Which of the following statements regarding capillary blood samples is TRUE?

The statement that capillary PO2 values correlate well with arterial PO2 values is accurate because capillary blood samples are commonly used to assess the oxygenation of peripheral tissues. The capillaries, being the smallest blood vessels, interact closely with the tissues and allow for the exchange of gases. Therefore, capillary blood can provide a reliable estimate of the oxygen tension in the body, especially when obtained correctly.

In clinical practice, while there may be some variability due to factors such as circulation and the site of collection, overall, capillary blood samples are often considered adequate for estimating arterial oxygen levels in neonates and children. This correlation is particularly relied upon in situations where obtaining arterial samples is difficult or poses a greater risk to the patient.

The other statements do not reflect the usual physiological correlations. For instance, capillary pH and PCO2 values can differ significantly from their arterial counterparts due to the effects of local metabolism and circulation dynamics. The warming technique associated with heelstick sampling, while commonly employed to enhance blood flow, typically involves a dry cloth rather than a wet cloth to prevent potential complications such as skin maceration or infection.