Techniques of Obtaining Arterial Blood from Newborn Infants

Respiratory diseases of the newborn continue to be major contributors to neonatal mortality and morbidity. One of the most important laboratory tests in the evaluation and monitoring of an infant with respiratory distress is the arterial blood gas. One of the most frequently used methods for obtaining intermittent arterial samples from neonates is a radial artery puncture. In addition to radial artery punctures, capillary or "arterialized" blood has also been used in the past for monitoring oxygen levels. This technique has been shown to have good correlation with arterial blood so far as pH and PCO 2 are concerned. However, the studies evaluating PO 2 are controversial. A properly done heelstick PO 2 may correlate well with arterial PO 2 as long as the level is below 60 to 70 mm Hg.