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Objective: To design an ambulatory blood pressure measuring system based on control of single chip microcomputer AT89C51 so as to accurately measure the blood pressure of human body. Methods: In the design, single chip computer AT89C51 was used as main controller, and pressure transducer MPX5050GP was used to collect signal of blood pressure of human body, and then through calculated and processed of single chip microcomputer to measure the blood pressure value. The peripheral design adopted on-off circuit and liquid crystal display (LCD) to monitor the start control and blood pressure value of system. Results: This system could convert the blood pressure signal of human body into electrical signal through pressure transducer. And after these weak electrical signals were amplified and filtrated, they were further convert into digital signal so as to be inputed in single chip microcomputer. And then, these measurement value were finally displayed on LCD through calculating and processing of main program for these signals. The results of this system has well stability, and its largest indication error was 3 mmHg, which was in the permissible error range, and the detection was qualified. Conclusion: The system can accurately measure the blood pressure of human body, and it has the advantages of small size, convenient using, clear display and so on.
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ObjectiveTo investigate the influence of the number of T-junctions between central venous catheter and pressure transducer on measurement of central venous pressure (CVP) in patients.Methods A prospective controlled study was conducted. The patients with CVP monitoring in Department of Critical Care Medicine of the Fifth Center Hospital in Tianjin from February to October in 2014 were enrolled. The patients were divided into three groups according to the number of T-junction between central venous catheter and pressure transducer: without T-junction control group and 1, 2, 3 T-junctions groups. In each patient, corresponding CVP values with different number of T-junctions placed between the central venous catheter and pressure sensors were determined within a certain period, and a square-wave graphic was obtained and preserved on the monitor. The own frequency (fn) and the attenuation coefficient (D) of the system of pressure measurement were calculated after measurement of the shock wave following a square-wave to obtain the distance between two vibrations and the amplitude of the shock wave. The difference in CVP, fn and D were compared among the groups.Results A total of 20 cases were enrolled, and 150 groups of data were collected.① With the increase in the number of T-junction, CVP showed a tendency of gradual reduction. The CVP of the groups of control and 1, 2, 3 T-junctions was (7.00±1.60), (7.00±3.00), (5.00±2.00), and (4.00±1.00) mmHg (1 mmHg = 0.133 kPa), respectively. The CVP of 3 T-junctions group was significantly lower than that of the control group (F = 9.333,P = 0.015).② With an increase in the number of T-junction, fn showed a tendency of gradual increase. The fn of groups control and 1, 2, 3 T-junctions was (12.30±0.79), (16.00±0.91),(18.10±1.75), (20.90±2.69) Hz, respectively. The fn of 1, 2, 3 T-junctions group was significantly higher than that of the control group (F1 = 45.962,F2 = 45.414,F3 = 46.830, allP = 0.000); the fn of groups 2 and 3 T-junctions was significantly higher than that of 1 T-junction group (F1 = 5.827,P1 = 0.042;F2 = 15.038,P2 = 0.004), but there was no significant difference between the groups of 2 T-junctions and 3 T-junctions (F = 3.800,P = 0.087).③ With an increase of the number of T-junction, D also showed a tendency of gradual increase. The D of 1, 2, 3 T-junction group was 1.62±0.27, 1.60±0.22, 1.82±0.25, and 2.15±0.58, respectively. There were no differences among four groups.ConclusionAfter the application of T-junctions between central venous catheter and pressure transducer, CVP values will be underestimated, the reason of which is considered to be the increase in length and thinner lumen of the T-junctions.
