The American journal of the medical sciences
-
Case Reports Comparative Study
Methodologic problems encountered with cooximetry in methemoglobinemia.
The objectives of this study were to examine the reported accuracy of cooximetry in determination of methemoglobin levels, to report the apparent discrepant values of "measured" methemoglobin and carboxyhemoglobin, and to discuss the effect that methemoglobinemia has on pulse oximetry readings. Secondly, relative oxygen saturations measured by pulse oximetry and calculated from arterial blood gas samples were compared. A retrospective analysis was performed in an academic medical center with two patients who were diagnosed with acute methemoglobinemia after taking sulfa-containing medications. ⋯ As a result, negative values of carboxyhemoglobin were recorded by the cooximeter, generating a total sum of 100%. Comparison of pulse oximetry and arterial blood gas oxygen saturation (measured and calculated values, respectively) revealed significant discrepancies; methemoglobin was > 9%, whereas oxygen saturation uniformly was lower with pulse oximetry. Therefore, we recommend that when methemoglobin levels exceed 10%, cooximetry be used as a screen for methemoglobinemia and that serial cooximeter measurements be used to guide therapy and reliance on noninvasive pulse oximetry.
-
Comparative Study Clinical Trial Controlled Clinical Trial
Comparison of manual versus automated blood pressure measurements in treated hypertensive patients.
This study assesses differences in blood pressure (BP) levels prospectively between office (manual) measurement and ambulatory blood pressure monitoring (ABPM) in 70 treated, essential, hypertensive patients. The objective was to determine whether ABPM is superior to office measurement for assessing adequacy of therapy. Twenty-four patients received monotherapy and 46 received multiple therapy. ⋯ In addition, no differences were noted in BP levels using either method for race. Thus, this study shows that the office measurement is grossly similar to ABPM for assessment of adequacy of therapy in treated hypertensive patients whose blood pressure is controlled adequately. However, ABPM is found to be superior to office measurement in identifying hypertensive patients whose blood pressure is not controlled adequately or is uncontrolled.