Capillary Blood Gas Sampling
An alternative to arterial blood gas sampling, capillary blood gas sampling is used to help monitor a patient’s respiratory status. The procedure can be performed in the presence of hypothermia and hypoperfusion (provided that hypertension isn’t present) and can be easier to perform than arterial blood gas sampling in these situations. It involves a simple fingerstick and is less painful than an arterial puncture.
Capillary blood must be collected in special balanced-heparin capillary blood gas collection tubes. Transport of samples to the laboratory should occur within 30 minutes of collection; a delay may alter the results because of cellular metabolism or hemolysis.
Equipment
Sterile lancet (1.5 mm in depth) ▪ antiseptic pad ▪ 2″ × 2″ sterile gauze pads ▪ gloves ▪ preheparinized glass capillary tube ▪ warming supplies (such as a chemical warmer or a warm cloth that’s less than 109°F [42.8°C]) ▪ sealing clay, wax sealer, or cap ▪ sample collection label ▪ plastic laboratory biohazard transport bag ▪ Optional: ice, topical anesthetic cream.
Implementation
Verify the doctor’s order.
Gather the necessary supplies, including the lancet.
Confirm the patient’s identity using at least two patient identifiers according to your facility’s policy.4
Explain the procedure to the patient, allowing him to ask questions and express anxiety as needed to promote better understanding of what is to be done.
Select the capillary puncture site. Either the earlobe or the finger is the preferred site in adults. If using a finger, select a site on the side of the finger, parallel to the side edges of the nail. Avoid the finger’s tip or pad to prevent additional discomfort.
Nursing Alert
Avoid using extremities with impaired circulation or localized infection.
Apply a topical anesthetic if indicated and time allows to decrease discomfort.
