This site is intended for health professionals only

Hypertension and the role of the practice nurse

People with hypertension risk developing heart disease, kidney failure, diabetes and strokes, but with some lifestyle modifications the condition is treatable and reversible. Helen Lewis argues that practice nurses are ideally placed to empower patients to make these changes

Helen Lewis
RN BSc(Hons)
BMid(Hons)
Practice Nurse
Brynderwen Surgery
St Mellons
Cardiff

The primary care nurse's role continues to evolve with the focus of patient care moving from secondary care. Increasingly, nurses are taking the lead in chronic disease management such as diabetes, respiratory conditions and of course hypertension. However, to do this safely nurses must have the necessary knowledge and skills in accordance with the NMC Code of Conduct, not only to protect the nurse but also the patient.(1) It is vital to the success of nurse-led clinics that an agreed set of guidelines is developed and an agreed framework is maintained and reviewed on a regular basis between GPs and nurses.
Hypertension is estimated to cause 4.5% of current global disease burden and is as prevalent in many developing countries as in the developed world. Blood pressure-induced cardiovascular risk rises continuously across the whole blood pressure range. Countries vary widely in capacity for management of hypertension, but worldwide the majority of diagnosed hypertensives are inadequately controlled. However, sound knowledge and management from healthcare professionals along with good compliance from the patient can prevent the onset of these diseases and reduce morbidity and mortality.
Hypertension has long been considered the "silent killer" as patients are often present asymptomatic. Recent research has suggested that one billion people will be affected by high blood pressure by 2027.(2) A study in The Lancet medical journal has estimated that 972 million people had high blood pressure in 2000.(3) Therefore in order to manage and treat hypertension with confidence it is essential that practice nurses have a good understanding of what constitutes normal blood pressure and what causes hypertension.
The cardiovascular system is responsible for circulating blood around the body, and consists of the blood, heart and blood vessels. Blood is composed of the liquid matrix plasma, which dissolves and suspends various cells and cell fragments. It is responsible for transporting oxygen from the lungs and nutrients from the gastrointestinal tract to the body's cells. The nutrients and oxygen diffuse from the blood into interstitial fluid and from there into the body's cells. Carbon dioxide and other waste products dissolve into the blood from the cells and are excreted out of the body via the kidneys and lungs.(4)
Marieb defined blood pressure as the force exerted by the blood against the walls of the vessels in which it is contained.(5) The differences in blood pressure between different areas of the circulation provide the driving force for the blood around the body.
The National Institute for Health and Clinical Excellence provides guidance on hypertension and suggests that in order to identify hypertension (persistent blood pressure above 140/90 mmHg in nondiabetic patients) the patient should be asked to return on at least two separate occasions, so the blood pressure can be measured from two readings under the best possible conditions. In addition, automated ambulatory blood pressure machines are not recommended as their use has not be effectively established.(6)
Hypertension can be identified under the following five headings.

Primary hypertension
Primary hypertension accounts for 95% of hypertensive patients. It is identified as a persistently elevated blood pressure with no attributed or identifiable cause. However, it may be multifactorial in nature corresponding to age, ethnicity, weight, diabetes, diet, alcohol and stress.

Secondary hypertension
A small percentage (5-10%) of patients have secondary hypertension, where the increase in blood pressure is linked to a recognised underlying disease, such as:

  • Pregnancy, which can cause preeclampsia.
  • Oral contraceptive pill.
  • Nonsteroidal antiinflammatory drugs (NSAIDs).
  • Renal artery stenosis.
  • Polycystic kidney disease.
  • Primary aldosteronism.
  • Coarctation of aorta.
  • Phaeochromocytoma.
  • Cushing's syndrome.
  • Thyroid disease.
  • Glomerular disease.
  • Diabetic nephropathy.
  • Chronic pyelonephritis.

Isolated systolic hypertension
This type of hypertension can be divided into grade 1 and grade 2. Grade 1 is when the systolic blood pressure (SBP) is 140-159 mmHg and the diastolic blood pressure (DBP) is 160 mmHg and the DBP

Pseudosystolic
This type of hypertension involves an SBP >140 mmHg, with a DBP

White coat hypertension
Patients with white coat hypertension do not show a generalised increase in blood pressure lability, nor an exaggerated pressor response while at work. The phenomenon is more pronounced when blood pressure is measured by a physician than by a technician. In such patients, the pressor response may be relatively specific to the physician's office and lead to significant misclassification of hypertension.(9)

Defining hypertension
Hypertension is difficult to define as there are a number of parameters to consider, as Box 1 shows. However, the World Health Organization (WHO) suggests an SBP of 140 mmHg or greater and DBP of 90 mmHg or greater on two or more separate blood pressure readings in individuals not taking antihypertensive medication is the standard by which healthcare professionals should work towards.(9)

[[nip44_box1_33]]
 
Due to the implications of hypertension for patients with diabetes, WHO recommends that hypertensive therapy should be commenced if the SBP is sustained above 140 mmHg and the DBP above 90 mmHg. The same is not true for nondiabetic patients where antihypertensive drugs are recommended only when the SBP rises above 160 mmHg and the DBP increases above 100 mmHg.(10) 
However, practice nurses should not be lulled into believing that all patients are the same and therefore a blanket approach to hypertension management can be adopted. The British Hypertension Society (BHS) acknowledges that achievement of the recommendations may be difficult to realise, especially if there is an underlying condition.(11)

