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Background The thyroid gland is one of the organs sensitive to ionizing radiation, and there are few studies on the effects of long-term exposure to low doses of ionizing radiation on the thyroid gland of radiation workers. Objective To investigate thyroid abnormalities in workers in medical radiology departments in Guangdong Province and to identify potential influencing factors of thyroid abnormalities. Methods A total of 1657 radiation workers from 48 hospitals in Guangdong Province were selected as survey subjects using convenience sampling, and their personal dose monitoring results and health examination information were retrospectively analyzed to determine the factors affecting thyroid abnormalities. Results The M (P25, P75) of thyroid absorbed dose (DT) was 1.55 (0.65, 3.96) mGy in the 1657 investigated workers. The attribute-specific medians of DT were 1.29, 1.38, 1.99, and 3.51 mGy for departments of diagnostic radiology, interventional radiology, radiotherapy, and nuclear medicine, respectively; and 1.10, 1.55, and 1.80 mGy for job titles of nurse, technician, and physician, respectively. Differences in DT by gender, age, years of radiological work, age of radiation exposure onset, occupational category, and job title were statistically significant (Z=−6.35, H=708.52, 918.20, 31.19, 95.64, 39.28, P<0.05). The positive rate of thyroid abnormalities in investigated workers was 46.53% (771/1657). Among them, the positive rate of abnormal thyroid function was 22.87% (379/1657), that of abnormal thyroid morphology was 33.98% (563/1657), and that of thyroid nodule was 26.55% (440/1657). The differences in thyroid abnormality rates by gender, age, years of radiation work, age of radiation exposure onset, DT, and job title of radiation workers were statistically significant (χ2=51.89, 49.64, 20.54, 18.29, 12.07, 16.16, P<0.05). The differences in abnormal thyroid function positive rate by gender, age of radiation exposure onset, and job title were statistically significant (χ2=26.21, 6.21, 8.32, P<0.05). The differences in the positive rates of abnormal thyroid morphology and nodules were statistically significant by gender, age, years of radiological work, age of radiation exposure onset, DT, and job title (abnormal thyroid morphology, χ2=40.24, 64.17, 37.63, 15.17, 19.28, 15.05; nodules, χ2=31.41, 77.98, 42.11, 19.16, 21.70, 13.52, P<0.05). The positive rates of thyroid abnormality, thyroid morphology abnormality, and nodules all showed a linear increasing trend with increasing age, years of radiation work, and age of radiation exposure onset (P<0.05). The results of logistic regression analysis indicated that the factors influencing thyroid abnormalities were female (OR=2.17, 95%CI: 1.72-2.74), increased years of radiological work (OR=1.04, 95%CI: 1.03-1.06), onset of radiation exposure in age groups of 30-34 and ≥35 years (OR=1.63, 95%CI: 1.12-2.37; OR=2.58, 95%CI: 1.74-3.29), and working in department of diagnostic radiology (OR=1.40, 95%CI: 1.07-1.84). Conclusion Long-term exposure to low doses of ionizing radiation has an effect on thyroid abnormalities in medical radiation workers. Among them, being female, physicians, and working in department of diagnostic radiology are at a higher risk of abnormal thyroid function; being female, increased years of radiation work, and radiation exposure onset at age ≥30 years are associated with a higher risk of reporting abnormal thyroid morphology.
