of assistance**

Most patients do not require intubation and mechanical ventilation, so the procedures can be performed with the patient in spontaneous breathing, mildly sedated, especially for analgesic purposes, by practising local anaesthesia at the site of the vascular accesses. In some cases, the interventional procedure to be performed

#### **Figure 6.** *Percutaneous femoral accesses for ECMO (A) and coronary angioplasty (B).*

requires continuous transoesophageal monitoring (i.e., Mitraclip), in these cases, it is preferable to practice general anaesthesia and mechanically ventilate the patient. In the case of intubation, lung-protective ventilation is performed during extracorporeal assistance and the gas supplied to the oxygenator is adjusted to achieve an arterial oxygen partial pressure of approximately 150 mmHg and normocapnia.

In all cases, the blood pressure is monitored and a central venous catheter is positioned for the measurement of the central venous pressure and the possible rapid administration of liquids or drugs. In addition, a bladder catheter is placed for monitoring diuresis.

Vascular access is performed under ultrasound guidance for the positioning of the small calibre introducers (usually 7-8Fr) necessary for both the positioning of the cannula for ECMO and for the execution of the interventional procedure. Once inserted, systemic heparinization is carried out, administering a quantity of heparin necessary to achieve an ACT (activating clotting time) of 250 sec (about 200 IU/kg). Once this value has been reached, the arterial and venous cannulas are positioned and extracorporeal circulation is started, usually in normothermia.

In most cases, total replacement of the pump and respiratory function is not required, but assistance is provided to the circulation, maintaining a flow equal to *ECMO in Cath-Lab for Coronary, Structural or Combined Percutaneous Cardiac Interventional... DOI: http://dx.doi.org/10.5772/intechopen.105933*

#### **Figure 7.**

*The arrow indicates transseptal pigtails for unloading the left ventricle during the TAVI procedure for severe aortic regurgitation.*

approximately 70% of the total theoretical flow, and calculated on the basis of the patient's body surface. During the various phases of the procedure, the flow will be modified according to the specific needs of the procedure itself, for example, it is reduced to a minimum during the release of the aortic prostheses in order to avoid a "pop down" of the prosthesis itself inside the left ventricle conversely, during manoeuvres, such as coronary rotational atherectomy, the flow is increased in order to support the circulation and facilitate the washing of intracoronary debris. As happens in cardiac surgery operating rooms, close and continuous collaboration between the operators and the perfusionist is, therefore, essential.

Every 30 minutes of extracorporeal assistance, a blood gas examination and ACT check are performed to monitor the patient's respiratory exchanges and metabolic balance.

At the end of the procedure, the pump flow is gradually weaned. If necessary, inotropic drugs can be used to promote hemodynamic stability. This operation can take from a few tens of minutes to a few hours, depending on the patient's needs. In case of impossibility of weaning (which has never happened in our experience), the ECMO can be kept at adequate flow, transferring the patient to the intensive care unit where slow weaning will be attempted in the following days.

#### **Figure 8.**

*The arrow indicates 8Fr catheter for unloading the left ventricle inserted transseptally during a combined procedure of TAVI and Mitraclip in a patient with severe aortic and mitral regurgitation.*

**Figure 9.** *Cannula positioned in the right internal jugular vein and connected to the venous line.*

Upon obtaining stable and valid hemodynamic at the complete weaning of care, the cannula can be removed and the protamine sulphate is administered.

In cases of surgical isolation, decannulation will be directed with surgical repair of the vessels (usually with the closure of previously packaged purse-string suture). In cases of percutaneous implantation, arterial decannulation is performed, when possible, by placing and inflating at low atmospheres, a haemostasis balloon of adequate calibre (usually at least 2 mm greater than the diameter of the external iliac artery) upstream from the cannulation site, by crossover of the femoral arteries or through a guide inserted in the radial artery and pushed up to the affected femoral, which allows the removal of the cannula itself and the closure of the femoral breach with the means of percutaneous haemostasis

*ECMO in Cath-Lab for Coronary, Structural or Combined Percutaneous Cardiac Interventional... DOI: http://dx.doi.org/10.5772/intechopen.105933*

#### **Figure 10.**

*Cannula in superior vena cava (A) and inferior vena cava with the tip at the level of the hepatic veins (B).*

#### **Figure 11.**

*Percutaneous repair procedure of the tricuspid valve with the Triclip system—the arrow indicates the final position of the venous cannula at the level of the hepatic veins to allow manoeuvres for the delivery of the Triclip in the right atrium.*

(Proglide or Manta) by limiting blood losses as much as possible (**Figures 12**–**15**). As for percutaneous venous decannulation, an external suture can be applied or a Proglide can be used.

**Figure 12.** *Femoral artery crossover.*

#### **Figure 13.**

*Haemostasis balloon placed in the right iliac artery for removal of the arterial introducer at the end of a TAVI procedure.*

Once haemostasis is achieved, compression dressings are applied to the access sites and the patient is transferred to the intensive care unit for monitoring for the first 24 hours.
