Effect Of Non-invasive Positive Pressure Ventilation On The AECOPD With Type ? Respiratory Failure With PH?7.35

BackgroundChronic obstructive pulmonary disease(COPD)is a common respiratory disease,with high incidence,high mortality and high medical costs,which is expected to be the third leading cause of death in the world in 2020.Acute exacerbation of COPD with respiratory muscle fatigue and poor drainage of sputum,often causes acute respiratory failure or acute exacerbation of chronic respiratory failure.Acute exacerbation of COPD with respiratory failure is one of the main reasons for hospitalization and death.Timely and effective correction of patients with respiratory failure is particularly important,which directly impacts on disease prognosis.In recent years,Non-invasive positive pressure ventilation(NPPV)has been widely used in the treatment of AECOPD combined with respiratory failure.A number of randomized controlled studies have shown that NPPV can reduce the rate of tracheal intubation and mortality,shorten the hospitalization time.NPPV can improve oxygenation,promote carbon dioxide exclusion,relieve respiratory muscle fatigue,relieve symptoms of dyspnea.Most of the studies were conducted with mild to moderate respiratory acidosis with p H value of 7.25~7.35 and Pa CO2>45mm Hg or respiratory failure patients with significant dyspnea as the object of study,NPPV significantly improved the success rate of treatment.However,whether patients with p H ? 7.35 can benefit from NPPV is still not clear.Small sample studies suggest that early use of NPPV in patients with AECOPD with a p H value greater than or equal to 7.35 can rapidly improve arterial blood gas and shorten hospitalization time.But the sample quantity is small,which is not that convincing.A randomized controlled trial was stratified by p H subgroup analysis.The results showed that NPPV reduced the need for tracheal intubation,and the authors hypothesized that it can reduce respiratory muscle fatigue and prevent further deterioration of respiratory function.At present,there are not many researches on the treatment effect of NPPV on AECOPD combined with ? respiratory failure with p H ? 7.35.So there is a big controversy in the use of NPPV on such patients.The recommended level is C.Prospective randomized controlled large sample study is conducive to further confirm the therapeutic value on such patients.However,to the relatively mild illness and poor compliance to NPPV of this group of patients makes it difficult to carry out prospective randomized controlled study.ObjectTo evaluate the therapeutical effect of non-invasive positive pressure ventilation on AECOPD combined with type II respiratory failure with p H value ? 7.35 by retrospective cohort analysis can provide more reference base for clinical decision.MethodThe admitted patients with AECOPD with respiratory failure in the Southwest Hospital of Third Military Medical University from January 2012 to December 2016 were analysed by retrospective cohort analysis.Standard of blood gas is: p H?7.35,Pa CO2>50mm Hg,40 cm Hg?Pa O2<60mm Hg(without oxygen)or 190?Pa O2 / Fi O2<300(with oxygen).According to the pre-established inclusion and exclusion criteria,49 patients with treatment of NPPV and 117 patients with conventional oxygen therapy were selected.The patients with NPPV treatment were set as NPPV group,1:1 match was made with the patients with conventional oxygen therapy through the basal variables of Oxygen,Pa O2,Pa O2 / Fi O2,Pa CO2 and PH value to get a control group.Finally,there were 41 pairs matched successfully with a total of 82 patients,of which there were 51 males and 31 females,with an average age of(69.30 ± 10.27).The clinical data of the two groups were collected,such as gender,age,course of disease,smoking index,nutritional status,RR,HR,blood gas index,treatment efficiency,tracheal intubation rate,hospital mortality,hospitalization time,use condition of NPPV,adverse reactions and other information.Compare the differences of each index before and after treatment between the two groups.Results1.General clinical dataThere were no significant differences in the age,sex,course of disease,nutritional status,smoking index and physiological index between the two groups(P>0.05),meaning the baseline data were well matched and