| Objective To investigate nitric oxide inhalational treatment and its possible mechanism for canines with oleic acid-induced acute respiratory distress syndrome.Methods The models of acute respiratory distress syndrome were reproduced by intravenous injection of oleic acid in 20 canines.The model was regarded successful when PaO2IFiO2 is not more than 200mmHg.The ARDS animals were randomly assigned to acute respiratory distress syndrome (ARDS) group and nitric oxide (NO)group. Animals in ARDS group received conventional mechanical ventilation,while the inhalation of 20ppm NO was additionally given in NO group for six hours. The parameters of ventilation in the two groups were alike(Fi0250%, Vt4O梸-15m1 ?kg1, PEEP5minHg). Blood gas, hemodynamic parametres,peripherial WBC,pulmonary dynamics were measured or recorded during the experimental period. Pa02/Fi02 and Qs/Qt were calculated at the same time. And pathology, lung water and BAL were assessed by the end of the experiment.Results(l)Blood gas: (DPaO2 and Pa02/Fi02: Pa02 in ARDS group decreased gruadually(P<0.0 1). However,Pa02 in NO group began to increasemarkedly at 0.5h ther NO whalation re<0.05),was higher than tha inWS N from lh to 6h postMS ry<0.0l). The change ofPaOz/FiOz was the same as that of PaO2. guaCO2' PaCO2 began tOincrease at lh in ARDS grouPre<0.05). And PaCO2 in NO grOuP didnO change sighficantiyrp>0.05),bu it began tO be markedly lowerthan that in ARDS grouP frOm 1h post-ARDSre<0.05). @MialpHtoHa)' pHa in ARDS grouP decreased grUaduaily and sighficantlylower from 2h post amS(P<0.05). And PHa in NO grOU wasmarkdly lower comPared to that before NO inhalation and that inWS N frOIn lh post-ARDS,respectively(P<0.0l).(3) Qs/Qtf Qs/Qt in NS N was stable at abou 36%. And Qs/Qt inNO grOuP was sighflcanly lower cOmPared to that before NOinhalation and that in ARDS grOU frOm 0.5h postaseS,resPectively(P<0.05 or 0.0l).(3)WBC cOUningf periPherial blood WBC couning reducedprogresshely in WS N' And it decreased first and then went uPIh NO M' Me were significan difference between twO grOuPs atlh,2h,4h,6h post-ARDS(P<0.05 Or 0.0l).(4) Hemodynamic t OS ysbo c circul ati on' NO sighfi cant di Hc e wasfound bbeen twO grouPs in the parameters of systendc cirCUationsuch as MAPng CVPP CWP C O, CI, S VR. twonary circul ation fBOth PAP and PVR in NS grouP inceased grUaduallyBut theseParameters in NO grouP markedly reduced gradually comPared tothOse befOre NO inhalation and thOse in amS grouP frOm 0.5hpost-ARDS, respectiVely(P<0.05).(5)Pulmonary dynndcst @Cdynf Cdyn in ARDS grouP decreasedprogressively And it also reduced in NO grOuP,but slower than thatin WS grouP.There were signfican differences betWeen tWogrouPs at 6h postNSry<0.05). @Aforay resistancemp)f AR inMS grOuP increased grUadually And AR in NO grouP alsoincreaded gradually and slowly,and were lower than that in ARDSgrouP frOm lh post-ARDSW<0.05). @PPeakt Ppeak in ARDSgrouP became significanly higher frOm lh postaseSre<0.05). AndPpeak in NO grOU also increased after inhalation of NO,but it wasmarkediy lower than that in ARDS grOU at 6h postnsS(P<0.05).(6)Lung water and BAL charaCetishcst @Lung watertLung watewas75%i 11% in ARDS group,while it was 62%f9 in NO grouP andlower than that in ARDS grouPW<0.05). @BALcharaCteristicstProtein,COP and cell coUning in BAL in ARDS grouP were higherthan thOse in NO grouP,resPectiVly W<0.05).(7)Pulmoary pathology f The inflanunatory reSPonse in NO grouPseemed less sghfican than that in ARDS grOU.Conclusion 20PPIn NO inhalation ndght significantiy twove the gasexchange, reduce the Qs/QL aileviate the deterioration of pulmonary6dynamics and decrease the neutrophil accumulation in lung in canines with oleic acid-induced acute respiratory distress syndrome. NO inhalation also could reduce lung water and protein ,COP and cell counting in BAL. There was no significant effect of NO inhalation on systemic hemodynamics. The study co... |
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