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Biomedical subjects

Richard L Braam

Publications and source records attributed to Richard L Braam.

5 recordsLinked to original sources
PubMed2006

Bromide as a marker to measure adherence to drug therapy.

OBJECTIVE: Several methods have been described to measure adherence to prescribed drug therapy. However, most of these have been shown to be inaccurate. Bromide is an anion that is readily absorbed in the gut and has an elimination half-life of about 12 days. In the present study, we investigated the pharmacokinetic properties of bromide with the objective to use it as a measure of drug adherence. METHODS: Three groups of each 8 healthy volunteers took 15, 24 or 30 mg potassium bromide, respectively, daily for 20 weeks. Serum concentrations of bromide were measured every two weeks. RESULTS: There was a linear relationship between the daily dosage taken and the mean increase of bromide concentration. In every group considerable inter-individual variability was seen. Correction for body weight resulted in an improved correlation between daily bromide dose and increase in concentration (r=0.78, p<0.01). CONCLUSIONS: Unfortunately, the inter-individual variability in clearance of bromide was considerable. This limits the use of bromide to primarily measuring adherence in individual patients during long term follow-up. Bromide appears to be a potentially useful marker to be added to drugs for assessment of individual adherence to long term drug therapy. This needs to be investigated in various patients, particularly for patients with relatively asymptomatic diseases (e.g. hypertension).

Bromides↗
PubMed2005

Is the accuracy of blood pressure measuring devices underestimated at increasing blood pressure levels?

BACKGROUND: In validation studies reporting on the accuracy of blood pressure measuring devices (ambulatory and non-ambulatory systems), it is frequently stated that the accuracy of blood pressure devices seems to decrease at increasing blood pressure levels. This has been shown for several ambulatory devices in the past. Whether more recently validated devices are less accurate at increasing blood pressure levels is unknown, however. OBJECTIVES: We therefore retrospectively searched the literature for studies performed between 1993 and 2003, reporting on the accuracy of blood pressure measuring devices over different blood pressure levels. When needed, additional information from the authors was requested. METHODS: In total, 30 studies were selected. Of these, the studies reporting on the accuracy of 14 different ambulatory and nine different non-ambulatory devices were useful. For both ambulatory and non-ambulatory devices, accuracy appeared to decrease at increasing blood pressure levels. This was particularly shown for systolic blood pressure. RESULTS: We speculate whether this finding is due to the oscillometric method of blood pressure measurement. Another explanation may exist, however. Blood pressure variability increases with higher blood pressure. Further, the British Hypertension Society protocol 1993 uses sequential measurements. This may be the reason that, owing to the increased blood pressure variability, the accuracy of most devices tends to decrease at higher blood pressure levels. Consequently, the accuracy of blood pressure measuring devices may be underestimated at higher blood pressure levels. CONCLUSION: Currently used automated blood pressure measurement devices seem to be less accurate at increasing blood pressure levels. It is important to be aware of this phenomenon when treating hypertensive patients. The reported decrease in accuracy, however, may well be explained by the increasing blood pressure variability at increasing blood pressure and the use of sequential measurements. If this is the case, then the accuracy of these devices is perhaps underestimated.

Blood Pressure↗
PubMed2004

Accuracy of the Omron RX-M, an automated blood pressure measuring device, measuring blood pressure at the wrist, according to a modified British Hypertension Society protocol.

OBJECTIVE: To determine the accuracy of the Omron RX-M, a device measuring blood pressure oscillometrically at the wrist. METHODS: In 89 subjects (mean age 55+/-14 years) blood pressure measurements at the wrist with the Omron RX-M were compared to sequential blood pressure measurements with a mercury sphygmomanometer at the (same) upper-arm and to simultaneous measurements with the Omron HEM-705 CP at the opposite arm.Measurements with analyzed according to the British Hypertension Society (BHS) - protocol 1993, to the protocol of the Association for the Advancement of Medical Instrumentation (AAMI) and (retrospectively) to the new 'International Protocol'. RESULTS: Mean differences (+/-SD) between the measurements with the mercury sphygmomanometer and the Omron RX-M were -7.5+/-8.4 mmHg for diastolic blood pressure (DBP) and -2.5+/-12.2 mmHg for systolic blood pressure (SBP), thus not fulfilling the AAMI-criteria (< or =5+/-8). According to the BHS-criteria a grade D was achieved for both DBP and SBP. Compared to the Omron HEM 705 CP results were -6.3+/-7.1 for DBP (grade D) and -4.1+/-12.7 for SBP (grade D). The Omron RX-M also failed to pass the new 'International Protocol' in phase 1. CONCLUSION: Although easy to use, based on this study the Omron RX-M can not be recommended to determine blood pressure accurately.

Adult↗
PubMed2002

Accuracy of the Welch Allyn Vital Signs Monitor 52000 automatic blood pressure measuring device according to a modified British Hypertension Society protocol.

The accuracy of the Welch Allyn Vital Signs Monitor, a compact device for the oscillometric measurement of blood pressure, was determined according to the British Hypertension Society protocol. The monitor achieved a grade C for diastolic and a grade D for systolic blood pressure. The device is suitable for monitoring a patient, for example post-operatively, in the emergency department or during an intervention. The device cannot, however, be recommended for an exact determination of blood pressure when compared with the mercury sphygmomanometer. In an earlier validation report, the Welch Allyn Vital Signs Monitor achieved a grade A for both diastolic and systolic blood pressure. After adjusting for the difference in method of calculating the grades used in the two studies, there remained a considerable difference in grading results, for which no clear reason could be found.

Adult↗