The Relationships Between Pulmonary Function Tests And VO₂ Max In COPD Patients

Background:Chronic obstructive pulmonary disease (COPD) is characterized by slowly progressive development of airflowlimitation that is not fully reversible and it will be exacerbation. The cause of disease have relation with abnormal Inflammation cause by harmful gas or grains. It is very common,and the prevalence and mortality is higher than others.The clinical feature is not only in Inflammation in lung but also affect the structure of the lung,due to the decrease of pulmonary function, It is the fourth leading cause of death in the United States but is expected to be the thirdby the year 2020.Resting pulmonary function test(PFT), is a major marker to certificat flow limitation which is ues the dignosis of COPD,and the degree of the disease,also affect the treatment and Prognosis.the most common index are FEV1/FVC and FEV1,FEV1/FVC is a sensitive indsx to evaluate the flow limitation,and it is a better index to evaluate the degree of COPD.FEV1 prediction is a uesfull index in dignosis of COPD and to classification also to prognosis.but FEV1 is reflected the degree of flow limitation, localized in evaluating COPD.because it can't reflected exercise tolerance and cardiac pulmonary reserve under exercise.Cardiopulmonary exercise testing(CPET)provides a global assessment of the integrative exercise responses involving pulmonary,cardiovascular,blood, neuropsycho logical, and skeletal muscle systems. CPET is an important element of physique study and healthy physical ability evaluation in various countries. It is arelatively noninvasive method, evaluating reserve function of the lungs and the heart,and exercise intolerance.It synthesizes the application breath gas monitor technology,the computer and the treadmill or the cycle technology,real-time examination under different load condition,organism oxygen consumption quantity and carbon dioxide displacement dynamic change, so that it objectively and quantitatively evaluates the reserve function of the lungs and heart and exercise intolerance, providing the physician with relevant information for clinical decision-making. CPET is one of the universal cardiopulmonary functional check methods in evaluating human respiration and cireulationmction levelsThe peak oxygen uptake (VO2 max) is that respiratory system and circulatory system intake the oxygen per min when people exhausted.using VO2 max/kg, eliminated the impact of weight, which could ues gender,age,hight,,weght,and exercise to predict.,but the real value is related with respiration, circulation of cadiovascular,and intake the oxygen of muscles.it is reflecting the exercise tolerance. compare with PFT or single heart function test,which is better in predicting complication and mortality after surgery but it is not appling generally,because some reason, some studies conclude compare with PFT,CPET is better in predicting survival rate and exercise tolerancein COPD,and the VO2max in CPET is related with PFT.also,in research the relationship between PFT and CPET.other stadies discovery some indexs are related with VO2max,for FEV1,MVV,PEF.some reaserch concluded the formula to account VO2max on abroad.Summary Purpose:The purpose of this study was to test the accuracy and practicality of formula,and examine exercise tolerance in patients with COPD from measurements of resting pulmonary function parameters,and to test the accuracy and practicality of formula which conclude from this reaserch. Objective:Subjects:During January 2009 and February 2010,129 out-patient of COPD in Gangdong provincial people's hospital needing PET.According to the date,from January 2009 to October 2009,104 out-patient as test groupmarriage, male 74,female 30.From november 2009 to February 2010,25 out-patient as a proog group,male member 8,female 7.1.Select normal people standard:stable COPD, avoid AECOPD at last 3months,and stop using Short-acting inhaledβ2-agonists or Anticholinergics at lest 4-6 hours,stop using Short-acting oralβ2-agonist or Theophylline at lest 8 hours,and the long-acting at lest 24 hours.stop using antihistaminc at lest 48 hrous, and avoid oral Corticosteroids at lest 24 hours and inhaled at lest 12 hours.2. Eliminated standard:(1)asthma or history of asthma or bronchodilatation is positive(2)severe of hypoxemia(PaO2<45mmHg) or hypercapnemia(PaCO2>70mmHg);(3)FEV1<20%;(4)abnormalities or heghts<155cm, periphery vessels disease or nervous system diseases which lead to limitated exercise; anemia(5)severe pulmonary hypertension.