Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 1998
Accuracy of volume measurements in mechanically ventilated newborns: a comparative study of commercial devices.
Ventilatory measurements in ventilated newborns are increasingly used to monitor and to optimize mechanical ventilation. The aim of this study was to compare the accuracy of volume measurements by different instruments using standardized laboratory conditions. ⋯ Most of the currently available neonatal spirometry devices allow sufficiently accurate volume measurements in the range of 10-60 ml and at frequencies between 30-60/min provided that an increased FIO2 is taken into account.
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J Clin Monit Comput · Aug 1998
Influence of the reference gas of paramagnetic oxygen analyzers on nitrogen concentrations during closed-circuit anesthesia.
Nitrogen (N2) may accumulate to unacceptable levels during closed-circuit anesthesia (CCA) when the sampled gases are redirected to the anesthesia circuit, because many gas analyzers entrain air as a reference gas to calibrate for oxygen analysis. Using oxygen instead of air as the reference gas for paramagnetic oxygen analysis could attenuate N2 accumulation. Forty-three adult ASA physical status I-III patients undergoing a variety of peripheral and abdominal procedures were assigned to one of two groups, depending on the reference gas used by a paramagnetic oxygen analyzer, either air (group I, n = 23) or oxygen (group II, n = 20). ⋯ N2Et0min, N2Et5min, and N2Et55min were 0.87+/-0.93, 2.6+/-1.5, and 10.1+/-2.9%, respectively. The correlation (r2) between N2Et55min and N2Et0min was 0.04, and between N2Et55min and N2Et5min it was 0.40. We conclude that paramagnetic oxygen analyzers that use oxygen as the reference gas significantly attenuate N2 accumulation during CCA, which may reduce the need for frequent flushing of the anesthesia system, may provide more constant oxygen and nitrous oxide concentrations, and may simplify pharmacokinetic studies of potent inhaled anesthetics.
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J Clin Monit Comput · Aug 1998
In vivo evaluation of a closed loop monitoring strategy for induced paralysis.
Reliable closed loop infusion systems for regulating paralysis level can be a great convenience to the anesthesiologists in automating their task. This paper describes the in vivo performance evaluation of a self-tuning controller that is designed to accommodate large variations in patient drug sensitivity, drug action delays and environmental interfering noise. ⋯ The system adapted to a large variation in the sample subject drug sensitivity. It remained stable despite large amplitude disturbances and maintained the paralysis at the desired level following the removal of the disturbances.
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J Clin Monit Comput · Aug 1998
Detection of lung injury with conventional and neural network-based analysis of continuous data.
To test if analysis of pressure and flow waveform patterns with an artificial intelligence neural network could distinguish between normal and injured lungs. ⋯ Normal and fully injured lungs display distinct flow and pressure waveform patterns which are independent of changes in calculated pulmonary mechanics variables. These patterns can be recognized by a neural network. Further research is needed to determine the full potential of automated pattern recognition for lung monitoring.