To study the effect of guide vane outlet angle on pump performance and impeller radial force in an axial-flow heart pump, guide vane outlet angle/34 is considered to be 20°, 15°, 10°, 5° and 3°...To study the effect of guide vane outlet angle on pump performance and impeller radial force in an axial-flow heart pump, guide vane outlet angle/34 is considered to be 20°, 15°, 10°, 5° and 3° respectively. Based on ANSYS Fluent, numerical results of pump head and efficiency are validated by exper/ment results, in which Xanthan gum solutions are used with concentration of 0.06 wt. % as working fluid. Then, the effects of/34 on pump performance and impeller radial force are discussed, the errors of head and efficiency between test and simulation are within 5%. The results a/so indicate that the pump performance and efficiency are much better than those of other angles when guide vane outlet angle/34 is 10°, and the maximum variations in head and efficiency are 1.9% and 2.2%, respectively. With/34 increasing, the pulsation of radial force decreases firstly and then increases, when/34 is 10°, the minimum pulsation is 0. 0392N, which is about 80% of the maximum pulsation amplitude.展开更多
Background Off-pump coronary artery bypass grafting (CABG) is becoming increasingly popular world - wide. But it is not always feasible. Current cardioplegic techniques do not consistently avoid myocardial ischemic da...Background Off-pump coronary artery bypass grafting (CABG) is becoming increasingly popular world - wide. But it is not always feasible. Current cardioplegic techniques do not consistently avoid myocardial ischemic damage. So we use on pump beating heart technique to supplement off-pump CABG. Methods Based on 860 off-pump CABG cases between Aug 1998 to Aug 2000. From Aug 1999 to Aug 2000, 46 CABG cases were performed with on pump beating heart technique at Mani-pal Hospital Heart Foundation, Bangalore, India. All surgeries were performed through a median sternotomy. Exposure techniques were tailored to individual vessels and cardiac regions and local immobilization was performed with octopus. Vascular control was achieved with occluders and shunts. Total cardiopulmonary bypass (CPB) was established before or during CABG and normolthemia was used. Results Among 46 on -pump beating heart CABG patients, 26 patients used CPB before or during OP - CABG because of unstable hemodynamics and electric instability , 7 had very deep intramyocardial left anterior descending arteries, 5 patients had poor LV function (LVEF < 30 % ), 8 patients had cardiomegaly. The average number of grafts was 3.5. No operative mortality. Three patients had postoperative myocardial infarction. Anesthetic time 4. 5±1. 2 hours, extubation time 10±2. 5 hours, blood lost 680±230 mL, blood requirement 540±150 mL, preoperative LVEF 50. 3±13 % , postoperative LVEF 64. 1±14 %, ICU stay 1. 5±0. 5 days, hospi- tal stay 9.2±1.8 days. Conclusion Complete coronary revascularization with on pump beating heart is a supplement for off - pump CABG when it is not feasible. It eliminates intraoperative globe myocardial ischemia and avoids transient myocardial injury during cardioplegic arrest and myocardial reperfusion.展开更多
