NICE clinical guideline 127 states that ABPM monitoring is the most accurate method for confirming a diagnosis of hypertension, and its use should reduce unnecessary treatment in people who do not have true hypertension. Originally published in 2013 it was updated in September 2015.
In a recent review with our technical support team I asked them what were the practical questions they were most frequently asked about the guideline and ABPM in general.
I thought I would share the results on our Blog as they may be of interest to other ABPM customers. In no particular order this is what they told me.
How many and how often should measurements be taken? NICE recommend a minimum of 14 readings, at least two measurements per hour, taken during the person’s usual waking hours. The average value of these 14 measurements should be used to confirm a diagnosis of hypertension.
What about night time readings? Although not specifically mentioned in the guidelines it is useful to record night time ABPM readings as well every 60 minutes, especially in patients with suspected nocturnal hypertension or unusual variability of blood pressure. Consideration should be given to shift and night workers whose ‘normal waking hours’ will differ.
How do I know if an ABPM recording has been successful and how easy is it to interpret the results? The PMS (Instruments) CardioVisions software used with Meditech ABPMs makes this easy using a unique textual analysis of key BP data recorded over 24 hours. Put simply it does the work for you, ensuring reliable, repeatable interpretation that isn’t user dependent. A sample is shown below.
The ABPM was worn by the patient for 24 hours. During this period the average daytime blood pressure was 138/93 and the pulse rate was 88 beats per minute. According to NICE guidelines the patient exhibits stage 1 hypertension. The examination was divided into day 06:00-22:00, night 22:00-06:00. 62 successful readings were taken during the daytime period and the NICE key quality requirement for 14 has been met. During the daytime there were 60 readings (96.8%) above the NICE guideline figure of 135/85. The highest reading was 179/118 recorded at 12:30 09/07/2016. During the night time period 16 successful readings were taken and the average blood pressure was 127/83.
Can I use a Meditech ABPM monitor on a patient with Atrial Fibrillation (AF)? Though the blood pressure measurement algorithm used in the Meditech ABPM monitors has been found to function properly on patients with atrial fibrillation or other common arrhythmias, the oscillometric blood pressure measurement method is generally recommended for use only with special caution in patients with arrhythmias. There can be large beat to beat variations when heart rhythm is irregular.
What cuff sizes do I need? Choose cuff sizes that will fit an arm correctly. Typically an adult (25-32cm) and large adult (32-42cm) cover most of the adult population but smaller (18-24cm) and extra-large (42-55cm) cuffs are available. Using the correct cuff size is crucial. Too small a cuff will overestimate blood pressure too large a cuff will underestimate. All Meditech cuffs have size range indicators.
Should patients keep a diary? It can be useful if the ABPM is being worn overnight to record what time they went to bed, woke up and whether they pushed the manual event button.
Should patients take the day off work? Normal daily activity should be maintained during the ABPM session. Patients should avoid vigorous exercise. If possible avoid driving during the 24 hour session. If not possible temporarily suspend the monitor whilst driving.
How often do cuff need to be cleaned? Be aware of infection control issues associated with devices that are in use. Ensure that local infection control requirements are met. Meditech cuff outers can be cleaned and wiped with Clinell general purpose disinfectant wipes.
