Bower LK, Barnhart SL, Betit P, Hendon B et al.(2001) Capillary blood gas sampling for neonatal and pediatric patients. Respiratory Care 46 : 506–513
Capillary blood gas (CBG) samples may be used in place of samples from arterial punctures or indwelling arterial catheters to estimate acid-base balance (pH) and adequacy of ventilation (PaCO2). Capillary PO2 measurements are of little value in estimating arterial oxygenation. A puncture or small incision is made with a lancet or similar device into the cutaneous layer of the skin at a highly vascularized area (heel, finger, toe). (The lancet may be used freehand or as part of a device that limits puncture depth.) To accelerate blood flow and reduce the difference between the arterial and venous gas pressures, the area is warmed prior to the puncture. As the blood flows freely from the puncture site, the sample is collected in a heparinized glass capillary tube.