Objectives To elucidate the clinical relevance of nonlinear HRV with postoperative arrhythmias in patients undergoing off-pump CABG. Methods Twenty-seven elective off-pump CABG patients were recruited in the present ...Objectives To elucidate the clinical relevance of nonlinear HRV with postoperative arrhythmias in patients undergoing off-pump CABG. Methods Twenty-seven elective off-pump CABG patients were recruited in the present study. Atrial fibrillation （AF）, ventricular tachycardia （VT）, linear and nonlinear HRV were analysed using 24-hour electrocardiogram before and after surgery. Results All time domain （SDNN, pNN50 and rMSSD）, frequency domain （LF and HF） of linear measures of HRV variables and nonlinear measures of HRV variable, the short-term fractal-like correlation α1 decreased significantly after surgery. The postoperative nonlinear HRV variable α1 tended to be lower in patients with postoperative AF （ P = 0. 056 ）. Significant depressed α1 was found in patients with postoperative VT （P = 0. 022 ）. Elder patient＇s age and longer inotropic treatment time negatively correlated with postoperative α1. Conclusions Off-pump CABG procedures resulted in significant depressed of linear and nonlinear HRV variables. The depressed nonlinear HRV variables α1 related to age, inotropic supports and postoperative AF and VT.展开更多
Fluorine-doped hydrogenated amorphous carbon (a-C:H:F) film was deposited on a flow-straightener, impeller and diffuser surface (SUS 304) of an enclosed-impeller type flow blood pump using the ionization deposition me...Fluorine-doped hydrogenated amorphous carbon (a-C:H:F) film was deposited on a flow-straightener, impeller and diffuser surface (SUS 304) of an enclosed-impeller type flow blood pump using the ionization deposition method with a source gas of C6F5H. The surface characteristics of the a-C:H:F film were examined using atomic force microscopy, X-ray photoelectron spectroscopy, and measurements of surface roughness, friction and surface potential. The a-C:H:F film tends to increase surface roughness and the negative surface charge. In addition, the surface energy and friction decrease with fluorine dopant in the a-C:H film. To estimate the hemolytic performance of a blood pump with the a-C:H:F film coating, the amount of hemolysis was measured using a mock circulatory system (in vitro test) with 500 mL of pig blood containing sodium citrate. In vitro test was conducted for 180 min with the blood flow and pump head maintained at 5 L/min and 100 mmHg, respectively. The a-C:H:F film coating reduced the amount of hemolysis and improved the hemolytic performance. Decreasing the surface energy and negative surface charge of the a-C:H:F film contributes to the improvement of the hemolytic performance. The a-C:H:F film coating is thus expected to be utilized in medical technology as a surface coating technology for artificial heart blood pumps.展开更多
Cardiac recovery from cardiogenic shock(CS) and end-stage chronic heart failure(HF) remains anoften insurmountable therapeutic challenge. The counterpulsation technique exerts numerous beneficial effects on systemic h...Cardiac recovery from cardiogenic shock(CS) and end-stage chronic heart failure(HF) remains anoften insurmountable therapeutic challenge. The counterpulsation technique exerts numerous beneficial effects on systemic hemodynamics and left ventricular mechanoenergetics, rendering it attractive for promoting myocardial recovery in both acute and chronic HF. Although a recent clinical trial has questioned the clinical effectiveness of short-term hemodynamic support with intra-aortic balloon pump(IABP, the main representative of the counterpulsation technique) in CS complicating myocardial infarction, the issue remains open to further investigation. Moreover, preliminary data suggest that long-term IABP support in patients with end-stage HF is safe and may mediate recovery of left- or/and right-sided cardiac function, facilitating long-term weaning from mechanical support or enabling the application of other permanent, life-saving solutions. The potential of long-term counterpulsation could possibly be enhanced by implementation of novel, fully implantable counterpulsation devices.展开更多
