Feature Article: PDF OnlyEvaluation of a New Control Valve for Indirect Blood Pressure MeasurementCRAP, MARY JO Ph.D., RN, CCRN; BOYLE, ANNE H. Ph.D.(C), RN; JAEGER, DORIS Ph.D., RN; EMBREY, JAMES P. Ph.D., RN, CRNA; ELSWICK, R. K. JR. Ph.D.Author Information School of Nursing, Virginia Commonwealth University, Richmond, Virginia Richmond, Virginia Department of Nurse Anesthesia, Virginia Commonwealth University, Richmond, Virginia Department of Biostatistics, Virginia Commonwealth University, Richmond, Virginia Journal of Clinical Engineering: November 1995 - Volume 20 - Issue 6 - p 484-490 Buy Abstract Although a relatively simple procedure, blood pressure (BP) measurement is fraught with pitfalls. One source of error is the BP cuff control valve. The Johnston valve regulates the rate of cuff deflation. This study compared the means and variances of the Johnston BP valve and the standard valve in 60 healthy volunteers and in 72 surgical patients. In these patients, all measurements were compared to intra-arterial pressure. In healthy volunteers, no statistically significant differences were found between the means or variances of the two devices. In surgical subjects, however, means for systolic blood pressure and variances for systolic and diastolic measurements differed significantly between the two devices. When differences from intra-arterial pressure were compared for both devices, variances of the systolic differences were significant. Given the wide variability of the standard cuff seen in this study, a patient could be defined as normotensive one moment and hypotensive the next. The Johnston valve has the advantage of significantly reducing the variability of systolic and diastolic blood pressure measurement. ©1995Aspen Publishers, Inc.