Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2023
Tracheal sound-based apnea detection using hidden Markov model in sedated volunteers and post anesthesia care unit patients.
The current method of apnea detection based on tracheal sounds is limited in certain situations. In this work, the Hidden Markov Model (HMM) algorithm based on segmentation is used to classify the respiratory and non-respiratory states of tracheal sounds, to achieve the purpose of apnea detection. Three groups of tracheal sounds were used, including two groups of data collected in the laboratory and a group of patient data in the post anesthesia care unit (PACU). ⋯ For the laboratory test data, apnea detection sensitivity, specificity, and accuracy were 96.9%, 95.5%, and 95.7%, respectively. For the clinical test data, apnea detection sensitivity, specificity, and accuracy were 83.1%, 99.0% and 98.6%. Apnea detection based on tracheal sound using HMM is accurate and reliable for sedated volunteers and patients in PACU.
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To determine the relationship between perfusion index and the emergency triage classification in patients admitted to the emergency department with dyspnea. ⋯ The perfusion index can help to determine the triage classification in emergency departments for dyspnea.
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J Clin Monit Comput · Aug 2023
Behaviour and stability of thermodilution signals in a closed extracorporeal circuit: a bench study.
Thermodilution is the gold standard for cardiac output measurement in critically ill patients. Its application in extracorporeal therapy is limited, as a portion of the thermal indicator is drawn into the extracorporeal circuit. The behaviour of thermodilution signals in extracorporeal circuits is unknown. ⋯ The distance to the injection port increased peak temperature and rise time and decreased exponential time constant significantly. The distance to the injection port did not influence catheter constants, but the properties of the thermodilution signal itself. This may influence measurements that depend on the exponential decay of the thermodilution signal such as right ventricular ejection fraction.