with diabetes. IV. Increase the pressure rapidly to 30 mmHg above the level at which the radial pulse is extinguished (to exclude the possibility of a systolic auscultatory gap). Continue to auscultate at least 10 mmHg below phase V* to exclude a diastolic auscultatory gap. V. Place the bell or diaphragm of the stethoscope gently and steadily over the brachial artery. VI. Open the control valve so that the rate of deflation of the cuff is approximately 2 mmHg per heart beat. A cuff deflation rate of 2 mmHg per beat is necessary for accurate systolic and diastolic estimation. VII. Read the systolic level (the first appearance of a clear tapping sound [phase l*]). Record the blood pressure to the closest 2 mmHg on the manometer (or 1 mmHg on electronic devices) as well as the arm used and whether the client was supine, sitting or standing. Avoid digit preference by not rounding up or down. Record the heart rate. The seated blood pressure is used to determine and monitor treatment decisions. The standing blood pressure is used to assess for postural hypotension, which if present, may modify the treatment. VIII. If Korotkoff* sounds persist as the level approaches 0 mmHg, then the point of muffling of the sound is used (phase lV*) to indicate the diastolic pressure. Nursing Management of Hypertension 30 31 IX. In the case of arrhythmia, additional readings may be required to estimate the average systolic and diastolic pressure. Isolated extra beats should be ignored. Note the rhythm and pulse rate. X. Leaving the cuff partially inflated for too long will fill the venous system and make the sounds difficult to hear. To avoid venous congestion, it is recommended that at least 1 minute should elapse between readings. XI. Blood pressure should be taken at least once in both arms and if an arm has a consistently higher pressure, that arm should be clearly noted and subsequently used for blood pressure measurement and interpretation. NOTE: Some steps may not apply when using automated devices. * For a definition of Korotkoff sounds and description of phases, refer to Appendix B Glossary of Clinical Terms. Figure 1: Proper positioning of cuff for blood pressure assessment Reproduced with permission. Canadian Hypertension Education Program Process, 2005. Nursing Best Practice Guideline Diagnosis In order to understand the process of diagnosing hypertension, the nurse needs to be aware of the following key definitions. Important Blood Pressure Definitions: Blood Pressure: measure of the pressure or force of the blood against the walls of the blood vessels. The pressure is measured in millimeters of mercury (mmHg) (HSFOa, 2005). Blood pressure is the product of the amount of blood pumped by the heart each minute (cardiac output) and the degree of dilation or constriction of the arterioles (systemic vascular resistance). It is a complex variable involving mechanisms that influence cardiac output, systemic vascular resistance, and blood volume (Woods et al., 2005). Hypertension or High Blood Pressure: medical condition in which blood pressure is consistently above the normal range (HSFOa, 2005). Hypertensive Emergency: may present as an asymptomatic elevation in blood pressure with a diastolic reading >130, or a systolic reading of >200 (CHEP, 2004). For details related to hypertensive emergencies, refer to Appendix G. Isolated Systolic Hypertension: As adults age, systolic blood pressure tends to rise, and diastolic tends to fall. When the systolic is ≥140, and the diastolic is <90, the individual is classified as having isolated systolic hypertension (Pickering et al., 2005). Primary, Idiopathic or Essential Hypertension: persistent and pathological high blood pressure for which no specific cause can be found (HSFOa, 2005). Secondary Hypertension: hypertension that is caused by another disease. About 5 to 10% of cases of high blood pressure are caused by medical problems such as heart or kidney disease, or as a side effect of medication (HSFOa, 2005). Target Organ Damage: subclinical vascular lesions and/or functional deterioration of the major target organs (e.g., brain, eye fundus, heart, conduit arteries and kidneys) (Birkenhager & deLeeuw, 1992; Cuspidi et al., 2000). White Coat Hypertension: term used to denote individuals who have blood pressures that are higher than normal in the medical environment, but whose blood pressures are normal when they are going about their daily activities (Verdecchis, Staessen, White, Imai & O’Brien, 2002). The diagnosis of white coat hypertension can be determined through the use of ambulatory and/or self-home monitoring of blood pressure. The risk of future cardiovascular disease events is less in individuals with white coat hypertension than in those with higher than normal ambulatory blood pressures (Verdecchis et al, 2002). Nursing Management of Hypertension 32 33 Recommendation 1.3 Nurses will be knowledgeable regarding the process