Previously we have shown that 4 Hz and 8 Hz EMF exposures have depressing effect on the thermodynamic activity of water, which decreases peroxide formation. It has also been shown that 4 Hz EMF-treated physiological s...Previously we have shown that 4 Hz and 8 Hz EMF exposures have depressing effect on the thermodynamic activity of water, which decreases peroxide formation. It has also been shown that 4 Hz EMF-treated physiological solution modulates the growth and development of microbes and heart muscle contractility, but 8 Hz EMF has pronounced inhibitory effect on bacterial growth and development. Therefore, in order to elucidate the possible mechanism of 4 Hz and 8 Hz EMF effects on heart muscle function, in the present work the effects of 4 Hz and 8 Hz EMF exposures on heart muscle tissue hydration, the sensitivity of 4 Hz and 8 Hz EMF-induced tissue hydration to 10−4 M ouabain (Na+/K+ pump inhibition) and 10−9 M ouabain (activation of intracellular signaling system) as well as the effects of 4 Hz and 8 Hz EMF exposures on the number of Na+/K+ pump units in the membrane of both young and old rats have been studied. The obtained data allow us to suggest that 8 Hz EMF exposure has more pronounced age-dependent modulation effect on tissue hydration of heart muscle than 4 Hz EMF and this effect is sensitive to Na+/K+ pump activity and intracellular signaling system.展开更多
Background Cardiopulmonary bypass (CPB) produces a well documented diffuse inflammatory response that affects multiple organ systems. To avoid the deleterious effects of cardiopulmonary bypass, off pump coronary art...Background Cardiopulmonary bypass (CPB) produces a well documented diffuse inflammatory response that affects multiple organ systems. To avoid the deleterious effects of cardiopulmonary bypass, off pump coronary artery bypass grafting is becoming increasingly popular world wide. We reviewed our experience of complete coronary artery revascularization on the beating heart without CPB. Methods From Aug 1998 to Aug 2000, 860 off pump revascularizations (99%since January 1999) were performed at Manipal Hospital Heart Foundation. The patients consist of males 757(88%), females 103(12%). Averaged age 64.2±15 years. All surgeries were performed through a median sternotomy. Exposure techniques are tailored to individual vessels and cardiac regions. Local immobilization is performed with octopus. Vascular control is achieved with occluders and shunts. Results Among 860 off pump CABG patients. Single graft 72 (8.3%), two grafts 208 (24.2%), three grafts 469 (54.5%), four grafts 101 (11.8%), five graft 10 (1.2%). The average number of grafts per patient was 2.72±0.32. Operative mortality was 0.69%(6 patients). Anesthetic time 3.9±1.2hours, extubation time 6±2.5 hours, Blood requirement 360±90 ml, Preoperative LVEF 60.2±8.5%, Post LVEF 64.1±14%Low cardiac output 48 patients (5.6%), IABP requirement: 25 patients(2.9%), 25 patients converted to CPB during OP CAB(2.9%)and 20 of them were done with on pump beating heart. 25 patients showed myocardial ischemic and 16 patients showed perioperative myocardial infarction. ICU stay 1.1±0.8 days, hospital stay 6.2±1.1 days. Conclusion Off-pump coronary artery bypass in complete revascularization is a safe, effective technique and suitable.展开更多
