Relationship between end-tidal carbon dioxide tension obtained from the distal ends of the tracheal tube and arterial pressure of carbon dioxide with the side stream capnometerin infants with congenital heart disease / 临床麻醉学杂志

ABSTRACT

Objective To determine the relationship between end-tidal carbon dioxide tension (PET CO 2 )obtained from the distal ends of the tracheal tube and arterial pressure of carbon dioxide (PaCO 2 ) compared with the sidestream capnometer in infants with congenital heart disease. Methods Twenty infants undergoing congenital heart disease surgery,12 males and 8 females,aged 3-48 months,ASA physical statusⅠ-Ⅲ were enrolled.Measurements of PET CO 2 were obtained from the distal ends of the tracheal tube using a sterile 22 G catheter that was inserted into the tube and from the proximal end with a sidestream capnometer in 20 intubated infants with congenital heart dis-ease.The data including PET CO 2 and the arterial PaCO 2 were obtained both after the anesthesia induc-tion and the CPB.Results The data of PET CO 2 obtained from the distal ends of the tracheal tube after the anesthesia induction [(36.8 ±2.7)mm Hg vs.(32.5 ± 1.4)mm Hg,P <0.05 ]and the CPB [(40.8±2.5)mm Hg vs.(36.5±1.6)mm Hg,P <0.05]were both higher than those from the proximal end with a sidestream capnometer.The difference between PaCO 2 and PET CO 2 obtained from the distal ends of the tracheal tube after the induction [(7.1 ±0.7)mm Hg vs.(1 1.4 ± 1.5 ) mm Hg,P <0.01]and the CPB [(9.3±1.2)mm Hg vs.(13.5±2.3)mm Hg,P <0.01]were sig-nificantly lower than that between PaCO 2 and PET CO 2 obtained from the proximal end.Distal side-stream PET CO 2 correlated with the PaCO 2 (R 2 =0.94 after induction and R 2 =0.93 after the CPB,P<0.05).However,the proximal PET CO 2 with the sidestream capnometer correlated very poorly with PaCO 2 whether after the induction (R 2 = 0.68,P < 0.05 )nor the CPB (R 2 = 0.66,P < 0.05 ). Conclusion We conclude that the PET CO 2 obtained from the distal ends of the tracheal tube provides accurate estimates of the PaCO 2 in critically ill infants with congenital heart disease.