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Objective:To investigate the exposure level of ionizing radiation in medical radiation workers in Guangdong province, as well as their abnormality in the lens of the eye, and to analyze associated influence factors.Methods:In this study, 1 501 radiation workers from 60 hospitals were selected by using convenient sampling method for retrospecotive analysis of absorbed doses ( DL) to the lens of the eye, health examination information and the relevant influence factors. Results:The median value M and the 25 th and 75 th percentile values ( P25, P75)of the distribution of absorbed doses were 4.86, 2.99 and 7.90 mGy, respectively. The median values for male and female were 5.14 and 3.94 mGy, respectively. The median values for the Levels I, Ⅱ and Ⅲ medical institutions were 2.95, 3.51 and 5.06 mGy, respectively. The median values were radiotherapy 4.05 mGy, radiodiagnosis 4.84 mGy, interventional radiology 5.39 mGy and nuclear medicine 6.71 mGy, as well as nurses 3.48 mGy, physicians 5.03 mGy and technologists 5.03 mGy, respectively. There were statistically significant differences in dose distribution for different gender, age, length of radiation service, age at the beginning of radiation exposure, level of medical institution, occupational category and post ( Z=-6.72, H=389.64, 511.17, 70.29, 53.29, 49.06, 39.89, P<0.05). The detectable rate for increased cortical density of lens was 22.45% (337/1 501) and for lens turbidity was 8.19% (123/1 501). The detectable rate of increased cortical density showed a linear increasing trend with the increase in age, age of radiation service, age at the beginning of exposure to radiation, level of medical institution and dose ( χ2=366.36, 313.77, 15.18, 21.61, 92.13, P<0.05). The detectable rate of lens opacity increased linearly with the increase in age, length of radiation service, level of medical institution and dose( χ2=69.64, 67.65, 67.65, 37.37, P<0.05), and decreased linearly with the increase in age at the beginning of radiation exposure ( χ2=4.25, P<0.05). Logistic regression analysis showed that age was the influencing factor of increased cortical density ( χ2=165.98, P<0.05), and the risk of cortical densification increased with age ( OR=1.33, 95% CI: 1.27-1.39). Age, length of radiation service and occupation were the influencing factors of lens opacity ( χ2=25.78, 4.99, 6.88, P<0.05). The risk of lens opacity increased with age ( OR=1.17, 95% CI: 1.10-1.24). The risk of lens opacity increased with age of radiation service ( OR=1.06, 95% CI: 1.01-1.12). The risk of ocular opacity was higher in interventional radiology than that in diagnostic radiology, radiotherapy and nuclear medicine ( OR=2.59, 95% CI: 1.27-5.25). Conclusions:Long-term exposure to low dose ionizing radiation has a certain correlation with the abnormal lens detectable rate of medical radiation workers. Age, length of radiation service and occupation are the influencing factors of lens opacity.
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Objective:To explore the investigation level of individual monitoring for medical radiation workers.Methods:Monitoring and analysis of individual doses to the medical radiation workers in Guangdong province were performed, from 2016 to 2019, by the Individual Dose Monitoring Department of Guangdong Provincial Hospital for Occupational Disease Prevention and Control.Results:The numbers of monitored workers were diagnostic radiology 53 674, dental radiology 2 563, nuclear medicine 5 001, radiotherapy 16 687, interventional radiology 22 272 and others 2 087 from 2016 to 2019, of which the number of individuals with doses in excess of investigation level 1.25 mSv, were 76, 6, 18, 28, 133 and 2 respectively. The non-real doses made up 67.1 %, 100 %, 55.6 %, 82.1 %, 76.7 % and 100 % of their respective totals. Their 99th percentile doses P99 were 0.37, 0.39, 0.67, 0.35, 0.54 and 0.30 mSv, and the average periodic dose equivalent were 0.07, 0.06, 0.11, 0.06, 0.07 and 0.05 mSv respectively, indicating a statistically significant difference existing in the average annual effective dose between groups ( Z=-26.139--2.681, P<0.001). Conclusions:Due to non-reality of doses in excess of investigation levels and high labor cost, it is suggested to currently use 0.40 mSv per 3 months as investigation level for diagnostic radiology, dental radiology, radiotherapy and others, and 0.70 mSv per 3 months as for nuclear medicine and interventional radiology.
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Objective To evaluate the effect of γ-aminobutyric acid (GABA) preconditioning on pathological stretch-induced damage to type Ⅱ alveolar epithelial cells by mechanical ventilation.Methods A549 cells cultured in vitro (0.2× 106/ml,2.5 ml/well) were randomly divided into 3 groups using a random number table:control group (group C),pathological stretch group (group P) and GABA preconditioning+pathological stretch group (group G).A549 cells were exposed to 20％ cyclic stretch at 0.3 Hz for 6 h in groups P and G;GABA 50 μmol/L was given 30 min before cyclic stretch in group G.After the end of pathological stretch,the cells were collected for determination of the cell viability by methyl thiazolyl tetrazolium assay and lactate dehydrogenase (LDH) release by colorimetricmethod;the expression of F-actin was observed with indirect immunofluorescence;the expression of Rho-associated kinase 1 (ROCK1) and GABAAR were determined by western blot.Results Compared with group C,the cell viability was significantly decreased,the amount of LDH released was increased,the expression of ROCK1 was significantly increased and the expression of GABAAR was significantly decreased in groups P and G (P＜0.05);Compared with group P,the cell viability was significantly increased,the amount of LDH released was decreased,F-actin was re constructed,the expression of ROCK1 was significantly decreased and the expression of GABAAR was significantly increased (P＜0.05) in group G.The reconstruction of F-actin in group P was better than that in group G and worse than that in group C.Conclusion GABA preconditioning can attenuate pathological stretch-induced damage to type Ⅱ alveolar epithelial cells probably through up regulating the expression of GABAA receptor.