目的 探讨老年原发性高血压(EH)患者心脏结构、泵血功能与动态血压变异性的关系。方法 选取2021年1月至2022年12月在郑州市中医院接受治疗的126例老年EH患者作为A组,其中79例H型高血压(HT)患者为H型HT组,47例非H型HT患者为非H型HT组。...目的 探讨老年原发性高血压(EH)患者心脏结构、泵血功能与动态血压变异性的关系。方法 选取2021年1月至2022年12月在郑州市中医院接受治疗的126例老年EH患者作为A组,其中79例H型高血压(HT)患者为H型HT组,47例非H型HT患者为非H型HT组。同期收治的130例非HT老年患者作为B组。比较A组和B组动态血压变异性指标、泵血功能、心脏结构,H型HT组和非H型HT组动态血压变异性指标、心脏结构、泵血功能,并采用Spearman相关性分析老年EH患者心脏结构、泵血功能与动态血压变异性指标的相关性。结果 A组夜间收缩压标准差(N-SSD)、24 h收缩压标准差(24 h SSD)、白天收缩压标准差(D-SSD)均高于B组(P<0.05)。A组每搏量、心排出量及室间隔厚度高于B组;A组左室射血分数(LVEF)及左心室后壁厚度低于B组(P<0.05)。相比于非H型HT组,H型HT组24 h SSD、N-SSD、D-SSD、每搏量、心排出量及室间隔厚度均更高;LVEF及左心室后壁厚度更低(P<0.05)。老年EH患者每搏量与24 h SSD、N-SSD、D-SSD呈正相关(r=0.548、0.508、0.487),心排出量与24 h SSD、N-SSD、D-SSD呈正相关(r=0.612、0.573、0.490);LVEF与24 h SSD、N-SSD、D-SSD呈负相关(r=-0.603、-0.489、-0.543);室间隔厚度与24 h SSD、N-SSD、D-SSD呈正相关(r=0.576、0.645、0.476);左心室后壁厚度与24 h SSD、N-SSD、D-SSD呈负相关(r=-0.524、-0.603、-0.498)(P<0.05)。结论 不同类型的老年EH患者动态血压变异性、心脏结构及泵血功能有所差异,患者24 h SSD、N-SSD、D-SSD与每搏量、心排出量、室间隔厚度呈正相关,与LVEF、左心室后壁厚度呈负相关。展开更多
基金Supported by the National Natural Science Foundation of China(No.51574161)the Education Science Project of Young and Middle-aged Teachers of Universities in Fujian Province(No.JZ160396)
文摘To study the effect of guide vane outlet angle on pump performance and impeller radial force in an axial-flow heart pump, guide vane outlet angle/34 is considered to be 20°, 15°, 10°, 5° and 3° respectively. Based on ANSYS Fluent, numerical results of pump head and efficiency are validated by exper/ment results, in which Xanthan gum solutions are used with concentration of 0.06 wt. % as working fluid. Then, the effects of/34 on pump performance and impeller radial force are discussed, the errors of head and efficiency between test and simulation are within 5%. The results a/so indicate that the pump performance and efficiency are much better than those of other angles when guide vane outlet angle/34 is 10°, and the maximum variations in head and efficiency are 1.9% and 2.2%, respectively. With/34 increasing, the pulsation of radial force decreases firstly and then increases, when/34 is 10°, the minimum pulsation is 0. 0392N, which is about 80% of the maximum pulsation amplitude.
文摘Background Off-pump coronary artery bypass grafting (CABG) is becoming increasingly popular world - wide. But it is not always feasible. Current cardioplegic techniques do not consistently avoid myocardial ischemic damage. So we use on pump beating heart technique to supplement off-pump CABG. Methods Based on 860 off-pump CABG cases between Aug 1998 to Aug 2000. From Aug 1999 to Aug 2000, 46 CABG cases were performed with on pump beating heart technique at Mani-pal Hospital Heart Foundation, Bangalore, India. All surgeries were performed through a median sternotomy. Exposure techniques were tailored to individual vessels and cardiac regions and local immobilization was performed with octopus. Vascular control was achieved with occluders and shunts. Total cardiopulmonary bypass (CPB) was established before or during CABG and normolthemia was used. Results Among 46 on -pump beating heart CABG patients, 26 patients used CPB before or during OP - CABG because of unstable hemodynamics and electric instability , 7 had very deep intramyocardial left anterior descending arteries, 5 patients had poor LV function (LVEF < 30 % ), 8 patients had cardiomegaly. The average number of grafts was 3.5. No operative mortality. Three patients had postoperative myocardial infarction. Anesthetic time 4. 5±1. 2 hours, extubation time 10±2. 5 hours, blood lost 680±230 mL, blood requirement 540±150 mL, preoperative LVEF 50. 3±13 % , postoperative LVEF 64. 1±14 %, ICU stay 1. 5±0. 5 days, hospi- tal stay 9.2±1.8 days. Conclusion Complete coronary revascularization with on pump beating heart is a supplement for off - pump CABG when it is not feasible. It eliminates intraoperative globe myocardial ischemia and avoids transient myocardial injury during cardioplegic arrest and myocardial reperfusion.
