Small variations in blood pressure measurements between the arms are usually not cause for alarm. However, a deviation of more than 10 mm Hg should be cause for concern.
A 2022 research published in the Annals of Surgery and Medicine proposed a notion that the dominant arm's higher blood pressure results from its greater frequency of activity. Thus, if you're right-handed, you should anticipate that the blood pressure in your right arm would be somewhat greater. (Corliss, 2014)
In that study, blood pressure readings from 2,030 healthy individuals aged 15 to 40 were examined. It was discovered that 26% of the participants had a systolic blood pressure difference of a minimum of 10 mmHg between arms, and nearly 31% had a diastolic blood pressure difference of least 10 mmHg between arms.
Individuals with a history of systolic blood pressure differences across arms of 10 to 15 mm Hg are at an increased risk of developing vascular disease. (Fred, 2013)
REASONS OF DEVIATION
- The American Heart Association (AHA) also emphasises the significance of having appropriately educated observers, placing the patient correctly, using the right cuff size.
- Taking a break and not consuming any coffee or smoke just before taking the patient's blood pressure.
- Although oscillometric (automatic) devices are less precise than auscultory (manual) equipment, they are nevertheless suitable for clinical usage, with the possible exception of patients with arrhythmias, trauma patients, and hypertensive patients.(Kulkarni et al., 2011)
- Variations and biases among observers, malfunctioning equipment, or a failure to standardise measuring methodologies are common causes of mistakes in blood pressure monitoring.
- A physical examination is made more intimate by gripping the patient's arm while the measuring instrument is being applied. This also shows warmth, sensitivity, sympathy, and empathy.(Hong et al., 2011)
CAUSES OF BP FLUCTUATIONS
The majority of the time, artery thickening and constriction which can result in reduced blood flow in a single arm can create blood pressure differences between the arms.
The Aortic coarctation (CoA)
This condition raises arterial pressure on the left ventricular by making the heart work longer to pump blood via the constricted aorta. (Corliss, 2014)
Because prolonged high blood glucose might harm blood vessels, poorly managed glucose levels has been related to differences in blood pressure across arms.
Cardiac Peripheral Ultrasound (PAD)
A large blood pressure differential between the arms may be a sign of peripheral artery disease (PAD), a condition where blood clots in the arteries supplying the arms (upper-extremity PAD) and legs. (Fred, 2013)
HOW MUCH OF A CHANGE IS ENOUGH TO RAISE AN ALARM?
According to the review paper from 2021 on hypertension, the authors determined that an interarm blood pressure differential of "10 mmHg can now be fairly regarded as a higher limit of normal". Additionally, they indicate that there may be a 1% to 2% increase in the risk of cardiovascular disease for every 1 mmHg increase. (Kulkarni et al., 2011)
HOW TO CORRECTLY MEASURE BP?
- The American Heart Association advises purchasing a validated arm-cuff blood pressure monitor.
- It's time to perfectly arrange your body once you've wrapped the cuff over the top of your arm (sleeveless, ensuring certain the bottom of each cuff is precisely above the bending point of your elbow).
- As it's normal to have elevations with activity, make sure that you're still for a minimum of thirty seconds before collecting the measurements to ensure that exercise efforts don't create a false elevation.(Hong et al., 2011)
- When determining the difference in blood pressure between the two arms, you should always choose the higher value as the accurate one.
- The Mayo Clinic advises testing your blood pressure multiple times a day, first in the morning (after urinating) and then in the evening before meals or medicines.(Fred, 2013)
- The greatest health present you can offer yourself if you smoke is to stop.
- The closest thing we have to miracle cures for heart disease along with other chronic illnesses are physical activity and exercise. (Corliss, 2014)
- If you're overweight, you may significantly lower your heart rate and blood sugar by merely reducing between five and ten percent of your initial weight.
- Include whole grains, beans, nuts, fish, chicken, and other sources of excellent protein along with fruits, vegetables, herbs, and spices.
- If you consume alcohol, do it in moderation.
- Using stress-reduction methods like physical activity, mindfulness, meditation, and other practises help reduce the strain on the heart as well as arteries.(Kulkarni et al., 2011)
To sum up, those of us who work directly with patients need to always be aware that inaccurate blood pressure readings and neglecting to take a reading in both arms might result in incorrect diagnosis, pointless testing, and unsuitable treatment.
We also need to acknowledge that, the supervising physicians, are ultimately accountable for precise blood pressure readings and interarm blood pressure calculations. The most effective approach to fulfil that obligation is to measure the patient's blood pressure yourself, especially at the first examination and in both hands, using appropriate methods and certified measuring devices.
Corliss, J. (2014, March 5). Big arm-to-arm difference in blood pressure linked to higher heart attack risk. Harvard Health. https://www.health.harvard.edu/blog/big-arm-arm-difference-blood-pressure-linked-higher-heart-attack-risk-201403057064#:~:text=Small%20differences%20in%20blood%20pressure
Fred, H. L. (2013). Accurate blood pressure measurements and the other arm: the doctor is ultimately responsible. Texas Heart Institute Journal, 40(3), 217–219. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3709227/
Kulkarni, P., Shekhar, S., Reddy, B., & Nirmala, B. (2011). Blood pressure measurement: one arm or both arm?. Indian Journal of Medical Sciences, 65(9), 406-406.
Hong, D., Wang, J., Su, H., Xu, J., Liu, Y., Peng, Q., & Wang, L. (2011). One arm exercise induces significant interarm diastolic blood pressure difference. Blood Pressure Monitoring, 16(3), 134-137.