Vascular Access

Abstract

In this chapter, we deal with vascular accesses in cancer patients, complications associated with those devices, and nursery care. Long-term venous catheters, especially tunneled catheters, are essential for cancer treatment, with wide applicability in various stages of treatment. In addition to enabling the infusion of drugs and blood products, they also allow the collection of blood samples for laboratory analysis, the monitoring of hemodynamic parameters, parenteral nutrition, and the performance of essential procedures for maintaining life, such as hemodialysis sessions.

The indications and types of catheters are discussed, taking into account the time of use, the compatibility of the drug with the peripheral venous system, and the risk of infection. Most frequent complications and how to avoid them are also a subject in this chapter.

Editors Comments

1.1 Echo-Guided Venous Access

Adequate venous access is essential for many patients, especially those admitted to hospitals. The choice of the best access route and the type of catheter are mainly related to the type of substance to be infused, the duration of therapy, and the existence of an adequate peripheral venous network.

Venous access should preferably be obtained through puncture rather than dissection, as it generates less tissue manipulation and lower morbidity rates.

Except for puncture of visible superficial veins and adequate caliber, the accesses must be eco-guided. In addition to the objectives mentioned, one of the applications of ultrasound is to verify the correct direction of the guidewire’s progression, especially in procedures performed at the bedside. As an example, when performing a puncture of the axillary/subclavian vein and with the transducer at the base of the neck at the height of the sternoclavicular junction, it is possible to quickly identify whether the guidewire traveled the wrong path to the ipsilateral internal jugular or had the appropriate path for the ipsilateral innominate venous trunk. If the guidewire has progressed to the internal jugular and with visualization concomitant with ultrasound, the guidewire is initially pulled until its “J” end exits the jugular. The “J” is rotated in the central direction, followed by compression of the transducer with one hand and concomitant progression of the guidewire with the other hand to direct the extremity to the innominate vein. Similarly, it is possible to check the internal or jugular access to the cranial or caudal direction of the guidewire and eventual repositioning.

There are two techniques for visualizing the needle: in-plane or out-of-plane. In the in-plane technique, there is a perfect alignment between the needle and the ultrasound beam during its entire path, which is visualized entirely from its entry into the skin until it reaches the target vessel. In the out-of-plane technique, there is no alignment, just an intersection of the ultrasound beam with the needle, so during the progression of the needle, there is no visualization of it. Visualization of its extremity occurs only when this crossing occurs in the center of the target vessel.

There is no superiority of one technique over another concerning venous access [44, 45].

There are two ways of visualizing the vessel: transverse axis (transducer perpendicular to the vascular bundle) or longitudinal axis (transducer parallel to the bundle).

The echo-guided puncture technique is a combination of the needle view and the vessel view. The best combination choice depends on the type of catheter, anatomical location of the target vessel, and professional experience: as an example, the in-plane puncture of the internal jugular on the longitudinal axis. The only advantage is the almost zero possibility of pneumothorax, as it is an extremely cranial puncture. For short-term catheters, there is a clear disadvantage of the discomfort caused by the catheter externalized far above the neck’s base, and for long-term catheters, the curvature necessary to perform the subcutaneous course is inadequate. Another example is the in-plane puncture of the axillary vein. There is the advantage of comfort in the exterior of the catheter for short-term catheters, but for long-term catheters, there is the disadvantage of curvature.

1.2 Positioning the Catheter Tip

Some imaging methods must be performed concomitantly or immediately after obtaining central venous access for proper positioning of its extremity, the most used being: fluoroscopy, intra-cavity electrocardiogram, and radiography.

The central catheters’ tip must be located in the cavoatrial junction or the right atrium [46, 47], especially in long-term accesses. Significant complications such as device dysfunction and deep venous thrombosis are correlated with poor positioning of the extremity (innominate vein or proximal superior vena cava), being attributed to factors such as the diameter of the vessel/catheter, blood flow speed, and the caustic/hypertonic nature of the solutions (chemotherapy, parenteral nutrition).

1.3 Prophylactic Anticoagulation

It is known that patients with malignant neoplasia have higher rates of thromboembolic events, with the presence of a central venous catheter among the various factors that cause it.

Chemoprophylaxis in these patients with catheters is controversial as to the results, type of anticoagulant (oral or parenteral), dose, and duration. Some studies show a decrease in the number of symptomatic and asymptomatic events [48, 49], others show no advantage, and routine use is not recommended [50, 51].

1.4 Maintenance of Ports

At the end of the use of all central venous catheters, a flush with saline solution is performed, followed by filling with a solution (lock) until further handling, aiming to avoid the deposit of crystals and blood in the lumen leading to dysfunction and/or occlusion.

In ports, heparin lock is classically used between chemotherapy sessions, however, with varying dilutions and time intervals. The use of heparin is based on the fact that it is an anticoagulant substance; therefore, it would minimize the mentioned complications.

Few studies compare maintenance with a heparin lock or saline solution, none of them showing the advantage of using heparin.

A retrospective study comparing occlusion rates with heparin lock (50 IU/mL) versus saline solution showed no difference [52].

A randomized study comparing the reflux dysfunction indices between heparin lock (100 IU/mL) versus saline solution showed no difference [53].

Another retrospective study comparing the reflux dysfunction rates, flow dysfunction, and occlusion between heparin lock (100 IU/mL) versus saline solution also showed no difference [54].