This procedure is used to gain vascular access in patients that are acutely hypovolaemic and have insufficient blood pressure to raise a vein in the normal way. The only tools required are a hypodermic needle, usually 21-gauge, and a pair of small curved mosquito haemostats. No special intravenous catheter is required - an ordinary 20-gauge or 22-gauge over-the-needle catheter is sufficient. Ideally, this procedure will be done on the foreleg of a patient in which catheterisation of the vein has not yet been attempted.

1.  With your dominant hand, use the sharp edge of the needle's bevel as a miniature scalpel to make a diagonal cut across the usual location of the cephalic vein, through the skin (Figure 1). Keep your non-dominant hand underneath the leg and use that hand's thumb and forefinger to draw the skin apart as you cut. Once through the skin, the dark blue line of the vein will be visible but do not attempt to place the catheter yet!

2.  Use the needle to make small cuts parallel to the vein, on both sides (Figure 2). This will help to free the vein from its subcutaneous tissue attachments.

3.  Use the small curved haemostats to perform further blunt dissection on both sides of the vein and finally underneath the vein, freeing it from the underlying tissue (Figure 3). Once you can insert the haemostats underneath the vein, do so. Ideally, turn them so that the handles will hold the weight and help act as a retractor.

4.  Using the haemostats to steady the vein, insert the catheter in the normal fashion, remove the haemostats and tape the catheter securely in place (Figure 4). I strongly recommend the use of a short extension set, as you do not want to disturb this catheter to disconnect and reconnect various fluids in the short term.

5.  The catheter should be removed in 6–12 hours, as it is likely that tissue preparation was minimal and this is an open wound. Tissue glue or sutures can be used to close the skin incision.

Figure 1. Diagonal cut through the skin.

Figure 2. Make small cuts parallel to the vein using the needle.

Figure 3. Free the vein using the haemostats.

Figure 4. Insert the catheter.