Viability Index Score & Survival

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The average Viability Index Score of the 294 ECMO patients calculated from the average AGc and the average venoarterial CO2 gradient.

This figure illustrates the Viability Index survival curve of the same 294 ECMO patients. Patients with scores of 16 or less had greater than 90% survival and patients with scores of 32 or greater had less than 10% survival. Between the scores of 16 and 32 is an indeterminate area of progressively increasing risk of dying.
The line of best fit for the VI survival curve is not parabolic in shape. This probably indicates there is not a prominent third physiologic mechanism besides the two already described herein (an anoxic lethal corner and a hypercapnic lethal corner) that is responsible for a lethal intracellular pH change.

Perfusion Theory is an educational platform for the Oxygen Pressure Field Theory (OPFT). August Krogh’s theoretical concept of the oxygen pressure field is explained and then applied to clinical applications in perfusion practice.