Orthostatic hypotension

Orthostatic hypotension (OH), a drop in BP on standing, is a contributing factor to falls (Ooi et al 2000, Lahrmann et al 2011). A change in position from lying to sitting, or from lying or sitting to standing causes a reduction in the volume of blood returning to the heart and blood to pool in the extremities. An inadequate physiological response to such postural changes can result in an abnormally large drop in BP, which is common in older people (Lowry et al 2016). This may be due to impaired homeostatic mechanisms; inadequate hydration, for example, because of anorexia, drowsiness, delirium and dementia; antihypertensive medication; or prolonged bedrest (Feldstein and Weder 2012). Acute causes of OH include dehydration or deconditioning, but chronic OH may be caused by neurodegenerative disorders such as Parkinson’s disease or autonomic failure. OH can cause people to feel dizzy, lightheaded and have blurred vision and blackouts, but some people with OH have few symptoms and cognitive impairment may affect their ability to report symptoms (Passant et al 1996, Arbogast et al 2009). OH in such patients who experience few symptoms may still contribute to the risk of falling.

Interventions to address OH in hospital include adjusting medication, treating dehydration or using compression stockings. Some cases of OH are difficult to treat especially in the context of congestive cardiac failure. However, all staff should know if a patient has OH as they may need to mitigate risk by encouraging the patient to stand in stages and with close supervision (Windsor et al 2016).

Assessment of OH is usually indicated for any patient presenting with a history of falls; unexplained syncope or pre-syncope; visual disturbances; dizziness; general weakness; fatigue; cognitive slowdown; leg buckling; and ‘coat-hanger’ ache, that is, in the shoulders and neck. These symptoms are more commonly found in older people. Additionally, the European Society of Cardiology lists six main classifications of OH, three of which – classical autonomic failure, progressive OH and progressive OH with reflex syncope – are more common in older age (Moya et al 2009).

There are many reasons why lying and standing BP is not measured in hospital inpatients, despite clinical guidance suggesting that it should be. Reasons for non-implementation of clinical guidance include (Grimshaw et al 2004):

Reasons for non-implementation of guidance on measurement of lying and standing BP may relate to: clarity of the guidance; uncertainties about roles and responsibilities; inadequate knowledge, skills or understanding to enable interpretation of findings; perceived importance of the test; or the availability of time or tools to undertake the observation in a clinical setting (Gagliardi et al 2011).

Aim

To promote the increased measurement of orthostatic BP and more consistency in how it is measured, thus improving routine clinical practice.

Methods

Results

Discussion

There was reasonable consistency in the literature on how to record lying and standing BP, the definition of a positive result and whether symptoms were required as well as a drop in BP. However, the literature was biased towards specialist clinical assessments of transient loss of consciousness or syncope with specialist equipment including tilt tables and omitted pragmatic advice for routine ward measurements.

A large number of health professionals caring for older people in hospitals were surveyed on how they recorded lying and standing BP. The findings identified that lying and standing BP measurement was a multidisciplinary task with a range of professionals involved.

Although there was some variance, responses concerning time supine and time to first and second measurements were in line with the guideline recommendations. The way the options were presented may have influenced these responses: allowing for a continuum of responses on times may have provided more nuanced information. Just over a third of respondents reported performing more than three measurements in total

Where there was no clear consensus, such as the number of measurements required or the interpretation of a positive result, this may have been because these aspects required an element of clinical decision-making specific to each patient, that is, if BP was still low after two standing measurements, further monitoring might be required until BP was normalised.

Clearer wording of the survey, so that categorical answers were based on routine testing and having a free-text section to describe any deviations from routine, may have resulted in greater consensus.

There were some outliers in measurement technique, for example, one respondent required a patient to lie supine for 30 minutes before measurement, one measured seven or more times and another measured systolic pressure using a cuff and palpating the brachial pulse. The first two examples increase the time required for the procedure and render testing more impractical. The latter method may be more practical where a patient requires support to stand and help from other staff is limited. However, this method does not record diastolic pressure.

