Journal of clinical monitoring and computing
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J Clin Monit Comput · Oct 2023
Effects of infusion tubing line lengths and syringe sizes on infusion system compliance: an experimental study using a syringe-type infusion pump at low flow rate.
Ideally, the flow delivery of an infusion system is proportional only to the rate of mechanical actuation of the syringe pump plunger. However, in the real world, overall infusion system compliance may be affected by components such as an extension of tubing lines, or different sizes of syringes. With higher compliance, there may be greater chances of flow irregularity. ⋯ In the occlusion alarm experiment, the occlusion alarm could be delayed by 69.76 ± 3.98 min for the 50-ml syringe with a 560 cm infusion line set-up. In conclusion, the compliance of a syringe pump system increases as the loaded syringe size, or the length of the infusion tubing increases. The occlusion alarm may be much delayed and not useful in highly compliant systems with respect to the potential occlusion of the infusion system, so more attention is required when using a highly compliant infusion system.
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J Clin Monit Comput · Oct 2023
Observational StudyEffects of ephedrine and phenylephrine on cerebral oxygenation: observational prospective study using near-infrared time-resolved spectroscopy.
It has been reported that cerebral oxygenation (ScO2) measured by near infrared spectroscopy is maintained or increased by treatment with ephedrine, whereas almost all previous reports demonstrated that phenylephrine reduced ScO2. As the mechanism of the latter, the interference of the extracranial blood flow, that is extracranial contamination, has been suspected. Accordingly, in this prospective observational study, we utilized time-resolved spectroscopy (TRS), in which the effect of extracranial contamination is thought to be minimal, and evaluated whether the same result was obtained. ⋯ The mean differences of tHb were less than 0.02 μM and the predicted mean differences were less than 0.2 μM for the drugs. The changes in ScO2 and tHb after treatments with ephedrine and phenylephrine were very small and clinically insignificant when measured by TRS. Previous reports about phenylephrine may have been affected by extracranial contamination.
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J Clin Monit Comput · Oct 2023
Effects of tidal volume challenge on the reliability of plethysmography variability index in hepatobiliary and pancreatic surgeries: a prospective interventional study.
The plethysmography variability index (PVI) is a non-invasive, real-time, and automated parameter for evaluating fluid responsiveness, but it does not reliably predict fluid responsiveness during low tidal volume (VT) ventilation. We hypothesized that in a 'tidal volume challenge' with a transient increase in tidal volume from 6 to 8 ml Kg- 1, the changes in PVI could predict fluid responsiveness reliably. ⋯ In hepatobiliary and pancreatic surgeries, tidal volume challenge improves the reliability of PVI for predicting fluid responsiveness and changes in PVI values obtained after tidal volume challenge are comparable to the changes in SVI.
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J Clin Monit Comput · Oct 2023
Reliability and reproducibility of the DICART device to assess capillary refill time: a bench and in-silico study.
Capillary refill time (CRT) is an important indicator of peripheral perfusion with a strong prognostic value, but it is sensitive to environmental factors and numerous measurement methods are reported in the litterature. DiCARTECH has developed a device that assesses CRT. We sought to investigate the robustness of the device and the reproducibility of the algorithm in a bench and in-silico study. ⋯ For the color-jitter modified video the coefficient of variation was 62% (95%CI: 55-70). We confirmed the ability of the DiCART™ II device to perform multiple measurements without mechanical or electronic dysfunction. The precision and reproducibility of the algorithm are compatible with the assessment of clinical small changes in CRT.
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J Clin Monit Comput · Oct 2023
Observational StudyLung ultrasound for evaluating perioperative atelectasis and aeration in the post-anesthesia care unit.
Lung ultrasound is widely accepted as a reliable, noninvasive tool for evaluating lung status at the bedside. We assessed the impact of perioperative variables on atelectasis and lung aeration using lung ultrasound, and their correlation with postoperative oxygenation in patients undergoing general anesthesia. ⋯ Lung ultrasound enables early postoperative evaluation of atelectasis and lung aeration, which are closely associated with postoperative oxygenation.