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Objective To investigate the effect of Shenfu injection preconditioning on ventilator-induced brain injury in rats.Methods Sixty healthy adult male Sprague-Dawley rats,weighing 300-320 g,were divided into 3 groups (n=20 each) using a random number table:control group (group C),ventilator-induced brain injury group (group VIBI) and Shenfu injection group (group SF).Rats were mechanically ventilated for 6 h with tidal volume of 40 ml/kg in VIBI and SF groups.Rats were mechanicaliy ventilated for 6 h with tidal volume of 10 ml/kg in group C.Shenfu injection 20 ml/kg was injected intraperitoneally at 30 min before ventilation in group SF.Blood samples were collected at 2 and 6 h of ventilation for measurement of the concentrations of serum S100β protein (by enzyme-linked immunosorbent assay).Then the rats were sacrificed at the end of ventilation,and brains were removed for determination of the contents of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-o) (by enzyme-linked immunosorbent assay) and expression of glutamate decarboxylase (GAD) and γ-aminobutyric acid type A (GABAA) receptor in brain tissues (by Westem blot).Results Compared with group C,the serum concentrations of S100β protein at each time point of ventilation and contents of IL-1β and TNF-α in brain tissues were significantly increased,and the expression of GAD and GABAA receptor was down-regulated in VIBI and SF groups (P＜0.05).Compared with group VIBI,the serum concentrations of S100β protein at each time point of ventilation and contents of IL-1β and TNF-α in brain tissues were significantly decreased,and the expression of GAD and GABAA receptor was up-regulated in group SF (P＜0.05).Conclusion Shenfu injection preconditioning can relieve ventilator-induced brain injury in rats,and the mechanism may be related to inhibiting inflammatory responses and activating GABA signaling pathway.
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Objective To evaluate the changes in activation of γ?aminobutyric acid(GABA)sig?naling pathway during ventilator?induced brain injury in rats. Methods Thirty?six pathogen?free adult male Sprague?Dawley rats, weighing 280-320 g, were divided into 3 groups(n=12 each)using a random number table: low tidal volume group(LV group), ventilation with high tidal volume for 2 h group(HV1 group)and ventilation with high tidal volume for 6 h group(HV2group). The rats were mechanically ven?tilated for 2 h with the tidal volume set at 10 ml∕kg and the respiratory rate 40 breaths∕min in group LV. The rats were mechanically ventilated for 2 h with the tidal volume set at 40 ml∕kg and the respiratory rate 40 breaths∕min in group HV1. The rats were mechanically ventilated for 6 h with the tidal volume set at 40 ml∕kg and the respiratory rate 40 breaths∕min in group HV2. Blood samples were collected at the end of ven?tilation for determination of serum neuron?specific enolase(NSE)and S100β protein concentrations by en?zyme?linked immunosorbent assay. Six rats were then sacrificed and their brains were removed for determi?nation of interleukin?1β(IL?1β)and tumor necrosis factor?α(TNF?α)contents(by enzyme?linked im?munosorbent assay)and expression of glutamic acid decarboxylase(GAD)and GABAAreceptors(by Western blot). Morris water maze test was performed on 2nd day after the end of ventilation. Results Compared with group LV, the serum concentrations of NSE and S100β protein and contents of IL?1β and TNF?α were significantly increased, the expression of GAD and GABAAreceptors was up?regulated, the es?cape latency was prolonged, and the percentage of swimming distance at the original platform was decreased in HV1and HV2groups(P<0.05). Compared with group HV1, the serum concentrations of NSE and S100β protein and contents of IL?1β and TNF?α were significantly increased, the expression of GAD and GABAAreceptors was up?regulated, the escape latency was prolonged, and the percentage of swimming distance at the original platform was decreased in group HV2(P<0.05). Conclusion Activation of GABA signaling pathway is enhanced during ventilator?induced brain injury, which may be involved in the patho?physiological mechanism of ventilator?induced brain injury in rats.
