We thank Dr McIntyre for his thoughtful letter in which he states that the importance of the respiratory effect on the measurement of cardiac output appears to have now been settled by our recent article. Dr McIntyre has briefly reviewed several of the critical factors influencing pulmonary interactions with cardiac output. He would have liked data describing respiratory variables included in our article since he thought that the order of initiation of injection at the three different times during the respiratory cycle was not randomized. There is no question that lung compliance, airway pressure, and inspiratory flow wave form all interact with cardiac function.1 However, we did not include respiratory variables since, in fact, the order of initiation of injection at the three different times during the respiratory cycle was randomized in our study. We utilized the Latin squares' technique. This is so stated in the "Methods"
Stevens JH, Raffin TA. Cardiac Output by Thermodilution-Reply. JAMA. 1985;254(17):2413. doi:10.1001/jama.1985.03360170053026