Annals of biomedical engineering
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Comparative Study
Validation of a semi-classical signal analysis method for stroke volume variation assessment: a comparison with the PiCCO technique.
This study proposes a Semi-Classical Signal Analysis (SCSA) method for stroke volume (SV) variations assessment from arterial blood pressure measurements. One of the SCSA parameters, the first systolic invariant (INVS₁), has been shown to be linearly related to SV. To technically validate this approach, the comparison between INVS₁ and SV measured with the currently used PiCCO technique was performed during a 15-min recording in 20 mechanically ventilated patients in intensive care. A strong correlation was estimated by linear regression and cross-correlation analysis (mean coefficient = 0.90 ± 0.01 SEM at the two tests).
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This article investigates the possibility of extracting gastric motility (GM) information from finger photoplethysmographic (PPG) signals non-invasively. Now-a-days measuring GM is a challenging task because of invasive and complicated clinical procedures involved. It is well-known that the PPG signal acquired from finger consists of information related to heart rate and respiratory rate. ⋯ The coherence analysis results demonstrate that a moderate coherence (range 0.5-0.7, SD 0.13, p < 0.05) exists between EGG and PPG signal in the "slow wave" frequency band, without any significant change in the level of coherence in postprandial state. These results indicate that finger PPG signal contains GM-related information. The findings are sufficiently encouraging to motivate further exploration of finger PPG as a non-invasive source of GM-related information.
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In patients with severe hemorrhage, complications such as shock or death may occur if the patient is not treated appropriately and expeditiously. To create a hemostat kit for severe hemorrhage, ultraviolet light irradiation was applied to photocrosslinkable chitosan hydrogel and calcium alginate. As a hemorrhage model, the femoral arteries and veins of anesthetized rats were cut. ⋯ WBC count increased 1 day after hemostasis. AST and ALT increased 1 day after hemostasis, but it decreased 3 days later. The photocrosslinkable chitosan hydrogel and calcium alginate were biodegraded at 3 and 28 days, respectively, by neutrophils and keratinocyte chemoattractant.