Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2016
The effect of head up tilting on bioreactance cardiac output and stroke volume readings using suprasternal transcutaneous Doppler as a control in healthy young adults.
To compare the performance of a bioreactance cardiac output (CO) monitor (NICOM) and transcutaneous Doppler (USCOM) during head up tilting (HUT). Healthy young adult subjects, age 22 ± 1 years, 7 male and 7 female, were tilted over 3-5 s from supine to 70° HUT, 30° HUT and back to supine. Positions were held for 3 min. ⋯ TFC decreased linearly with HUT. The NICOM does not provide linear changes in SV as predicted by physiology when patients are tilted. Furthermore there is a lack of agreement with USCOM measurements at baseline and during tilting.
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J Clin Monit Comput · Oct 2016
Continuous-wave near-infrared spectroscopy is not related to brain tissue oxygen tension.
Near-infrared spectroscopy (NIRS) has gained acceptance for cerebral monitoring, especially during cardiac surgery, though there are few data showing its validity. We therefore aimed to correlate invasive brain tissue oxygen measurements (PtiO2) with the corresponding NIRS-values (regional oxygen saturation, rSO2). We also studied whether NIRS was able to detect ischemic events, defined as a PtiO2-value of <15 mmHg. ⋯ Continuous-wave-NIRS was unable to reliably detect ischemic cerebral episodes, defined as a PtiO2 value <15 mmHg. Displayed NIRS-values did not correlate with invasively measured PtiO2-values. CW-NIRS should not be used for the detection of cerebral ischemia.
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J Clin Monit Comput · Oct 2016
Evaluation of a fiber-optic technique for recording intramuscular pressure in the human leg.
To evaluate a forward-sensing fiber-optic pressure technique for recording of intramuscular pressure (IMP) in the human leg and investigate factors that may influence IMP measurements used in diagnosing compartment syndromes. IMP in the tibialis anterior muscle was recorded simultaneously by a fiber-optic technique and needle-injection technique in 12 legs of 7 healthy subjects. Both measurement catheters were placed in parallel with the muscle fibers to the same depth, as verified by sonography. ⋯ The fiber-optic technique may be used for IMP measurements in a muscle with both normal and abnormally elevated IMP. It has good dynamic properties allowing for measurement of IMP oscillations. Saline injection used with needle-injection systems to ensure catheter patency compromises IMP readings at least one minute after injection.
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J Clin Monit Comput · Oct 2016
Observational StudyInfluence of different infracardial positions of central venous catheters in hemodynamic monitoring using the transpulmonal thermodilution method.
Hemodynamic measurements are often conducted by the transpulmonary thermodilution (TPTD)-based PiCCO(®)-system. This requires a central-venous (CVC) and a thermistor-tipped arterial catheter, usually placed in the femoral artery. In certain clinical situations, CVC devices have to be placed in the inferior vena cava. ⋯ The LoA yielded at -3.4 and +6.1 mL/kg with a bias of +1.3 mL/kg. Percentage errors revealed clinically acceptable limits for CI and GEDVI, but not for EVLWI. Using TPTD via an infracardial central vein, measurements of CI showed high accuracy and precision while GEDVI measurements were precise with a lower accuracy, irrespective of the position of the infracardial CVC.
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J Clin Monit Comput · Oct 2016
Importance of re-calibration time on pulse contour analysis agreement with thermodilution measurements of cardiac output: a retrospective analysis of intensive care unit patients.
We assessed the effect of re-calibration time on cardiac output estimation and trending performance in a retrospective analysis of an intensive care unit patient population using error grid analyses. Paired thermodilution and arterial blood pressure waveform measurements (N = 2141) from 222 patient records were extracted from the Multiparameter Intelligent Monitoring in Intensive Care II database. Pulse contour analysis was performed by implementing a previously reported algorithm at calibration times of 1, 2, 8 and 24 h. ⋯ Shorter calibration times improved the agreement of cardiac output pulse contour estimates with thermodilution. Use of minimally invasive pulse contour methods in intensive care monitoring could benefit from prospective studies evaluating calibration protocols. The applied pulse contour analysis method and thermodilution showed poor agreement to monitor changes in cardiac output.