Comparative Study of the Prognosis of Patients with Septic Shock Related to Ventilator Associated Pneumonia Using Variance of Arterial and Venous CO2 versus Serum Lactate
Authors: Abd El-Hameed Hatem S , Fahmy Niven G , Fangary Moustafa M 
Published: August 2023

Abstract

Introduction
Ventilator associated pneumonia “VAP” is the second most common nosocomial infection nearly half of the cases diagnosed with VAP develop septic shock with much higher mortality rate. During the past decade, the role of biomarkers to assist in the diagnosis and prognosis of septic shock has been extensively explored with different sensitivity and specificity.

Aim of the Work
The aim of this study is to compare the variance between arterial and central venous carbon dioxide versus serum lactate as an early bedside prognostic factor in cases of septic shock due to ventilator associated pneumonia.

Methods
Through the period of six month started from first of November 2020 to the end of April 2021 80 consecutive patients (males and females) who were admitted to Critical care units of Ain Shams University and were indicated for endotracheal intubation and later diagnosed with VAP were observed and included in this Cross-sectional study in which patients were managed and investigated in the hospital setting for definite diagnosis, management and prognosis and was performed after ethical committee approval and informed consent from the patient or legal guardian after full explanation of the procedure, possible side effects and complications.

Results
Males and females in mortality group were 19(70.4%), 33(62.3%) and in survival group were 8(29.6%) and 20(37.7%) respectively. There was no statistical significant difference regarding age and gender (P &gt; 0.05), Diabetic cases were higher in mortality group followed by HTN with 9(33.3%) and IHD with 6(22.2%). In survive group, HTN was higher with 20(37.7%) followed by IHD with 17(32.1%) and diabetic 13(24.5%), The central morbidity was higher in mortality group with 16 (59.3%) followed by cardiac morbidity 10 (37%) also in survival group, central morbidity was higher with 19 (35.8%) followed by cardiac morbidity 9 (17%), There was statistical significant difference between survival and mortality groups regarding CPIS score (P &lt; 0.05), There was a highly significant increase in noradrenaline dose per day in mortality group more than the survival from the day 2 till the end of follow up (P &lt; 0.001), there was a highly significant increase in serum lactate and CO2 variance measured every 12 hours in mortality group more than the survival group from the day 1 till the end of follow up (P &lt; 0.001), (P &lt; 0.0023) respectively. Regarding noradrenaline, there was positive correlation regarding serum lactate, PCO2 gap, heart rate while there was negative correlation regarding mean BP, urine output, vasopressor Days and ICU stay days. Regarding serum lactate, there was positive correlation regarding PCO2, heart rate and while there was negative correlation regarding mean BP, urine output, vasopressor days and ICU stay days.

Conclusion
This study found that PCO2 variance is a reliable and sensitive biomarker to detect early tissue hypo-perfusion and to predict the prognosis of septic shock as high levels of PCO2 variance was related with higher mortality, it can also be used as a helpful tool to assess patient adequate perfusion and response to vasopressor therapy as it was found in this study a positive correlation with the level of PCO2 variance and the dose of noradrenaline used to treat shock state.