ANY PHYSICIANS BELIEVEthat the pulmonary artery catheter (PAC) is useful for the diagnosis and treatment of cardiopulmonary disturbances and for assessing volume status in critically ill patients. 1,2However, investigators have raised doubts about the safety of the PAC 3,4 because its use may be associated with direct complications 5 or harmful effects related to inappropriate decisions resulting from misinterpretation of the data. 6he most serious concern was raised by the retrospective study by Connors et al, 4 which suggested that the use of PAC within 24 hours following admission