**3. ProtekDuo® cannula**

The ProtekDuo® is a single-site, dual-lumen cannula that is most commonly placed in the right internal jugular vein (IJV). When in its intended position, the cannula drains blood from its proximal ports in the right atrium and blood flow is directed through an extracorporeal circuit with or without oxygenator before being returned via the distal ports into the pulmonary artery. The cannula is available in two sizes, 29 and 31 French (Fr.) Placement in the IJV allows for ambulation of the patient. The percutaneous placement of this device has allowed it to be a less invasive support option in patients requiring mechanical (RV) support. See **Figure 1**.

#### **Figure 1.**

*a: Percutaneous right ventricular assist device (RVAD) with a Protek Duo cannula. b: Without oxygenator, and c: with oxygenator. From: Condello, I. Percutaneous right ventricular assist device, rapid employment in right ventricular failure during septic shock. Crit Care 24, 674 (2020).With kind permission from Critical Care (Open access).*

#### **3.1 ProtekDuo® cannulation technique**

Placement of a ProtekDuo® involves use of the modified Seldinger technique. Initially the right IJV is assessed for adequate size and an 8-Fr to 9-Fr introducer sheath is placed. Using the sheath, a balloon tipped catheter is guided and placed into the right pulmonary artery (PA) under fluoroscopy. Then a long 0.035-inch Lunderquist Extra Stiff Wire Guide (Cook Medical, Denmark) is guided through the balloon tipped catheter under fluoroscopic guidance and inserted into the right PA. The balloon-tipped catheter is then removed carefully under fluoroscopic guidance to ensure that the stiff wire remains in place in the right PA. Then the neck sheath is removed, and the site is progressively dilated to a size below the size of the cannula being used. A heparin bolus, dosed to achieve an activated clotting time of 300 seconds is given and then the ProtekDuo® cannula is placed under continuous fluoroscopy with the goal of having the cannula outflow port in the main PA [19]. Alternative anticoagulation may be achieved with direct thrombin inhibitors (DTI) [20], such as argatroban [21] or bivalirudin [22].

Transesophageal echocardiography (TEE) is useful to verify position of the cannula in the PA if fluoroscopy is not available. Both ports are clamped and then a wetto-wet connection is made with the drainage and return ports. Pump flow is increased per the clinician's discretion. The device is secured in place with a purse-string suture around the insertion site. Direct suturing to cannula body should be avoided as it may provoke erosion of the cannula wall. Suture rings are provided with the cannula which enable indirect fixation.

Once flow is initiated, a heparin or DTI infusion is initiated to maintain a partial thromboplastin time of 40-60 seconds, depending on the circuit used, which can later be adjusted to institutional protocols [19].

#### **3.2 ProtekDuo® cannulation complications**

There is limited data about ProtekDuo® related complications. Some authors have reported vascular injury during insertion, cannula thrombosis and cannula migration requiring repositing, but the occurrence of these seems to be low [23–26]. Additionally, there is also a case report about right coronary artery compression caused by the cannula which was resolved by repositioning [27] and a case series of superior vena cava syndrome in two patients [28].

#### **3.3 Device weaning**

Patients should be evaluated daily for readiness-to-wean from support with the ProtekDuo cannula® once myocardial recovery occurs in addition to improvement in hemodynamic parameters including [29, 30]. While no standardized protocol currently exists for device weaning, recommended strategies include incremental reduction of device flow by 0.5 L/min until flow is at 2 L/min [29, 30]. Once device flow is low, assessment of hemodynamic parameters as well as ventricular function by echocardiography and laboratory parameters such as lactate are performed [29, 30]. If needed, low doses of vasopressors or inotropes can be used to provide hemodynamic support [29]. If weaning parameters are acceptable, then device removal can be considered if appropriate [29, 30].
