Radial artery pressures compared with subclavian artery pressure during coronary artery surgery

ABSTRACT

Radial artery and subclavian artery pressures were measured in nine men undergoing coronary artery surgery requiring cardiopulmonary bypass. Radial artery pressures were measured simultaneously through short (10.2 cm) and long (106.9 cm) tubing using two transducers in a branched tubing system. Interaction between the branches was minimal in an in vitro test system. The radial artery pressures were compared with simultaneous subclavian artery pressures measured through a catheter introduced into the axillary artery. Pre-bypass, the systolic pressures were greater in the radial than in the subclavian artery (P <0.005), by typically 10%. There was no significant difference between long and short branches of the radial artery tubing system; the exaggeration of systolic pressures under these conditions resulted from use of the radial artery per se. After weaning from bypass, the mean and diastolic pressures were lower in the radial artery than in the subclavian artery. Average systolic pressure was not significantly lower. The ratio of radial to subclavian systolic pressures showed increased variance. By the end of the operation, radial mean pressure was similar to the subclavian pressure, although the difference remained significant.