Accurate measurement of blood pressure (BP) is important in diagnosis and treatment of hypertension. Non-invasive BP, including automated oscillometric BP (NBP) measurement has become increasingly popular and is now gaining more and more acceptance by patients and clinicians. But few studies show the difference between NBP and invasive arterial blood pressure (IBP). The aim of this study was to evaluate how accurate NBP compared to IBP and what are normal values for NBP.Design and Method:
The study was a prospective analysis of the findings in patients performed invasive coronary angiography. A total of 88 patients who underwent angiography via radial approach were enrolled. All patients were measured IBP to use radial sheath directly and NBP to use automated BP device (Omron HEM 7080IT). 54 of 88 patients were also measured manual BP (MBP) using mercury sphygmomanometer. All measurements of BP were performed in cardiac catheterization laboratory, twice. Degree of difference between NBP and IBP was calculated as ‘mean IBP – mean NBP’Results:
Mean age of subjects was 63.84 ± 10.34 and 39 were female. Mean IBP was 141.6/72.33 ± 21.4/9.8 mmHg, mean NBP was 137.34/74.97 ± 21.6/9.5 mmHg and mean MBP was 137.03/78.37 ± 22.0/10.8 mmHg. Mean systolic IBP was significantly higher compared with NBP and MBP (respectively p = 0.001, p = 0.002). However, mean diastolic IBP was significantly lower compared with NBP and MBP (respectively p < 0.001, p < 0.001). Difference between mean systolic NBP and mean systolic MBP was not significant (p = 0.536). Age, sex, history of hypertension, diabetes and smoking did not correlate with difference of BP by measurement methods.Conclusions:
Non-invasive systolic BP was underestimated comparing to the invasive systolic BP. On the contrary, Non-invasive diastolic BP was overestimated comparing to invasive diastolic BP. In non-invasive measurements, there was no significant difference between systolic MBP and ABP.