Limitations of the of the oscillometric method for blood pressure measurements in dialyzed patients

BACKGROUND: Despite more frequent use of the oscillometric method (OSC) for arterial blood pressure (BP) measurement, little is known about OSC's accuracy when used with hemodialysed patients. This study was undertaken to determine if hemodialysis (HD) and individual features in examined patients can affect the accuracy of OSC for BP measurement. MATERIAL/METHODS: In 54 hemodialysed patients (57 ± 15 years), during 2 sessions (before and after HD), 3 pairs of BP measurements each were performed on arms, alternately employing OSC and auscultatory method, with mercury manometers by 2 observers (REF). RESULTS: No difference was found in systolic BP measured before and after HD (SBP before HD: REF -147.3 ± 27.3, OSC -147.5 ± 25.0 mmHg, p>0.05, SBP after HD: REF-141.1 ± 33.9, OSC-141.2 ± 31.5 mmHg, p>0.05, respectively), but diastolic BP (DBP) was significantly higher both before and after HD during REF measurement in comparison with OSC (DBP before HD: REF -79.0 ± 17.0, OSC -76.7 ± 15.0 mmHg, DBP after HD: REF -78.6 ± 18.8, OSC -76.7 ± 16.7 mmHg, p<0.001, respectively). No significant correlation between loss of body weight caused by HD and differences in BP measured by REF and OSC after HD was indicated (Pearson's correlation coefficients: for SBP -0.041, for DBP 0.030). However, a significant correlation between differences in BP measured by REF and OSC before HD and differences in BP measured by REF and OSC after HD was observed (Spearman's rank correlation coefficients: for SBP 0.502 and for DBP 0.557, p<0.000001). CONCLUSIONS: Our study found that individual features, not HD, determine the accuracy of OSC for BP measurement in hemodialysed patients.