involved in the diagnosis of hypertension. Level of Evidence = IV Discussion of Evidence Although nurses are not directly responsible for establishing a diagnosis of hypertension, they require knowledge of the process in order to participate in, expedite and support the client through the diagnosis phase. Previous Canadian recommendations outlined a process to diagnose hypertension that included up to 6 office visits over a 6-month period of time. The 2005 Canadian Hypertension Guidelines (CHEP, 2005) place new emphasis on expediting the diagnosis of hypertension. This is in response to recent studies that indicated the benefits of early recognition and early treatment of hypertension in terms of reducing hypertension related complications. Based on the CHEP 2005 recommendations, a diagnosis of hypertension can now be made in one, two or three visits based on the algorithm found in Figure 2. In summary, these recommendations state that: ■ For clients with hypertensive urgencies/emergencies a diagnosis of hypertension can be made at an initial visit where hypertension is comprehensively assessed. ■ For clients with one of the following: a) target organ damage b) chronic kidney disease c) diabetes mellitus or d) BP ≥180/110 a diagnosis of hypertension can be made on the second visit made to assess blood pressure. ■ For clients with BP ≥160-179/100-109 (and not already diagnosed based on the criteria outlined above), a diagnosis can be made at the third visit. In this diagnostic algorithm, preliminary visits where elevated blood pressures are noted (but in the absence of any specific assessment for the causes of hypertension or for hypertensive complications) would not be considered as an “initial” hypertension-related visit. Although office/clinic-based measurement has remained the “gold standard” for the diagnosis of hypertension, the most recent evidence suggests that, when properly assessed, self/home (refer to Figure 3) and ambulatory blood pressure monitoring (ABPM – refer to Figure 4) are as, or more effective in facilitating a diagnosis of hypertension (CHEP, 2005). As a result, the 2005 CHEP recommendations now encourage practitioners to use any or all of the three validated monitoring technologies, office/clinic-based measurement, self/home and ambulatory blood pressure monitoring (alone or in combination), to make a diagnosis of hypertension. Nursing Best Practice Guideline Nursing Management of Hypertension 34 Figure 2: The expedited assessment and diagnosis of patient with hypertension: Focus on validated technologies for blood pressure assessment Reproduced with permission. Canadian Hypertension Education Program Process, 2005. Elevated Out of the office BP measurement Clinic BPM Hypertension Visit 3 >160 SBP or Diagnosis of HTN >100 DBP <160/100 ABPM or S/H BPM if available Hypertension Visit 4-5 >140 SBP or Diagnosis of HTN >90 DBP <140/90 Continue to follow-up Elevated Random Office BP measurement Yes No Hypertensive Urgency/Emergency Diagnosis of HTN Hypertensive Visit 1 BP Measurement, History and Physical Examination Diagnostic tests ordering at visit 1 or 2 Target organ damage or Diabetes or Chronic Kidney Disease or BP >180/110 BP: 140-179/90-109 APBM (if available) Awake BP < 135/85 or 24-hour < 130/80 Continue to follow-up Awake BP >135 SBP or >85 DBP or 24-hour >130 SBP or >80 DBP Diagnosis of HTN S/H BPM (if available) < 135/85 > 135/85 Continue to follow-up Diagnosis of HTN Hypertensive Visit 2 Within 1 month or or HTN: Hypertension BPM: Blood pressure monitoring ABPM: Ambulatory blood pressure monitoring S/H BPM: Self/home blood pressure monitoring 35 Recommendation 1.4 Nurses will educate clients about self/home blood pressure monitoring techniques and appropriate equipment to assist in potential diagnosis and the monitoring of hypertension. Level of Evidence = IV Discussion of Evidence Self/home blood pressure monitoring involves the client’s self-measurement of blood pressure. While this technology is now recognized as playing an important role in the diagnosis of hypertension it must be used by educated clients and requires the use of validated and properly calibrated equipment (CHEP, 2005). The cost of a monitor is approximately $80-$140 (HSFOb, 2005) and they can be purchased at pharmacies and medical supply stores. Clients should be advised to purchase devices that are appropriate for the individual (e.g., correct cuff size) and have been tested for accuracy using a recognized validation protocol. Figure 3 provides details regarding points to consider when purchasing and using a self/home blood pressure monitor. Refer to Appendix B – Glossary of Clinical Terms, for details regarding validation protocols. Community-based Self Monitoring Devices Community-based self monitoring devices are available in many public locations, including grocery chains and pharmacies. Clients may ask nurses and other health professionals if these