Fluke Biomedical Cufflink - Manual (Page 137)

A-1
Appendix A
Non-Invasive Blood Pressure (NIBP)
Monitoring Tutorial
Introduction
Manufacturers of NIBP monitors that use the oscillometric technique have performed
clinical trials to determine the correlation between both auscultatory techniques and
invasive (arterial line) methods of measuring blood pressure to the oscillometric
technique. Various interpretations have emerged from these manufacturers with varying
degrees of agreement. Because no regulatory agency has put forth a standard as to how
pulse amplitudes should be interpreted to determine blood pressure, the accuracy and
repeatability of these monitors is difficult to determine.
Because the Analyzer produces a stable live subject response to the cuff during the
measurement cycle, it is possible to determine the repeatability and agreement of these
monitors. The Analyzer produces the same response, independent of the inflate/deflate
cycle or the algorithm used by the monitor; therefore, we offer the term Target Value as
an approximation of the patient's actual blood pressure.
Absolute dynamic accuracy cannot be assigned to MAP, diastolic, and systolic target
values at this time because no standard exists. Should any public standards emerge, the
Analyzer can be programmed to implement them and test blood pressure monitor
accuracy.
NIBP Monitoring
Blood pressure can be measured using a variety of techniques. They can be classified
into two major categories. They are known as invasive and non-invasive. The invasive
approach inserts a catheter into an artery of a test subject. The catheter may contain a
pressure transducer at its tip or it may be fluid filled and couple the blood pressure thru
the fluid to an external transducer. The change of fluid pressure (blood pressure) in the
subject's artery is said to be measured invasively. This technique is also referred to
as a direct measurement, because the parameter being measured is directly coupled to the
transducer.
The non-invasive technique can be realized several ways. It usually involves the use of an
inflatable cuff wrapped around the limb of a test subject. The cuff is inflated and deflated
at a controlled rate and physical parameters are observed. The auscultatory and