Application value of end-tidal CO2 partial pressure monitoring in COPD patients

Objective To investigate the correlation between end-tidal carbon dioxide tension (PETCO2) and the arterial PCO2 (PaCO2) in patients with chronic obstructive pulmonary disease COPD.Methods One hundred and sixty-eight patients with COPD,with 20 cases of COPD Ⅰ,25 cases of COPD Ⅱ,30 cases of COPDⅢ,93 cases of COPDⅣ,82 cases without respiratory failure,86 cases with respiratory failure,concurrently.They were both tested by eupnea method and prolonged expiratory method,and the PaCO2 was recorded.Results PaCO2 was (55.65 ± 16.69) mm Hg,PET CO2 (Q) was (51.09 ± 12.29)mm Hg,PET CO2 (P)was (55.23 ± 15.62)mm Hg,there was no significant difference between the PET CO2 (Q) and PaCO2 of COPD Ⅰ,COPD Ⅱ,without respiratory failure groups (P ＞0.05),the PETCO2 (Q)of COPD Ⅲ 、COPDⅣ,with respiratory failure groups was lower than PaCO2 (P ＜0.05),there was no significant difference between the PETCO2 (P) and PaCO2 of each group(P ＞0.05),PETCO2 (P) was remarkably positive correlated with PaCO2 (r =0.92,P ＜ O.05).Conclusions In COPD patients,the value of PETCO2 can reflect the changes of PaCO2 in different degrees of COPD,which will provide an valuable non-invasive method for monitoring PaCO2 in COPD patients. Key words: End-tidal carbon dioxide partial pressure; Chronic obstructive pulmonary disease