Evaluation of normal and large sphygmomanometer cuffs using the Omron 705CP

Sphygmomanometers are usually sold with a single cuff though some are suppl ied with a short cuff as standard and offer a longer one for larger arms. H owever, data on the differences in measurements taken with different cuffs applied to different sized arms are conflicting and this study set out to i nvestigate the difference between those taken with 'normal' and 'large' cuf fs in arms 28 cm or more in circumference. We avoided observer error by usi ng a semi-automatic digital sphygmomanometer, the Omron 705CP, The 22 subje cts employed were selected from one general practice as having a range of p revious office blood pressures and a variety of arm sizes above 28cm in cir cumference. Omron 'normal' and 'large' cuffs were used alternately, taking five blood pressures with each to a total of 30 readings per patient, resul ting in 660 readings, 330 with each cuff. There were mean systolic/diastoli c differences of 2.7/3.8 (s.d.s 4.7/2.8) for all subjects. These were great er in the normotensive, When divided into two groups with systolic blood pr essures below and equal to or above 140 mm Hg, differences were -1.9/3.0 to 7.1/4.7. From the results of the study, we recommend that large cuffs shou ld be used for all patients with an arm circumference of 28 cm or above but the Omron large cuff still requires formal validation.