Single arterial puncture vs arterial cannula for arterial gas analysis after exercise. Change in arterial oxygen tension over time.

In an attempt to find the least invasive, safest, easiest, and cheapest method of obtaining resting and exercise samples of arterial blood, a comparison was made between samples from an arterial needle puncture and an arterial cannula. This study demonstrated that samples of arterial blood may be obtained by radial arterial puncture both at rest and during exercise in practically all cases without morbidity. Samples from arterial needle puncture provide the same results as those from arterial cannulas. In the very rare patient in whom arterial puncture during maximal exercise is unsuccessful, the arterial oxygen pressure (PaO 2 ) measured at 10 seconds after exercise correlates very well with the PaO 2 at maximal exercise, and the 15-second value correlates nearly as well. Arterial cannulas are needed in the infrequent case when arterial puncture is not accomplished during maximal exercise and the 10-second or 15-second PaO 2 decreases from the resting value. In this instance, determination of the exact extent of the hypoxemia requires an exercise sample obtained by cannula; however, the decrease in PaO 2 obtained by arterial needle puncture at 10 or 15 seconds will be all that is needed many times to make a clinical decision. Values obtained at 20 seconds after maximal exercise reflect less of the exercise measurement and cannot be used; however, all episodes of significant hypoxemia (PaO 2