Motion Trajectory of 3-PH/R Ankle Rehabilitation Robot / 医用生物力学

Objective To study the influence of different trajectories of 3-PH/R ankle rehabilitation robot on joints and muscles. Methods The 3-PH/R ankle rehabilitation robot was simplified and imported into biomechanical modeling software by analyzing the kinematics principles. Using the actual motion trajectory of ankle rehabilitation robot as model driving, the joint and muscle forces were compared under three different trajectories, namely, dorsiflexion/plantarflexion, inversion/eversion and nutation. The correlation analysis on three motion trajectories was conducted. Results Nutation could satisfy the function of both plantar dorsiflexion/plantarflexion, and inversion/eversion, and made the ankle muscles fully exercised. The maximum difference in joint force under three different rehabilitation trajectories was 0.3 N. Different muscles had different sensitivity to trajectories. Conclusions The continuous dynamic analysis of muscle force and joint force under three kinds of rehabilitation trajectories was implemented. The results have certain theoretical significance and clinical reference value for the clinical application of ankle rehabilitation robot and the formulation of rehabilitation trajectory.

Brachiocephalic artery-sparing aortic arch repair combined with stent-graft elephant trunk technique for Stanford type A aortic dissection: analysis of 23 cases / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the clinical outcomes of brachiocephalic artery-sparing aortic arch repair combined with stent-graft elephant trunk technique for treatment of Stanford type A aortic dissection.</p><p><b>METHODS</b>Twenty-three patients with Stanford type A aortic dissection requiring arch replacement underwent brachiocephalic artery-sparing aortic arch repair combined with stent-graft elephant trunk technique. The operations were performed within 72 h (20 cases) or 3-14 days (3 cases) after the onset of aortic dissection.</p><p><b>RESULTS</b>There was no perioperative death in these cases. The mean extracorporeal circulation time was 209∓52 min, the aortic cross clamp time was 85∓21 min, and the mean chest tube output within the first 24 h after the operation was 570∓263 mL; none of the patients required chest reopening for management of bleeding. Postoperative acute renal failure requiring hemodialysis occurred in 3 cases, transient neurologic dysfunction in 2 cases, paraplegia in case and hematosepsis in 1 case. No such complications as permanent neurologic deficit or postoperative visceral malperfusion occurred in these cases. All the patients survived and were discharged from hospital without experiencing severe complications in the follow-up for 6-18 months.</p><p><b>CONCLUSION</b>Brachiocephalic artery-sparing aortic arch repair combined with stent-graft elephant trunk technique is a safe and simple procedure with controllable bleeding and can serve as an optional procedure for aortic arch replacement.</p>

Effect of one lung ventilation preconditioning on oxygenation during pediatric video-assisted thoracoscopic surgery / 南方医科大学学报

<p><b>OBJECTIVE</b>To observe the effect of one lung ventilation (OLV) preconditioning on perioperative oxygenation during pediatric video-assisted thoracoscopic surgeries (VATS).</p><p><b>METHODS</b>A total of 171 children aged 5 days to 11 years underwent VATS for empyema dissection and abscess excisions (n=55), mediastinal tumor resection (n=34), repair of the diaphragmatic hernia or diaphragmatic plication (n=21), pulmonary lobectomy or biopsy (n=43), or esophageal disease (n=18). Of these patients, 127 were younger than 3 years of age. A 5-Fr pediatric endobronchial blocker was used for OLV with a delivered inspired oxygen fraction (FiO(2)) of 1.0. After lateral decubitus, a sequential protocol of a 5- to 8-min OLV preconditioning and a 5-min two lung ventilation (TLV) was performed followed by OLV again before incision for VATS. In cases of a SpO(2)<95% without malposition of the blocker during OLV, a 5 cm H(2)O positive end expiratory pressure was applied; TLV was maintained for a SpO(2)<90%.</p><p><b>RESULTS</b>OLV provided good surgical conditions in 160 cases. Acceptable saturations were achieved in 166 cases during OLV. In 2 cases in empyema group and 3 in esophageal disease group, the ventilation protocol was converted to intermittent TLV during the operation due to hypoxemia. In esophageal disease group, the procedure and OLV duration, postoperative ventilation time and length of stay (LOS) were the longest among the groups, and the number of cases developing postoperative atelectasis was greater than that in diaphragmatic hernia and pulmonary disease groups. In empyema and esophageal disease groups, the oxygenation index (PaO(2)/FiO(2)) after total collapse of the lung in OLV and after extubation were lower than that in mediastinal tumor group (P<0.05 or 0.01).</p><p><b>CONCLUSION</b>A OLV preconditioning can maintain an acceptable oxygenation during pediatric OLV. A longer procedure and OLV duration is associated with a prolonged postoperative length of ventilation and LOS.</p>

Effects of selective left lower lobar blockade by Coopdech endobronchial blocker tube on intrapulmonary shunt and arterial oxygenation: a comparison with double-lumen endobronchial tube / 南方医科大学学报

