Q: Why extra care should be taken to prevent air embolism in arterial lines?


Answer: Extra care should be taken to prevent air embolism in arterial lines because in contrast to venous lines which have pulmonary capillaries sitting as filter before emboli travel to arterial sides, "A-Lines" have no such natural protection. Experiment has shown that even if 2 cc of air get injected in radial artery with a standard pressurized infusion apparatus can cause significant clinical cerebral air emboli. 2 major risk factors for air emboli from arterial lines are smaller size patients and patients who are sitting upright. 


Reference: 

Chang C, Dughi J, Shitabata P, et al. Air embolism and the radial arterial line. Crit Care Med 1988; 16:141.