An important cause of dyspnea after coronary artery bypass grafting: phrenic nerve paralysis.

Diaphragmatic paralysis (DP) due to phrenic nerve paralysis is a rare complication after cardiac surgery. A 48-year-old male patient developed respiratory insufficiency, tachypnea, sinus tachycardia, chest pain, pneumonia, and fever immediately after coronary artery bypass grafting. Paradoxical movement of the epigastrium was noted during spontaneous ventilation and the chest X-ray showed elevation of the left hemidiaphragm. The diagnosis of DP was confirmed by ultrasonographic assessment. Antibiotherapy and intermittent positive airway pressure ventilation by a nasal mask resulted in significant improvement in the general condition of the patient. Respiratory problems were observed only on exertion. Spontaneous recovery of DP was considered and the patient was discharged 10 days after surgery with grade 1 dyspnea. However, after six months of follow-up, increased elevation of the left hemidiaphragm was noted on the chest X-ray with worsening respiratory discomfort even at rest. Thoracoscopic diaphragmatic plication was performed. After the operation, dyspnea disappeared, the chest X-ray showed the left hemidiaphragm in its normal position, and there was marked improvement in spirometric values.