Hematological analysis is essential for patients who are supported by a mechanical circulatory support (MCS). The laboratory methods used to analyze blood components are conventional and accurate, but they require a mandatory turn-around-time for laboratory results, and because of toxic substances, can also be hazardous to analysis workers. Here, a simple and rapid point-of-care device is developed for the measurement of plasma free hemoglobin (PFHb) and hematocrit (Hct), based on colorimetry. The device consists of camera module, minimized centrifuge system, and the custom software that includes the motor control algorithm for the centrifuge system, and the image processing algorithm for measuring the color components of blood from the images. We show that our device measured PFHb with a detection limit of 0.75 mg/dL in the range of (0–100) mg/dL, and Hct with a detection limit of 2.14% in the range of (20–50)%. Our device had a high correlation with the measurement method generally used in clinical laboratories (PFHb R = 0.999, Hct R = 0.739), and the quantitative analysis resulted in precision of 1.44 mg/dL for PFHb value of 14.5 mg/dL, 1.36 mg/dL for PFHb value of 53 mg/dL, and 1.24% for Hct 30%. Also, the device can be measured without any pre-processing when compared to the clinical laboratory method, so results can be obtained within 5 min (about an 1 h for the clinical laboratory method). Therefore, we conclude that the device can be used for point-of-care measurement of PFHb and Hct for MCS.
Photoplethysmogram (PPG) is one of the most widely measured biosignals alongside electrocardiogram (ECG). Due to the simplicity of measurement and the advent of wearable devices, there have been growing interest in using PPG for a variety of healthcare applications such as cardiac function estimation. However, unlike ECG, there are not many large databases available for clinically significant analyses of PPG. To overcome this issue, a Generative Adversarial Network-based model to generate PPG using ECG as input is proposed. The network was trained using a large open database of biosignals measured from surgical patients and was externally validated using an alternative database sourced from another hospital. The generated PPG was compared with the reference PPG using percent root mean square difference (PRD) and Pearson correlation coefficient to evaluate the morphological similarity. Additionally, heart rate measured from the reference ECG, reference PPG, and generated PPG, and compared through repeated measure analysis of variance to test for any significant differences. The mean PRD was 3210% and the mean correlation coefficient was 0.950.05 in the test dataset. The HR from the three biosignals showed no significant difference with a p-value of 0.473. When the optimized GAN model was tested on atrial fibrillation ECG from a third dataset, the mean correlation coefficient between the generated PPG heart rate and the ECG heart rate was 0.940.15, with paired t-test resulting in p-value of 0.64. The results indicate that the proposed method may provide a valuable alternative to augmenting biosignal databases that are abundant in one signal while lacking in another.
OBJECTIVES This study was conducted to measure suture tie-down forces and evaluate cyclic contractile forces (CCFs) in beating hearts after undersized 3-dimensional (3D) rigid-ring tricuspid valve annuloplasty (TAP). METHODS Eight force transducers were attached to the 3D rigid TAP ring. Segments 1 to 8 were attached from the mid-septal to anterior-septal commissural area in a counterclockwise order. Two-sizes-down ring TAPs were performed in 6 sheep. Tie-down forces and CCF were recorded and analysed at the 8 annular segments and at 3 levels of peak right ventricular pressure (RVP: 30, 50 and 70 mmHg). RESULTS The overall average tie-down forces and CCF were 4.34 ± 2.26 newtons (N) and 0.23 ± 0.09 N, respectively. The CCF at an RVP of 30 mmHg were higher at 3 commissural areas (segments 3, 5 and 8) than at the other segments. The increases in the CCF following changes in the RVP were statistically significant only at the 3 commissural areas (P = 0.012). However, mean CCFs remained low at all annular positions (ranges of average CCF = 0.06–0.46 N). CONCLUSIONS The risk of suture dehiscence after down-sized 3D rigid-ring TAP might be minimal because the absolute forces remained low in all annular positions even in the condition of high RVP. However, careful suturing in the septal annular area and commissures is necessary to prevent an annular tear during a down-sized 3D rigid-ring TAP.
OBJECTIVES This study evaluated suture tie-down forces and cyclic contractile forces after undersized tricuspid annuloplasty using a hybrid band. METHODS Downsized tricuspid annuloplasty was planned in adult male sheep using eight force transducers attached from the septal to the anterior annular areas of the ring (segments 1 and 2, flexible septal; segments 3 and 4, semi-rigid posterior; segments 5 and 6, semi-rigid anterior; segments 7 and 8, flexible anterior). Cyclic contractile forces were analyzed at three different levels of peak right ventricular pressure: 30, 50, and 70 mmHg. RESULTS Eight 5-year-old male Corriedale sheep (average body weight = 66.8 kg) were used. The average suture tie-down force was 4.42 (standard deviation: 2.32) N. When the forces were compared, it was lowest in the flexible anterior area and highest in the flexible septal area (p < 0.001). With right ventricular pressure of 30 mmHg, the average cyclic contractile forces was lowest at segment 3 (0.07 [standard deviation: 0.07] N) and highest at segment 7 (0.15 [standard deviation: 0.08] N). The cyclic contractile forces were 0.12 (standard deviation: 0.1) N, 0.09 (standard deviation: 0.12) N, 0.14 (standard deviation: 0.1) N, and 0.13 (standard deviation: 0.09) N in the flexible septal, semi-rigid posterior, semi-rigid anterior, and flexible anterior parts, respectively (p = 0.208). As the peak right ventricular pressure increased to 50 and 70 mmHg, the cyclic contractile forces of each area increased significantly (p < 0.001). Despite this increase, the cyclic contractile forces remained low (0.1 and 0.3 N), and differences in cyclic contractile forces between segments and between annular areas showed similar patterns. CONCLUSIONS The flexible end of the hybrid band reduces the cyclic contractile forces and might prevent annular tears after ring tricuspid annuloplasty, and the risk of tear would be low even in the septal area.
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