PURPOSE:To investigate the relationship between the development of the diabetic retinopathy(DR)and the changes of ocular hemodynamics. METHODS:The hemodynamic parameters (Vmax,Vmin,RI)of central relinal artery(CRA )and central retinal vein(CRV)were measured both in the diabetes mellitus(DM) group(72 cases)and the control group(28 cases)with color Doppler flow imaging(Acuson-128XP/10). RESULT:The hemodynamic changes in CRA and CRV in the different stages of DR had their own characteristicS. The blood flow in CRA of the DM patients without DR was higher than that of the control (Plt;0.05). With tile deterioration of the retinopathy the blood flow in CRA decreased. The velocity of the blood flow in CRA of the proliferative DR group was less than that in the control ,DM without DR patients and background DR patients(Plt;0.05). The velocity of the flow in CRV of the DM patients was higher than that of control (Plt;0.001 )and exhibited its remarkable pulsative pattern. CONCLUSIONS:The changes of the hemodynamics in CRA.CRV was associated with the development of the diabetic retinopathy. （Chin J Ocul Fundus Dis,1997,13: 210-212 ）
Objective To investigate the hemodynamic performance of valved bovine jugular vein conduits (BJVC) for right ventricular outflow tract reconstruction in canine model. Methods The BJVC that were treated with the glutaraldehyde were implanted between the pulmonary artery and right ventricle in seven young canines. Right ventricular and pulmonary artery pressures were measured directly before and after the implantation. Hemodynamic evaluations were carried out by echocardiography and cardiac catheterization after the implantation. Results Seven canines were survival one year after the implantation. The pulmonary artery pressures (including systolic pressure, diastolic pressure and mean pressure) had not significantly changed after reconstruction with the conduits. The right ventricular diastolic pressures had not increased after the reconstruction, but the right ventricular systolic pressure and mean pressure had increased. One year later, the echocardiography showed valve motion with no obvious thickening of the leaflets. No graft kinking or obvious regurgitation of the valve was observed. Cardiac catheterization and angiography showed that the pressure gradients between the right ventricle and the conduits varied from 3 to 19mmHg, the diastolic pressures in the conduits were higher than that of right ventricle((Plt;)0.01), and the conduits and pulmonary arteries had no obvious obstruction. Conclusion The glutaraldehyde-fixed bovine jugular vein conduit has good hemodynamic performance in the pulmonary circulation.
Objective Comparing postoperative change of blood gas and hemodynamic status in patients underwent a right ventricletopulmonary artery (RVPA) conduit or a modified BlalockTaussig (mBT) shunt for pulmonary atresia with ventricular septal defect and without major arterial pulmonary collaterals (MAPCAs), to affirm the effect on oxygen supply /demand with different procedure. Methods From July 2006 to October 2007, 38 patients with pulmonary atresia and ventricular septal defect without MAPCAs were divided into two groups according to different procedures: RVPA group (n=25) and mBT group (n=13).Perioperative mortality, blood gas and hemodynamic data during postoperative 48 hours, including heart rate, blood pressure, systemic oxygen saturation, mixed venous oxygen saturation, oxygen excess factor, inotropic score were compared in both groups. Results The difference in the mortality between RVPA group (4.0％，1/25) and mBT group （7.7％，1/13) showed no statistical significance（Pgt;0.05）. The total of 33 patients were followed up, the followup time was from 6 to 18 months.11 patients (4 patients in mBT group, 7 patients in RVPA group) underwent corrected procedures during 9 to 18 months after palliative procedures, one case died of elevated pulmonary vascular resistance and right ventricle failure. The mixed venous oxygen saturation at 24h and 48h after surgery were higher than that at 6h after surgery (Plt;0.01) both in RVPA group and mBT group. The systolic blood pressures at 6h, 24h, 48h after surgery in RVPA group were lower than those in mBT group (P=0.048，0.043， 0.045)，the mean systemic blood pressures in RVPA group were higher than those in mBT group (P=0.048, 0.046, 0.049),the diastolic blood pressures in RVPA group were higher than those in mBT group (P=0.038, 0.034, 0.040)， the inotropic scores in RVPA group were lower than those in mBT group (P=0.035， 0.032，0.047). Conclusion The blood pressures and inotropic scores are found significantly different in RVPA conduit and mBT procedures, while postoperative systemic oxygen delivery areequivalent. Both RVPA and mBT patients decline to nadir in hemodynamic status at 6 h after surgery.
