Use of Venous to Arterial Carbon Dioxide Tension Difference to Guide Resuscitation Therapy in Septic Shock

Abstract Background Early recognition and correction of tissue hypoperfusion is a cornerstone in the management of septic shock patients. The venous to arterial carbon dioxide tension difference, which is a marker of the adequacy of cardiac output to global metabolic demand, is a helpful additional means to detect patients who stay under resuscitation after optimization of o2 derived parameters. In this regard, its monitoring should help the clinicians for the decision of giving therapy targeting at increasing cardiac output. Aim of the Work Venous To arterial carbon dioxide tension difference to guide resuscitation therapy in septic shock. Patients and Methods This study was a prospective, cross sectional study done on patients recruited from Respiratory ICU at Ain Shams University Results The P(v-a)CO2/C(a-v)O2 ratio might provide additional information for assessments of oxygen debt, it may become a specific end point for resuscitation. However, the P(v-a)CO2/C(a-v)O2 ratio depends on complex interactions between the central venous oxygen saturation (Scvo2), P(v-a)CO2, hemoglobin concentration (Hb), arterial oxygen saturation (Sao2), and arterial oxygen tension (Pao2). Thus, many factors can influence the calculation of the P(v-a)CO2/C(a-v)O2 ratio in real clinical practice. The value of the P(v-a)CO2/C(a-v)O2 ratio remains controversial. Conclusion In the presence of a normal/high ScvO2 (≥ 70%), an elevated ΔPCO2 still suggests that rising cardiac output can be indicated with the purpose of reducing global tissue hypoxia. However, if both ScvO2 and ΔPCO2 are normal in a state of global anaerobic metabolism, manipulating the microcirculation will probably be ineffective to reduce oxygen deficit.