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Objective To evaluate the effects of lung-protective ventilation on the cerebral oxygen metabolism and postoperative cognitive function in elderly patients requiring one-lung ventilation (OLV).Methods Sixty patients of both sexes,aged 65-80 yr,weighing 45-75 kg,of American Society of Anesthesiologists physical status Ⅱ or Ⅲ,scheduled for elective radical resection for esophageal cancer performed via video-assisted thoracoscope with general aneshesia,were divided into 2 groups (n =30 each)using a random number table:volume-controlled ventilation group (group VCV) and protective ventilation group (group PV).In group VCV,the tidal volume (VT) was set at 10 ml/kg during two-lung ventilation (TLV) and at 7 ml/kg during OLV.In group PV,the VT was set at 7 ml/kg during TLV and at 5 ml/kg during OLV with positive end-expiratory pressure of 5 cmH2O,and lung recruitment maneuver was performed every 45 min with inspiratory pressure at 15,20 and 25 cmH2O,PEEP 5 cmH2O,3 breaths per pressure,5 s/breath.Before induction of anesthesia (T1),at 10 min of TLV (T2),at 30 min of OLV (T3) and at 15 min after restoration of TLV (T4),blood samples were taken from the radial artery and jugular bulb for blood gas analysis,and pH value,arterial oxygen partial pressure (PaO2),arterial carbon dioxide partial pressure (PaCO2),arterial oxygen saturation (SaO2) and jugular venous oxygen saturation (SjvO2) were recorded.Oxygenation index (OI),intrapulmonary shunt (Qs/Qt),arteriovenous blood O2 content difference (Da-jvO2) and cerebral O2 extraction rate (CERO2) were calculated at the same time.Cognitive function was assessed using Mini-Mental State Examination at 7 days and 1 month after operation,and the development of postoperative cognitive dysfunction was recorded.Results PaO2,DajvO2,CERO2 and Qs/Qt were significantly higher and SjvO2 and OI were lower at T2-4 than at T1 in two groups (P＜0.05).PaO2,SjvO2 and OI were significantly lower and Qs/Qt and CERO2 were higher at T3 than at T2,and Da-jvO2 was higher at T3-4 than at T2 in two groups (P＜0.05).Compared with group VCV,PaO2,PaCO2,SjvO2 and OI were significantly increased and Qs/Qt,Da-jvO2 and CERO2 were decreased at T3,the Mini-Mental State Examination scores were increased on postoperative day 7,and the incidence of postoperative cognitive dysfunction was decreased in group PV (P＜O.05).Conclusion Lungprotective ventilation is helpful in improving postoperative brain function of elderly patients requiring OLV.
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Objective To evaluate the effect of ulinastatin on γ-aminobutyric acid (GABA) signal pathway in mice with ventilator-induced lung injury (VILI).Methods Thirty-six male Wister mice were randomly divided into 3 groups using a random number table:control group (group C), ventilator-induced lung injury group (group VILI),and ventilator-induced lung injury+ ulinastatin group (group UTI),n =12 in each group.VILI was induced by 4 h mechanical ventilation with tidal volume 40 ml/kg in groups VILI and UTI.Ulinastatin 1×10 5 U/kg was injected intraperitoneally 1 h before ventilation in group UTI,while the equal volume of normal saline was given in groups C and VILI.The mice were then sacrificed,the left lung was lavaged,and broncho-alveolar lavage fluid (BALF)was collected for determination of concentrations of protein,tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β)and intercellular adhesion molecule-1 (ICAM-1).The lung tissues were re-moved for determination of the wet to dry lung weight (W/D)ratio,the mRNA expression level of IL-1β,TNF-αand ICAM-1.The pathological changes of the lungs were determined under light micro-scope and the lung injury scores were also determined.Immunohistochemistry and Western blot were used to detected the protein expression level of GAD and GABAA R.Results The W/D ratio (6.7 ± 2.4 vs.8.5±2.3)and lung scores [(6.9±2.3)scores vs.(1 1.8±2.7)scores]were significantly de-creased in group UTI than those in group VILI.The concentrations of IL-1β[(56±1 1)ng/L vs.(77 ±1 5)ng/L],TNF-α[(105±29)ng/L vs.(1 58±37)ng/L]and ICAM-1 [(205±46)ng/L vs.(293 ±61)ng/L]in BALF in group UTI were significantly decreased than those in group VILI.The mRNA ex-pression levels of IL-1β(1.81±0.26 vs.2.58±0.34),TNF-α(1.61±0.15 vs.2.94±0.27)and ICAM-1 (1.74±0.27 vs.2.79±0.31)were significantly decreased in group UTI than those in group VILI.The protein expression levels of GAD (0.44±0.08 vs.0.18 ±0.04)and GABAA R (0.30 ±0.09 vs.0.15 ± 0.04)were significantly increased in group UTI than those in group VILI.Conclusion Ulinastatin can at-tenuate VILI probably through activating GABA signaling pathway.
