Presentation on theme: "Blood Pressure measurement"— Presentation transcript:
1 Blood Pressure measurement “The measurement of blood pressure is the clinical procedure of greatest importance that is performed in the sloppiest manner.”Kaplan N. M. Amer J Hypertension 1998: 11: 134-6Blood pressure is the single most important test that we do, if left untreated it causes strokes, heart attcaks and peripheral vascular disease.
2 The ‘silent killer’ Causes death from: Strokes Heart Attacks Peripheral Vascular DiseaseIf untreated, leads to:Renal failure, heart failure
3 Blood Pressure classification Category Systolic BP Diastolic BPOptimal < <80High normal BP < <85High normal BPGrade 1 (mild)Grade 2 (moderate)Grade 3 (severe) ≥ ≥110ISH (Grade 1) <90ISH (Grade 2) ≥ <90ISH = Isolated Systolic Hypertension
4 Thresholds for intervention BP ≥ 220/120 mmHg: treat immediatelyBP > /110/119 mmHg: confirm over 1-2 weeks, then treatBP / mmHg: with CVD complications: confirm over 3-4 weeks, then treatBP /90-99 mmHg: with CVD risk confirm over 12 weeks, then treat.
5 Blood pressure measurement sources of error Errors due to manometerErrors due to cuffErrors due to the observerErrors due to the patient.
6 Which machine?Every practice/ward should be using a validated manometerAll manometers should be recalibrated and serviced annuallyAneroid machines (not recommended) should be serviced more often as they deteriorate rapidlyUseful website:-
7 Talk about different devices currently available. Ref to BHS website for guidance re validated machines.
8 Manometers – electronic advantages You can effortlessly take several readingsMeanwhile you can check pt recordsSome ‘whitecoat’ effect can be detectedYou can rely on the readings of other health care professionals.(These advantages partly outweigh the disadvantage of the possible, slight inaccuracy of some devices).
9 Manometers – automatic disadvantages Inadequate choice of cuff sizesLarge cuffs are long enough but too deepNeed for the equivalent of the ‘alternative adult cuff’ only available with the mercury manometer.
10 BP measurement Three or more readings, separated by 1 minute Discard first reading and average last twoIf large difference take further readings.
11 BP measurement -cuffs Cuff too small or too big Normal cuff too small for 15% of patientsCuff not level with the heartLeaky rubber tubing or bladder*Faulty inflation/deflation device** Applies to mercury manometers only.Cuff too small BP over read. Cuff too big, BP over read. Last 2 bullet points apply to mercury manometers
12 Often too wide for ‘fat’ arms Cuff sizesTypeSizeSuitabilityAdult12cm by 23cmfor smaller armsAlternative cuff12cm by 36cmwill cover 95% armsLarge adult15cm by 36cmOften too wide for ‘fat’ armsIt is difficult to obtain an accurate BP in very overweight people as there are no appropriate cuffs available. To gain as accurate a BP as possible ensure that the centre of the bladder is over the brachial artery
13 Which arm?6% of hypertensives can have as much as a 10 mmHg difference between armsIf BP higher in one arm than the other, this arm must be used from then onDocument this in records so that everyone uses the same arm.All newly diagnosed hypertensives should have their BP measured in both arms, on one occasion only. !0% of patients will have a significant difference. The arm with the highest reading should be used from now on. This must be documented so that all health professionals use the same arm
14 Technique Patient seated and relaxed, not talking, legs uncrossed Tight arm clothing removedCorrect cuff sizeArm supported with cuff horizontal with heartInform patient of discomfort and that several measurements will be takenMercury manometer on firm and level surface at eye levelLocate brachial or radial pulse.
