Fig. 1
From: Pulmonary shunt in critical care: a practical approach with clinical scenarios
Illustration of the sampling sites required for pulmonary shunt calculation. The Swan-Ganz catheter allows blood sampling in the pulmonary artery, enabling the measurement of mixed venous O2 saturation (\({{\varvec{S}}}_{{\varvec{v}}{{\varvec{O}}}_{2}}\)), whereas the central venous catheter samples blood from the superior vena cava — right atrium junction, enabling the measurement of the so-called central venous O2 saturation (\({{\varvec{S}}}_{{\varvec{c}}{\varvec{v}}{{\varvec{O}}}_{2}}\)). Displayed formulas are discussed in the text. \({{\varvec{C}}}_{{\varvec{a}}{\varvec{r}}{\varvec{t}}}\), arterial O2 content; \({{\varvec{C}}}_{{\varvec{c}}{\varvec{a}}{\varvec{p}}}\), capillary O2 content; \({{\varvec{C}}}_{{\varvec{v}}{\varvec{e}}{\varvec{n}}}\), venous O2 content; \({{\varvec{Q}}}_{{\varvec{s}}}\), pulmonary shunt; \({{\varvec{Q}}}_{{\varvec{t}}}\), total amount of blood transported to the lungs