(6)diabetes mellitus(7)hypertension(8)heart disease(coronary heart disease; myocardial infarction; angina pectoris, acute pulmonary embolism or pulmonary embolism;Ⅱ-Ⅲdegree atrioventricular block; severe arrhythmia; severe aortic stenosis; congestive heart failure; heart valve diseases);(9)rejection participate our research.Methods1. Resting pulmonary function check and arterial blood gas analysis:Before the test, accurately record height, weight, age, sex,BSA,BMI.The pulmonary function test using ATS/ERS control standard. Spirometry(FVC, FEV1, FEV1/FVC, FEF3, FEF25%-75%, PEF), MVV, VC, IC, TLC, RV, Raw,, DLCO, and the value of the prediction were performed and arterial blood gas analysis.2. CPET check:The exercise instrument uses ergometry cycling.3. Exercise testing method:Data were subsequently collected during a 1-min rest period followed by a 3-min period of unloaded cycling. The patient then continued to exercise on a ramp-patterned incremental exercise test until exhaustion occurred. The work rate was increased at a same rate, depending on the formula. A visual pedal rate indicator maintained a pedalling frequency of 60 revolutions/min. throughout each test.4. Assessment VO2maxVO2max (L/min)= (FEF25-75%×0.47)+(BAS×0.988)+(MVV×0.024)-0.913 (r2=0.81)5. Statistical method:Carried on the data processing using the SPSS 13.0 statistics soft-ware. The measurement material expressed with the mean value±standard deviation. Beteen the VO2max of Formula to calculate and VO2max from CPET ues independentt-test.P<0.05(two-tailed test) was considered statistically significant. Stepwise multiple regression was performed on the test group to determine the best predictors of VO2max from independent variables.Result:1.104 patients in testing group (male 74,female 30).stage 1 of COPD is 12,stageⅡof COPD is 81,stageⅢof COPD is 24;stegeⅣof COPD is 0,25patient in proof group (male 18,female 7), stage 1 of COPD is 1,stageⅡof COPD is 11,stageⅢandⅣof COPD is 0,the mean value±standard deviation of testing group and proof group,the results are mean age (65.57±6.71 vs 64.56±7.56, t=0.657; P=0.512), hights(1.64±0.07 vs 1.66±0.08；t=-1.131；P=0.260),weight(58.48±9.63 vs 59.36±8.32；t=-0.420,P=0.675),BSA(1.60±0.14 vs 1.62±0.12；t=-0.724；P=0.470), BMI(21.66±3.69 vs 21.63±3.65；t=0.045;P=0.965),FVC(2.95±0.55 vs 3.12±0.65；t=-1.380；P=0.170),FVC% prediction(87.05±12.88 vs 89.84±9.34), FEV1(1.72±0.42 vs 1.80±0.38；t=-0.840;P=0.402),FEV1％prediction(65.31±12.57 vs 66.84±9.86),FEV1／FVC%(58.14±8.30 vs 57.80±8.82),FEV3(2.39±0.62 vs 2.60±0.63;t=-1.484;P=0.140),FEV3% prediction(75.10±15.50 vs 80.44±11.95),FEF25-75%(1.03±0.49 vs 1.04±0.37；t=-0.101；P=0.920), FEF25-75% prediction(44.43±17.40 vs 43.92±15.00),FEF50% (1.11±0.49 vs 1.18±0.45,t=-0.582；P=0.562),FEF50% prediction(34.13±13.54 vs 35.88±12.88)FEF75%(0.36±0.15 vs 0.35±0.18；t=-0.343;P=0.732),FEF75% prediction (42.57±20.13 vs 47.00±32.51),PEF(3.83±1.22 vs 4.23±1.27；t=-1.433；P=0.154),PEF% prediction(47.72±13.35 vs 51.44±13.44),MVV(60.00±18.43 vs 62.12±15.79;t=-0.530:P=0.597),MVV% prediction(56.31±14.59 vs 59.36±13.63),VC(3.12±0.55 vs 3.20±0.56;t=-0.640;P=0.523),VC% prediction (89.90±11.62 vs 91.56±9.94),IC(1.60±0.54 vs 1.66±0.42:t=-0.512；P=0.609) and IC% prediction(62.72±19.79 vs 65.84±16.83),TLC(6.73±0.73 vs 6.78±0.87;t=-0.291;P=0.772)and TLC% prediction(117.62±9.91 vs 120.12±11.92), RV(3.48±0.49与3.53±0.66；t=-0.514；P=0.608)and RV%prediction(149.93±28.93 vs 149.16±28.10),RV/TLC(52.71±6.42 vs 52.28±5.96),DLCO% prediction(80.87±19.74 vs 83.32±14.70；t=-0.583；P=0.561),Raw(3.18±0.47 vs 2.95±0.40:t=2.295;P=0.023),PH(7.42±0.04 vs 7.42±0.04;t=0.223；P=0.824),PO2(11.52±0.84 vs 10.80±0.85；t=3.845；P=0.000),PCO2(4.31±0.57 vs 4.37±0.27,t=-0.752;P=0.454)2.The VO2max calculation beteen fOrmula calculate(2.59±0.71)and CPET test(1.06±0.30),t=20.267,P<0.001。3.Using age,height,weight,BMI,BAS,FVC,FEV1,FEF3,FEF25-75%, FEF50%,FEF75%,PEF,MVV,VC,IC,TLC,RV,DLCO,Raw as independent variables and VO2max as dependent variable, Stepwise multiple regressions in variables revealed that peak oxygen consumption (VO2 max) was predicted best by the following equation:VO2max (L/min)=(FEF25-75%×0.133)+(BAS×0.603) +(MVV×0.003)+(DLCO×0.005)-0.646 (R2=0.716)4. In the proof group the VO2max calculation beteen Formula calculate(1.07±0.17) and CPET test(1.08±0.24), t=0.150, P=0.881.Conclusion:1. Compare with formula of Efremidis,VO2max is highter than the real test value, P<0.001 which was considered statistically significant.2,Stepwise multiple regressions in variables revealed that peak oxygen consumption (VO2max) was predicted best by the following equation:VO2max (L/min)= (FEF25-75%×0.133)+(BAS×0.603)+(MVV×0.003)+(DLCO×0.005)-0.646 (R2=0.716) for the first time.maximum exercise tolerance is predicted reasonably well from measurements of resting pulmonary function in these COPD patients. The most consistent predictors of VO2 max were measurements of FEF25-75%, MVV, BAS and DLCO.3,In the proof group compare with formul:VO2max (L/min)= (FEF25-75%×0.133)+(BAS×0.603)+(MVV×0.003)+(DLCO×0.005)-0.646 (R2=0.716), and the real test value was not considered statistically significant,which can used to calculate VO2max.