Effect of Cuff Design on Auscultatory and Oscillometric Blood Pressure Measurements.

Background: Two-piece blood pressure (BP) cuffs are the historical cuff standard. Use of 1-piece cuffs is increasing. Substituting 1-piece for 2-piece cuffs has an unknown effect on measurement accuracy. We compared these cuff types in a 2-phase study using auscultatory and oscillometric techniques.

Methods: Consenting subjects (aged ≥18 years) with BP levels between 80 and 220mm Hg/50 and 120mm Hg and arm circumferences between 25 and 43cm were studied using the International Standards Organization (ISO) 2013 protocol (modified). A Baum 2-piece cuff was used as the reference standard. A 1-piece Welch Allyn cuff was the comparator. In phase 1 (2-observer auscultation with a mercury sphygmomanometer), 88 subjects were required to obtain 255 paired BP determinations. In phase 2 (oscillometric measurement with a Spacelabs 90207 device), 85 subjects were studied. Each phase was analyzed separately using paired t-tests.

Results: Phase 1 mean age was 54.2±20.5 years, mean arm circumference was 29.9±3.7cm, 60% were female, and 32% had hypertension. One-piece cuff mean BPs were lower than the 2-piece cuff means (115.5±15.5/66.4±9.3 vs. 117.8±15.2/67.9±9.2; difference of -2.4±3.6/-1.5±2.4; P values <0.0001 for systolic and diastolic comparisons). Phase 2 mean age was 52.8±20.8 years, mean arm circumference was 29.4±3.9cm, 67% were female, and 38% had hypertension. Mean BPs were lower for the 1-piece compared to the 2-piece cuff (116.5±12.8/67.1±8.1 vs. 120.8±13.5/70.4±8.5; difference of -4.4±3.6/-3.3±2.7; P values <0.0001 for both).

Conclusions: Mean BP is lower with 1-piece cuffs vs. 2-piece cuffs. Differences are greater with oscillometry. When performing validation studies and measurements for clinical purposes, cuff type should be taken into account.