The Royal Marsden Hospital Manual of Clinical Nursing Procedures - Lisa Dougherty [470]
The stethoscope
It is recommended that the stethoscope be of high quality with wellfitting earpieces (O’Brien et al. 2003). It should be placed over the brachial artery at the antecubital fossa (O’Brien et al. 2003). The bell part of the stethoscope may capture the low pitch of the Korotkoff sounds better than the diaphragm but the diaphragm has a larger surface area and is easier to manipulate with one hand (O’Brien et al. 2003).
Specific patient preparations
It is important to maintain a standardized environment in which to take the patient’s blood pressure (NICE 2006). The patient should be seated (unless thigh or orthostatic blood pressure measurements are required) in a relaxed, quiet, temperate setting (NICE 2006). Their arm should be outstretched and supported, as in unsupported arms diastolic blood pressure may be increased by 10% (O’Brien et al. 2003). The brachial artery at the antecubital fossa should be positioned equal to heart level, approximately equal to where the fourth intercostals space meets the sternum (Bickley and Szilagyi 2009).
The patient’s back should be supported (Turner et al. 2008) and their feet should be on the floor as systolic blood pressure can increase by an average of 6.6 mmHg in people with their legs crossed (van Groningen et al. 2008). Blood pressure should be taken after a short period of rest, as slight hypertension on standing and moving is initiated by the baroreceptor reflex (Turner et al. 2008). Correct patient positioning can be seen in Figure 12.12.
Figure 12.12 Correct blood pressure reading techniques.
Blood pressure should initially be measured in both arms as often people have a significant difference in blood pressure measurement between their arms (NICE 2006). Those patients who have a large and persistent disparity may have underlying conditions such as occlusive artery disease (Eguchi et al. 2007, O’Brien et al. 2003). Differences up to 10 mmHg can be due to random variation (Eguchi et al. 2007). The arm with the highest reading should be the one used for subsequent measurements (NICE 2006).
Procedure guideline 12.3 Blood pressure measurement (manual)
Essential equipment
A range of cuffs
Sphygmomanometer, working and calibrated
Stethoscope
Chair with arm rest
Documentation
Alcohol handrub
Detergent wipes
Optional equipment
Pillow if required to provide extra arm support
If necessary a bed or examination bench, so the patient can have their blood pressure measured lying down
Preprocedure
Action Rationale
1 Explain to the patient that you need to measure their blood pressure and discuss the procedure. To ensure that the patient understands the procedure and gives their valid consent (NMC 2008b, C).
2 Wash hands using bactericidal soap and water or bactericidal alcohol handrub, and dry. To minimize the risk of infection (Fraise and Bradley 2009, E)
3 Ask the patient if they have any of the following conditions: lymphoedema or are at risk
an arteriovenous fistula
trauma to their arm
brachial artery surgery.
To ensure there are no contraindications to using a particular arm (Bickley and Szilagyi 2009, E; Curran 2009, E; Turner et al. 2008, E).
4 Provide a standardized environment which should be relaxed and temperate. The patient needs to be seated comfortably, in a chair with back support, for at least 5 min prior to measuring blood pressure (Bickley and Szilagyi 2009, O’Brien et al. 2003, Turner et al. 2008). To enable comparisons to be drawn with prior blood pressure results (NICE 2006, C).
Variations in temperature and emotions can alter blood pressure readings (O’Brien et al. 2003, E).
5 Ensure the manometer is no more than 1 metre away, vertical and at eye level (O’Brien et al. 2003). If using a mercury manometer, the meniscus should