Simulation of the human biological lung is a crucial method for medical professionals to learn and practice the use of new pulmonary interventional diagnostic and therapeutic devices. The study on ventilation effects of the simulation under positive pressure ventilation mode provide valuable guidance for clinical ventilation treatment. This study focused on establishing an electrical simulation ventilation model, which aims to address the complexities in parameter configuration and slow display of air pressure and airflow waveforms in simulating the human biological lung under positive pressure ventilation mode. A simulated ventilation experiment was conducted under pressure-regulated volume control (PRVC) positive pressure ventilation mode, and the resulting ventilation waveform was compared with that of normal adults. The experimental findings indicated that the average error of the main reference index moisture value was 9.8% under PRVC positive pressure ventilation mode, effectively simulating the ventilatory effect observed in normal adults. So the established electrical simulation ventilation model is feasible, and provides a foundation for further research on the simulation of human biological lung positive pressure ventilation experimental platform.
In this work, we investigated the influence of the bifurcation geometry of the iliac artery on the propagation properties of the pulse wave, and applied software to establish the straight bifurcation and curved bifurcation bi-directional fluid-solid coupling finite element analysis models based on the iliac artery, and compared and analyzed the influence of the bifurcation angle of the blood vessel on the propagation characteristics of the pulse wave. It was found that the bifurcation geometry had a significant effect on the pulse wave propagation in the iliac arteries, and the pressure and velocity pulse wave amplitudes predicted by these two models had a good agreement with that before the vessel bifurcation in a cardiac cycle. The curvilinear bifurcation model predicted the pulse wave amplitude to be lower and the pressure drop to be smaller after the bifurcation, which was more in line with the actual situation of the human body. In addition, the bifurcation point is accompanied by the stress concentration phenomenon in the vessel wall, and there is a transient increase in the velocity pulse waveform amplitude, which was consistent with the fact that the bifurcation site is prone to phenomena such as arterial stenosis and hardening. The preliminary results of this paper will provide some reference for the use of pulse waveforms in the diagnosis of arterial diseases.
Objective To observe the changes of force bearing area and pressures of the rabbit tibiofemoral contact area and the biomechanical reconstruction level of joint after meniscal allograft. Methods A total of 28 Japanese rabbits were involved, weighing 3.0-3.5 kg, male or female. Of 28 rabbits, 7 were selected as meniscus donors, the remaining 21 rabbits were randomized into group A (n=7), group B (n=7), and group C (n=7). Group A underwent single knee opening and suturing, group B underwent medial meniscus excision and suturing, and group C underwent medial meniscus allograft after medial meniscus excision and suturing. The rabbits were sacrified at 12 weeks after operation for biomechanical observation through biomechanical machine and color imaging system. The meniscus tissue specimens were harvested from groups A and C to perform histological and immunohistochemical staining. Results After operation, all rabbits in 3 groups survived to the end of experiment. There were significant differences in the force bearing area and pressures at 0-90° flexion between group B and groups A, C (P lt; 0.05) at 12 weeks, showing no significant difference between group A and group C (P gt; 0.05); and there were significant differences in the force bearing area and pressures at 120° flexion among 3 groups (P lt; 0.05). The histological observation showed that the number of cartilage cells and collagen fibers returned to normal in group C, and the immunohistochemical staining showed that transplanted meniscus of group C contained large amounts of collagen fibers consisting of collagen type I and collagen type II. After 12 weeks of operation, the collagen type I contents were 0.612 5 ± 0.059 8 in group A and 0.587 2 ± 0.063 9 in group C, showing no significant difference (t=0.765, P=0.465); the collagen type II contents were 0.772 4 ± 0.081 5 and 0.814 3 ± 0.051 7, respectively, showing no significant difference (t= —0.136, P=0.894). Conclusion The allograft of rabbit meniscus can significantly increase the force bearing area of the tibiofemoral contact area and reduce the average pressure. Therefore, biomechanically speaking, the meniscus allograft can protect the articular cartilage and reconstruct the biomechanical balance.
Myocardial remodeling is one of the important pathological basis when myocardial infarction or pressure overload occurs, whereas mangiferin which is a naturally occurring xanthone has a broad range of therapeutic effect on postinfarction myocardial remodeling. Mangiferin attenuates myocardial infarction by preventing the accumulation of myocardial collagen and the development of intercellular fibrosis. Mangiferin's inhibition to p38 mitogen activated protein kinases plays an important role in the cardioprotective effect. Inhibition of p38 mitogen activated protein kinases significantly decreases TNF-α and then brings the cardioprotective effect. Similarly, p38 mitogen activated protein kinases in pressure overload disease also play a very important role. Understanding of these has direct implications for clinical therapy.