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Objective To evaluate the effect of mechanical stretch preconditioning on pathological stretch-induced activation of γ-aminobutyric acid (GABA) signaling pathway in human type Ⅱ alveolar epithelial cells (AEC Ⅱ).Methods AEC Ⅱ cell line (A549 cells) culturedin vitro were divided into control group (group C), pathological stretch group (group P1) and mechanical stretch preconditioning group (group P2). In group C, A549 cells were cultured routinely. In group P1, A549 cells were exposed to 20% cyclic stretch for 6 hours. In group P2, A549 cells were exposed to 5% cyclic stretch for 60 minutes, and then exposed to 20% cyclic stretch for 6 hours. The cells were harvested for determination of the cell viability by methyl thiazolyl tetrazolium assay, lactate dehydrogeuase (LDH) release was determined by colorimetric method, the levels of interleukin (IL-1β and IL-6) and tumor necrosis factor-α (TNF-α) were determined by enzyme linked immunosorbent assay (ELISA), the mRNA expressions of IL-1β, IL-6 and TNF-α were determined by reverse transcription-polymerase chain reaction (RT-PCR), and the protein expressions of glutamic acid decarboxylase (GAD) and γ-aminobutyric acid A receptor (GABAAR) were determined by Western Blot.Results Compared with group C, the cell viability of group P1 was significantlydecreased (A value: 0.196± 0.071 vs. 0.886±0.107), the release rate of LDH was significantly increased [(12.3±2.4)% vs. (1.9±0.5)%]; the contents and mRNA expressions of IL-1β, IL-6 and TNF-α in cell culture medium were significantly increased [IL-1β (ng/L): 138.6±19.7 vs. 32.7±7.4, IL-6 (ng/L): 196.5±31.7 vs. 55.4±13.8, TNF-α (ng/L): 111.3±21.8 vs. 20.8±7.6; IL-1β mRNA (2-ΔΔCT): 2.79±0.44 vs. 0.83±0.12, IL-6 mRNA (2-ΔΔCT): 1.99±0.25 vs. 0.56±0.11, TNF-α mRNA (2-ΔΔCT): 2.54±0.37 vs. 0.72±0.09]; the protein expressions of GAD and GABAAR were significantly decreased [GAD (gray value): 0.38±0.12 vs. 1.75±0.45, GABAAR (gray value): 0.29±0.09 vs. 1.68±0.39; allP < 0.05]. Compared with group P1, the cell viability of group P2 was significantly increased (A value: 0.523±0.132 vs. 0.196±0.071),the release rate of LDH was significantly decreased [(6.9±1.7)% vs. (12.3±2.4)%]; the contents and mRNA expressions of IL-1β, IL-6 and TNF-α in cell culture medium were significantly decreased [IL-1β (ng/L): 79.2±11.6 vs. 138.6±19.7, IL-6 (ng/L): 89.6±15.6 vs. 196.5±31.7, TNF-α (ng/L): 55.9±11.4 vs. 111.3±21.8; IL-1β mRNA (2-ΔΔCT): 1.92±0.36 vs. 2.79±0.44, IL-6 mRNA (2-ΔΔCT): 1.09±0.18 vs. 1.99±0.25, TNF-α mRNA (2-ΔΔCT): 1.77±0.25 vs. 2.54±0.37]; the protein expressions of GAD and GABAAR were significantly increased [GAD (gray value): 1.26±0.33 vs. 0.38±0.12, GABAAR (gray value): 1.04±0.15 vs. 0.29±0.09; allP < 0.05]. Conclusion The mechanism by which mechanical stretch preconditioning attenuates pathological stretch-induced injury in human AECⅡ is related to the activation of GABA signaling pathway.
