A continuous and non-invasive arterial pressure monitoring system in dialysis patients

As symptomatic intradialytic hypotension in the hemodialysis (HD) patient is often a sudden event whose onset cannot be predicted by means of extemporary measures, continuous blood pressure (BP) measurement would be far more useful. We tested a new continuous noninvasive BP monitoring system, Harmonized Alert Sensing Technology (HASTE), which, by means of the analysis of the finger pulse wave, obtained from an O2 sensor, estimates a beat-to-beat systolic pressure value (Esys) and supplies a continuous read-out. The study aim sought to verify the reliability of this non-invasive instrument in continuously providing systolic pressure values during HD.

We studied 18 patients during HD treatment, initially comparing the Esys with the invasive blood pressure measurement (SYS). Subsequently, the Esys derived from the O2 sensor in the arm with the shunt (S) and the arm without (N), respectively, were both compared with the cuff measurement.

The mean difference between SYS and Esys was 0.7 +/- 13.3 mm Hg (p < 0.01; r = 0.80). There was a mean difference of 0.2 +/- 21.9 mm Hg (p = NS; r = 0.67) between Esys(N) and Esys(S). The correlation was not statistically significant even between Esys(N) or Esys(S) versus the cuff measurement, respectively. Patient movement compromised the accuracy of the estimations made using the O2 sensor in the non-fistula arm.

A good correlation between the data estimated by HASTE compared with invasive BP suggests that the instrument may prove useful for continuously monitoring the blood pressure trends during the dynamic hemodialysis situation. However, its sensibility needs to be improved in order to be used indifferently in both arms with a view to achieving real intradialytic hypotension prevention.