Phrenic nerve palsy after topical cardiac hypothermia

Evidence of phrenic nerve paralysis was found in 16 of 172 (9.3%) consecutive adult cardiac surgical patients who survived surgical procedures using topical cardiac hypothermia; two patients had bilateral phrenic nerve paralysis and 14 had left phrenic nerve paralysis. One or more pulmonary complications occurred in 13 of 16 patients (81.3%) with phrenic nerve paralysis while 80 of 156 (56%) had one or more pulmonary complications among patients who had no hypothermic phrenic nerve injury. Average postoperative hospital stay was 13.6 days for patients with left phrenic nerve paralysis, and 22.5 days for patients having bilateral phrenic nerve paralysis. This postoperative complication predominated in males; 15 of 16 (93.8%) of those in our series with phrenic paralysis were males, while 118 of 172 (68.6%) patients were males. Phrenic paralysis did not correlate with the length or degree of systemic hypothermia on cardiopulmonary bypass. No deaths were attributed to phrenic nerve injury. With a minimum of one year follow-up, 12 of 16 patients had return of normal diaphragmatic motion, four had residual paralysis when examined between 12 and 19 months postoperatively.