15 Technique – cont’d Place stethoscope gently over brachial artery Inflate mercury rapidly, 30 mmHg above occlusion of pulseDeflate very slowly, 2 mmHg per secondRecord first of regular sounds (systolic BP)Record diastolic as disappearance of soundRecord measurements to the nearest 2 mmHgRepeat twice more and average last two.Place stethoscope gently over brachial pulse so as not to occlude sounds, especially in the elderly who often have quite prominent arteries
16 BP measurement - observer Mercury column not level with the eyesFailure to hear the Korotkoff soundsWrong diastolic endpoint (K4 or K5)Subjective detection of Korotkoff soundsRapid cuff deflationSingle one off reading.Subjective detection of sounds means that everyone hears sounds in a different way.
17 Gardiner – Hospital Doctor - 1993 Stethoscope‘I have never managed to communicate to any patient, that there is really no point in trying to talk to me when I am using a stethoscope’.Gardiner – Hospital Doctor
18 Stethoscope Good quality Short tubing Well fitting ear pieces (cleaned regularly)Place gently over the brachial arteryAvoid touching the cuff and tubing.Short tubing gives a clearer sound as the sounds have less distance to travel it also gives a slight pull on ears which also gives a clearer sound
19 Posture Routine - seated Standing in patients with symptoms or diabetic (diabetic nephropathy) and the elderlySupine position unnecessary, inconvenient and cuff position often below the heart.Standing BP’s should be taken immediately on standing and 2 minutes after standing to evaluate spontaneous or drug induced postural falls in pressure. In most people, systolic blood pressure falls and diastolic pressure rises by a few mmHg on standing up. In older people significant drops of 20 mm Hg are more common. Diabetic nephropathy, a complication of diabetes, is when the kidney(s) become damaged and more protein than usual collects in the urine. As the disease progresses more of the kidney is destroyed. Over time the kidneys ability to function starts to decline which will lead to Chronic Renal Failure (CRF). Consequences are high protein levels in urine.
20 BP measurement - patient Anxiety and unfamiliarityAnimated discussion about the latest newsAmbient temperatureFull bladder!Postural hypotensionDifference between arms.
21 Patient Consent is taken as read when patient rolls up sleeve Explain the procedure, that it may be a little uncomfortable and that several readings will be takenSeated, relaxed, not speakingTight arm clothing removedArm supported (not hyper extended) with cuff level with the heart.Even when the arm is hyper extended blood pressure readings will be higher
22 Explanation to the patient Tell the patient their blood pressure readingWrite BP down – use co-operation cardsGive relevant leaflets/booklets on life style issues (not too many at a time)Reassure patient that this is a risk factor not a disease (unless left untreated)Do not lose to follow-up.
23 ‘White coat’ hypertension Effective method of diagnosing a rise in blood pressure associated with having blood pressure measuredMaybe from anxiety10-20% of subjects labelled ‘hypertensive’ may have ‘white coat’ effect.Whitecoat hypertension is not innocent and pts tend to get lost to follow up. These pts may well become truly hypertensive over time. LVH present in ‘white-coaters’ but not to the same level as hypertensives. Any sign of LVH is a warning for urgent action
25 ABPMCan be expensiveShould be comfortable for patient to wear (light and quiet)Use of correct cuff sizeNeed to be familiar with equipmentTime to instruct patient, full explanation to patient of what is requiredRequires patient co-operation in order to obtain as many readings as possible.
26 ABPM cont ….Normal activity to be maintained, except when measurements are being madeSubject’s arm to be still during measurementSubject’s usual activities to be carried outWorking days not compared to recreational daysFor clinical use recordings are usually programmed for every 30 minutes during the day and hourly at nightSubject required to keep a diary of activities and symptoms.Night time dippers = good prognosis, those that do not dip bad news. Black patients often do not dip.
27 Home monitoring Gives patients empowerment May improve medication concordanceDevice used must be validatedMultiple day time recordings, over 7 days (eliminating ‘white coat’ effect) with BP taken in the morning and eveningFirst 24 hour readings should be discardedHome measurements usually lower than clinic readings.Very little evidence, to date, that home monitoring predicts cardiovascular risk or outcomes more effectively than clinic readings. Wrist devices not recommended.