ObjectiveTo investigate the operation and effect of pressure ulcers group (PUG) on the procedure of clinical management of pressure ulcers. MethodsThe in-hospital patients with high-risk pressure ulcers and patients with pressure ulcers from outside of the hospital (n=145) before the founding of PUG in 2011 were regarded as group A, and patients in this group were treated by traditional therapies. After PUG was founded in our hospital in January 2012, 192 patients with high-risk pressure ulcers and from outside of the hospital in 2012 were considered as group B. In addition, group C contained 380 patients treated in 2013. Group B and C were both treated by PUG that developed a management system of pressure ulcers and took active measures to control and prevent pressure ulcers. PUG trained 30 clinical nurse supervisors, who were recommended from relevant clinical departments. The incidence of inevitable pressure ulcer of hospitalized patients, the cure rate of patients with pressure ulcers from outside of the hospital, pressure ulcer knowledge level of clinical nurse supervisors were comparatively analyzed between group A and B, and between group A and C, respectively. ResultsAfter the establishment of PUG, the incidence of inevitable pressure ulcer of hospitalized patients in group A, B, and C was 76.20%, 17.02%, and 14.61%, respectively. The cure rate of patients from outside of the hospital was 54.84%, 86.84%, and 87.97%, respectively. Differences between group A and B, and between group A and C both were significant (P<0.01). The pressure ulcer knowledge level of all nurse supervisors improved significantly (P<0.001). ConclusionThe establishment of PUG makes the clinical pressure ulcer management more scientific and objective. Furthermore, it can effectively reduce the incidence of pressure ulcers, and also improve the quality of medical care and ensure the safety of patients.
ObjectiveTo explore the best nursing interventions for advanced-age diabetes with pressure ulcer in Sichuan area. MethodsWe retrospectively analyzed the reasons for pressure ulcer and the nursing process for 37 patients with diabetes treated between March 2012 and March 2013 in our hospital. Then, we analyzed and summarized the susceptibility factors, wound nursing, nutritional support and blood sugar monitoring in all the patients. ResultsThrough intensive nursing, pressure ulcer in 36 patients were cured, and one patient died due to lung infection. ConclusionThe risk of pressure ulcer is high in advanced-age diabetes patients, and they need promising nursing. Individualized plan is necessary for them to improve their life-quality.
ObjectivesTo investigate simple assess method of the degree of low transvalvular gradient aortic stenosis patients with impaired left ventricular function and to investigate aortic valve replacement indications, short and mid-term outcome of this kind of patients. MethodsWe retrospectively analyzed the clinical data of 21 low-gradient patients with impaired left ventricular function in our hospital from January 2011 through May 2014. There were 15 males and 6 females aged 41-66 (54.6± 10.7) years with mean aortic transvalvular gradient less than 40 mm Hg and left ventricular ejection fraction (LVEF) less than 50%. ResultsIn response to dobutamine echocardiography stress test, 20 patients underwent aortic valve replacement. The result of intraoperative pathology showed 11 patients were with bicuspid aortic valve malformation, 4 patients with degenerative changes, 4 patients with rheumatic disease. During the same period, 3 patients underwent atrial fibrillation ablation, 1 patient with ascending aorta replacement, 2 patients with coronary artery bypass grafting, 1 patient with mitral valvuloplasty. One patient died of multiple organ failure on the fourth day after operation. The remaining patients recovered. The patients were followed up for 3 to 37 months after operation. Heart function of majority improved to gradeⅠorⅡin 3 months after surgery. The result of echocardiogram showed prosthetic valve function was good and LVEF increased (preoperative 35.7%± 8.2% vs. postoperative 49.4%± 7.2%). One patient suffered sudden death of unknown cause in the 11th months after operation. ConclusionsFor patients whose dobutamine echocardiography stress test displayed with true severe aortic stenosis and left ventricular contractile reserve capacity, after aortic valve replacement and relief of the obstruction, the left ventricular afterload decreases significantly, the left ventricular function also improves, LVEF and the quality of life improve significantly after operation.
