Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to infection, if not recognized early and managed promptly, it can lead to septic shock, multiple organ failure and death. Sepsis is associated with high mortality, and the early recognition of the signs of tissue hypo perfusion is crucial in its management.

This prospective study was aimed to detect that PCO2 gap can be taken as a reliable prognostic tool in septic patients

In the community setting, sepsis often presents as the clinical deterioration of common and preventable infections. Sepsis also frequently results from infections acquired in health care settings, which are one of the most frequent adverse events during care delivery and affect hundreds of millions of patients worldwide every year The venous-to-arterial carbon dioxide difference (Pv-aCO2) can indicate the adequacy of microvascular blood flow in the early phases of resuscitation in sepsis. Hence, other resuscitation goals, such as PCO2 gap, have been suggested, due to their ability to predict adverse clinical outcomes and simplicity in patients achieving normal oxygen-derived parameters during the early phases of resuscitation in septic shock.

Blood lactate level is also useful in evaluating sepsis. Serum lactate is a good indicator of the presence of hypoxic tissue during septic shock, since its production takes place during Anerobic metabolism.

Procalcitonin (PCT) is the precursor of calcitonin, and higher levels are associated with the development of sepsis. Com¬monly, there is an elevation of PCT levels 4 h after the on¬set of symptoms, peaking between 8 h and 24 h.

Inclusion Criteria:

• Adult septic patients ≥ 21 years old

Exclusion Criteria:

• Patients with history of chronic obstructive pulmonary disease and bronchial asthma.

patients admitted in ICU departments with sepsis