Friday March 24, 2006
Is Forearm Blood Pressure Reliable ?
It is one of the common practice to use forearm as non-invasive blood pressure monitoring in case upper arm blood pressure measurements having problems. Folks from Delaware did blood pressure measurement in the forearm and then in the upper arm of 221 supine patients with their arms resting at their sides. Similar exercise was repeated with patients' head of the bed elevated at 45 degree. Analysis showed that: Noninvasive measurements of blood pressure in the forearm and upper arm cannot be interchanged irrespective of position. Important aspect of forearm BP monitoring:
1. Forearm BP measurement is not recommended but if absolutely required, as if proper-size upper arm cuff is not available, make sure correct cuff size for forearm is used.
2. Use and follow forearm Blood Pressure serially and DO NOT interchange Blood Pressure measurement with upper arm readings.
3. Be cautious that systolic, diastolic and mean forearm blood pressure measurements are higher than upper arm blood pressure measurements with following values
* Systolic BP is about 8 mm Hg higher in supine and 14 mm Hg higher at 45 degree,
* Diastolic BP is about 4 mm Hg higher in supine and 9.5 mm Hg higher at 45 degree,
* Mean BP is about 5 mm Hg higher in supine and 11 mm Hg higher at 45 degree.
Clinical Comparison of Automatic, Noninvasive Measurements of Blood Pressure in the Forearm and Upper Arm With the Patient Supine or With the Head of the Bed Raised 45?: A Follow-Up Study - American Journal of Critical Care. 2006;15: 196-205