A study has identified pleural effusion in 100% of the patients withdecompensated HF in the prehospital setting,13 and another by Prosen et al.18 has concluded that PU can differentiatecardiac from pulmonary dyspnea, mainly when associating with the use of BNP,observing an increase in diagnostic sensitivity and specificity for theassociation of PU and BNP. The gene discussed is NPPB; the disease is hydrops fetalis.