Nursing

The semi-recumbent position works well for the brachial approach, too, but you'll need to hyperextend the patient's arm and place a small pillow under the elbow to maintain the position. If you're using a femoral artery, place the patient in a supine position, keeping the leg to be accessed as straight as possible.

Now you're ready to do the arterial stick

Don nonsterile gloves and goggles and begin cleansing the site. Using a circular motion, start in the center and spiral outward for 30 seconds. Allow the area to dry completely.

Next, take off the nonsterile gloves, wash your hands, and don sterile gloves. With your non-dominant hand, feel for the pulse. Take a few seconds to note the precise point where the pulse feels the strongest and center your index finger over that point.

Lightly stabilize the artery with your index and middle fingers while continuing to concentrate on the pulse point: The tip of the needle should enter the skin right in front of your index finger.

Hold the ABG syringe with the needle bevel up at about a 30 – 60 degree angle for a radial or brachial puncture or a 60 – 90 degree angle for a femoral stick.

Then, in one smooth motion, slowly enter the skin and arterial wall. Once the needle has entered the artery, you should see a flashback of blood pulsate into the syringe. (Blood gas syringes fill by themselves, stopping at about 2 ml.) If you don't see blood pulsing into the syringe, you may have missed the artery—or gone through it. In that case, you'll need to slowly withdraw the needle until blood starts filling the syringe.

If you still don't get a blood return, withdraw the needle to skin level, re-angle the syringe toward the artery, and try again. If there's still no return, withdraw the needle completely and start over at a new site. Excessive probing could injure both the artery and any nearby nerves.

Once the syringe has filled, hold it steady to prevent the aspiration of air and withdraw the needle. Immediately place a gauze pad over the site and firmly apply pressure for at least five minutes—or for 30 minutes or more if you used a femoral artery.

With your other hand, hold the sample upright and check the syringe for air bubbles. Slowly eject any that you find onto a gauze pad.

Then, immediately seal the needle or tip of the syringe with a rubber stopper to prevent the influx of air. Gently roll the syringe between your fingers to mix the blood with the heparin. Be sure that the sample has the correct name, date, time, and puncture site on the label and the requisition. Indicate, too, whether your patient was breathing room air or on supplemental oxygen. If he's receiving respiratory therapy, jot down the type, including the amount of oxygen being given.

Plunge the syringe into the ice and send it off to the lab without delay. For best results, ABG samples should be analyzed within 10 minutes of collection.

Apply a pressure dressing to the site and leave it in place for 30 minutes, or until hemostasis is established. Don't ask a patient on anticoagulant therapy to take over this task, since inadequate pressure could lead to hemorrhage and hematoma formation. If you need help, ask a colleague to assist as you prepare the specimen for transfer to the lab.

It's not over yet: A look at after-care

Following an arterial blood draw, you'll need to monitor the site and extremity for any sign of circulatory problems or nerve damage. Check frequently for swelling and monitor vital signs, including the assessment of distal pulses. Note the color and temperature of the extremity distal to the puncture site. Ask the patient if he's experiencing any pain, numbness or tingling. Immediately report any problems to the physician. And document everything, including the results of the Allen's test, if applicable.