文摘Objectives To elucidate the clinical relevance of nonlinear HRV with postoperative arrhythmias in patients undergoing off-pump CABG. Methods Twenty-seven elective off-pump CABG patients were recruited in the present study. Atrial fibrillation （AF）, ventricular tachycardia （VT）, linear and nonlinear HRV were analysed using 24-hour electrocardiogram before and after surgery. Results All time domain （SDNN, pNN50 and rMSSD）, frequency domain （LF and HF） of linear measures of HRV variables and nonlinear measures of HRV variable, the short-term fractal-like correlation α1 decreased significantly after surgery. The postoperative nonlinear HRV variable α1 tended to be lower in patients with postoperative AF （ P = 0. 056 ）. Significant depressed α1 was found in patients with postoperative VT （P = 0. 022 ）. Elder patient＇s age and longer inotropic treatment time negatively correlated with postoperative α1. Conclusions Off-pump CABG procedures resulted in significant depressed of linear and nonlinear HRV variables. The depressed nonlinear HRV variables α1 related to age, inotropic supports and postoperative AF and VT.
文摘Fluorine-doped hydrogenated amorphous carbon (a-C:H:F) film was deposited on a flow-straightener, impeller and diffuser surface (SUS 304) of an enclosed-impeller type flow blood pump using the ionization deposition method with a source gas of C6F5H. The surface characteristics of the a-C:H:F film were examined using atomic force microscopy, X-ray photoelectron spectroscopy, and measurements of surface roughness, friction and surface potential. The a-C:H:F film tends to increase surface roughness and the negative surface charge. In addition, the surface energy and friction decrease with fluorine dopant in the a-C:H film. To estimate the hemolytic performance of a blood pump with the a-C:H:F film coating, the amount of hemolysis was measured using a mock circulatory system (in vitro test) with 500 mL of pig blood containing sodium citrate. In vitro test was conducted for 180 min with the blood flow and pump head maintained at 5 L/min and 100 mmHg, respectively. The a-C:H:F film coating reduced the amount of hemolysis and improved the hemolytic performance. Decreasing the surface energy and negative surface charge of the a-C:H:F film contributes to the improvement of the hemolytic performance. The a-C:H:F film coating is thus expected to be utilized in medical technology as a surface coating technology for artificial heart blood pumps.
文摘Cardiac recovery from cardiogenic shock(CS) and end-stage chronic heart failure(HF) remains anoften insurmountable therapeutic challenge. The counterpulsation technique exerts numerous beneficial effects on systemic hemodynamics and left ventricular mechanoenergetics, rendering it attractive for promoting myocardial recovery in both acute and chronic HF. Although a recent clinical trial has questioned the clinical effectiveness of short-term hemodynamic support with intra-aortic balloon pump(IABP, the main representative of the counterpulsation technique) in CS complicating myocardial infarction, the issue remains open to further investigation. Moreover, preliminary data suggest that long-term IABP support in patients with end-stage HF is safe and may mediate recovery of left- or/and right-sided cardiac function, facilitating long-term weaning from mechanical support or enabling the application of other permanent, life-saving solutions. The potential of long-term counterpulsation could possibly be enhanced by implementation of novel, fully implantable counterpulsation devices.
文摘Previously we have shown that 4 Hz and 8 Hz EMF exposures have depressing effect on the thermodynamic activity of water, which decreases peroxide formation. It has also been shown that 4 Hz EMF-treated physiological solution modulates the growth and development of microbes and heart muscle contractility, but 8 Hz EMF has pronounced inhibitory effect on bacterial growth and development. Therefore, in order to elucidate the possible mechanism of 4 Hz and 8 Hz EMF effects on heart muscle function, in the present work the effects of 4 Hz and 8 Hz EMF exposures on heart muscle tissue hydration, the sensitivity of 4 Hz and 8 Hz EMF-induced tissue hydration to 10−4 M ouabain (Na+/K+ pump inhibition) and 10−9 M ouabain (activation of intracellular signaling system) as well as the effects of 4 Hz and 8 Hz EMF exposures on the number of Na+/K+ pump units in the membrane of both young and old rats have been studied. The obtained data allow us to suggest that 8 Hz EMF exposure has more pronounced age-dependent modulation effect on tissue hydration of heart muscle than 4 Hz EMF and this effect is sensitive to Na+/K+ pump activity and intracellular signaling system.
