Central Venous-To-Arterial Carbon Dioxide Difference In Critically Ill With Pediatric Septic Shock

ObjectiveSeptic shock has a high mortality rate, tissue hypoperfusion and hypoxia is the key point. To assess the indicator of organ perfusion and oxygen utilization, blood lactate and lactate clearance rate is reliable,but in the case of certain metabolic abnormalities, patients may have lactic acidosis. While central venous oxygen saturation as the main target guiding the treatment of septic shock can significantly reduce mortality. EGDT?early goal-directed therapy? has gradually become septic shock resuscitation treatment goal. However, when the microcirculation failed ScvO₂ >70%, but there may still be poor tissue perfusion performance, so under certain conditions ScvO₂ had limited significance. In recent years, studies have found that central venous and arterial carbon dioxide partial pressure [central venous-to-arterial PCO₂, P?cv-a? CO₂] is probably one of septic shock resuscitation index. The lack of relevant studies in children, the present study was to to assess the value of central venous-to-arterial carbon dioxide difference[ P? cv-a? CO₂ ] in evaluation of disease severity and prognosis in children with septic shock who already had ScvO₂ greater than 70% after early resuscitation. MethodIn this Prospective study, 48 septic shock children in Shanghai Children's Hospital,Shanghai Jiao Tong University were enrolled from Jun 2012 to May 2014. 36?75.0%?were Male, 12?25.0%?were female,the average age was?31.9±24.5?months.The Critically ill patients with septic shock were treated to achieve ScvO₂ greater than 70% dependening on early goal-directed therapy?EGDT?. All patients were divided into two groups, based on P?cv-a?CO₂, low P?cv-a?CO₂ group with P?cv-a?CO₂< 6 mm Hg?1 mm Hg=0.133 k Pa? and high P?cv-a?CO₂ group with P?cv-a?CO₂ ? 6 mm Hg.The parameters of hemodynamics including mean blood pressure?MAP?, heart rate?HR?, central venous pressure?CVP?, perfusion-related indexes [ScvO₂, P?cv-a?CO₂, serum lactate?Lac?, Lac clearance rate], pediatric critical illness score,PRISM?score,and 28 days in-hospital mortality were recorded for all patients.Result 1. Of the 48 cases with septic shock whose ScvO₂ was higher than 70%,17 patients?35.4%? had high P?cv-a?CO₂??6 mm Hg? and 31?65.6%? had lower P?cv-a?CO₂?<6 mm Hg?.There were no significant differences between the two groups of patients in age,PRISM?score and pediatric critical illness score? P>0.05?. 2. Two groups of patients had significant differences in Lac [?4.2±2.9? vs.? 2.4±2.2? mmol/L, P<0.05] and P?cv-a?CO₂ [?9.7±2.4? vs.? 4.7±1.8? mmol/L, P<0.05] 3. 24 h after resuscitation campared with high P?cv-a?CO₂ group, low P?cv-a? CO₂ group patients had lower lac values [?2.0±1.3? vs.? 2.7±1.2? mmol/L, P<0.05] 4. 24 h after resuscitation,two groups of patients had significant differences inpediatric critical illness score[?76.1 ± 2.5? vs.?81.9 ± 3.8?, P<0.05]and PRISM?score[?16.5±2.3? vs.?13.8±1.9?, P<0.05]. Campared with high P?cv-a? CO₂ group, Low P?cv-a? CO₂ group patients had higher lactate clearance rate[?31±10?% vs.?26±6?%,P<0.05]. 5. Low P?cv-a? CO₂ group patients had shorter duration of variety vasoactive drugs use than high P?cv-a? CO₂ group[?16±14? vs.?44±21?h,P<0.05],low P?cv-a? CO₂ group patients had lower 28 days in-hospital mortality than high P?cv-a? CO₂ group [32.3% vs. 64.7%,P<0.05].Conclusion When ScvO₂> 70% was achieved after early resuscitation in septic shock children, P?cv-a? CO₂ is a sensitive biomarker to assess tissue perfusion,and high P?cv-a? CO₂ group patients had poor outcome.