Objective      To investigate the pathological and physiological changes of circulation

respiratory function and blood gas during endoscopic surgery in breast cancer with carbon dioxide (CO

2

) insufflation in the Uighur population.       Methods        Twenty Uygur patients who had breast cancer at Ⅰ-Ⅱ stages and underwent endo

scopic surgery were reviewed. Changes of heart rate (HR)

pulse oxygen saturation (SpO

2

)

mean arterial pressure (MAP)

peak airway pressure (Ppeak)

pH

arterial partial pressure of oxygen [p(O

2

)

]

arterial partial pressure of carbon dioxide [p(CO

2

)

]

and pressure end-tidal CO

2

(PetCO

2

) at baseline

10 min

30 min

60 min after CO

2

insufflation and 15 min after CO

2

deflation were measured.       Results        HR and MAP increased rapidly after CO

2

insufflation. MAP reached peak level after 30-60 min insufflation

which was significantly different from that at the baseline (P0.05). There was no significant difference of SpO

2

at different time points of insufflation (P0.05). Compared with the baseline

Ppeak and PetCO

2

increased significantly after CO

2

insufflation (P0.05)

and PetCO

2

after CO

2

deflation was still higher than that at the baseline. The pH value decreased significantly after CO

2

insufflation and deflation compared with that at the baseline (P0.05). p(CO

2

) increased after CO

2

insufflation and was still higher after CO

2

deflation compared with that at the baseline (P0.05).       Conclusion        Breast cancer patients who underwent endoscopic surgery with CO

2

insufflation show an increase in HR

MAP

Ppeak

PetCO

2

p(CO

2

) and an decrease in pH. It is necessary to monitor blood gas level to ensure patients’ safety.