Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Sternotomy wires and a mitral valve prosthesis are constant . Atelectasis at the left lung base is improving . Platelike atelectasis in the mid left lung persists . Small bilateral pleural effusions are best appreciated on the lateral view under probably unchanged . No pneumothorax . The postoperative appearance of the heart and mediastinum are unchanged .
    OUTPUT:
    
Small , bilateral pleural effusions , only appreciated on the lateral view .