Obtaining reliable blood pressure measurements relies on following several rules and understanding the many factors that influence blood pressure reading.
- Don’t drink coffee or smoke cigarettes 30 minutes before having your blood pressure measured.
- The patient should not be on any adrenergic stimulants, such as those found in many cold medications
- Before the test, sit for five minutes with back supported and your feet flat on the ground.
- To take a blood pressure reading, you need to be relaxed and comfortably seated, with your arm well supported. Alternatively, you can lie on an examination couch.
- Rest your arm on a table at the level of your heart. Wear short sleeves so your arm is exposed.
- Evacuate your bladder prior to the reading. A full bladder can change your blood pressure reading.
- The cuff should be at the level of the heart and the cuff should be deflated at a rate of 2 to 3 mmHg/s.
- Get two readings, taken at least two minutes apart, and average the results. Cuff size is also important.
- The bladder should encircle and cover two-thirds of the length of the arm.
- When taking manual measurements, the person taking the measurement should be careful to inflate the cuff suitably above anticipated systolic pressure.
- Stethoscope should be placed lightly over the brachial artery.
- Two measurements should be made at least 5 minutes apart, and, if there is a discrepancy of more than 5 mmHg, a third reading should be done.
- The readings should then be averaged.
- An initial measurement should include both arms.
- In elderly patients who particularly when treated may show orthostatic hypotension, measuring lying sitting and standing BP may be useful.
- The BP should at some time have been measured in each arm, and the higher pressure arm preferred for subsequent measurements.