The primary objective is to compare the difference in the pain score in radial arterial puncture using the insulin needle versus the standard 23G hypodermic needle.

In a randomised, crossover design, healthy volunteers were recruited to receive bilateral radial arterial punctures. They were assigned to receive either the insulin or the standard needle as the first puncture using block randomisation. The primary outcome was the pain score measured on a 100mm visual analogue scale (VAS) and the secondary outcomes were procedural complications and rate of haemolysis.

Inclusion Criteria:

• age above 21

Exclusion Criteria:

• concurrent antipyretic use in the last 24 hrs,
• presence of painful conditions eg fracture, rheumatoid arthritis
• history of peripheral vascular disease