Blood Pressure Monitoring Methods Inconsistent

Blood pressure monitoring errors leave room for improvement

(RxWiki News) Having accurate blood pressure readings is critical. Inaccurate measurements could lead to misdiagnosis or unneeded treatment.

Though monitoring is key, a recent study found that when routine blood pressure monitoring in clinics is compared with measurements based on the latest American Heart Association guidelines, the majority of readings may be inaccurate.

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Gretchen Ray, a researcher from the University of New Mexico College of Pharmacy, concluded that measurements may lead to misclassified patients because some health care providers follow official recommendations instead of the American Heart Association's updated recommendation for taking blood pressure made in 2005.

The updated guidelines were made to ensure consistency. Many factors can affect blood pressure readings including body or arm position, cuff size and cuff placement.

During the study researchers compared the blood pressure readings of 40 patients using the traditional method utilized routinely in clinics, as well as the American Heart Association's recommended method.

They took the two blood pressure readings (one by each method) and asked three physicians to provide hypothetical treatment recommendations based on the readings, medical history, medications taken, drug allergies, vital signs, presence of any pain, physical exam and lab findings.

The blood pressure readings were found to vary greatly between the two methods, and in 93 percent of patients there was a difference between the two readings of either at least 5 mmHg systolic, the top number in the reading, or more than 2 mmHg diastolic.

Researchers suggested the discrepancies could lead to cardiovascular complications.

During the actual blood pressure measuring, investigators observed multiple technical errors that could result in the differences between the pairs of readings. The American Heart Association defines 10 guidelines, and researchers discovered that the average number of errors per patient based on the traditional blood pressure assessment was four.

The most common error was forgoing measurements on both arms. The reason was likely time, since the average time for the recommended method takes about 8 minutes as it includes a 5-minute resting period between arm measurements. The traditional method takes about two minutes.

The three doctors who made treatment recommendations indicated that 45 percent of patients would have received different treatments based on the two blood pressure readings.

"Inaccurate blood pressure assessment is common and may impact hypertension treatment," Ray said. "Clinic staff need to be educated on the AHA recommendations for accurate blood pressure measurement, and encouraged to follow them in order to obtain a more accurate reading.

More accurate blood pressure measurement could result in improved hypertension management decisions."

The study was recently published in Journal of General Internal Medicine.

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Review Date: 
December 14, 2011