The relationship between volumetric capnography and the severity of chronic obstructive pulmonary disease / 中华老年医学杂志

ABSTRACT

Objective To explore the correlation between volumetric capnography(VCap)and traditional pulmonary function in chronic obstructive pulmonary disease(COPD),so as to assess whether VCap can be used as alternative indicators for the evaluation of COPD severity when some of the elderly COPD patients do not accomplish the traditional pulmonary function tests.Methods 960 patients admitted to Fujian Geriatric Hospital from June 2008 to June 2015 and undergoing pulmonary function tests were included in the study.They were divided into 2 groups of the COPD group(640 cases)and the control group(320 cases).The pulmonary function of COPD group was divided into 4 subgroups(Ⅰ~Ⅳ).All persons received tests of traditional pulmonary function and VCap.The correlations between VCap and traditional pulmonary function indexes and between VCap and COPD severity were observed.Results The differences in Vm25-50/VT,Vm50-75/VT,dC/dV3,SR23 of VCap between the 4 subgroups(COPDⅠ~COPDⅣ)and control group were statistically significant(all P0.05).The difference in CO2 max between the COPD Ⅲ group(severe or more severe group)and control group was statistically significant(t=6.91 and 4.65,all P0.555,P<0.05).The specificity of Vm25-50/VT of VCap for the diagnosis of COPD was best,but its sensitivity was poor than other indexes of VCap.The indexes with both high sensitivity and high specificity were Vm50-75/VT and dC/dV3.Conclusions When the patients with COPD manifest the mild airflow limited,Vm25-50/VT,Vm50-75/VT,dC/dV3 and SR23 of VCap are gradually increased with abnormal VCap figures when the illness progressed.The CO2max of VCap might be one of the indexes for assessing the severity of severe or more severe COPD.