Accuracy of oscillometric blood pressure algorithms in healthy adults and in adults with cardiovascular risk factors.

BACKGROUND: Fixed-ratio and slope-based algorithms are used to derive oscillometric blood pressure (BP). However, a paucity of published data exists assessing the accuracy of these methods. Our objective was to determine the accuracy of fixed-ratio and slope-based algorithms in healthy adults and in adults with cardiovascular risk factors. PATIENTS AND METHODS: Overall, 85 healthy adults (age≥18 years) and 85 adults with cardiovascular risk factors were studied. Three oscillometric and four two-observer mercury-based auscultation measurements were performed in each, according to International Standards Organization 2013 methodology. Two fixed-ratio algorithms and one slope-based algorithm were applied to process oscillometric waveform envelopes and derive oscillometric BP. Paired and unpaired t-tests were used to compare mean oscillometric BP within and between each group, respectively. RESULTS: For healthy adults, mean age was 50.3±17.8 years, mean arm circumference was 30.4±3.8 cm, and 62% were female. In the cardiovascular risk group, mean age was 63.8±12.4 years, mean arm circumference was 31.9±4.2 cm, and 62% were female. For systolic BP, the fixed-ratio algorithms produced the lowest mean error and narrowest SD. For diastolic BP, mean errors were similar for all three algorithms, but the fixed-ratio algorithms had higher precision. The comparison of healthy adults and those with cardiovascular risk factor showed high variability for systolic and diastolic BP (SD: 8.113.9 mmHg). CONCLUSION: In both healthy adults and in those with cardiovascular risk factors, the fixed-ratio technique performed better than the slope-based algorithm. High between-group variability indicates that subject-specific algorithms may be needed.

Catheter related infection in hemodialysis patients.

To determine the frequency of hemodialysis (HD) catheter related infection, causative microorganisms and predisposing factors contributing to these infections at our center, we conducted a prospective study in 2007 involving 57 (45.6% males) patients in whom a temporary catheter was inserted for HD. The patients were followed for one month to document any episodes of hemodialysis catheter related infection (HCRI). There were 11 (19.3%) patients who developed HCRI proven by blood culture; 5 patients were infected with more than one organism. Staphylococcus Coagulase negative and Staphylococcus aureus (S. aureus) remain the most common pathogens. All the organisms were sensitive to antibiotics administered empirically, however, 3 patients developed multiple resistant S. aureus (MRSA). All the infected patients experienced previous episodes of HCRI, which formed a risk factor in addition to low albumin when compared to the non-infected group (P=0.024 and P= 0.001, respectively). We conclude that the rate of HCRI and the causative organisms found in our study is comparable to previous reports. We still need to adopt measures to minimize the use of temporary vascular accesses by creation of fistulas in a timely fashion.