1) If the effects of the drug are short-lived (temporary) due to the body's normal compensatory mechanisms, it is more suitable to investigate cardiac output using the Working Heart preparation (with Transonics Flow Probes). The isolated heart model enables more efficient investigation of drug effects (directly on the heart) because the compensatory effects from other regions in the body have been removed.
2) If the drug has long terms effects, the Cardiac Output Pod and thermodilution method can be used in vivo. The Cardiac Output Module (for LabChart) can then be used to calculate cardiac output (in small animals).