Application of P (cv-a) CO₂ /C(a-cv)O₂ ratio in fluid resuscitation of patients with septic shock

Objective To evaluate the clinical value of P (cv-a) CO₂/C(a-cv)O₂ratio in fluid resuscitation in patients with septic shock. Methods According to the monitoring results of P(cv-a)CO₂/C(A-CV)O₂ ratio after resuscitation treatment for 6 h, 43 patients with septic shock were divided into two groups. Treatment group(n=31): P(cv-a)CO₂/C(A-CV)O₂ ratio<1.8, central venous oxygen saturation(ScvO₂)≥70%. Control group(n=12): P(cv-a)CO₂/C(A-CV)O₂ ratio≥1.8, ScvO₂≥70%. The following data were collected: heart rate(HR), mean arterial pressure(MAP), cardiac index(CI), central venous pressure(CVP) at the beginning of resuscitation(T₀), 6 h(T₆)and 24 h(T₂₄)after resuscitation, and the blood gas analysis results of arterial blood and central venous blood were also recorded. Lactate acid, ScvO₂and PaCO₂were recorded, and P(cv-a)CO₂ was calculated. Arterial oxygen content, central venous blood oxygen content, oxygen delivery(DO₂) and oxygen consumption(VO₂) were also calculated. The Acute Physiology and Chronic Health Evaluation Ⅱ(APACHE Ⅱ) scores, length of ICU stay and total hospital stay, in-hospital mortality and 28-d mortality were recorded. Results At T₂₄, HR and lactate acid level decreased in the treatment group, and DO₂and VO₂increased more significantly than the control group(P<0.05). At T₆ and T₂₄, CI increased more significantly in the treatment group than that in the control group(P<0.05). After treatment, the APACHE II scores decreased in both groups, and the decrease in the treatment group was more obvious at T₂₄, and the difference was statistically significant compared with the control group(P<0.05). Compared with the control group, the length of ICU stay and total hospital stay of the treatment group were shortened(P<0.05). There was no significant difference between the two groups in hospital mortality and 28-d mortality(P>0.05). Conclusions P(cv-a)CO₂/C(a-cv)O₂ can reflect tissue microcirculation perfusion and tissue cell oxygen uptake in patients with septic shock. The tissue oxygen supply in patients with P(cv-a)CO₂/C(a-cv)O₂≥1.8 is better than that in patients with P(cv-a)CO₂/C(a-cv)O₂ <1.8, with significantly shortened length of ICU stay and total hospital stay, but the mortality between the two groups is not statistically significant.