CO2 Gap Changes Versus Inferior Vena Cava Collapsibility in Relation to Cardiac Index as a Prognostic Value in Septic Shock

"CO2 gap will be measured by insertion of radial arterial cannula and internal jugular C.V.P~* I.V.C collapsibility will be measured by abdominal us at the subcostal area and the IVC diameters will be measured in M-mode coupled to 2D mode 3 cm before the IVC joined the right atrium to ensure that IVC diameter measurements are accurate and that the inter- and intra-observer variability of IVC can be minimized. The IVC collapsibility index (IVCCI) will be calculated as follows: (maximum diameter on expiration (IVC max) - minimum diameter on inspiration (IVC min).~* Echocardiography for all patients to asses cardiac index in a parasternal (2D) view. The aortic diameter (AoD) will be measured at the aortic valve annulus. The aortic area (AA) will be calculated using the formula: AA = π × (AoD2/ 4). We measured the aortic blood flow using pulsed"