Journal of clinical monitoring and computing
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J Clin Monit Comput · Jun 2004
Increased tidal volume variability in children is a better marker of opioid-induced respiratory depression than decreased respiratory rate.
During opioid administration, decreasing respiratory rate is typically used as a predictor of respiratory depression. Prior to opioid-induced apnea, progressively irregular breathing patterns have been noticed. We hypothesize that opioid administration to children will increase tidal volume variability (TV(var)) and that this will be a better predictor of respiratory depression than a decrease in respiratory rate. ⋯ TV(var) increases as children approach opioid-induced respiratory depression. This is a more useful predictor of respiratory depression than a fall in respiratory rate because the TV(var) increase is 10 times the drop in respiratory rate. A TV(var) increase also correctly predicts respiratory depression twice as often as decreased respiratory rate and is independent of age-related alterations in physiologic respiratory rates.
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For determining the adequacy of ventilation, conventional pulse oximetry should be amended by PaCO2 (= arterial carbon dioxide partial pressure). This study investigates the precision of carbon dioxide measurements of the first digital ear-clip sensor providing continuous non-invasive monitoring of PaCO2, SpO2 (= functional arterial oxygen saturation as estimated with a pulse oximeter) and pulse rate and compares it to two conventional analog oximeters. ⋯ Combined digital SpO2/ PcCO2 ear sensors are very promising to allow for a fast and reliable monitoring of patient's oxygenation, hyper-/hypocapnia and ventilation with one single non-invasive probe. Optimal primary signal processing--amplification and digitalisation within the probe--allow for fast and reliable downstream signal processing algorithms. The resulting short SpO2 response times give the medical staff more time to take appropriate actions.
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J Clin Monit Comput · Apr 2004
Clinical TrialAn on line technique to detect cardiac output variations and cardiovascular performances during abdominal aortic surgery.
Cardiac output (CO) is a parameter usually requested to assess hemo dynamic status of patient and efficacy of therapy especially in critically ill patients. This paper, in line with other research activities and new market availability, intends to correlate a parameter derived from data already acquired in standard patient monitoring (systemic arterial pressure--Pas) in order to identify CO trends and, more generally, to obtain information on the efficiency of cardiovascular system of the patient in examination. ⋯ To evaluate further diagnostic capability of max (dPas/dt), we compare its trend with other parameters but no statistical significant results have been obtained. Therefore the target parameter can be profitably used in the examined patients to monitor CO trend and, in correlation with other parameters, as a sign of efficiency of the cardio circulatory system.
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During long experimental set ups, a protocol book usually guides cosmonauts. This is not very easy to work with in microgravity conditions and is not very efficient. For the cardiovascular physiology experiment CARDIOCOG during the Belgian Soyuz Mission (Odissea, November 2002) we developed a software program that guided the cosmonauts through the experiment. The software was developed in LabVIEW, thoroughly tested by CNES and the Russian space authorities and transported to the ISS as a stand-alone application. An adapted version was used during the Spanish Cervantes Mission in October 2003. ⋯ Less training was necessary for the cosmonauts to learn the experiment. Reconstruction of the experiment timing was easy. Exact breathing frequencies were obtained at each repetition. The program HICOPS worked to the overall satisfaction of the cosmonauts and they preferred working with HICOPS instead of with paper flow sheets. Data for the cardiovascular experiment during both missions were obtained in a standardised way.
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J Clin Monit Comput · Apr 2004
Comparative StudyA dual closed-loop control system for mechanical ventilation.
Closed-loop mechanical ventilation has the potential to provide more effective ventilatory support to patients with less complexity than conventional ventilation. The purpose of this study was to investigate the effectiveness of an automatic technique for mechanical ventilation. ⋯ The controller maintained the arterial blood gases within normal limits under steady-state conditions and the transient response of the system was robust under various disturbances. The results of the study have showed that the proposed dual closed-loop technique has effectively controlled mechanical ventilation under different test conditions.