Values of mixed venous oxygen saturation and difference of mixed venous-arterial partial pressure of carbon dioxide in monitoring of oxygen metabolism and treatment after open-heart operation / 中华危重病急救医学

ABSTRACT

Objective To explore the clinic values of early goal directed treatment (EGDT)with the target of mixed venous oxygen saturation (SvO2)and difference of mixed venous-arterial partial pressure of carbon dioxide (Pv-aCO2) in monitoring of oxygen metabolism and treatment for patients post open-heart operation. Methods A prospective study was conducted. The adult patients admitted to Third People's Hospital of Chengdu from December 2011 to March 2014 with SvO22 mmol/L when admitted in intensive care unit(ICU)were selected on whom elective open-heart operation and pulmonary artery catheter examination were done. All patients received EGDT with the target of SvO2≥0.65 and Pv-aCO2<6 mmHg (1 mmHg=0.133 kPa)and were divided into three groups by the values of SvO2 and Pv-aCO2 at 6-hour after ICU admissionA group with SvO2≥0.65 and Pv-aCO2<6 mmHg,B group with SvO2≥0.65 and Pv-aCO2≥6 mmHg,and C group with SvO2<0.65. Then the changes and prognosis of the patients in different groups were observed. Results 103 cases were included,44 in A group,31 in B group and 28 in C group. The acute physiology and chronic health evaluationⅡ (APACHEⅡ)score in group A were significantly lower than that in group B or C at 6,24,48 and 72 hours (T6,T24,T48,T72)of ICU admission (T611.4±5.8 vs. 13.9±5.4,13.7±6.4;T248.8±3.7 vs. 10.8±4.8,11.8±5.4;T488.7±4.1 vs. 9.6 ±4.2,10.2 ±5.1;T727.5 ±3.4 vs. 8.6 ±2.9,9.2 ±4.2,all P<0.05),and the sequential organ failure assessment (SOFA)showed the same tendency (T66.5±4.3 vs. 8.0±3.8,9.1±4.5;T246.6±3.6 vs. 8.6±3.9, 8.5±3.3;T485.2±3.4 vs. 7.0±3.6,7.6±5.1;T724.6±2.4 vs. 5.8±2.5,6.8±3.5,all P<0.05). The values of blood lactic acid (mmol/L)in group A and B were significant lower than that in group C at T6,T24,T48 and T72 (T61.60 ±0.95,2.20 ±1.02 vs. 2.55 ±1.39;T242.26 ±1.26,2.70 ±1.36 vs. 3.34 ±2.36;T482.01 ±1.15, 2.17 ±1.51 vs. 2.42 ±1.63;T721.62 ±1.14,1.64 ±0.75 vs. 2.11 ±1.29,all P<0.05). The time of machine ventilation(days)in group A or B was significantly shorter than that in group C(2.8±2.0,3.6±2.3 vs. 5.0±3.1,both P<0.05). ICU day (days)in group A was significant shorter than that in group C (4.6±2.5 vs. 6.5±3.7,P<0.05). The 7-day mortalities after operation in three groups were significantly different. Compared with group A (2.3%),the odds ratio (OR)in group B (22.6%)was 12.5 (P<0.05),group C (25.0%)14.3 (P<0.05). The morbidity and 28-day mortality in three groups were not significantly different. Pv-aCO2 negatively correlated with cardiac index(CI, r=-0.685,P=0.000),but not correlated with blood lactic acid(r=0.187,P=0.080). Conclusions EGDT with the target of SvO2≥0.65 and Pv-aCO2<6 mmHg improved the general condition and tissue hypoxia,shortened the time of machine ventilation and duration of hospitalization in ICU,and decrease the 7-day mortality.