Chapter 1
Venous Access Glossary
Cannulas
Midline
Peripherally Inserted Central Catheter (PICC) Line
Central Line
Tunnelled Catheter
Renal Dialysis Catheters
Totally Implanted Port
Cannulas
Cannulas are short peripheral access devices that are intended for short periods of use, i.e., <96 hours. In adult use, they range in size from the smallest (blue) up to the largest (orange). They are typically inserted via the back of the hand or in the forearm/antecubital fossa. Cannulas can be inserted under direct vision; however, the use of ultrasound is helpful in cases of difficult cannulation (Figures 1.1 to 1.3).
Figure 1.1 Cannula gauges and indications.
Figure 1.2 Blue and pink cannulas.
Figure 1.3 Larger cannulas (green, grey and orange).
Midline
The midline is inserted under ultrasound guidance, traditionally via the upper arm basilic vein. It has to be inserted under strict aseptic conditions. Midlines can be used for both short-term and long-term venous access (i.e., weeks to months). The most common indication for a midline insertion in our unit is for long-term intravenous antibiotics. However, they can be used for the same indications as a peripheral cannula. If peripheral access is needed for over 4 days, then a midline should be considered instead of repeated peripheral cannula insertions (Figure 1.4).
Figure 1.4 Midline with black dots representing the basilic vein marked with ultrasound.
Peripherally Inserted Central Catheter (PICC) Line
The PICC line is of a similar design to a midline. It is inserted in the same way, but because of its extra length, the tip is placed in the central venous system, i.e., in the super vena cava/cavo-atrial junction. It is usually inserted under x-ray or electrocardiogram (ECG) guidance. It is recommended for use in cases when medium-/long-term central access is required, e.g., for chemotherapy, total parenteral nutrition, etc. PICC lines can last up to 12 months or more if they are well cared for (Figures 1.5 and 1.6).
Figure 1.5 Double-lumen PICC line.
Figure 1.6 Right-sided PICC x-ray confirmation with the tip approaching the cavo-atrial junction.
Central Line
Central lines are predominantly inserted into the neck via the internal jugular vein. They can also be inserted via the subclavian vein just below the clavicle, or, as a last resort, via the common femoral vein in the groin. They are used when short-term central access is required (<10 days). They come in either single-lumen or multi-lumen forms. They can be used for the administration of all intravenous solutions, including antibiotics, fluids, medications, parenteral nutrition and chemotherapy. They are excellent for resuscitation and haemodynamic monitoring. Patients having major surgery often have them inserted in theatre (Figure 1.7).
Figure 1.7 Central line – left internal jugular vein (IJV).
Tunnelled Catheter
These lines are used in cases when long-term central access is required. They are inserted via the subclavian or internal jugular veins and the line is tunnelled out onto the skin of the chest wall. The line typically has a cuff that creates...
