A New Methodology For Intraoperative Monitoring Of The Functional Integrity Of The Phrenic Nerve During Cardiothoracic Surgery

Introduction: The phrenic nerve could be easily injured during cardiothoracic surgeries because of its anatomical relationships. The aim of this study is to describe a new, feasible, and reproducible methodology to achieve a continuous intraoperative neuromonitoring of the phrenic nerve. Methods: Consecutive patients who underwent open-chest surgery were included. The recording active electrode was placed 5 cm superior to the tip of the xiphoid process, and a hook wire inserted at the motor point of the ipsilateral hemidiaphragm was used as the reference electrode. Results: We studied 45 patients (92% men, mean age 67 years). Mean height and weight were 167 +/- 6.9 cm and 75.6 +/- 12.3 kg, respectively. A reproducible compound motor action potential was recorded in 38 (85%) subjects. The mean latency and amplitude values were 9.68 +/- 2.40 ms and 1.36 +/- 3.83 mV, respectively. No intraoperative events were recorded. Conclusions: We reported a new methodology which allows the assessment of phrenic nerve functional integrity during surgical procedures.