Patient assessment
Communication skills are an important factor when obtaining a thorough history from a patient and have been identified as a "distinctive feature" of the nurse's role. Aminoff and Kjellgren found:(12)

  • Patients had longer conversations with nurses than doctors.
  • Nurses talked to patients about other vascular risk factors more frequently than doctors.
  • Doctor-patient consultations tended to be medication focused.
  • Patients raise more new topics with nurses than doctors.
  • It is vital that adequate time is given to complete an holistic assessment for hypertension. The Nurses' Hypertension Association suggests an initial appointment time of 30 minutes to assess cardiovascular assessment and give both dietary and lifestyle advice, while an annual review should be allotted 15-20 minutes.

Box 1 gives a breakdown of the initial assessment required for hypertension diagnosis in nondiabetic patients.

Lifestyle advice
The benefits of lifestyle changes to reduce hypertension is not always considered beneficial by either patients or some professionals. However, Table 1 shows that a simple adjustment to lifestyle can have a dramatic effect on a patient's SBP and DBP.

[[nip44_table1_34]]

Lifestyle advice should be included at every consultation; patients who are motivated and are given the correct support will be able to reduce their blood pressure by making some simple lifestyle changes.(13)

Diet
Simple dietary changes should be suggested, such as reducing total fat and saturated fat intake to 30% and 10% respectively of daily calorie intake. Transfatty acids should at best be eliminated or reduced significantly; polyunsaturated fats should make up 10% of calorie intake per day and monounsaturated fats 10-15% of calories per day.
Salt intake should be reduced by at least one-third, ideally to All patients should be encouraged to eat a minimum 400 g of a range of fresh fruit and vegetables a day, as well as wholegrains and pulses.
 
Exercise
Exercise has also been proven to reduce blood pressure and it is important for the practice nurse to assess frequency, time and intensity. The World Health Organization recommends a minimum of 30 minutes moderate exercise per day as a way of reducing a patient's risk of developing cardiovascular disease; the activity should cause the patient to feel warm and raise their pulse. A patient who is not familiar with physical activity could be encouraged to try short bursts of 10 minutes per day every day in order to build up their fitness - remember hypertension and its management is not a "one size fits all" approach.

Alcohol intake
Alcohol has a high sugar content and therefore can contribute to hypertension if taken in excess. The recommended allowance is below 21 units per week for men and 14 units per week for women. Routine questioning should form part of the consultation to assess the risk of cardiovascular disease.(15)

Conclusion
Primary care nurses owe it to themselves and their patients to be fully informed of the chronic diseases they manage to achieve maximum patient compliance and satisfaction. Hypertension is a reversible condition, not a disease. Well-informed, confident practitioners will be able to deliver evidence-based structured advice, and in doing so reduce morbidity and mortality rates from cerebrovascular accidents and cardiovascular disease for patients regardless of age, gender or ethnicity.

References

  1. Nursing and Midwifery Council. Code of conduct. London: NMC; 2007.
  2. MacMahon S, Peto R, Cutler J, et al. Blood pressure, stroke, and coronary heart disease. Part 1. Prolonged differences in blood pressure: prospective observational studies corrected for the regression dilution bias. Lancet 1990;335:765-74.
  3. World Health Report. Reducing Risks, promoting a healthy life. 2002.
  4. O'Brien E, Staessen JA. What is hypertension? Lancet 1999;353:1541-3.
  5. Marieb EM. Human anatomy and physiology. 4th ed. California: Benjamin Cummins; 1998.
  6. National Institute for Health and Clinical Excellence. Hypertension guidelines. London: NICE; 2006.
  7. Beevers G, Lip GYH, O'Brien E. ABC of hypertension. London: BMJ Publishing Group; 2001.
  8. McEniery CM, Wilkinson IB, Cockcroft JR. Systolic hypertension in young adults: spurious definition of a genuine condition. J Hypertens 2006;24:2316-7
  9. Whitworth JA, World Health Organization, International Society of Hypertension Writing Group. 2003 World Health Organization/International Society of Hypertension statement on management of hypertension. J Hypertens 2003;21:1983-92.
  10. WHO. 1999 WHO/ISH guidelines for the management of hypertension. J Hypertens 1999:17:151-83.
  11. Ramsay LE, Williams B, Johnston GD, et al. Guidelines for management of hypertension: report of the third working party of the British Hypertension Society. J Hum Hypertens 1999;13:569-92.
  12. Aminoff UB, Kjellgren Kl. The nurse - a resource in hypertension care. J Adv Nurs 2001;35:582-9.
  13. World Health Organization. Pocket guideline with WHO/ISH Cardiovascular Risk Prediction Charts for WHO epidemiological sub-regions EUR A, EUR B, EUR C. 2007. Available from: http://www.who.int
  14. He FJ, Markandu ND, MacGregor GA. Modest salt reduction lowers blood pressure in isolated systolic hypertension and combined hypertension. Hypertension 2005;46:66-70.
  15. Anderson P. Self administered questionnaire for diagnosis of alcohol abuse. In: Watson R. Diagnosis of alcohol abuse. Florida: CRC Press; 1989.