Measure well
The second factor to consider is that a correct technique should be used to take blood pressure readings in the doctor’s office or clinic so as not to produce inaccurate results that could lead to underdiagnosis, overdiagnosis, or a poor assessment of the patient’s response to prescribed treatments. An observational study performed in Uruguay in 2017 showed that only 5% of 302 blood pressure measurements followed appropriate procedures.
A new fact sheet from the PAHO lists the following eight requirements for obtaining an accurate reading: don’t have a conversation, support the arm at heart level, put the cuff on a bare arm, use the correct cuff size, support the feet, keep the legs uncrossed, ensure the patient has an empty bladder, and support the back.
Though most guidelines recommend taking three readings, the “pragmatic” focus proposed in the international consensus accepts at least two readings separated by a minimum of 30 seconds. The two readings should then be averaged out. There is evidence that simplified protocols can be used, at least for population screening.
The authors of the new document also recommend preparing the patient before taking the measurement. The patient should be asked not to smoke, exercise, or consume alcohol or caffeine for at least 30 minutes beforehand. He or she should rest for a period of 3-5 minutes without speaking or being spoken to before the measurement is taken.
Lastly, clinically validated automated measurement devices should be used, as called for by the PAHO HEARTS initiative in the Americas. “The sphygmomanometer or classic aneroid tensiometer for the auscultatory method, which is still used way too often at doctor’s office visits in the region, has many weaknesses – not only the device itself but also the way it’s used (human error). This produces a rounded, approximate reading,” stressed Dr. Zilberman.
Automated devices also minimize interactions with the patient by reducing distractions during the preparation and measurement phases and freeing up time for the health care professional. “To [check for a] fever, we use the appropriate thermometer in the appropriate location. We should do the same for blood pressure,” she added.
The STRIDE-BP database, which is affiliated with the European Society of Hypertension, the International Society of Hypertension, and the World Hypertension League, contains an updated list of validated devices for measuring blood pressure.
The signers of the consensus likewise recognized that, beyond taking blood pressure measurements during office visits, the best measurements are those taken at home outside the context of medical care (doctor’s office or clinic) and that the same recommendations are directly applicable. “Few diseases can be detected so easily as with a simple at-home assessment performed by the individual himself or herself. If after three consecutive measurements, readings above 140/90 mm Hg are obtained, the individual should see the doctor to set up a comprehensive treatment program,” said Pablo Rodríguez, MD, secretary of the Argentinian Society of Hypertension. From now through September 14 (Day for Patients With Hypertension), the society is conducting a campaign to take blood pressure measurements at different locations across the country.
Dr. Zilberman and Dr. López-Jiménez disclosed no relevant financial relationships.