The next step is identifying a good venipuncture site, that is the site where you will 'puncture a vein' by inserting the IV cannula. Figure 22.2 shows some commonly used sites in the hand and forearm.
In selecting the site for venipuncture:
- Ask the patient which is the hand she most often uses, e.g. to hold a knife or a tool. If she says she is 'right handed', this is her 'dominant' hand and her left is her 'non-dominant' hand.
- Look first at possible venipuncture sites on her non-dominant hand and then look higher up the arm.
- Select a vein which is large enough for the cannula, avoiding sites near to joints like the wrist or the elbow.
- Make sure that when you insert the cannula, it will not interfere with woman's ability to move her hand or arm.
- Avoid a site which is painful to touch.
The visibility of the veins can be improved by encouraging the woman to close her hand into a fist and then open it again several times, lowering the arm and stroking the chosen venipuncture site. As you become more experienced, you will find it easier to choose a suitable vein which is easily visible, not twisted, where you think you can enter your cannula easily.