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Variations in blood pressure monitoring in primary care

Janet Gear
RGN CHCN
Practice Nurse
Southlea Surgery
Aldershot
Hampshire
Practice Nurse Trainer
Blackwater Valley and Hart PCT
E:janet@the-gears.freeserve.co.uk

Since the introduction of the "GP Contract",(3) the role of the practice nurse within the primary healthcare team has expanded to include various opportunities for screening, health promotion and involvement in chronic disease management.(4) This places practice nurses in a prominent position to improve the rate of detection of hypertension, monitor those on treatment, and offer relevant lifestyle advice. 
A study carried out to explore the views of patients with established heart disease on a structured programme of follow-up care provided by practice nurses identified the importance of easy access to a health professional who possessed knowledge and technical expertise along with the necessary social and emotional skills to offer support and motivation.(5) However, the study concluded that in order to develop high-quality practice nurse-led services, standards of training, continuity of follow-up care, integration of primary and secondary care, and development of the practice nurse's status within the primary healthcare team need to be taken into consideration. 
The launch of the National Service Framework for Coronary Heart Disease has provided the impetus for ensuring access to training, improving links between secondary and primary care, and implementing evidence-based guidelines within the primary healthcare team.(1)
The author is a practice nurse in a busy practice where the primary healthcare team includes eight GPs, seven practice nurses, two district nurses, one community staff nurse and four health visitors. The patient population of almost 14,000 covers a wide spectrum of health and social needs, with pockets of severe deprivation alongside the upper middle class. This is relevant as it is known that working men in the lowest social class are 50% more likely to die from coronary heart disease than men in the population as a whole.(1) Despite a relatively low elderly population (4.3%), a computer search identified 1,546 patients (11%) with a diagnosis of angina, myocardial infarction or hypertension. This represents a significant number of patients with identified risk factors who undergo regular blood pressure (BP) monitoring, as well as those who have their BP recorded in relation to primary prevention and opportunistic screening. 
Acknowledging that BP could be recorded by any member of the primary healthcare team, using a variety of equipment, raised questions about the accuracy and standardisation of technique. The importance of accurately measuring BP cannot be overemphasised - it not only confirms a diagnosis and ascertains whether treatment is required, but also ensures continuity of follow-up care and the ability to achieve optimum control.(6) 
The "Joint British Recommendations on Prevention of Coronary Heart Disease" are based on the best current scientific evidence and valued judgments of specialists in the fields of hyperlipidaemia, hypertension, cardiac care and diabetes (Table 1).(7) The evidence within these recommendations was used to underpin the assessment of knowledge, skills and equipment used in the practice, and to support any changes suggested to enhance the level of accuracy and continuity of care in BP monitoring.

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With the proposed phasing out of BP measurement devices containing mercury,(8) there is an increasing number of alternative devices on the market. However, many of these have not been independently evaluated for accuracy,(9) and mercury devices remain the gold standard provided they are well maintained and regularly serviced. 
In order to link theory to practice, a multiprofessional skills update was planned and facilitated. A questionnaire completed before the session identified some variations in relation to the current guidelines:

  • 80% used only a mercury sphygmomanometer, 20% also used an aneroid, and a further 20% also used digital wrist monitors.
  • The right arm was generally used by 30%, with 50% using the left, and 20% using either arm.
  • Most respondents occasionally recorded both a sitting and standing reading, but only 20% mentioned the importance of both in elderly patients and patients with diabetes.
  • 80% agreed that small and large cuffs were used, but in practice these were not readily available.