ObjectiveTo observe the effects of carotid artery stenting (CAS) on ophthalmic artery blood flow in patients with ischemic ophthalmopathy (IOP).MethodsA prospective case-control study. Sixty IOP patients (60 eyes) who met inclusive criteria for CAS were enrolled in this study. There was 50% stenosis of internal carotid artery on one side at least confirmed by color doppler flow imaging (CDFI). Among 60 eyes, there were 3 eyes with central retinal artery occlusion, 15 eyes with retinal vein occlusion, 37 eyes with ischemic optic neuropathy, 5 eyes with ocular ischemia syndrome. The patients were randomly divided into CAS group (32 eyes of 32 patients) and medicine therapy group (28 eyes of 28 patients). The difference of age (t=1.804) and sex (χ2=1.975) between two groups was not significant (P＞0.05). The examinations of fundus fluorescein angiography (FFA), CDFI and digital substraction angiography (DSA) were performed before, 1 week and 6 months after treatment. The following parameters were recorded: arm-retinal circulation time (A-Rct), peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistance index (RI) in the ophthalmic artery (OA) and central retinal artery (CRA), and the best corrected visual acuity (BCVA).ResultsThere was no significant differences in A-Rct (t=1.354) and BCVA (t=0.376) between the two groups before treatment (P＞0.05). Also, there was no significant differences in PSV (t=−0.294, −2.446), EDV (t=0.141, −0.305), and RI (t=−0.222, −0.694) of OA and CRA between the two groups before treatment before treatment (P＞0.05). Compared with the medicine therapy group, the lower A-Rct was found in the CAS group at different time points after the treatment. The difference was significant on 1 week after treatment (t=−3.205, P＜0.05), but not on 6 months after treatment (t=1.345, P＞0.05). The BCVA of eyes in the two groups were increasing with the extending of time of therapy. Compared with the medicine therapy group, the better BCVA was found in the CAS group at different time points after the treatment (t=0.800, 1.527; P＜0.05). Compared with the medicine therapy group, the higher PSV, EDV and lower RI of OA and CRA were found in the CAS group at different time points after the treatment. (P＜0.05).ConclusionCompared with conventional medicine therapy, CAS shows earlier effects in improving ocular hemodynamics for IOP patients with carotid artery stenosis, which benefits visual function improvement of the patients.
To explore the influence of bionic texture coronary stents on hemodynamics, a type of bioabsorbable polylactic acid coronary stents was designed, for which a finite element analysis method was used to carry out simulation analysis on blood flow field after the implantation of bionic texture stents with three different shapes (rectangle, triangle and trapezoid), thus revealing the influence of groove shape and size on hemodynamics, and identifying the optimal solution of bionic texture groove. The results showed that the influence of bionic texture grooves of different shapes and sizes on the lower wall shear stress region had a certain regularity. Specifically, the improvement effect of grooves above 0.06 mm on blood flow characteristics was poor, and the effect of grooves below 0.06 mm was good. Furthermore, the smaller the size is, the better the improvement effect is, and the 0.02 mm triangular groove had the best improvement effect. Based on the results of this study, it is expected that bionic texture stents have provided a new method for reducing in-stent restenosis.
Controlling intraoperative bleeding is the core technology of liver surgery, and it is also an important way to improve the benefits of liver surgery and reduce the risk of surgery. In recent years, a number of methods to maintain low central venous pressure have been proposed, including inferior vena cava clamping, restricted fluid infusion, postural changes, intraoperative assisted ventilation, intraoperative hypovolemic venous incision, etc. In addition, more and more indicators used to guide intraoperative fluid input management to maintain low central venous pressure have been discovered, including global end-diastolic volume and stroke volume variability. Therefore, this article summarizes the relationship between low central venous pressure and surgical effect in liver surgery, and the ways to achieve low central venous pressure on the basis of previous research.
ObjectiveTo observe the hemodynamic parameters of retrobulbar vessels of eyes with primary open-angle glaucoma (POAG) by using color Doppler imaging (CDI) technique. Methods Pertinent publications were retrieved from the PubMed of The National Library of Medicine, the ISI Web of Knowledge of The Institute for Scientific Information, and Cochrane Central Register of Controlled Trials. Case control studies involved POAG patients were included. Changes in retrobulbar blood flow parameters including peak systolic velocity (PSV), end diastolic velocity (EDV) and resistive index (RI) of the ophthalmic artery (OA), central retinal artery (CRA) and short posterior ciliary artery (SPCA) were evaluated by CDI. The searching time was from the data base established up to April, 2014. Meta analysis was used on the included articles, the mean difference (MD) along with 95% confidence interval (95% CI) of the blood flow parameters were calculated. ResultsTwenty-four articles were retrieved, including 1336 eyes as cases, 1102 eyes as controls. PSV of POAG eyes was statistically signiflcantly lower than controls in the OA (MD=-3.05, 95%CI:-4.49--1.61, P < 0.001), CRA (MD=-1.66, 95%CI:-1.95--1.38, P < 0.001), SPCA (MD=-0.87, 95% CI:-1.49--0.26, P=0.005). EDV of POAG eyes was statistically significantly reduced than controls in the OA (MD=-1.78, 95%CI:-2.14--1.41, P < 0.001), CRA (MD=-0.95, 95%CI:-1.17--0.74, P < 0.001), SPCA (MD=-0.53, 95%CI:-0.71--0.36, P < 0.001). Statistically significant increases in RI of POAG eyes than controls in the OA (MD=0.04, 95%CI: 0.03-0.05, P < 0.001), CRA (MD=0.06, 95%CI: 0.05-0.07, P < 0.001), SPCA (MD=0.04, 95%CI: 0.03-0.06, P < 0.001). ConclusionThis meta-analysis suggests that significant decreased velocity and increased resistance of retrobulbar blood flow are found in POAG eyes.