文摘Background Cardiopulmonary bypass (CPB) produces a well documented diffuse inflammatory response that affects multiple organ systems. To avoid the deleterious effects of cardiopulmonary bypass, off pump coronary artery bypass grafting is becoming increasingly popular world wide. We reviewed our experience of complete coronary artery revascularization on the beating heart without CPB. Methods From Aug 1998 to Aug 2000, 860 off pump revascularizations (99%since January 1999) were performed at Manipal Hospital Heart Foundation. The patients consist of males 757(88%), females 103(12%). Averaged age 64.2±15 years. All surgeries were performed through a median sternotomy. Exposure techniques are tailored to individual vessels and cardiac regions. Local immobilization is performed with octopus. Vascular control is achieved with occluders and shunts. Results Among 860 off pump CABG patients. Single graft 72 (8.3%), two grafts 208 (24.2%), three grafts 469 (54.5%), four grafts 101 (11.8%), five graft 10 (1.2%). The average number of grafts per patient was 2.72±0.32. Operative mortality was 0.69%(6 patients). Anesthetic time 3.9±1.2hours, extubation time 6±2.5 hours, Blood requirement 360±90 ml, Preoperative LVEF 60.2±8.5%, Post LVEF 64.1±14%Low cardiac output 48 patients (5.6%), IABP requirement: 25 patients(2.9%), 25 patients converted to CPB during OP CAB(2.9%)and 20 of them were done with on pump beating heart. 25 patients showed myocardial ischemic and 16 patients showed perioperative myocardial infarction. ICU stay 1.1±0.8 days, hospital stay 6.2±1.1 days. Conclusion Off-pump coronary artery bypass in complete revascularization is a safe, effective technique and suitable.
文摘目的 探讨老年原发性高血压(EH)患者心脏结构、泵血功能与动态血压变异性的关系。方法 选取2021年1月至2022年12月在郑州市中医院接受治疗的126例老年EH患者作为A组,其中79例H型高血压(HT)患者为H型HT组,47例非H型HT患者为非H型HT组。同期收治的130例非HT老年患者作为B组。比较A组和B组动态血压变异性指标、泵血功能、心脏结构,H型HT组和非H型HT组动态血压变异性指标、心脏结构、泵血功能,并采用Spearman相关性分析老年EH患者心脏结构、泵血功能与动态血压变异性指标的相关性。结果 A组夜间收缩压标准差(N-SSD)、24 h收缩压标准差(24 h SSD)、白天收缩压标准差(D-SSD)均高于B组(P<0.05)。A组每搏量、心排出量及室间隔厚度高于B组;A组左室射血分数(LVEF)及左心室后壁厚度低于B组(P<0.05)。相比于非H型HT组,H型HT组24 h SSD、N-SSD、D-SSD、每搏量、心排出量及室间隔厚度均更高;LVEF及左心室后壁厚度更低(P<0.05)。老年EH患者每搏量与24 h SSD、N-SSD、D-SSD呈正相关(r=0.548、0.508、0.487),心排出量与24 h SSD、N-SSD、D-SSD呈正相关(r=0.612、0.573、0.490);LVEF与24 h SSD、N-SSD、D-SSD呈负相关(r=-0.603、-0.489、-0.543);室间隔厚度与24 h SSD、N-SSD、D-SSD呈正相关(r=0.576、0.645、0.476);左心室后壁厚度与24 h SSD、N-SSD、D-SSD呈负相关(r=-0.524、-0.603、-0.498)(P<0.05)。结论 不同类型的老年EH患者动态血压变异性、心脏结构及泵血功能有所差异,患者24 h SSD、N-SSD、D-SSD与每搏量、心排出量、室间隔厚度呈正相关,与LVEF、左心室后壁厚度呈负相关。
