Journal of clinical monitoring and computing
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J Clin Monit Comput · Dec 1999
The influence of left lateral position on cardiac output changes after head up tilt measured by impedance cardiography.
The value of the impedance cardiography (IC) method for measuring cardiac output (CO) with the subject in the left lateral position has not yet been established. We compared the CO after a 30 degrees head-up tilt with the subjects in the supine and left lateral position. ⋯ When using the IC method of SV measurement, the absolute value of the CI changes when moving from the supine to lateral positions. It is not clear whether this change is physiologic or an artifact of the measurement technique. However, changes in CI in response to a 30 degree head up tilt are the same in either position. We conclude that changes in CI can be measured with the IC method in the lateral position.
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J Clin Monit Comput · Dec 1999
Comparative Study Clinical TrialA comparison of lithium dilution cardiac output measurements made using central and antecubital venous injection of lithium chloride.
We have previously described an indicator dilution technique of measuring cardiac output in which lithium chloride is injected as a bolus via a central venous catheter and cardiac output derived from the arterial lithium dilution curve recorded from a lithium-selective electrode, which we have developed for this purpose. It would be an advantage if the lithium could be injected via the basilic vein (in the antecubital fossa) in those patients who do not need central venous catheterisation for other reasons. We have therefore compared cardiac output measurements made using these two routes of lithium chloride administration. ⋯ Injection of lithium chloride via the basilic vein in the antecubital fossa allows accurate lithium dilution cardiac output measurements to be made in patients who do not have central venous catheters in place.
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J Clin Monit Comput · Dec 1999
Comparative Study Clinical TrialMonitoring of heart and respiratory rates in newborn infants using a new photoplethysmographic technique.
A new photoplethysmographic (PPG) device for respiratory and heart rate monitoring has been evaluated in the neonatal care units at the University Children's Hospital of Uppsala, Sweden. The purpose of this study was to compare this new device with more established techniques, i.e., transthoracic impedance plethysmography (TTI) for monitoring of respiratory rate and ECG for heart rate monitoring. ⋯ Electrode and motion artefacts seem to disturb the ECG signals and, particularly, the impedance signals. During periods of high quality ECG and impedance signals, the new optical device produces signals of equal quality to these traditional methods, and is in some cases even better. The new device is non-invasive and has a small optical probe. These factors indicate further advantages of the photoplethysmographic method.