The Clinical Study Of Transcutaneous Oxygen/Carbon Dioxide Partial Pressure Monitoring In Combination With Arterial Blood Gas Analysis In ICU Patients With Sepsis

Objective To assess the correlation and consistency between transcutaneous blood gases(Ptc O2,Ptc CO2)and arterial blood gases(Pa O2,Pa CO2)in ICU sepsis patients,and to explore the monitoring and prognostic value of transcutaneous oxygen/carbon dioxide partial pressure related indicators for perfusion of the peripheral microcirculation in patients with septic shock.Methods A prospective observational study was conducted.Sixty-five patients with sepsis admitted to the department of critical care medicine of General Hospital of Ningxia Medical University from May 1st 2021 to June 30 th 2022 were enrolled.At the same time,thirty-two patients after elective non-cardiac surgery transferred to ICU as a control.At the same time,32 patients were in the control group.After ICU admission,the patient’s baseline information was collected,and transcutaneous oxygen/carbon dioxide partial pressure monitoring was carried out for 24 hours from the start of standardized treatment,and arterial blood samples were collected at 0h,6h,12 h,and 24 h of standardized treatment for blood gas analysis.Ptc O2,Ptc CO2,Pa O2,Pa CO2,Lac,heart rate,blood pressure,respiratory rate,oxygen saturation and other data at these four recorded time points.According to the case inclusion criteria,they were divided into sepsis group(study group)and non-sepsis group(control group).According to the APACHE II score within 24 hours of ICU admission of sepsis patients,those with ≥ 16 points were into severe sepsis group,and those with < 16 points were into general sepsis group.According to whether shock was combined,sepsis patients were divided into septic shock group and sepsis non-shock group.According to the discharge outcome,patients with sepsis were divided into survival and death groups.According to the lactate value of septic patients after 6 hours of standard treatment,septic patients were divided into normal lactate group(Lac<2mmol/l)and lactate abnormal group(Lac≥2mmol/l).SPSS26.0 statistical software was used to statistically analyze the study data,and a value of P< 0.05 was considered statistically significant.Results1.The sepsis group compared to the general non-sepsis group,there were no significant differences in gender,age,height,weight,white blood cell count,diabetes,high blood pressure and total hospital days(P>0.05).There were significantly different(P < 0.05)in platelets,hemoglobin,bilirubin,creatinine,24 h input,24 h output,24 h balance,GCS score,APACHE II score,SOFA score,number of mechanical ventilation,ICU days and 28-day mortality.The platelets,hemoglobin,GCS score were higher in the non-sepsis than in the sepsis group.Bilirubin,creatinine,24 h input,24 h output,24 h balance,APACHEII score,SOFA score,number of mechanical ventilation,ICU days and 28-day mortality were lower than the sepsis group.2.There was no significant difference in Ptc CO2 at four time points between the sepsis group and the non-sepsis group(P>0.05).In the sepsis group,6h and 12 h Ptc O2 was lower than the non-sepsis group(P<0.05),with statistical significance.3.Ptc CO2 and Pa CO2 were positively correlated in both sepsis and non-sepsis groups(r=0.591,0.642,both P<0.0001).The agreement between the two variables was assessed using Bland-Altman analysis,with the mean difference and its 95% confidence interval being3.4(-13.57-20.37)mm Hg between Ptc CO2 and Pa CO2 in the sepsis group and 2.5(-9.09-14.09)mm Hg in the non-sepsis group.There was a weak correlation between Ptc O2 and Pa O2 in the sepsis and non-sepsis groups(r=0.349,0.222,both P<0.05).4.Multiple linear regression analysis showed that heart rate(P=0.044)and positive endexpiratory pressure(P=0.013)were independent influencing factors of Ptc CO2 value.The dose of norepinephrine(P=0.001)and positive end-expiratory pressure(P=0.001)were independent influencing factors of Ptc O2 value.5.In the septic shock group,the Ptc CO2 and oxygen offset were significantly higher than the non-shock group,while the Ptc O2,transcutaneous index,transcutaneous oxygen index were lower than those in the non-shock group(all P<0.05),which were statistically significant.There was no significant difference in Ptc O2 between severe sepsis group and general sepsis group(P>0.05),In all sepsis patients,a decrease in Ptc O2 was observed at 4time points over the 24 hours of treatment,and P<0.05,with statistical significance.There was no significant difference in Ptc CO2 values between the sepsis survival group and the death group(P>0.05).6.In patients with septic shock,Ptc O2 and transcutaneous index were weakly correlated with lactate(r=-0.219,-0.212,both P<0.05),and Ptc CO2 difference from 0-6h was moderately correlated with lactate clearance(r=0.479,P=0.001).The 6h lactate value in the death group of septic shock was significantly higher than that in the survival group(P<0.05),which was statistically significant,while the difference in transcutaneous monitoring indicators at 0h and 6h between the survival group and the death group was not statistically significant(both P>0.05).7.The areas under ROC of 12 h 1/Pt O2,APACHE II score combined with 6h Ptc CO2 and APACHE II score combined with 12 h 1/Pt O2 that evaluates septic shock were 0.696,0.701 and 0.738,respectively,close to the area under ROC of 0h Lac,which was 0.843.Conclusion1.Transcutaneous blood gas(Ptc O2,Ptc CO2)was associated with arterial blood gas(Pa O2,Pa CO2)in sepsis patients,and Ptc CO2 was more consistent with Pa CO2 and could be used as a supplemental monitoring of invasive arterial CO2 fractionation.2.Early Ptc CO2 differences in patients with septic shock are associated with the clearance of lactic acid and can be used as a noninvasive indicator to evaluate tissue perfusion.