In their conclusion, Gerardi and colleagues questioned the necessity of obtaining routine chest roentgenograms after thoracentesis in hospitalized patients who remained free of symptoms. However, the presence of pneumothorax was not predicted by the development of new symptoms. Only two of the nine patients developed new symptoms during or after the procedure. Therefore, symptoms alone could not predict the presence of pneumothorax or the need for intervention, although the development of new symptoms should never be ignored. However, because of the small number of events in our sample, we cannot determine whether each factor independently predicts the incidence of pneumothorax.
Further research involving more patients is needed.
Because the incidences of both pneumothorax and associated morbidity after thoracentesis in our study were low and because a chest roentgenogram obtained immediately after the procedure may not identify all serious complications associated with thoracentesis, indiscriminate use of chest roentgenography after thoracentesis does not appear warranted. Ultimately, the individual clinician must decide what frequency of unsuspected pneumothorax is acceptable. A larger study that more precisely defines the frequency of unsuspected pneumothorax and confirms that the clinical consequences are minimal is needed. Our study of hospitalized patients shows that the overall risk for significant morbidity after thoracentesis is low, that the chest roentgenogram obtained immediately after the procedure does not identify all serious complications associated with thoracentesis, and that the indiscriminate use of chest roentgenography after thoracentesis does not appreciably alter patient management. The absence of pneumothorax after thoracentesis can be predicted in hospitalized patients who are clinically stable, have not previously received chest irradiation, have had only one pass at thoracentesis attempted without the aspiration of any air, and have no other indications of pneumothorax.