For patients with inconspicuous peripheral vein exposure and difficulty in puncturing of vasospasm, apply a cotton swab dipped in 1% nitroglycerin on the back of the hand, and apply moist heat to the area for about 3 minutes, and the superficial venules fill up quickly.
It has been confirmed by clinical observation and instrument testing that this method can significantly increase the diameter of the vein, enhance the vascular filling degree, and no allergic reaction occurs.
But infants, glaucoma, cardiovascular patients, high fever convulsions, irritability should be used with caution. With 2% anisodamine, wipe the local skin 4 times, the blood vessels have poor elasticity, large fragility, thin blood vessels, unclear, and patients with difficult puncture, and no adverse reactions occur.

 (2) Hot compress method:

Local hot compress can increase the temperature of local tissues, improve blood circulation, dilate blood vessels, and expose veins. Scientists have compared the local puncture method with hot compress and conventional puncture method to patients with traumatic and hemorrhagic shock.
For the puncture of the finger and toe veins, and for the patients with poor circulation caused by diarrhea in children, the vein collapses, and it is difficult to puncture, it is recommended to cooperate with the hot compress method, which will help to improve the success rate of the puncture.
04# Non-clenched fist piercing method

When performing venipuncture on the back of the hand, it is recommended that the hand to be punctured should be placed naturally, and the nurse uses the left hand to fix the patient's hand into a cup-shaped hand, so that the blood vessel can be protruded from this part and easy to be punctured. Let him make a half fist (the heart of the fist is empty), or ask him to make and release his fist repeatedly. Repeatedly clenching and loosening the fist can make the interphalangeal muscles contract, promote the centripetal return of blood, significantly fill the veins on the back of the hand, reduce the pain of the patient during puncture, and improve the work efficiency.