<p><b>OBJECTIVE</b>To compare the differences in intrapulmonary shunt (Qs/Qt) and arterial oxygenation between selective left lower lobar blockade by Coopdech endobronchial blocker tubes (BB) and one lung ventilation (OLV) by left-sided double-lumen endobronchial tubes (DLT) in patients with normal pulmonary function.</p><p><b>METHODS</b>Thirty-six patients (aged 32-64 years) scheduled for lower esophageal surgery were allocated randomly into BB and DLT groups (n=18). Anesthesia was induced and maintained with Propofol by target controlled infusion with intravenous administration of sufentanil and cisatracurium if needed. A 35 to 39 French tube was placed in the DLT group, and an 8.0-mm (internal diameter) single-lumen endotracheal tube was used in the BB group where a 9 French Coopdech BB was advanced into the left lower lobar bronchus guided by a fiberoptic bronchoscope. The variables recorded were blood gas analysis data from the venous and arterial blood samples at 20 min after two-lung ventilation in supine position (T(1)), 20 min after initiation of one-lung ventilation or selective left lower lobar blockade by inflating BB balloons in the right lateral decubitus position (T(2)), total collapse of the left lung or the left lower lobe after the pleura was opened (T(3)), and before tracheal extubation (T(4)). Qs/Qt was calculated using a standard formula based on the three-compartment model. Upon pleura opening, the effectiveness of lung collapse was evaluated by the surgeon who performed the surgery. Chest radiograph and arterial blood gas analyses were performed the day after the operation.</p><p><b>RESULTS</b>Both of the groups were similar with regard to rank of the surgical exposure, pH, PaCO(2), hemoglobin from T(1) to T(4), Qs/Qt, PaO(2), PO(2), and oxygenation index at T1. In BB group, a significant reduction of Qs/Qt and greater improvements in PaO(2), PO(2), oxygenation index at T(2), T(3) and T(4) were observed in comparison with those in DLT group (P<0.05 or <0.01). No lobe collapse was observed postoperatively in BB group, but 2 patients in DLT group showed left lower lobe atelectasis. The patients in BB group showed better postoperative arterial oxygenation and shorter postoperative hospital stay (P<0.01).</p><p><b>CONCLUSION</b>Selective left lower lobar blockade by Coopdech endobronchial blocker tube during lower esophageal surgery provides a lower intraoperative intrapulmonary shunt and a better intra- and postoperative arterial oxygenation..</p>

Design and experimental application of a device for direct vision intracardiac operation without cardiopulmonary bypass / 南方医科大学学报

<p><b>OBJECTIVE</b>To design a device for direct vision intracardiac operation without cardiopulmonary bypass, and assess its applicability preliminarily.</p><p><b>METHODS</b>The device was designed according to the clinical needs of intracardiac operation and used in operations for repairing atrial septal defect in 5 ex vivo porcine heart models. The practical applicability of this device was thoroughly tested and the results of the operations were evaluated.</p><p><b>RESULTS AND CONCLUSION</b>Direct vision operation for repairing atrial septal defect was successfully performed using this device, which can be a well applicable in some intracardiac operations, but its clinical effects need further evaluation.</p>

Evaluation of ultramicroporous expanded polytetrafluoroethylene mitral valve under pulsatile flow condition in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To test 25# and 27# ultramicroporous expanded polytetrafluo-roethylene mitral valve (UPMV) under pulsatile flow condition in vitro.</p><p><b>METHODS</b>Six 25# and six 27#UPMV were tested using TH-1200 HV Prosthesis Pulsatile Flow Tester in vitro at the cycling rate of 70 cycle/min, with the systolic pressure maintained at about 16 kPa (120 mmHg), diastolic pressure at 10.7 kPa (80 mmHg), and the percentage of mean forward flow at 35%. The stimulant cardiac output was maintained at 2, 3, 4, 5 and 6 L/min, respectively, for the testing.</p><p><b>RESULTS</b>The mean pressure difference for the 25#UPMV under stimulant cardiac output of 2, 3, 4, 5 and 6 L/min was 2.488-/+0.378, 4.427-/+0.240, 5.460-/+0.449, 6.776-/+0.391 and 8.327-/+0.490 mmHg, and its effective valvular orifice was 1.430-/+0.333, 1.993-/+0.208, 2.260-/+0.477, 3.204-/+0.174 and 3.652-/+0.158 cm(2), respectively. The regurgitant fraction of the 25#UPMV under each stimulant cardiac output was (5.731-/+0.643) %, (5.431-/+0.312) %, (5.059-/+0.708) %, (3.545-/+0.097) % and (2.615-/+0.125) %, respectively. The mean pressure difference of the 27#UPMV under each stimulant cardiac output was 1.618-/+0.497, 3.448-/+0.440, 4.825-/+0.434, 5.494-/+0.446 and 7.482-/+0.455 mmHg, effective valvular orifice was 1.773-/+0.364, 2.113-/+0.305, 2.409-/+0.295, 3.326-/+0.417 and 4.522-/+0.445 cm(2), and regurgitant fraction was (5.357-/+0.509) %, (5.407-/+0.110) %, (4.999-/+0.182) %, (4.010-/+0.254) % and (2.584-/+0.114)%, respectively.</p><p><b>CONCLUSION</b>The mean pressure difference, effective valvular orifice and regurgitant fraction of the UPMVs can measure up to the national criteria for artificial heart valve prosthesis of China.</p>

Accelerated fatigue test in vitro of expanded polytetrafluoroethylene artificial heart valve / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the durability of expanded polytetrafluoroethylene artificial heart valve (ePTFE AHV).</p><p><b>METHODS</b>Six ePTFE AHVs were tested for 400 million times against accelerated fatigue using TH-2200 artificial heart valve exosomatic accelerated fatigue instrument. Hydromechanical parameters of fore-and-aft accelerated fatigue test of the 6 AHVs were obtained by TH-1200 artificial heart valve exosomatic pulsatile stream instrument.</p><p><b>RESULTS AND CONCLUSION</b>The mean gradient pressure spanning the valve and the effective orific area of ePTFE AHVs did not undergo significant changes after fore-and-aft the fatigue test, but the regurgitation volume and regurgitation rate of ePTFE AHVs were reduced after the accelerated fatigue test, suggesting good durability of ePTFE AHV.</p>