Journal of clinical monitoring and computing
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J Clin Monit Comput · Feb 2012
Respiratory and non-respiratory sinus arrhythmia: implications for heart rate variability.
The quantity of blood arriving at the left side of the heart oscillates throughout the breathing cycle due to the mechanics of breathing. Neurally regulated fluctuations in the length of the heart period act to dampen oscillations of the left ventricular stroke volume entering the aorta. We have reported that stroke volume oscillations but not spectral frequency variability stroke volume measures can be used to estimate the breathing frequency. ⋯ Both respiratory and non-respiratory sinus arrhythmia was observed amongst healthy adults. This observation at least partly explains why heart period parameters and heart rate variability parameters are not reliable estimators of breathing frequency. In determining the validity of spectral heart rate variability measurements we suggest that it is the position of the spectral peaks and not the breathing frequency that should be the basis of decision making.
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J Clin Monit Comput · Feb 2012
New airway device for ventilation and monitoring in pediatric patients undergoing MRI study.
A method of administering continuous positive airway pressure via a new airway device to prevent upper airway obstruction and preserve spontaneous respiration under total intravenous anesthesia has been adapted for children undergoing deep sedation for MRI studies. Presented herein is a retrospective study of 45 pediatric patients, ages 5 months to 7 years, who underwent an MRI study under general anesthesia using a modified nasal vestibule airway (NVA®), a pressure-sealing nasal cannula that can be used in conjunction with an anesthesia circuit to deliver nasal-CPAP during anesthesia. After inhalation induction of anesthesia with sevoflurane, an intravenous infusion of propofol was used to maintain anesthesia. ⋯ A new approach is offered to maintain airway patency, monitoring and spontaneous respirations in pediatric patients undergoing MRI study. This pressure-sealing nasal cannula can deliver CPAP under anesthesia while avoiding the requirement of an invasive airway and facilitating additional monitoring and control not possible with an ordinary nasal cannula. This NVA may be used in other locations in pediatric patients where endotracheal intubation is not necessary or impossible.
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J Clin Monit Comput · Feb 2012
Classification of sleep apnea types using wavelet packet analysis of short-term ECG signals.
Obstructive sleep apnea (OSA) causes a pause in airflow with reduced breathing effort. In contrast, central sleep apnea (CSA) event is not accompanied with breathing effort. The aim of this study is to differentiate CSA and OSA events using wavelet packet analysis and support vector machines of ECG signals over 5 s period. ⋯ The classification result indicates the possibility of non-invasively classifying CSA and OSA events based on shorter segments of ECG signals.