ObjectiveTo evaluate the effect of positive end-expiratory pressure (PEEP) on respiratory function and hemodynamics in acute lung injury (ALI) with intra-abdominal hypertension (IAH). MethodsSix pigs were anesthetized and received mechanical ventilation (MV). Volume controlled ventilation was set with tidal volumn(VT) of 8 mL/kg,respiratory rate(RR) of 16 bpm,inspired oxygen concentration (FiO2) of 0.40,and PEEP of 5 cm H2O. ALI was induced by repeated lung lavage with diluted hydrochloric acid (pH<2.5) until PaO2/FiO2 declined to 150 mm Hg or less to established ALI model. Intra-abdominal hypertension was induced by an nitrogen inflator to reach intra-abdominal pressure of 20 mm Hg. Respiratory parameters and hemodynamics were continuously recorded at different PEEP levels(5,10,15,and 20 cm H2O). Every level was maintained for one hour. ResultsPaO2/FiO2 in PEEP5,10,15 and 20 were 90±11,102±10,172±23 and 200±34 mm Hg respectively. PaO2/FiO2 in PEEP15 and 20 were significantly higher than those in PEEP5 and 10 (P<0.05). Chest wall compliance (Ccw) in PEEP5,15 and 20 were 26±3,76±15 and 85±14 mL/cm H2O respectively. Ccw in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in lung compliance (CL) in different PEEP levels (P>0.05). Plateau pressure(Pplat) in PEEP5,10,15 and 20 were 30±3,31±2,36±2 and 38±4 cm H2O respectively. Pplat in PEEP15 and 20 were significantly higher than those in PEEP5 and 10 (P<0.05). There was no significant difference in Pplat between PEEP15 and 20 (P>0.05). Heart rate (HR) in PEEP5,15 and 20 were 113±17,147±30,and 160±30 beat/min respectively. HR in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in HR between PEEP15 and 20 (P>0.05).Cardiac index (CI) in PEEP5 and 20 were 4.5±0.6 and 3.5±0.6 L·min-1·m-2 respectively. CI in PEEP20 was significantly lower than that in PEEP5 (P<0.05). There was no significant difference in CI in PEEP5,10 or 15(P>0.05). Central venous pressure(CVP) in PEEP5,15 and 20 were 12±2,17±2,and 18±3 mm Hg respectively. CVP in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in CVP between PEEP15 and 20 (P>0.05). There were no significant differences in MAP,SVRI,ITBVI,GEDI,PVPI,or EVLWI between different PEEP levels. ConclusionConcomitant ALI and IAH can induce great impairments in respiratory physiology. When PEEP is gradually increased,oxygenation and the respiratory function are improved without significant secondary hemodynamic disturbances.
ObjectivesTo systematically review the efficacy of lidocaine injected prior to tracheal extubation in preventing hemodynamic responses to tracheal extubation in general anesthesia.MethodsPubMed, Ovid, Web of Science, EMbase, The Cochrane Library, CBM, CNKI, VIP and WanFang Data databases were electronically searched to collect randomized controlled trials (RCTs) on the efficacy of lidocaine administrated prior to extubation in preventing hemodynamic responses to tracheal extubation in patients undergoing general anesthesia from inception to October, 2018. Two reviewers independently screened literature, extracted data and assessed risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 and Stata 13.0 software.ResultsA total of 10 RCTs involving 525 patients were included. The results of meta-analysis showed that: compared with control group, lidocaine could reduce mean arterial pressure in 5 min after extubation (MD=–5.10, 95%CI –9.41 to –0.79, P=0.02), weaken the increase in systolic blood pressure caused by extubation from the moment before extubation to 5 minutes after extubation (before extubation: MD=–7.22, 95%CI –10.34 to –4.11, P<0.000 01; at extubation: MD=–14.02, 95%CI –19.42 to –8.62, P<0.000 01; 1 minutes after extubation: MD=–15.82, 95%CI –22.20 to –9.45, P<0.000 01; 3 minutes after extubation: MD=–12.55, 95%CI –20.36 to –4.74, P=0.002; and 5 minutes after extubation: MD=–12.05, 95%CI –20.35 to –3.74, P=0.004), and weakened extubation-induced increase in diastolic blood pressure at extubation (MD=–9.71, 95%CI –16.57 to –2.86, P=0.005). In addition, lidocaine inhibited heart rate in all time points except the moment of before and at 10 minutes after extubation.ConclusionsCurrent evidence shows that lidocaine can inhibit the increase in blood pressure and heart rate caused by extubation at certain times. Due to limited quality and quantity of the included studies, more high-quality studies are needed to verify above conclusions.