Measurement of O₂ consumption in isolated organs without venous cannulation

A new two-sensor technique for measurement of O₂ consumption in isolated organs without venous cannulation was successfully applied to the isolated rat heart. Because this technique eliminates the net exchange of O₂ between venous effluent and the environment, measurement of the O₂ concentration is conveniently made by use of a polarographic sensor in a collected pool of effluent at the bottom of a closed organ chamber. The method was validated against conventional techniques using cannulation of the pulmonary artery. The two-sensor technique allows O₂ consumption measurements to be made in isolated organ preparations in which representative venous cannulation is prohibitively difficult, for example in organs with multiple venous drains, or those in which cannulation would be expected to cause excessive perturbation of physiological status.