ABSTRACT
Objective To observe and explore the effects of different tidal volume (VT) ventilation on right ventricular (RV) function in patients with critical respiratory failure.Methods Consecutive respiratory failure patients who were treated with invasive ventilator over 24 h in the Department of Critical Care Medicine at the Fourth Hospital of Hebei Medical University from June to December in 2015 were enrolled in this study.Clinical data including patients′ vital signs, ventilator parameters and RV echocardiography were collected within 6 h (D0), day1(D1), day2 (D2) and day3 (D3) after ventilation started.According to the VT, patients with acute respiratory distress syndrome (ARDS) were assigned to low VT group [S6, ≤6 ml/kg predicted body weight (PBW)] and high VT group (L6, >6 ml/kg PBW), while non-ARDS patients were also assigned to low VT group (S8, ≤8 ml/kg PBW) and high VT group (L8, >8 ml/kg PBW).Results A total of 84 patients were enrolled in this study.44.2% ARDS patients and 58.5% non-ARDS patients were in low VT groups.After ventilation, tricuspid annulus plane systolic excursion(TAPSE)decreased progressively in S6 [from 18.30(16.70,20.70) mm to 17.55(15.70,19.50) mm, P=0.001], L6 [from 19.50(17.00,21.00) mm to 16.30(15.00,18.00) mm P=0.001], S8[from 18.00(16.00,21.00) mm to 16.50(15.50,18.00) mm, P=0.001] and L8 [from 19.00(17.50,21.50) mm to 16.35(15.15,17.00) mm, P=0.001] groups.However, TAPSE decreased less in small VT groups (S6 and S8) than those of in large VT groups (S8 and L8) without significant differences.There were not statistical differences between different VT groups in terms of ventilation days, including right ventricle area/left ventricle area (RVarea/LVarea),TAPSE,peak mitral flow velocity of the early rapid filling wave (E),peak mitral flow velocity of the late rapid filling wave (A),early diastolic velocity of the tricuspid annulus (e′),pulmonary artery systolic pressure,inferior vena cava diameter (all P>0.05).Compared to L6 group, low VT (S6 group) resulted in decreased mortality at 28 days [1/19 vs 37.5%(9/24), P=0.014].There were not statistical differences between different VT groups in terms of ventilation days, length of intensive care unit stay, length of hospital stay (all P>0.05).Logistic regression analysis showed that VT could be the independent factor of TAPSE (OR=1.104,95%CI 0.100-1.003,P=0.049).Conclusions Positive pressure mechanical ventilation resulted in RV systolic dysfunction.Lower VT may have the protective effect on RV function.Trial registration Chinese Clinical Trial Registry,ChiCTR-POC-15007563.
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Objective To investigate the possibility of hair follicle reformation induced by hair follicle bulb cells implanted into collagen/chitosan porous scaffolds in vivo, and to observe the angiogenesis in implanted scaffolds.Methods Hair follicle bulb cells obtained by enzyme digestion from the hack skin of C57BL/6J mice were implanted into collagen/chitosan porous scaffolds followed by 2-week organotypie culture.Then,these collagen/chitosan porous scaffolds were transplanted subcutaneously into the dorsal skin of nude mice.Those nude mice transplanted with empty collagen/chitosan porous scaffolds served as the controls.The growth of hair was observed with naked eyes.Six weeks after the transplantation,skin samples were obtained from the recipient site and subjected to histological examination.Results Five weeks after the transplantation,hair growth was observed in the dorsal skin of nude mice.Six weeks later,histological examination revealed fully differentiated hair follicles and vessel-like structures in the center of collagen/chitosan porous scaffolds.However,the transplantation with empty collagen/chitosan porous scaffolds failed to elicit the same response.No hair or follicles were observed in the control mice alpng with small number of vessel-1ike structures.Con-clusions Hair follicle bulb ceils implanted into collagen/chitosan porous scaffolds in vivo could induce hair follicle reformation and promote the formation of vessel-like structure in the scafffold center.
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The vehicle-mouted medical PSA oxygen generation system for driver on plateau is developed independently,according to the environment characteristics of high altitude and low air pressure on the Qinghai-Tibet Plateau,aiming at the actual vehicles support work of plateau troops,through two years' research and experiment again and again.By system workflow design,tests under various conditions,and applicability analysis,especially,the tests conducted on the simulation plateau artificial environment and the vehicle loading tests under five typical environments of Qinghai-Tibet Route at different altitudes,the system is proved to be reliable,satisfied and can meet the requirements of national standard for medical oxygen.