Journal of clinical monitoring and computing
-
J Clin Monit Comput · Apr 2013
Non-invasive accurate measurement of arterial PCO2 in a pediatric animal model.
The PCO2 in arterial blood (PaCO2) is a good parameter for monitoring ventilation and acid-base changes in ventilated patients, but its measurement is invasive and difficult to obtain in small children. Attempts have been made to use the partial pressure of CO2 in end-tidal gas (PETCO2), as a noninvasive surrogate for PaCO2. Studies have revealed that, unfortunately, the differences between PETCO2 and PaCO2 are too variable to be clinically useful. ⋯ The PET-aCO2 of all samples was (mean ± 1.96 SD) 0.4 ± 2.7 mmHg. Our study demonstrates that, in ventilated juvenile animals, end-inspiratory rebreathing maintains PET-aCO2 to what would be a clinically useful range. If verified clinically, this approach could open the way for non-invasive monitoring of arterial PCO2 in critically ill patients.
-
J Clin Monit Comput · Apr 2013
Comparative StudyCardiac output measured by uncalibrated arterial pressure waveform analysis by recently released software version 3.02 versus thermodilution in septic shock.
To evaluate the 3.02 software version of the FloTrac/Vigileo™ system for estimation of cardiac output by uncalibrated arterial pressure waveform analysis, in septic shock. Nineteen consecutive patients in septic shock were studied. FloTrac/Vigileo™ measurements (COfv) were compared with pulmonary artery catheter thermodilution-derived cardiac output (COtd). ⋯ Eighty-five percent of the measurements were within the 30°-330° of the polar axis. COfv with the latest software still underestimates COtd at low SVR in septic shock. The tracking capacities of the 3.02 software are moderate-good when clinically relevant changes are considered.
-
J Clin Monit Comput · Apr 2013
Spinal cord injury from electrocautery: observations in a porcine model using electromyography and motor evoked potentials.
We have previously investigated electromyographic (EMG) and transcranial motor evoked potential (MEP) abnormalities after mechanical spinal cord injury. We now report thermally generated porcine spinal cord injury, characterized by spinal cord generated hindlimb EMG injury activity and spinal cord motor conduction block (MEP loss). Electrocautery (EC) was delivered to thoracic level dural root sleeves within 6-8 mm of the spinal cord (n = 6). ⋯ Depolarization and facilitation of lumbar motor neurons by thermally excited descending spinal tracts likely explains both hindlimb EMG and an enhanced MEP signal (seen before conduction block) respectively. A thermal mechanism may play a role in some unexplained MEP losses during intraoperative monitoring. EMG recordings might help to detect abnormal discharges and forewarn the monitorist during both mechanical and thermal injury to the spinal cord.
-
J Clin Monit Comput · Apr 2013
Identification of apnea during respiratory monitoring using support vector machine classifier: a pilot study.
To determine the use of photoplethysmography (PPG) as a reliable marker for identifying respiratory apnea based on time-frequency features with support vector machine (SVM) classifier. The PPG signals were acquired from 40 healthy subjects with the help of a simple, non-invasive experimental setup under normal and induced apnea conditions. Artifact free segments were selected and baseline and amplitude variabilities were derived from each recording. ⋯ Classification accuracy of 97.22 % was obtained for the combination of power ratio and reflection index features using SVM classifier. The pilot study indicates that PPG can be used as a cost effective diagnostic tool for detecting respiratory apnea using a simple, robust and non-invasive experimental setup. The ease of application and conclusive results has proved that such a system can be further developed for use in real-time monitoring under critical care conditions.
-
This letter proposes an automated region mask for the detection of cardiac chambers from ultrasonic fetal heart biometry. The fetal biometry consists of two dimensional ultrasonic cine-loop sequences of apical four chamber view of fetal heart, which are comparatively The clinical motion information of individual frame is extracted by keeping a constant frame rate of 25 frames per second (fps). ⋯ The borders and edges of all four chambers are thus recognized leading to formation of binary region mask. Experimental study based on second trimester cine-loop sequences confirms the suitability of the proposed technique for detection of heart chambers.