the two groups were comparable.2.Physiological index changes2.1 In the NPPV group,After treatment for 24 h,RR and HR were slower than those at 0 h(22.1 ± 1.8 vs.23.7 ± 2.6 times / min,P <0.05;95.2 ± 13.4 vs.101.5 ± 14.7 times / min,P <0.05).And after treatment for 72 h,RR was further slower than 24 h(21.3 ± 1.6 vs.22.1 ± 1.8times / min,P <0.05).Patients in NPPV group had respiratory rhythm from shallow to deep,reduced cough,increased expectoration,reduced dyspnea.Lips,Limb end cyanosis and sanity improved than before.After treatment for 24 h,Pa O2 and Pa O2 / Fi O2 in NPPV group were significantly improved compared with 0 h(67.2 ± 12.9vs.52.1 ± 7.5mm Hg,263.2 ± 50.0 vs.218.1 ± 25.1),the difference of which had statistic significance(P <0.05).After 72 hours of treatment,Pa CO2 improved(55.9 ± 10.7vs.63.1 ± 8.7 mm Hg,P <0.05)compared with 0h.After treatment for 24 hours and 72 hours,the p H value of the patients was higher than that of 0 h,but the difference of which had no statistic significance(P> 0.05).In this study,for the 9 cases of ineffective conventional oxygen therapy,the blood gas analysis results improved after changing to NPPV.Pa O2(67.4±11.1vs.54.3±7.7,P<0.05).2.2In the Control group: After routine treatment for 24 h and 72 h,both the RR and HR of patients were lower than 0h(P <0.05),Pa O2 and Pa O2 / Fi O2 were improved(P <0.05),PH value and Pa CO2 had no significant change(P> 0.05).After 72 hours of treatment,compared with 24 h,there was no significant difference in the HR,RR(P>0.05),Pa O2 and Pa O2 / Fi O2(P > 0.05).There was a slightly increase in Pa O2?Pa O2/Fi O2,but with no significant statistic difference between the two groups(P> 0.05).2.3 Comparison of two groups: The RR and HR of the two groups were lower than those before treatment,but there was no significant difference between the two groups,with RR(22.1 ± 1.8 vs.2.1 ± 1.8 times/min,P>0.05)and HR(95.2 ± 13.4 vs.95.8 ± 11.9 times/min,P > 0.05).The p H value of NPPV group was higher than that of control group(7.42 ± 0.06 vs.7.39 ± 0.05,P = 0.017).Pa O2 increased more significantly(67.2 ± 12.9 vs.62.1 ± 10.1mm Hg,P<0.05).There was no significant difference in Pa CO2.Pa O2 / Fi O2 was significantly higher than that in the control group(263.2 ± 50.0 vs.240.6 ± 31.2,P=0.016).After treatment for 72 hours,the Pa CO2 in the NPPV group was lower than that in the control group(55.9 ± 10.7vs.60.7 ± 10.7 mm Hg,P= 0.046),the p H value was higher than that in the control group(7.42 ± 0.05 vs.7.39 ± 0.05,P=0.040).However,there was no significant difference in RR,HR,Pa O2 and Pa O2 / Fi O2 between the two groups(P> 0.05).3.The end of outcome indicatorsThe effective rate was 82.9%(34/41)in the NPPV group and 79.0%(32/41)in the control group.There was no significant statistic difference between the two groups(?2=3.11,P =0.577),including patient deterioration rate(4.9% vs.9.8%,P=0.675),tracheal intubation rate(2.4%vs.7.3%,P=0.616)and mortality(7.3% vs.4.9%,P=1.00).There was no significant statistic difference between the NPPV group and the control group in the average hospitalization time(10.3±5.8 vs.10.1 ± 5.2 day,P=0.655).4.Major adverse reactionsIn this NPPV group,the main adverse reactions include: 2 cases(4.9%)of local skin damage,6 cases(14.6%)of gastrointestinal flatulence,2 cases(4.9%)of sputum obstruction,5 cases(12.2%)of irritation or fear,0 case of Pneumothorax or hemodynamic disorders.ConclusionCompared with conventional oxygen therapy,Non-invasive Positive Pressure Ventilation can improve the patient's Pa O2/Fi O2,and eliminate excessive CO2 from the body more quickly and effectively on the treatment of AECOPD with Type II Respiratory failure with PH?7.35.However,we did not find advantages of NPPV in the end treatment efficiency,tracheal intubation rate,hospital mortality,hospitalization time,compared with conventional oxygen therapy.Prospective randomized controlled studies on large sample are still needed to make a more objective evaluation.NPPV is not recommend to those AECOPD patients with type?respiratory failure with p H?7.35 routinely.However,for those patients whose condition do not get improvement or even get worse after blood gas analysis,NPPV can be used appropriately.If the condition is significantly getting worse,invasive mechanical ventilation should be applied timely.