Our criteria were also dependent on the chest x-ray film, which was not obtained in every case. Fifteen subjects did not have a chest roentgenogram obtained, none of whom met criteria for congestive heart failure. Therefore, it is likely that the absence of a chest x-ray film led to an underestimate of subjects actually meeting criteria for congestive heart failure. However, only one of these 15 subjects had an S3 gallop; this subject had seven points on the congestive heart failure score without the chest x-ray film, and quite probably should have been diagnosed as having congestive heart failure (although this patient denied a history of congestive heart failure and had neither a primary nor secondary emergency room diagnosis of congestive heart failure). This patient had an absent overshoot to Valsalva, and no hepatojugular reflux; reclassifying her as having congestive heart failure had little if any effect of the assessment of these maneuvers. buy asthma inhaler
Another limitation of this study is the potential for observer bias. Every precaution was taken to avoid this possibility: the history and physical were obtained independently, by different observers; the x-ray films were read blinded to the identity of the subject; and there was no communication between the emergency room physician and the study team regarding clinical assessments or study objectives. However, all maneuvers, as well as the routine physical examination, were performed by one observer. It is possible that the presence, for example, of hepatojugular reflux would bias the observer to a physical finding critical to make the diagnosis of congestive heart failure.