The authors tested the effects of injectate temperature and of changing cardiac output on the measurement of lung water by the thermoconductivity technique (ETVL). Cardiac output in dogs was increased and decreased with isoproterenol and halothane, respectively. Post mortem extravascular lung water (pulmonary extravascular tissue weight [PETW]) was determined using a weighing technique. Cardiac output varied between 0.7 and 8.8 1/min and did not influence the ETVLmeasurement. The authors conclude ETVLmeasured by the thermoconductivity technique is not influenced by large changes in cardiac output.