Intraoperative somatosensory evoked potential monitoring predicts peripheral nerve injury during cardiac surgery.
BACKGROUND
Brachial plexus injury may occur without obvious cause in patients undergoing cardiac surgery. To determine whether such peripheral nerve injury can be predicted intraoperatively, we monitored somatosensory evoked potentials (SEPs) from bilateral median and ulnar nerves in 30 patients undergoing coronary artery bypass surgery.


METHODS
SEPs were analyzed for changes during central venous cannulation and during use of the Favoloro and Canadian self-retaining sternal retractors, events hereto implicated in brachial plexus injury. Brachial plexus injury was evaluated during physical examination in the postoperative period by an individual blinded to results of SEP monitoring.


RESULTS
Central venous cannulation was associated with transient changes in SEPs in four patients (13%). These changes occurred intermittently during insertion of the cannula but completely resolved within 5 min. Postoperative neurologic deficits did not occur in these cases. Use of the Canadian and Favoloro retractors was associated with significant changes in 21 patients (70%). In 16 of these, waveforms reverted toward baseline levels intraoperatively and were not associated with postoperative neurologic deficits. Five patients demonstrated a neurologic deficit postoperatively. In each of these, SEP change associated with use of surgical retractors persisted to the end of surgery compared to the immediate pre-bypass period.


CONCLUSIONS
Intraoperative upper extremity SEPs may be used to predict peripheral nerve injury occurring during cardiac surgery.
Hickey
C
C
Department of Anesthesia, Brigham and Women's Hospital, Boston, Massachusetts 02115.
Gugino
L D
LD
Aglio
L S
LS
Mark
J B
JB
Son
S L
SL
Maddi
R
R
D001917:Brachial Plexus / Q000293:injuries*; D002405:Catheterization, Central Venous / Q000009:adverse effects; D001026:Coronary Artery Bypass; D005073:Evoked Potentials, Somatosensory; D006801:Humans; D008475:Median Nerve / Q000502:physiology; D016343:Monitoring, Intraoperative; D011237:Predictive Value of Tests; D013525:Surgical Instruments / Q000009:adverse effects; D014459:Ulnar Nerve / Q000502:physiology