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Objective To evaluate the lung-protective effect of lung-protective ventilation (LPV) combined with ventilatory mode pressure-controlled ventilation-volume guaranteed (PCV-VG) in elderly patients undergoing one-lung ventilation (OLV).Methods Eighty American Society of Anesthesiologists physical status Ⅰ-Ⅲ patients,aged 65-80 yr,with body mass index of 15-28 kg/m2,scheduled for elective radical resection for esophageal cancer performed via video-assisted thoracoscope,were divided into 4 groups (n=20 each) using a random number table:control group (group C),PCV-VG group,LPV group and LPV combined with PCV-VG group (group LPV+PCV-VG).At 20 min after changing the body position during two-lung ventilation (T1),30 min of OLV (T2) and 20 min after restoration of two-lung ventilation (T3),blood samples were collected from the radial artery for blood gas analysis and for determination of peak airway pressure (Ppeak),mean airway pressure (P) and dynamic lung compliance (Cdyn).Alveolar-arterial oxygen gradient,intrapulmonary shunt (Qs/Qt),dead space fraction (Vd/VT) and respiratory index were calculated at T2.Blood samples were collected from the radial artery before induction of anesthesia and at the end of operation for determination of plasma neutrophil elastase (NE) concentrations by enzyme-linked immunosorbent assay.The Clinical Pulmonary Infection Score (CPIS) was assessed at 1 and 7 days after operation,and the development of pulmonary complications such as respiratory failure,pulmonary atelectasis and pulmonary infection was recorded within 7 days after operation.Results Compared with group C,Ppeak was significantly decreased,and P was increased in group PCV-VG,Ppeak and PaCO2 were significantly increased and pH value,Vd/VT and Qs/Qt were decreased in group LPV,Ppeak,Vd/VT,Qs/Qt,pH value and postoperative CPIS were significantly decreased,and P Cdyn and PaO2 were increased in group LPV+PCV-VG,and the NE concentration at the end of operation was significantly decreased in PCV-VG,LPV and LPV+PCV-VG groups (P＜0.05).Compared with group PCV-VG,P Cdyn and PaO2 were significantly increased,and pH value,Qs/Qt,NE concentration at the end of operation and CPIS were decreased in group LPV+PCV-VG (P＜0.05).Compared with group LPV,Ppeak,Qs/Qt,NE concentration at the end of operation and CPIS were significantly decreased,and Cdyn was increased in group LPV+PCV-VG (P＜0.05).Pulmonary complications such as respiratory failure,pulmonary atelectasis and pulmonary infection were not observed after operation in the four groups.Conclusion LPV combined with PCV-VG can optimize the lung-protective effect in elderly patients undergoing OLV.
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Objective To understand the specimen source of clinical isolated Acinetobacter(A.)baumannii and its department distribution and drug resistance in order to guide the clinical standardized medication for preventing the drug resistance increase. Methods The drug resistance of A.baumannii was monitored by using the unified scheme,materials,methods and criteria (CLSI2010).Results Among 579 strains of A.Baumannii,39 strains(2.2%)were isolated in 2011,187 strains(10.5%)were isola-ted in 2012 and 353 strains(15.4%)were isolated in 2013.In the department distribution,271 strains were isolated from ICU and 104 strains from the department of respiratory medicine.In the positive isolation rates of various specimens,the positive rate was dominated by the sputum specimen(5.55%),followed by wound secretion and pus.The antibacterial susceptibility tests showed that A.baumannii had lowest resistance to cefoperazone/sulbactam(40.1%),which could be used as the drug of first choice.Con-clusion A.baumannii has the higher resistance to many kinds of antibacterial drugs.The drug resistance monitoring of A.bauman-nii should be strengthened in clinc and antibacterial drugs should be selected and used rationally.
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This paper introduces a type of heart sound recording, analysis and processing system based on USB interface. The system consists of high performance sensor sampling heart sounds, the preprocessing circuit, the A/D conversion module and the USB based high-speed computer communications interface. The experiments show that it is noninvasive, convenient, inexpensive and rapid in detecting the cardiac contractility of patients with heart disease as well as of healthy subjects. This system has provided a reliable technical platform for evaluating the cardiac contractility reserve.
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Humans , Computer-Aided Design , Equipment Design , Heart Sounds , Physiology , Phonocardiography , Methods , Signal Processing, Computer-AssistedABSTRACT
In this paper,heart rate (HR) and heart rate variability (HRV) are extracted from ECG,and the five indexes in both time and frequency domains are analyzed.The result shows that the standard deviation (SDNN) of R-R intervals,the value of total power (TP),the power value of low frequency (LF) of HRV and the value of LF/HF increase obviously,while the power value of high frequency (HF) decreases markedly after fatigue.The physical fatigue level is classified according to the rate of increase and decrease of the indexes above.It is suggested that these five ECG indexes be used to reflect and evaluate the degree of physical fatigue quantitatively.