Journal of clinical monitoring
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We wished to determine whether the individual bias (mean difference) and precision (standard deviation of the difference) values of 2 variables, arterial oxygen saturation (SaO2) and mixed venous oxygen saturation (SvO2), could be used to predict the bias and precision values of the combined dual oximetry variable (SaO2-SvO2). ⋯ The bias of a (SaO2-SvO2) measurement method is simply the bias of the SaO2 measurement method less the bias of the SvO2 measurement method. s delta(SaO2-SvO2) is best predicted by the derived equation, RMS error with correction term. The same principles and equations also apply to other situations in which 2 variables with the same dimensions are combined into 1 variable, such as (PaCO2-EtCO2) gradients and perfusion-pressure gradients. Although the difference between the s delta(SaO2-SvO2) predicted by the RMS error equation and the derived RMS error equation with correction term was small, the difference may be significant for other combined variables.
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Case Reports
The detection of peripheral venous pulsation using the pulse oximeter as a plethysmograph.
The pulse oximeter can serve as a sensitive photoelectric plethysmograph in the operating room. It was noted in several cases that the plethysmographic waveform showed a high degree of variability during diastole. ⋯ Further investigation revealed that these diastolic peaks appear to correlate with peripheral venous pulsation, which seems to have a central venous origin. Evidence is presented that the plethysmographic detection of the venous-pulse may be useful in estimating the changing volume status of the patient.
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Pulse oximetry appears to improve quality of care by the early detection of hypoxia noninvasively. We tested the hypothesis that the widespread use of pulse oximetry over a 5-year period in the operating rooms at our institution had resulted in a reduction in blood gas measurements and in departmental operating costs. ⋯ The total cost to provide oximetry, capnography, and blood gas measurements in 1989-1990 was less than the cost to provide blood gas measurements alone in 1985-1986. The introduction of these technologies was accomplished without an increase in cost: $76,880 in 1985-1986 versus $71,025 in 1989-1990.