Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 1998
Comparative Study Clinical TrialMeasurement of blood concentration of indocyanine green by pulse dye densitometry--comparison with the conventional spectrophotometric method.
Pulse dye densitometry (PDD) uses two wavelengths (805 and 890 nm) in association with pulse oximetry to compute the arterial blood concentration ratio of indocyanine green (ICG) to hemoglobin (Hb). When Hb is measured in the usual way, this permits the PDD to compute cardiac output, plasma or blood volume, and liver blood flow following an intravenous injection of ICG. In this study, we evaluate the accuracy of the PDD calculation of dye concentration by comparing it with measurement of the dye concentration in blood (Cb) measured by the spectrophotometric cuvette method during dye clearance in patients. ⋯ These errors are of similar size to those associated with thermal cardiac output measurement, suggesting that PDD should be valuable clinically as a noninvasive tool especially since it provides values for blood volume and liver blood flow.
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J Clin Monit Comput · Dec 1998
Stabilization and stability of twitch force during mechanomyography of the adductor pollicis muscle.
In order to study the stabilization time, the increase in twitch force during stabilization and the maintenance of stability during mechanomyography of the adductor pollicis muscle, neuromuscular function was monitored in 20 patients anaesthetized without the use of a neuromuscular blocking agent. The effect of the type of stimulation (single twitch [ST; 0.1 Hz], or train-of-four [TOF; 4 stimuli at 2 Hz, repeated every 12 s]) on these variables was studied. When applying TOF stimulation, the variables were also investigated for the TOF percentage [quotient of fourth and first twitch of a TOF stimulus x 100%]. ⋯ Stabilization of twitch force takes too long for many studies of neuromuscular function in the clinical research setting. Therefore, we do not recommend its routine use when performing mechanomyography of the adductor pollicis muscle.