Bilateral diaphragmatic paralysis complicating local cardiac hypothermia during open heart surgery

Filling the pericardial sac with ice and saline during open heart surgery protects the myocardium during periods of ischemic arrest. Bilateral diaphragmatic paralysis complicated intense local hypothermia in five patients undergoing coronary artery bypass surgery. All complained of severe orthopnea, exertional dyspnea, insomnia, and excessive daytime somnolence. All exhibited paradoxic inward movement of the abdominal wall with inspiration. The diagnosis of bilateral diaphragmatic paralysis was confirmed with upright and supine spirometry and, in one patient, with transdiaphragmatic pressure measurements. Although paralysis has resolved in four patients, all experienced months of disabling impairment. One patient required four months of mechanical ventilatory support prior to her recovery. Alternative methods of intraoperative myocardial preservation that avoid this complication should be developed.