The answers about the type of device used deviated from guidance recommendations. It is suggested that staff use a manual sphygmomanometer (O’Brien et al 2003) but in this survey the highest proportion of respondents did not use a manual device. There are good clinical reasons why a manual device is advised. Automated sphygmomanometers often fail to record BP on standing and often fail to record at all if an arrhythmia is present.

In cases of large drops in pressure, an automated device may not detect a low pressure resulting in an error message. However, in this survey, health professionals reported limited access to manual machines on the wards and a lack of clarity on the respective merits of manual or automatic sphygmomanometers.

Where possible, a manual machine should be used, but an automatic machine may suffice provided there is no evidence of arrhythmias and the user reverts to a manual sphygmomanometer if error messages occur.

There was no consensus on the importance of symptoms in determining a positive result with nearly half of respondents considering a drop in systolic BP of 20mmHg and symptoms as significant.

One of the arguments used to support the measurement of OH in hospital inpatients is that it is not always associated with symptoms, particularly in people with dementia or delirium (Passant et al 1996, Arbogast et al 2009). This was raised by respondents in free-text responses. Therefore, while symptoms are useful in supporting a diagnosis, it is important not to rule out a diagnosis based on lack of symptoms. Addressing this issue differently in the survey, for example, by separating a question about the numerical scale of the BP drop from the importance of symptoms, may have provided more useful information.

Important areas for improvements

Nurses have an important role in assessing patients at risk of falling and taking preventive measures. They need to have a clear understanding of the importance of underlying symptoms of OH and the significance of any drop in BP. Accurate recording and reporting of this observation is essential in nursing practice.

The health professionals invited to take part in the survey had an interest in falls and/or bone health. Although most respondents reported that they measured lying and standing BP in line with the guidance recommendations, a minority reported measuring it incorrectly. Most patients in the National Audit of Inpatient Falls (RCP 2015a) did not have a lying and standing BP measured, suggesting that practical implementation was lacking. Possible reasons for this may be because the ward-based clinical staff involved with the care of the patients audited were either not aware of the guidance or found its practical application challenging. Therefore, the objective of this work was to use the survey findings in conjunction with guidance to develop standardised, pragmatic advice on how to measure patients’ lying and standing BP on hospital wards.

The aim is to promote the increased measurement of orthostatic BP and more consistency in how it is measured, thus improving routine clinical practice.

The guide produced (Figure 1) provides clarity and may prevent unnecessary and time-consuming practice, that is, supine lying for 30 minutes, or potentially ineffective assessment, that is, automatic sphygmomanometer measurement in the presence of cardiac arrhythmias. It also provides a clear rationale that can be explained to clinical staff during training and enables good practice to be embedded. It could be used in the education of students, clinical staff, hospital and community teams who look after older people at risk of falls.

Figure 1

How to measure lying and standing blood pressure as part of a falls assessment

Implications for nursing practice

Recording, interpreting and acting on the assessment of vital signs including temperature, pulse, respiration, blood pressure and pulse oximetry are fundamental clinical nursing skills. The correct assessment of OH will not only support diagnosis and treatment, but also allow opportunities for the safe management of mobility and prevention of falls.

Conclusion

Guidance states that measuring lying and standing BP in older people in hospital is good clinical practice and part of a multidisciplinary falls risk assessment. Current guidelines and published articles do not always define OH or describe how to measure lying and standing BP, but are broadly consistent where they do. Despite this a snapshot audit of nearly 5,000 acute inpatients aged over 65 years found that only 16% had a lying and standing BP recorded by the third day of their admission (RCP 2015a). The survey of health professionals reported in this article showed the need for clarity and pragmatism in the measurement of lying and standing BP. A new guide developed in the light of the survey results might give clinical staff the confidence to know they are measuring a vital sign in a sensible way and to determine a clinically significant result. Whether this aim is achieved will be evaluated in this year’s national inpatient re-audit of falls prevention measures.