Automatic blood pressure monitors. A clinical evaluation of five models in adults.

Five automatic blood pressure monitors were evaluated by comparing their values with almost simultaneous blood pressure readings from radial artery catheters. A total of 583 comparisons were made on 48 patients. Statistical analysis was performed on the pooled comparisons of systolic and diastolic pressure for each monitor. Agreement between the pressure measurements was variable between both patients and machines. For systolic pressure, two machines (Copal and Sentron) had correlation coefficients of over 0.9 while for the other machines (Dinamap 845XT, Narco and Vitastat 9001S) the values lay between 0.7 and 0.8. The steepest regression lines were also found with the Copal (0.93) and Sentron (0.86) data, but the other machines had considerably flatter slopes (0.55 to 0.67). The intercepts on the Y axes ranged from +14.1 (Copa) to +50.1 (Dinamap). In clinical use, popularity of the different machines reflected the degree to which the machine reproduced the behaviour of the direct pressure measurement.