Agreements between mean arterial pressure from radial and femoral artery measurements in refractory shock patients

Abstract

Radial and femoral artery catheterization is the most common procedure for monitoring patients with shock. However, a disagreement in mean arterial pressure (MAP) between the two sites has been reported. Hence, the aim of this study was to compare the MAP from the radial artery (MAPradial) with that of the femoral artery (MAPfemoral) in patients with refractory shock. A prospective study was conducted in the medical intensive care unit. The radial and femoral were simultaneously measured MAP in the patients every hour, for 24 h. In total, 706 paired data points were obtained from 32 patients. MAPradial strongly correlated with MAPfemoral (r = 0.89, p < 0.0001). However, overall MAPradial was significantly lower than MAPfemoral 7.6 mmHg. The bias between MAPradial and MAPfemoral was − 7.6 mmHg (95% limits of agreement (LOA), − 24.1 to 8.9). In the subgroup of patients with MAPradial < 65 mmHg, MAPradial moderately correlated with MAPfemoral (r = 0.63) and the bias was increased to − 13.0 mmHg (95% LOA, − 28.8 to 2.9). There were 414 (58.6%) measurements in which the MAP gradient between the two sites was > 5 mmHg. In conclusion, the radial artery significantly underestimated MAP compared with the femoral artery in patients with refractory shock.