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PURPOSE: Study was conducted to determine and assess the effect of different type of denture adhesives on the incisal bite force of complete denture wearers until the dislodgement of upper denture, using pressure transducer. MATERIALS AND METHODS: 30 patients out of 100 were included in the study. Based on the Kapur's method of scoring denture retention and stability, these patients were divided into 3 groups- Group A - Clinically good dentures; Group B - Clinically fair dentures; and Group C - Clinically poor dentures. A custom made occlusal force meter was constructed based on the load cell type of pressure transducers. Different adhesives (powder, paste and adhesive strips) were used in the study. Complete denture wearers were asked to bite on the load cell and the readings of incisal bite force were recorded. The readings of incisal bite force were subjected to statistical analysis using Repeated measures ANOVA followed by post-hoc bonferroni test. RESULTS: The result suggests that denture adhesives improved the incisal bite force of complete denture wearers significantly The incisal bite force (in kg) in Group A without using adhesives, with powder adhesive, with paste adhesive and with adhesive strips was found to be 2.48 (+/- 0.16), 3.43 (+/- 0.11), 6.01 (+/- 0.11), 3.22 (+/- 0.09) respectively. The incisal bite force (in kg) in Group B without using adhesives, with powder adhesive, with paste adhesive and with adhesive strips was found to be 1.87 (+/- 0.18), 3.35 (+/- 0.14), 5.34 (+/- 0.18), 3.21 (+/- 0.12) respectively. The incisal bite force (in kg) in Group C without using adhesives, with powder adhesive, with paste adhesive and with adhesive strips was found to be 1.00 (+/- 0.17), 3.07 (+/- 0.14), 4.37 (+/- 0.26), 2.99 (+/- 0.14) respectively. CONCLUSION: Within the limitations of the study, it was concluded that the use of denture adhesive was found to be significantly effective in improving the incisal bite force of complete dentures until the dislodgement of upper denture. Fittydent paste adhesive was found to be more effective than the powder and strips adhesives. The improvement in incisal bite force was found to be higher in Group C in comparison to that of Group A and Group B.
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Humans , Adhesives , Bite Force , Bites and Stings , Denture Retention , Denture, Complete , Dentures , Polyvinyls , Reading , Transducers, PressureABSTRACT
This paper presented the thinking of security problems of the pulse pressure transducer which was widely used in TCM field. And we suggest that the selection of the pulse sensor should be flexible, the pressure should be comply with the security value of the body's tolerance range, and pulse instrument operator should pay attention to the accuracy and safety, so that the pulse instrument will be more humane, scientific and security-oriented.
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0 but was obviously lower than P_ sys in no endoleak. P_ sac approached P_ sys in type Ⅰ and type Ⅳ endoleaks. Some researches showed that P_ sac in type Ⅱ endoleak was higher than that in no endoleak and even approached P_ sys , however the other researches showed that P_ sac in type Ⅱ endoleak was lower than that in no endoleak. Conclusion Postoperative P_ sac dropping greatly eliminated the risk of aneurysm rupture, which symbolized the success of endovascular therapy. Even if the type Ⅰ endoleak of small size might lead to obvious elevation of P_ sac , which necessitates management. The impairment and management tactics of type Ⅱ endoleak remained equivocal, which required further study.
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OBJECTIVES: The sensitivity and accuracy of thermistor airflow signal has been debated. The purposes of this study were to compare apnea-hypopnea index(AHI) detected from a conventional thermistor signal and a nasal pressure transducer of airflow(NPT), to evaluate the value of NPT for the diagnosis of upper airway resistance syndrome (UARS), and to measure airway pressure fluctuations which produced respiratory arousals in UARS by naso-oro-esophageal manometer catheter. The subjects were 30 patients with obstructive sleep apnea syndrome [mild(540), 10), and 6 UARS patients. Airway resistance arousal in this study was defined as arousals which were not associated with apnea or hypopnea of thermistor signal, but showed significant decrease of nasal airflow pressure just before arousal and a prompt recovery of nasal airflow pressure after arousal, The airway pressure fluctuations were measured during 260 airway resistance arousals observed in 10 patients with OSAS, 2 with UARS. RESULTS: Mean AHIs of patients with OSAS were 33.4 by thermistor and 48.4 by NPT. The AHIs of mild, moderate and severe OSAS group were 10.2, 32.1, 65.4 respectively by thermistor and 23.1, 45.9, 76.4 by NPT. The mean AHI of patients with UARS was 3.2 by tehrmistor and 108 by NPT. The mean AHI of patients with nonspecific arousals was 2.7 by thermistor and 4.4 by NPT. The mean airway pressure changes during resiratory arousals of different groups were 8.7 cmH2O in mild OSAS, 11.4 cmH2O in moderate OSAS, 24.7 cmH2O in severs OSAS and 6.6 cmH2O in UARS. CONCLUSION: The nasal pressure transducer of airflow was more sensitive and accurate for assessing respiratory disturbances of patients with OSAS and was extremely helpful for the diagnosis of UARS without esophageal pressure monitoring. From the results, we would like to propose carefully the NPT diagnostic criteria for sleep disordered breathing as follows : NPT-AHI 5-15->UARS, 15-35->mild OSAS, 35-55->moderate OSAS and >55 ->severe OSAS.