Anesthesia Student Survival Guide.pdf - Index of

AnesthesiA eQuiPment And mOnitOrs ● 135
Blood Pressure Monitoring
Manual blood pressure monitoring is easily achieved via auscultation of Korotkoff
sounds as learned by every medical student. However, automatic blood
pressure monitoring is more practical and is generally achieved via a technique
known as oscillometry. Here, the cuff is inflated to a high pressure, then
deflated slowly. Oscillations in the cuff pressure begin to be detected when the
cuff pressure first falls below systolic pressure. As deflation continues, the mean
blood pressure is identified as the cuff pressure at which the amplitude of the
oscillations is the greatest. The oscillations then vanish as the diastolic pressure
is approached (see Fig. 11.1).
Pressure [mm Hg]
150
100
50
0
4
2
0
−2
−4
Oscillations [mm Hg] 200
Recording of Cuff Pressure
and Oscillations in Pressure
−5 0 5 10 15
Time [sec.]
20 25 30 35
Figure 11.1 Sample blood pressure measurement using oscillometry. The peak oscillation
corresponds to the Mean Arterial Pressure. (Reproduced with permission from The Biomedical
Engineering Handbook, 2nd ed., Joseph D. Bronzino, Springer, 2000).