Objective To investigate the relationship between the changes in P(cv-a)CO?/C(a-cv)O? ratio and hypoxic states in patients with hemorrhagic shock after effective fluid resuscitation.Methods Thirty hemorrhagic shock patients who were admitted to ICU Dongguan Eighth People's Hospital from October 1,2021 to November 30,2023 were selected as research objects.All the patients underwent early fluid resuscitation.Arterial and central venous blood gas analysis was performed,and arterial lactate concentration was measured before resuscitation,and at 2 h,6 h,12 h,and 24 h after resuscitation.The P(cv-a)CO2/C(a-cv)O2,the gradient of P(cv-a)CO2/C(a-cv)O2,and lactate clearance rate were calculated.Results There was a positive correlation between the P(cv-a)CO?/C(a-cv)O? ratio and lactate concentration,as well as between the gradient of P(cv-a)CO?/C(a-cv)O? and lactate clearance rate at each time point(P<0.05).There were significant differences in the P(cv-a)CO?/C(a-cv)O?,gradient of P(cv-a)CO?/C(a-cv)O?,and lactate clearance rate after resuscitation among patients with different prognoses(P<0.05).Conclusion The P(cv-a)CO2/C(a-cv)O2 and its change rate,as well as lactate clearance rate,can predict the prognosis of patients with hemorrhagic shock.