The questionnaire demonstrated some gaps in knowledge and evidence-based skills and the potential for improving patient care through sharing updated knowledge and skills.
The skills session was attended by five GPs, three practice nurses and two health visitors. Most participants agreed that they followed the guidelines for recommended techniques. However, time was spent discussing not only the relevance, but also the practical ease of always using the right arm for measuring BP. The optimal targets were identified in the practice protocol, but there was no standardisation of the equipment used. The aneroid monitors were generally used by district nurses as they are more easily transported. This is acceptable provided these monitors are calibrated at least every six months. The team agreed to use mercury sphygmomanometers as currently recommended by the British Hypertension Society. These are serviced annually, and standard and large-sized cuffs were to be made available in all consulting rooms.
The team considered the use and acceptability of home BP monitoring and the incidence of "white-coat hypertension" in primary care. One study identified that white-coat hypertension affects 10-20% of hypertensives and often does not require drug treatment.(10) The team discussed equipment, costs, training needs and levels of patient compliance, and agreed to investigate some form of ambulatory monitoring in the future.
Evaluation of the skills session by attendees suggested that it was a worthwhile exercise. Positive comments supported the need for a consistent approach to BP monitoring and highlighted the benefits of multidisciplinary learning. Relating the session to team-building in primary care,(11) some benefits were highlighted - such as improved communication, learning from each other and a consistent approach to patient care. However, some of the barriers to effective teamwork were also apparent - such as the shortage of time and increased workload, which prevented some colleagues attending the session.
Within a large primary healthcare team with a variety of monitoring equipment available, basic inaccuracies of BP recordings are possible. Reflecting on the scope and diversity of the practice nurse role identified that patients benefit from direct access to a health professional for screening, monitoring and health education. Provided practice nurses have the essential communication skills and access to the relevant training and education, they can improve the rate of diagnosis of hypertension and the level of optimum control. The multiprofessional skills session not only achieved the objective of cascading the latest evidence- based guidelines, but was also key to improving the level of accurate BP monitoring by creating a forum for team discussion. This resulted in a consensus approach to the theory and practice of BP recording, and an agreement to use the mercury sphygmomanometer until it is phased out and validation studies support alternative monitoring equipment.
Although it is difficult to quantify the accuracy of BP monitoring within the primary healthcare team, it is reassuring to know that colleagues are keen to update their knowledge and skills, to openly discuss their views, and to deliver patient care according to the latest evidence.

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References

  1. Department of Health. National Service Framework for Coronary Heart Disease. London: Department of Health; 2000.
  2. NHS Centre for Reviews and Dissemination. Effectiveness Matters. Drug Treatment of Essential Hypertension in Older People. London: NHS Centre for Reviews and Dissemination; 1999.
  3. Department of Health. General Practice in the National Health Service. The 1990 Contract. London: HMSO; 1990.
  4. Centre for Innovation in Primary Care. What do practice nurses do? A study of roles, responsibilities and patterns of work. Sheffield: CIPC; 2000.
  5. Wiles R. Empowering practice nurses in the follow-up of patients with established heart disease: lessons from patient's experiences. J Adv Nurs 1997;26:729-35.
  6. Curzio J. Hypertension. In: Lindsay GM, Gaw A, editors. Coronary Heart Disease Prevention. A Handbook for the Health Care Team. London: Churchill Livingstone; 1999. p. 59-79.
  7. Joint British Recommendations on Prevention of Coronary Heart Disease in Clinical Practice. Heart 1998;80 Suppl 2.
  8. Thomson J. Changes in equipment for blood pressure measurement. Professional Nurse 2002;17:350-3.
  9. O'Brien E, et al. Blood pressure measuring devices: recommendations of the European Society of Hypertension. BMJ 2001;322:531-6.
  10. Aylett M, et al. Home blood pressure monitoring: its effect on the management of hypertension in general practice. Br J Gen Pract 1999;49:466, 725-8.
  11. Gillow J. Team building in primary care. In: Gastrell P, Edwards J, editors. Community Health Care Nursing: Frameworks for Practice. London: Ballière Tindall; 1996. p. 207-16.

Resources
British Hypertension Society Information Service
Blood Pressure Unit
Department of Medicine
St George's Medical School
London SW17 0RE
W:www.hyp.ac.uk
British Heart Foundation
Heart Save Project
University of Oxford
Institute of Health Sciences
Old Road
Headington
Oxford OX3 7LF
T:01865 226975
E:info@heartsave.org.uk