They also play an important role in the provision of education to their clients, which includes sharing blood pressure results with the client and other members of the healthcare team. Detection Recommendation 1.1 Nurses will take every appropriate opportunity to assess the blood pressure of adults in order to facilitate early detection of hypertension. Level of Evidence = IV Discussion of Evidence Hypertension is often referred to as the “silent killer.” Regular blood pressure checks are a means to assess the need for antihypertensive treatment and to monitor a client’s vascular risk (Pickering et al., 2005). As the largest group of healthcare professionals, nurses work with clients in a wide range of settings and are in a key position to facilitate early detection of elevated blood pressure. CHEP (2005) recommends assessing all adult blood pressures at all appropriate visits. A specific interval for screening is not recommended, however it is suggested that checking a blood pressure in a normotensive client every 2 years and every year in the client with borderline blood pressure would be prudent (Sheridan, Pignone & Donahue, 2003). Recommendation 1.2 Nurses will utilize correct technique, appropriate cuff size and properly maintained/calibrated equipment when assessing clients’ blood pressure. Level of Evidence = IV Discussion of Evidence The most frequent error in the clinic-based blood pressure assessment is the utilization of an inappropriate blood pressure cuff, with under-cuffing a large arm accounting for 84% of all errors (See Table 1) (CHEP, 2004; Graves, Bailey, & Sheps, 2003). When the cuff is correctly sized, the bladder of the cuff should encircle 80 -100% of the arm. Utilizing a blood pressure cuff that is too small may lead to a significant overestimation of blood pressure. Fonseca-Reyes et al. (2003) found that when a cuff is too small, for every 5 cm increase in arm circumference, there was a 2-5 mmHg increase in systolic blood pressure and a 1-3 mmHg increase in diastolic blood pressure. In contrast, use of a cuff that is too large leads to an underestimation of blood pressure. Regular calibration of aneroid and electronic blood pressure monitors is required in order to ensure that blood pressure measurements begin from a starting point of zero. Monitors can drift from a zero starting point due to use and over inflation, resulting in potentially inaccurate blood pressure readings. Monitors Nursing Management of Hypertension 28 29 are manufactured with instructions for calibration, which should be utilized to develop a maintenance schedule and procedure. CHEP (2005) recommends that aneroid devices should be calibrated every 6-12 months. Table 2 provides a description of the appropriate technique for measuring blood pressure, and Figure 1 illustrates proper positioning of a blood pressure cuff. Table 1: Appropriate cuff sizing based on arm circumference Reproduced with permission. Canadian Hypertension Education Program Process, 2005. Arm circumference (cm) Size of cuff (cm) 18-26 9x18 (child) 26-33 12x23 (standard adult) 33-41 15x33 (large, obese) More than 41 18x36 (extra large, obese) ➪ Practice Point: ■ The client should be seated comfortably for five minutes with the back supported and the upper arm bared without constrictive clothing. The legs should not be crossed (Pickering et al., 2005). ■ The arm should be supported at heart level, and the bladder of the cuff should encircle at least 80% of the arm circumference (Pickering et al., 2005). ■ The mercury column should be lowered at a rate of 2 to 3 mmHg/sec, and the first and last audible sounds should be taken as systolic and diastolic pressure. The column should be read to the nearest 2 mmHg (Pickering et al., 2005). ■ Neither the client nor the observer should talk during the measurement (Pickering et al., 2005). ■ No smoking or nicotine in preceding 15-30 min (CHEP, 2005). ■ No caffeine in the preceding hour (CHEP, 2005). Nursing Best Practice Guideline Table 2: Recommended technique for measuring blood pressure using a sphygmomanometer and stethoscope Reproduced with permission. Canadian Medical Association, 1999. I. Measurement should be taken with a sphygmomanometer known to be accurate. Although a mercury manometer may be preferable, a recently calibrated aneroid or a validated and recently calibrated electronic device can be used. Aneroid devices and mercury columns need to be clearly visible at eye level. II. Choose a cuff with an appropriate bladder width matched to the size of the arm. III. Place the cuff so that the lower edge is 3 cm above the elbow crease and the bladder centered over the brachial artery. The client should be resting comfortably for 5 minutes in the seated position with back support. The arm should be bare and supported with the antecubital fossa at heart level, as a lower position will result in erroneously higher systolic blood pressure and diastolic blood pressure. There should be no talking and client’s legs should not be crossed. At least two measurements should be taken in the same arm with the client in the same position. Blood pressure should also be assessed after 2 minutes of standing, and at times when clients report symptoms suggestive of postural hypotension. Supine blood pressure measurements may also be helpful in the assessment of elderly in those