Journal of clinical monitoring and computing
-
J Clin Monit Comput · Jun 2009
Case ReportsOxygraphy: an unexplored perioperative monitoring modality.
Capnography waveforms and capnometry are useful perioperative monitoring tools. The paramagnetic oxygen analyzers incorporated in many clinical monitoring systems estimate oxygen concentration in the breathing circuit during various phases of ventilation. The oxygen concentration is plotted as a real-time waveform and displayed as an oxygraph. ⋯ The oxygraphy peak-to-baseline scale difference can be compressed to as low as to 6% of oxygen concentration. When the peak-to-baseline scale difference is 6 mmHg, the oxygraph becomes sensitive to even minute changes in respiratory flow characteristics. Oxygraphy may have a potential role in clinical monitoring.
-
J Clin Monit Comput · Jun 2009
Comparative Study Clinical TrialCardiac index value measurement by invasive, semi-invasive and non invasive techniques: a prospective study in postoperative off pump coronary artery bypass surgery patients.
The authors prospectively compared three techniques of continuous cardiac index measurements. They were, invasive Continuous Cardiac Index using thermodilution flow-directed Swan-Ganz pulmonary artery catheters, semi invasive Flotrac-arterial pressure derived cardiac index and the non invasive cardiac index measurement-body impedance plethsmography. The cardiac index measurements were made simultaneously in the postoperative period in 20 patients who underwent elective uncomplicated off pump coronary artery bypass graft. ⋯ The values obtained were interchangeable. The bias and precision respectively were 0.02 and +/-0.06 for continuous cardiac index and Flotrac, 0.18 and +/-0.08 for Flotrac and body impedance plethysmography and 0.16 and +/-0.08 for continuous cardiac index and body impedance plethysmography. Flotrac appears to be more useful during off pump coronary artery bypass surgery.
-
J Clin Monit Comput · Jun 2009
Clinical TrialHaemodynamic changes during craniotomy monitored by a bioimpedance plethysmographic noninvasive cardiac output monitor.
Profound cardiovascular changes may occur at various stages during a craniotomy. These changes require a detailed haemodynamic analysis including cardiac output. In the present study, we used a monitor based on electrical bioimpedance method for noninvasive cardiac output measurement. ⋯ Bioimpedance plethysmography is a useful noninvasive technique for monitoring and detailed analysis of the rapidly changing systemic haemodynamics during a craniotomy. The device could be useful for investigating important haemodynamic changes in specific neurosurgical settings.
-
J Clin Monit Comput · Jun 2009
Differential effect of halothane on motor evoked potentials elicited by transcranial electric or magnetic stimulation in the monkey.
Halothane (HAL) is known to depress motor evoked potentials produced by transcranial magnetic (tcMMEP) or transcranial electric (tcEMEP) stimulation. This study was designed to determine if differences existed between tcEMEP and tcMMEP with increasing HAL concentra- tions. ⋯ These differences in sensitivity to HAL are consistent with other studies with intravenous anesthesia and are consistent with the known difference in the physiological mechanisms by which magnetic and electrical stimulation activates the motor cortex.
-
J Clin Monit Comput · Apr 2009
Sensor fusion using a hybrid median filter for artifact removal in intraoperative heart rate monitoring.
Intraoperative heart rate is routinely measured independently from the ECG monitor, pulse oximeter, and the invasive blood pressure monitor if available. The presence of artifacts, in one or more of theses signals, especially sustained artifacts, represents a critical challenge for physiological monitoring. When temporal filters are used to suppress sustained artifacts, unwanted delays or signal distortion are often introduced. The aim of this study was to remove artifacts and derive accurate estimates for the heart rate signal by using measurement redundancy. ⋯ The hybrid median filter combines the structural and temporal information from two or more sensors and generates a robust estimate of heart rate without requiring strict assumptions about the signal's characteristics. This method is intuitive, computationally simple, and the performance can be easily adjusted. These considerable benefits make this method highly suitable for clinical use.