Cardiac Output in the Large Cephalopod Octopus Dofleini

Abstract

The cardiac output in Octopus dofleini has been measured, making use of the Fick principle. The measurements were made on intact animals, resting or free-swimming, after previous chronic implantation of intravascular catheters for collection of blood samples. The respiratory exchange was measured with a specially designed respirometer. In addition to cardiac output the following parameters were measured or computed: oxygen consumption; oxygen tension, oxygen content and percentage saturation of venous and arterial blood; arterial pressure; heart rate; stroke volume and stroke work. A detailed discussion of the results obtained is limited by the lack of comparable information for other invertebrates.