ObjectiveTo investigate the effect of pressure control ventilation-volume guaranteed (PCV-VG) for patients undergoing da Vinci robotic-assisted pulmonary lobotomy. MethodA total of 40 patients undergoing Da Vinci robotic-assisted pulmonary lobotomy were randomly divided into two groups:a PCV-VG group (G group) and a volume-controlled ventilation (VCV) group (V group). There were 20 patients in each group with 13 males and 7 females at age of 49.0±5.5 years in the G group, 16 males and 4 females at age of 51.0±3.9 years in the V group. Haemodynamics indexes and oxygenation parameters were recorded at different times and compared between the two groups. ResultsDuring one-lung ventilation (OLV) period, the peak inspiratory pressure (Ppeak), respiratory index (RI) and arterial partial pressure of carbon dioxide (PaCO2) in the G group were statistically lower than those in the V group (P<0.05). While the Cdyn and inspired oxygen fraction(OI) were higher in the G group than those in the V group (P<0.05). ConclusionCompared with the traditional VCV ventilation mode, the PCV-VG ventilation mode improves Ppeak, Cdyn, OI, and RI of the patients undergoing da Vinci robotic-assisted pulmonary lobotomy.
Objective To investigate the correlation between dynamic intrinsic positive endexpiratory pressure ( PEEPidyn) and volume dependence of elastance and resistance of respiratory system ( Evd/Rvd) derived from nonlinear analysis of respiratory mechanics in COPD patients during pressure support ventilation ( PSV) . Methods Twenty-five COPD patients mechanically ventilated using mode of PSV were ventilated at a PSV level of no less than 20 cm H2O in a period of 15 minutes to attain so-callednear-relaxation state. The pressure( P) , flow( V′) and volume( V) data were analyzed by nonlinear mode of respiratory motion. PEEPidyn was determined by esophageal balloon-tipped catheter technique. The correlations between PEEPidyn and Evd, Rvd as well as Evd ×Rvd were analyzed. Results The correlation coefficients between PEEPidyn and Evd, Rvd as well as Evd ×Rvd were 0. 85,0. 80, and 0. 90, respectively. Conclusions Nonlinear mode of respiratory motion is suitable to analyze respiratory mechanics of COPD patients mechanically ventilated using mode of PSV. There are good correlations between PEEPidyn and Evd,Rvd as well as Evd ×Rvd which may be used to noninvasively monitor PEEPidyn in mechanically ventilated COPD patients using mode of PSV.
ObjectiveTo explore the preventive role of maintaining constant pressure of the endotracheal catheter cuff on ventilator-associated pneumonia (VAP). MethodsFrom January to December 2015, 96 patients of type Ⅱ respiratory failure were selected as the trial group who underwent intubation and mechanical ventilation more than 48 hours in the Intensive Care Unit (ICU). We used pressure gauges to measure the endotracheal catheter cuff pressure regularly and maintained a constant pressure in addition to the application of artificial airway cluster management. We recorded the initial pressure value which was estimated by pinching with finger and set initial pressure to 30 cm H2O (1 cm H2O=0.098 kPa). We measured endotracheal catheter cuff pressure and recorded it during different intervals. We reviewed 88 patients with the same disease as the control group who only accepted artificial airway cluster management between January and December 2014. Mechanical ventilation time, VAP occurrence time, ICU admission time, the incidence of VAP were recorded and analyzed for both the two groups of patients. ResultsIn the trial group, the initial pressure of endotracheal catheter cuff which was estimated by pinching with finger showed that only 11.46% of pressure was between 25 and 30 cm H2O and 82.29% of the pressure was higher than 30 cm H2O. We collected endotracheal catheter cuff pressure values during different interval time by using pressure gauges to maintain a constant management. The ratio at the pressure between 25 and 30 cm H2O was respectively 41.32%, 43.75%, 64.20%, 76.54%, 91.13%, and 91.85%. ICU admission time, mechanical ventilation time in patients of the trial group decreased more, compared with the control group, and the differences were statistically significant (t=4.171, P<0.001; t=4.061, P<0.001). The VAP occurrence time in patients of the trial group was later than the control group (t=2.247, P<0.001). ConclusionThe endotracheal catheter cuff pressure estimated by pinching with finger has errors. We recommend using pressure gauges to detect pressure every four hours, which utilizes minimal time to maintain effective pressure. The method of artificial airway of cluster management combined with the pattern of maintaining constant endotracheal catheter cuff pressure can shorten ICU admission time, mechanical ventilation time and delay the occurrence of VAP.